diff options
Diffstat (limited to 'Documentation')
25 files changed, 1677 insertions, 1060 deletions
diff --git a/Documentation/ABI/testing/debugfs-kmemtrace b/Documentation/ABI/testing/debugfs-kmemtrace new file mode 100644 index 00000000000..5e6a92a02d8 --- /dev/null +++ b/Documentation/ABI/testing/debugfs-kmemtrace @@ -0,0 +1,71 @@ +What: /sys/kernel/debug/kmemtrace/ +Date: July 2008 +Contact: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro> +Description: + +In kmemtrace-enabled kernels, the following files are created: + +/sys/kernel/debug/kmemtrace/ + cpu<n> (0400) Per-CPU tracing data, see below. (binary) + total_overruns (0400) Total number of bytes which were dropped from + cpu<n> files because of full buffer condition, + non-binary. (text) + abi_version (0400) Kernel's kmemtrace ABI version. (text) + +Each per-CPU file should be read according to the relay interface. That is, +the reader should set affinity to that specific CPU and, as currently done by +the userspace application (though there are other methods), use poll() with +an infinite timeout before every read(). Otherwise, erroneous data may be +read. The binary data has the following _core_ format: + + Event ID (1 byte) Unsigned integer, one of: + 0 - represents an allocation (KMEMTRACE_EVENT_ALLOC) + 1 - represents a freeing of previously allocated memory + (KMEMTRACE_EVENT_FREE) + Type ID (1 byte) Unsigned integer, one of: + 0 - this is a kmalloc() / kfree() + 1 - this is a kmem_cache_alloc() / kmem_cache_free() + 2 - this is a __get_free_pages() et al. + Event size (2 bytes) Unsigned integer representing the + size of this event. Used to extend + kmemtrace. Discard the bytes you + don't know about. + Sequence number (4 bytes) Signed integer used to reorder data + logged on SMP machines. Wraparound + must be taken into account, although + it is unlikely. + Caller address (8 bytes) Return address to the caller. + Pointer to mem (8 bytes) Pointer to target memory area. Can be + NULL, but not all such calls might be + recorded. + +In case of KMEMTRACE_EVENT_ALLOC events, the next fields follow: + + Requested bytes (8 bytes) Total number of requested bytes, + unsigned, must not be zero. + Allocated bytes (8 bytes) Total number of actually allocated + bytes, unsigned, must not be lower + than requested bytes. + Requested flags (4 bytes) GFP flags supplied by the caller. + Target CPU (4 bytes) Signed integer, valid for event id 1. + If equal to -1, target CPU is the same + as origin CPU, but the reverse might + not be true. + +The data is made available in the same endianness the machine has. + +Other event ids and type ids may be defined and added. Other fields may be +added by increasing event size, but see below for details. +Every modification to the ABI, including new id definitions, are followed +by bumping the ABI version by one. + +Adding new data to the packet (features) is done at the end of the mandatory +data: + Feature size (2 byte) + Feature ID (1 byte) + Feature data (Feature size - 3 bytes) + + +Users: + kmemtrace-user - git://repo.or.cz/kmemtrace-user.git + diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci index ceddcff4082..e638e15a889 100644 --- a/Documentation/ABI/testing/sysfs-bus-pci +++ b/Documentation/ABI/testing/sysfs-bus-pci @@ -1,3 +1,46 @@ +What: /sys/bus/pci/drivers/.../bind +Date: December 2003 +Contact: linux-pci@vger.kernel.org +Description: + Writing a device location to this file will cause + the driver to attempt to bind to the device found at + this location. This is useful for overriding default + bindings. The format for the location is: DDDD:BB:DD.F. + That is Domain:Bus:Device.Function and is the same as + found in /sys/bus/pci/devices/. For example: + # echo 0000:00:19.0 > /sys/bus/pci/drivers/foo/bind + (Note: kernels before 2.6.28 may require echo -n). + +What: /sys/bus/pci/drivers/.../unbind +Date: December 2003 +Contact: linux-pci@vger.kernel.org +Description: + Writing a device location to this file will cause the + driver to attempt to unbind from the device found at + this location. This may be useful when overriding default + bindings. The format for the location is: DDDD:BB:DD.F. + That is Domain:Bus:Device.Function and is the same as + found in /sys/bus/pci/devices/. For example: + # echo 0000:00:19.0 > /sys/bus/pci/drivers/foo/unbind + (Note: kernels before 2.6.28 may require echo -n). + +What: /sys/bus/pci/drivers/.../new_id +Date: December 2003 +Contact: linux-pci@vger.kernel.org +Description: + Writing a device ID to this file will attempt to + dynamically add a new device ID to a PCI device driver. + This may allow the driver to support more hardware than + was included in the driver's static device ID support + table at compile time. The format for the device ID is: + VVVV DDDD SVVV SDDD CCCC MMMM PPPP. That is Vendor ID, + Device ID, Subsystem Vendor ID, Subsystem Device ID, + Class, Class Mask, and Private Driver Data. The Vendor ID + and Device ID fields are required, the rest are optional. + Upon successfully adding an ID, the driver will probe + for the device and attempt to bind to it. For example: + # echo "8086 10f5" > /sys/bus/pci/drivers/foo/new_id + What: /sys/bus/pci/devices/.../vpd Date: February 2008 Contact: Ben Hutchings <bhutchings@solarflare.com> diff --git a/Documentation/ABI/testing/sysfs-firmware-memmap b/Documentation/ABI/testing/sysfs-firmware-memmap index 0d99ee6ae02..eca0d65087d 100644 --- a/Documentation/ABI/testing/sysfs-firmware-memmap +++ b/Documentation/ABI/testing/sysfs-firmware-memmap @@ -1,6 +1,6 @@ What: /sys/firmware/memmap/ Date: June 2008 -Contact: Bernhard Walle <bwalle@suse.de> +Contact: Bernhard Walle <bernhard.walle@gmx.de> Description: On all platforms, the firmware provides a memory map which the kernel reads. The resources from that memory map are registered diff --git a/Documentation/DocBook/Makefile b/Documentation/DocBook/Makefile index dc3154e4927..1462ed86d40 100644 --- a/Documentation/DocBook/Makefile +++ b/Documentation/DocBook/Makefile @@ -6,7 +6,7 @@ # To add a new book the only step required is to add the book to the # list of DOCBOOKS. -DOCBOOKS := z8530book.xml mcabook.xml \ +DOCBOOKS := z8530book.xml mcabook.xml device-drivers.xml \ kernel-hacking.xml kernel-locking.xml deviceiobook.xml \ procfs-guide.xml writing_usb_driver.xml networking.xml \ kernel-api.xml filesystems.xml lsm.xml usb.xml kgdb.xml \ diff --git a/Documentation/DocBook/device-drivers.tmpl b/Documentation/DocBook/device-drivers.tmpl new file mode 100644 index 00000000000..94a20fe8fed --- /dev/null +++ b/Documentation/DocBook/device-drivers.tmpl @@ -0,0 +1,418 @@ +<?xml version="1.0" encoding="UTF-8"?> +<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN" + "http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []> + +<book id="LinuxDriversAPI"> + <bookinfo> + <title>Linux Device Drivers</title> + + <legalnotice> + <para> + This documentation is free software; you can redistribute + it and/or modify it under the terms of the GNU General Public + License as published by the Free Software Foundation; either + version 2 of the License, or (at your option) any later + version. + </para> + + <para> + This program is distributed in the hope that it will be + useful, but WITHOUT ANY WARRANTY; without even the implied + warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. + See the GNU General Public License for more details. + </para> + + <para> + You should have received a copy of the GNU General Public + License along with this program; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, + MA 02111-1307 USA + </para> + + <para> + For more details see the file COPYING in the source + distribution of Linux. + </para> + </legalnotice> + </bookinfo> + +<toc></toc> + + <chapter id="Basics"> + <title>Driver Basics</title> + <sect1><title>Driver Entry and Exit points</title> +!Iinclude/linux/init.h + </sect1> + + <sect1><title>Atomic and pointer manipulation</title> +!Iarch/x86/include/asm/atomic_32.h +!Iarch/x86/include/asm/unaligned.h + </sect1> + + <sect1><title>Delaying, scheduling, and timer routines</title> +!Iinclude/linux/sched.h +!Ekernel/sched.c +!Ekernel/timer.c + </sect1> + <sect1><title>High-resolution timers</title> +!Iinclude/linux/ktime.h +!Iinclude/linux/hrtimer.h +!Ekernel/hrtimer.c + </sect1> + <sect1><title>Workqueues and Kevents</title> +!Ekernel/workqueue.c + </sect1> + <sect1><title>Internal Functions</title> +!Ikernel/exit.c +!Ikernel/signal.c +!Iinclude/linux/kthread.h +!Ekernel/kthread.c + </sect1> + + <sect1><title>Kernel objects manipulation</title> +<!-- +X!Iinclude/linux/kobject.h +--> +!Elib/kobject.c + </sect1> + + <sect1><title>Kernel utility functions</title> +!Iinclude/linux/kernel.h +!Ekernel/printk.c +!Ekernel/panic.c +!Ekernel/sys.c +!Ekernel/rcupdate.c + </sect1> + + <sect1><title>Device Resource Management</title> +!Edrivers/base/devres.c + </sect1> + + </chapter> + + <chapter id="devdrivers"> + <title>Device drivers infrastructure</title> + <sect1><title>Device Drivers Base</title> +<!-- +X!Iinclude/linux/device.h +--> +!Edrivers/base/driver.c +!Edrivers/base/core.c +!Edrivers/base/class.c +!Edrivers/base/firmware_class.c +!Edrivers/base/transport_class.c +<!-- Cannot be included, because + attribute_container_add_class_device_adapter + and attribute_container_classdev_to_container + exceed allowed 44 characters maximum +X!Edrivers/base/attribute_container.c +--> +!Edrivers/base/sys.c +<!-- +X!Edrivers/base/interface.c +--> +!Edrivers/base/platform.c +!Edrivers/base/bus.c + </sect1> + <sect1><title>Device Drivers Power Management</title> +!Edrivers/base/power/main.c + </sect1> + <sect1><title>Device Drivers ACPI Support</title> +<!-- Internal functions only +X!Edrivers/acpi/sleep/main.c +X!Edrivers/acpi/sleep/wakeup.c +X!Edrivers/acpi/motherboard.c +X!Edrivers/acpi/bus.c +--> +!Edrivers/acpi/scan.c +!Idrivers/acpi/scan.c +<!-- No correct structured comments +X!Edrivers/acpi/pci_bind.c +--> + </sect1> + <sect1><title>Device drivers PnP support</title> +!Idrivers/pnp/core.c +<!-- No correct structured comments +X!Edrivers/pnp/system.c + --> +!Edrivers/pnp/card.c +!Idrivers/pnp/driver.c +!Edrivers/pnp/manager.c +!Edrivers/pnp/support.c + </sect1> + <sect1><title>Userspace IO devices</title> +!Edrivers/uio/uio.c +!Iinclude/linux/uio_driver.h + </sect1> + </chapter> + + <chapter id="parportdev"> + <title>Parallel Port Devices</title> +!Iinclude/linux/parport.h +!Edrivers/parport/ieee1284.c +!Edrivers/parport/share.c +!Idrivers/parport/daisy.c + </chapter> + + <chapter id="message_devices"> + <title>Message-based devices</title> + <sect1><title>Fusion message devices</title> +!Edrivers/message/fusion/mptbase.c +!Idrivers/message/fusion/mptbase.c +!Edrivers/message/fusion/mptscsih.c +!Idrivers/message/fusion/mptscsih.c +!Idrivers/message/fusion/mptctl.c +!Idrivers/message/fusion/mptspi.c +!Idrivers/message/fusion/mptfc.c +!Idrivers/message/fusion/mptlan.c + </sect1> + <sect1><title>I2O message devices</title> +!Iinclude/linux/i2o.h +!Idrivers/message/i2o/core.h +!Edrivers/message/i2o/iop.c +!Idrivers/message/i2o/iop.c +!Idrivers/message/i2o/config-osm.c +!Edrivers/message/i2o/exec-osm.c +!Idrivers/message/i2o/exec-osm.c +!Idrivers/message/i2o/bus-osm.c +!Edrivers/message/i2o/device.c +!Idrivers/message/i2o/device.c +!Idrivers/message/i2o/driver.c +!Idrivers/message/i2o/pci.c +!Idrivers/message/i2o/i2o_block.c +!Idrivers/message/i2o/i2o_scsi.c +!Idrivers/message/i2o/i2o_proc.c + </sect1> + </chapter> + + <chapter id="snddev"> + <title>Sound Devices</title> +!Iinclude/sound/core.h +!Esound/sound_core.c +!Iinclude/sound/pcm.h +!Esound/core/pcm.c +!Esound/core/device.c +!Esound/core/info.c +!Esound/core/rawmidi.c +!Esound/core/sound.c +!Esound/core/memory.c +!Esound/core/pcm_memory.c +!Esound/core/init.c +!Esound/core/isadma.c +!Esound/core/control.c +!Esound/core/pcm_lib.c +!Esound/core/hwdep.c +!Esound/core/pcm_native.c +!Esound/core/memalloc.c +<!-- FIXME: Removed for now since no structured comments in source +X!Isound/sound_firmware.c +--> + </chapter> + + <chapter id="uart16x50"> + <title>16x50 UART Driver</title> +!Iinclude/linux/serial_core.h +!Edrivers/serial/serial_core.c +!Edrivers/serial/8250.c + </chapter> + + <chapter id="fbdev"> + <title>Frame Buffer Library</title> + + <para> + The frame buffer drivers depend heavily on four data structures. + These structures are declared in include/linux/fb.h. They are + fb_info, fb_var_screeninfo, fb_fix_screeninfo and fb_monospecs. + The last three can be made available to and from userland. + </para> + + <para> + fb_info defines the current state of a particular video card. + Inside fb_info, there exists a fb_ops structure which is a + collection of needed functions to make fbdev and fbcon work. + fb_info is only visible to the kernel. + </para> + + <para> + fb_var_screeninfo is used to describe the features of a video card + that are user defined. With fb_var_screeninfo, things such as + depth and the resolution may be defined. + </para> + + <para> + The next structure is fb_fix_screeninfo. This defines the + properties of a card that are created when a mode is set and can't + be changed otherwise. A good example of this is the start of the + frame buffer memory. This "locks" the address of the frame buffer + memory, so that it cannot be changed or moved. + </para> + + <para> + The last structure is fb_monospecs. In the old API, there was + little importance for fb_monospecs. This allowed for forbidden things + such as setting a mode of 800x600 on a fix frequency monitor. With + the new API, fb_monospecs prevents such things, and if used + correctly, can prevent a monitor from being cooked. fb_monospecs + will not be useful until kernels 2.5.x. + </para> + + <sect1><title>Frame Buffer Memory</title> +!Edrivers/video/fbmem.c + </sect1> +<!-- + <sect1><title>Frame Buffer Console</title> +X!Edrivers/video/console/fbcon.c + </sect1> +--> + <sect1><title>Frame Buffer Colormap</title> +!Edrivers/video/fbcmap.c + </sect1> +<!-- FIXME: + drivers/video/fbgen.c has no docs, which stuffs up the sgml. Comment + out until somebody adds docs. KAO + <sect1><title>Frame Buffer Generic Functions</title> +X!Idrivers/video/fbgen.c + </sect1> +KAO --> + <sect1><title>Frame Buffer Video Mode Database</title> +!Idrivers/video/modedb.c +!Edrivers/video/modedb.c + </sect1> + <sect1><title>Frame Buffer Macintosh Video Mode Database</title> +!Edrivers/video/macmodes.c + </sect1> + <sect1><title>Frame Buffer Fonts</title> + <para> + Refer to the file drivers/video/console/fonts.c for more information. + </para> +<!-- FIXME: Removed for now since no structured comments in source +X!Idrivers/video/console/fonts.c +--> + </sect1> + </chapter> + + <chapter id="input_subsystem"> + <title>Input Subsystem</title> +!Iinclude/linux/input.h +!Edrivers/input/input.c +!Edrivers/input/ff-core.c +!Edrivers/input/ff-memless.c + </chapter> + + <chapter id="spi"> + <title>Serial Peripheral Interface (SPI)</title> + <para> + SPI is the "Serial Peripheral Interface", widely used with + embedded systems because it is a simple and efficient + interface: basically a multiplexed shift register. + Its three signal wires hold a clock (SCK, often in the range + of 1-20 MHz), a "Master Out, Slave In" (MOSI) data line, and + a "Master In, Slave Out" (MISO) data line. + SPI is a full duplex protocol; for each bit shifted out the + MOSI line (one per clock) another is shifted in on the MISO line. + Those bits are assembled into words of various sizes on the + way to and from system memory. + An additional chipselect line is usually active-low (nCS); + four signals are normally used for each peripheral, plus + sometimes an interrupt. + </para> + <para> + The SPI bus facilities listed here provide a generalized + interface to declare SPI busses and devices, manage them + according to the standard Linux driver model, and perform + input/output operations. + At this time, only "master" side interfaces are supported, + where Linux talks to SPI peripherals and does not implement + such a peripheral itself. + (Interfaces to support implementing SPI slaves would + necessarily look different.) + </para> + <para> + The programming interface is structured around two kinds of driver, + and two kinds of device. + A "Controller Driver" abstracts the controller hardware, which may + be as simple as a set of GPIO pins or as complex as a pair of FIFOs + connected to dual DMA engines on the other side of the SPI shift + register (maximizing throughput). Such drivers bridge between + whatever bus they sit on (often the platform bus) and SPI, and + expose the SPI side of their device as a + <structname>struct spi_master</structname>. + SPI devices are children of that master, represented as a + <structname>struct spi_device</structname> and manufactured from + <structname>struct spi_board_info</structname> descriptors which + are usually provided by board-specific initialization code. + A <structname>struct spi_driver</structname> is called a + "Protocol Driver", and is bound to a spi_device using normal + driver model calls. + </para> + <para> + The I/O model is a set of queued messages. Protocol drivers + submit one or more <structname>struct spi_message</structname> + objects, which are processed and completed asynchronously. + (There are synchronous wrappers, however.) Messages are + built from one or more <structname>struct spi_transfer</structname> + objects, each of which wraps a full duplex SPI transfer. + A variety of protocol tweaking options are needed, because + different chips adopt very different policies for how they + use the bits transferred with SPI. + </para> +!Iinclude/linux/spi/spi.h +!Fdrivers/spi/spi.c spi_register_board_info +!Edrivers/spi/spi.c + </chapter> + + <chapter id="i2c"> + <title>I<superscript>2</superscript>C and SMBus Subsystem</title> + + <para> + I<superscript>2</superscript>C (or without fancy typography, "I2C") + is an acronym for the "Inter-IC" bus, a simple bus protocol which is + widely used where low data rate communications suffice. + Since it's also a licensed trademark, some vendors use another + name (such as "Two-Wire Interface", TWI) for the same bus. + I2C only needs two signals (SCL for clock, SDA for data), conserving + board real estate and minimizing signal quality issues. + Most I2C devices use seven bit addresses, and bus speeds of up + to 400 kHz; there's a high speed extension (3.4 MHz) that's not yet + found wide use. + I2C is a multi-master bus; open drain signaling is used to + arbitrate between masters, as well as to handshake and to + synchronize clocks from slower clients. + </para> + + <para> + The Linux I2C programming interfaces support only the master + side of bus interactions, not the slave side. + The programming interface is structured around two kinds of driver, + and two kinds of device. + An I2C "Adapter Driver" abstracts the controller hardware; it binds + to a physical device (perhaps a PCI device or platform_device) and + exposes a <structname>struct i2c_adapter</structname> representing + each I2C bus segment it manages. + On each I2C bus segment will be I2C devices represented by a + <structname>struct i2c_client</structname>. Those devices will + be bound to a <structname>struct i2c_driver</structname>, + which should follow the standard Linux driver model. + (At this writing, a legacy model is more widely used.) + There are functions to perform various I2C protocol operations; at + this writing all such functions are usable only from task context. + </para> + + <para> + The System Management Bus (SMBus) is a sibling protocol. Most SMBus + systems are also I2C conformant. The electrical constraints are + tighter for SMBus, and it standardizes particular protocol messages + and idioms. Controllers that support I2C can also support most + SMBus operations, but SMBus controllers don't support all the protocol + options that an I2C controller will. + There are functions to perform various SMBus protocol operations, + either using I2C primitives or by issuing SMBus commands to + i2c_adapter devices which don't support those I2C operations. + </para> + +!Iinclude/linux/i2c.h +!Fdrivers/i2c/i2c-boardinfo.c i2c_register_board_info +!Edrivers/i2c/i2c-core.c + </chapter> + +</book> diff --git a/Documentation/DocBook/kernel-api.tmpl b/Documentation/DocBook/kernel-api.tmpl index 5818ff75786..bc962cda650 100644 --- a/Documentation/DocBook/kernel-api.tmpl +++ b/Documentation/DocBook/kernel-api.tmpl @@ -38,58 +38,6 @@ <toc></toc> - <chapter id="Basics"> - <title>Driver Basics</title> - <sect1><title>Driver Entry and Exit points</title> -!Iinclude/linux/init.h - </sect1> - - <sect1><title>Atomic and pointer manipulation</title> -!Iarch/x86/include/asm/atomic_32.h -!Iarch/x86/include/asm/unaligned.h - </sect1> - - <sect1><title>Delaying, scheduling, and timer routines</title> -!Iinclude/linux/sched.h -!Ekernel/sched.c -!Ekernel/timer.c - </sect1> - <sect1><title>High-resolution timers</title> -!Iinclude/linux/ktime.h -!Iinclude/linux/hrtimer.h -!Ekernel/hrtimer.c - </sect1> - <sect1><title>Workqueues and Kevents</title> -!Ekernel/workqueue.c - </sect1> - <sect1><title>Internal Functions</title> -!Ikernel/exit.c -!Ikernel/signal.c -!Iinclude/linux/kthread.h -!Ekernel/kthread.c - </sect1> - - <sect1><title>Kernel objects manipulation</title> -<!-- -X!Iinclude/linux/kobject.h ---> -!Elib/kobject.c - </sect1> - - <sect1><title>Kernel utility functions</title> -!Iinclude/linux/kernel.h -!Ekernel/printk.c -!Ekernel/panic.c -!Ekernel/sys.c -!Ekernel/rcupdate.c - </sect1> - - <sect1><title>Device Resource Management</title> -!Edrivers/base/devres.c - </sect1> - - </chapter> - <chapter id="adt"> <title>Data Types</title> <sect1><title>Doubly Linked Lists</title> @@ -298,62 +246,6 @@ X!Earch/x86/kernel/mca_32.c !Ikernel/acct.c </chapter> - <chapter id="devdrivers"> - <title>Device drivers infrastructure</title> - <sect1><title>Device Drivers Base</title> -<!-- -X!Iinclude/linux/device.h ---> -!Edrivers/base/driver.c -!Edrivers/base/core.c -!Edrivers/base/class.c -!Edrivers/base/firmware_class.c -!Edrivers/base/transport_class.c -<!-- Cannot be included, because - attribute_container_add_class_device_adapter - and attribute_container_classdev_to_container - exceed allowed 44 characters maximum -X!Edrivers/base/attribute_container.c ---> -!Edrivers/base/sys.c -<!-- -X!Edrivers/base/interface.c ---> -!Edrivers/base/platform.c -!Edrivers/base/bus.c - </sect1> - <sect1><title>Device Drivers Power Management</title> -!Edrivers/base/power/main.c - </sect1> - <sect1><title>Device Drivers ACPI Support</title> -<!-- Internal functions only -X!Edrivers/acpi/sleep/main.c -X!Edrivers/acpi/sleep/wakeup.c -X!Edrivers/acpi/motherboard.c -X!Edrivers/acpi/bus.c ---> -!Edrivers/acpi/scan.c -!Idrivers/acpi/scan.c -<!-- No correct structured comments -X!Edrivers/acpi/pci_bind.c ---> - </sect1> - <sect1><title>Device drivers PnP support</title> -!Idrivers/pnp/core.c -<!-- No correct structured comments -X!Edrivers/pnp/system.c - --> -!Edrivers/pnp/card.c -!Idrivers/pnp/driver.c -!Edrivers/pnp/manager.c -!Edrivers/pnp/support.c - </sect1> - <sect1><title>Userspace IO devices</title> -!Edrivers/uio/uio.c -!Iinclude/linux/uio_driver.h - </sect1> - </chapter> - <chapter id="blkdev"> <title>Block Devices</title> !Eblock/blk-core.c @@ -381,275 +273,6 @@ X!Edrivers/pnp/system.c !Edrivers/char/misc.c </chapter> - <chapter id="parportdev"> - <title>Parallel Port Devices</title> -!Iinclude/linux/parport.h -!Edrivers/parport/ieee1284.c -!Edrivers/parport/share.c -!Idrivers/parport/daisy.c - </chapter> - - <chapter id="message_devices"> - <title>Message-based devices</title> - <sect1><title>Fusion message devices</title> -!Edrivers/message/fusion/mptbase.c -!Idrivers/message/fusion/mptbase.c -!Edrivers/message/fusion/mptscsih.c -!Idrivers/message/fusion/mptscsih.c -!Idrivers/message/fusion/mptctl.c -!Idrivers/message/fusion/mptspi.c -!Idrivers/message/fusion/mptfc.c -!Idrivers/message/fusion/mptlan.c - </sect1> - <sect1><title>I2O message devices</title> -!Iinclude/linux/i2o.h -!Idrivers/message/i2o/core.h -!Edrivers/message/i2o/iop.c -!Idrivers/message/i2o/iop.c -!Idrivers/message/i2o/config-osm.c -!Edrivers/message/i2o/exec-osm.c -!Idrivers/message/i2o/exec-osm.c -!Idrivers/message/i2o/bus-osm.c -!Edrivers/message/i2o/device.c -!Idrivers/message/i2o/device.c -!Idrivers/message/i2o/driver.c -!Idrivers/message/i2o/pci.c -!Idrivers/message/i2o/i2o_block.c -!Idrivers/message/i2o/i2o_scsi.c -!Idrivers/message/i2o/i2o_proc.c - </sect1> - </chapter> - - <chapter id="snddev"> - <title>Sound Devices</title> -!Iinclude/sound/core.h -!Esound/sound_core.c -!Iinclude/sound/pcm.h -!Esound/core/pcm.c -!Esound/core/device.c -!Esound/core/info.c -!Esound/core/rawmidi.c -!Esound/core/sound.c -!Esound/core/memory.c -!Esound/core/pcm_memory.c -!Esound/core/init.c -!Esound/core/isadma.c -!Esound/core/control.c -!Esound/core/pcm_lib.c -!Esound/core/hwdep.c -!Esound/core/pcm_native.c -!Esound/core/memalloc.c -<!-- FIXME: Removed for now since no structured comments in source -X!Isound/sound_firmware.c ---> - </chapter> - - <chapter id="uart16x50"> - <title>16x50 UART Driver</title> -!Iinclude/linux/serial_core.h -!Edrivers/serial/serial_core.c -!Edrivers/serial/8250.c - </chapter> - - <chapter id="fbdev"> - <title>Frame Buffer Library</title> - - <para> - The frame buffer drivers depend heavily on four data structures. - These structures are declared in include/linux/fb.h. They are - fb_info, fb_var_screeninfo, fb_fix_screeninfo and fb_monospecs. - The last three can be made available to and from userland. - </para> - - <para> - fb_info defines the current state of a particular video card. - Inside fb_info, there exists a fb_ops structure which is a - collection of needed functions to make fbdev and fbcon work. - fb_info is only visible to the kernel. - </para> - - <para> - fb_var_screeninfo is used to describe the features of a video card - that are user defined. With fb_var_screeninfo, things such as - depth and the resolution may be defined. - </para> - - <para> - The next structure is fb_fix_screeninfo. This defines the - properties of a card that are created when a mode is set and can't - be changed otherwise. A good example of this is the start of the - frame buffer memory. This "locks" the address of the frame buffer - memory, so that it cannot be changed or moved. - </para> - - <para> - The last structure is fb_monospecs. In the old API, there was - little importance for fb_monospecs. This allowed for forbidden things - such as setting a mode of 800x600 on a fix frequency monitor. With - the new API, fb_monospecs prevents such things, and if used - correctly, can prevent a monitor from being cooked. fb_monospecs - will not be useful until kernels 2.5.x. - </para> - - <sect1><title>Frame Buffer Memory</title> -!Edrivers/video/fbmem.c - </sect1> -<!-- - <sect1><title>Frame Buffer Console</title> -X!Edrivers/video/console/fbcon.c - </sect1> ---> - <sect1><title>Frame Buffer Colormap</title> -!Edrivers/video/fbcmap.c - </sect1> -<!-- FIXME: - drivers/video/fbgen.c has no docs, which stuffs up the sgml. Comment - out until somebody adds docs. KAO - <sect1><title>Frame Buffer Generic Functions</title> -X!Idrivers/video/fbgen.c - </sect1> -KAO --> - <sect1><title>Frame Buffer Video Mode Database</title> -!Idrivers/video/modedb.c -!Edrivers/video/modedb.c - </sect1> - <sect1><title>Frame Buffer Macintosh Video Mode Database</title> -!Edrivers/video/macmodes.c - </sect1> - <sect1><title>Frame Buffer Fonts</title> - <para> - Refer to the file drivers/video/console/fonts.c for more information. - </para> -<!-- FIXME: Removed for now since no structured comments in source -X!Idrivers/video/console/fonts.c ---> - </sect1> - </chapter> - - <chapter id="input_subsystem"> - <title>Input Subsystem</title> -!Iinclude/linux/input.h -!Edrivers/input/input.c -!Edrivers/input/ff-core.c -!Edrivers/input/ff-memless.c - </chapter> - - <chapter id="spi"> - <title>Serial Peripheral Interface (SPI)</title> - <para> - SPI is the "Serial Peripheral Interface", widely used with - embedded systems because it is a simple and efficient - interface: basically a multiplexed shift register. - Its three signal wires hold a clock (SCK, often in the range - of 1-20 MHz), a "Master Out, Slave In" (MOSI) data line, and - a "Master In, Slave Out" (MISO) data line. - SPI is a full duplex protocol; for each bit shifted out the - MOSI line (one per clock) another is shifted in on the MISO line. - Those bits are assembled into words of various sizes on the - way to and from system memory. - An additional chipselect line is usually active-low (nCS); - four signals are normally used for each peripheral, plus - sometimes an interrupt. - </para> - <para> - The SPI bus facilities listed here provide a generalized - interface to declare SPI busses and devices, manage them - according to the standard Linux driver model, and perform - input/output operations. - At this time, only "master" side interfaces are supported, - where Linux talks to SPI peripherals and does not implement - such a peripheral itself. - (Interfaces to support implementing SPI slaves would - necessarily look different.) - </para> - <para> - The programming interface is structured around two kinds of driver, - and two kinds of device. - A "Controller Driver" abstracts the controller hardware, which may - be as simple as a set of GPIO pins or as complex as a pair of FIFOs - connected to dual DMA engines on the other side of the SPI shift - register (maximizing throughput). Such drivers bridge between - whatever bus they sit on (often the platform bus) and SPI, and - expose the SPI side of their device as a - <structname>struct spi_master</structname>. - SPI devices are children of that master, represented as a - <structname>struct spi_device</structname> and manufactured from - <structname>struct spi_board_info</structname> descriptors which - are usually provided by board-specific initialization code. - A <structname>struct spi_driver</structname> is called a - "Protocol Driver", and is bound to a spi_device using normal - driver model calls. - </para> - <para> - The I/O model is a set of queued messages. Protocol drivers - submit one or more <structname>struct spi_message</structname> - objects, which are processed and completed asynchronously. - (There are synchronous wrappers, however.) Messages are - built from one or more <structname>struct spi_transfer</structname> - objects, each of which wraps a full duplex SPI transfer. - A variety of protocol tweaking options are needed, because - different chips adopt very different policies for how they - use the bits transferred with SPI. - </para> -!Iinclude/linux/spi/spi.h -!Fdrivers/spi/spi.c spi_register_board_info -!Edrivers/spi/spi.c - </chapter> - - <chapter id="i2c"> - <title>I<superscript>2</superscript>C and SMBus Subsystem</title> - - <para> - I<superscript>2</superscript>C (or without fancy typography, "I2C") - is an acronym for the "Inter-IC" bus, a simple bus protocol which is - widely used where low data rate communications suffice. - Since it's also a licensed trademark, some vendors use another - name (such as "Two-Wire Interface", TWI) for the same bus. - I2C only needs two signals (SCL for clock, SDA for data), conserving - board real estate and minimizing signal quality issues. - Most I2C devices use seven bit addresses, and bus speeds of up - to 400 kHz; there's a high speed extension (3.4 MHz) that's not yet - found wide use. - I2C is a multi-master bus; open drain signaling is used to - arbitrate between masters, as well as to handshake and to - synchronize clocks from slower clients. - </para> - - <para> - The Linux I2C programming interfaces support only the master - side of bus interactions, not the slave side. - The programming interface is structured around two kinds of driver, - and two kinds of device. - An I2C "Adapter Driver" abstracts the controller hardware; it binds - to a physical device (perhaps a PCI device or platform_device) and - exposes a <structname>struct i2c_adapter</structname> representing - each I2C bus segment it manages. - On each I2C bus segment will be I2C devices represented by a - <structname>struct i2c_client</structname>. Those devices will - be bound to a <structname>struct i2c_driver</structname>, - which should follow the standard Linux driver model. - (At this writing, a legacy model is more widely used.) - There are functions to perform various I2C protocol operations; at - this writing all such functions are usable only from task context. - </para> - - <para> - The System Management Bus (SMBus) is a sibling protocol. Most SMBus - systems are also I2C conformant. The electrical constraints are - tighter for SMBus, and it standardizes particular protocol messages - and idioms. Controllers that support I2C can also support most - SMBus operations, but SMBus controllers don't support all the protocol - options that an I2C controller will. - There are functions to perform various SMBus protocol operations, - either using I2C primitives or by issuing SMBus commands to - i2c_adapter devices which don't support those I2C operations. - </para> - -!Iinclude/linux/i2c.h -!Fdrivers/i2c/i2c-boardinfo.c i2c_register_board_info -!Edrivers/i2c/i2c-core.c - </chapter> - <chapter id="clk"> <title>Clock Framework</title> diff --git a/Documentation/PCI/PCIEBUS-HOWTO.txt b/Documentation/PCI/PCIEBUS-HOWTO.txt index 9a07e38631b..6bd5f372ade 100644 --- a/Documentation/PCI/PCIEBUS-HOWTO.txt +++ b/Documentation/PCI/PCIEBUS-HOWTO.txt @@ -93,7 +93,7 @@ the PCI Express Port Bus driver from loading a service driver. int pcie_port_service_register(struct pcie_port_service_driver *new) -This API replaces the Linux Driver Model's pci_module_init API. A +This API replaces the Linux Driver Model's pci_register_driver API. A service driver should always calls pcie_port_service_register at module init. Note that after service driver being loaded, calls such as pci_enable_device(dev) and pci_set_master(dev) are no longer diff --git a/Documentation/cgroups/cgroups.txt b/Documentation/cgroups/cgroups.txt index d9e5d6f41b9..93feb844448 100644 --- a/Documentation/cgroups/cgroups.txt +++ b/Documentation/cgroups/cgroups.txt @@ -252,10 +252,8 @@ cgroup file system directories. When a task is moved from one cgroup to another, it gets a new css_set pointer - if there's an already existing css_set with the desired collection of cgroups then that group is reused, else a new -css_set is allocated. Note that the current implementation uses a -linear search to locate an appropriate existing css_set, so isn't -very efficient. A future version will use a hash table for better -performance. +css_set is allocated. The appropriate existing css_set is located by +looking into a hash table. To allow access from a cgroup to the css_sets (and hence tasks) that comprise it, a set of cg_cgroup_link objects form a lattice; diff --git a/Documentation/cgroups/cpusets.txt b/Documentation/cgroups/cpusets.txt index 5c86c258c79..0611e9528c7 100644 --- a/Documentation/cgroups/cpusets.txt +++ b/Documentation/cgroups/cpusets.txt @@ -142,7 +142,7 @@ into the rest of the kernel, none in performance critical paths: - in fork and exit, to attach and detach a task from its cpuset. - in sched_setaffinity, to mask the requested CPUs by what's allowed in that tasks cpuset. - - in sched.c migrate_all_tasks(), to keep migrating tasks within + - in sched.c migrate_live_tasks(), to keep migrating tasks within the CPUs allowed by their cpuset, if possible. - in the mbind and set_mempolicy system calls, to mask the requested Memory Nodes by what's allowed in that tasks cpuset. @@ -175,6 +175,10 @@ files describing that cpuset: - mem_exclusive flag: is memory placement exclusive? - mem_hardwall flag: is memory allocation hardwalled - memory_pressure: measure of how much paging pressure in cpuset + - memory_spread_page flag: if set, spread page cache evenly on allowed nodes + - memory_spread_slab flag: if set, spread slab cache evenly on allowed nodes + - sched_load_balance flag: if set, load balance within CPUs on that cpuset + - sched_relax_domain_level: the searching range when migrating tasks In addition, the root cpuset only has the following file: - memory_pressure_enabled flag: compute memory_pressure? @@ -252,7 +256,7 @@ is causing. This is useful both on tightly managed systems running a wide mix of submitted jobs, which may choose to terminate or re-prioritize jobs that -are trying to use more memory than allowed on the nodes assigned them, +are trying to use more memory than allowed on the nodes assigned to them, and with tightly coupled, long running, massively parallel scientific computing jobs that will dramatically fail to meet required performance goals if they start to use more memory than allowed to them. @@ -378,7 +382,7 @@ as cpusets and sched_setaffinity. The algorithmic cost of load balancing and its impact on key shared kernel data structures such as the task list increases more than linearly with the number of CPUs being balanced. So the scheduler -has support to partition the systems CPUs into a number of sched +has support to partition the systems CPUs into a number of sched domains such that it only load balances within each sched domain. Each sched domain covers some subset of the CPUs in the system; no two sched domains overlap; some CPUs might not be in any sched @@ -485,17 +489,22 @@ of CPUs allowed to a cpuset having 'sched_load_balance' enabled. The internal kernel cpuset to scheduler interface passes from the cpuset code to the scheduler code a partition of the load balanced CPUs in the system. This partition is a set of subsets (represented -as an array of cpumask_t) of CPUs, pairwise disjoint, that cover all -the CPUs that must be load balanced. - -Whenever the 'sched_load_balance' flag changes, or CPUs come or go -from a cpuset with this flag enabled, or a cpuset with this flag -enabled is removed, the cpuset code builds a new such partition and -passes it to the scheduler sched domain setup code, to have the sched -domains rebuilt as necessary. +as an array of struct cpumask) of CPUs, pairwise disjoint, that cover +all the CPUs that must be load balanced. + +The cpuset code builds a new such partition and passes it to the +scheduler sched domain setup code, to have the sched domains rebuilt +as necessary, whenever: + - the 'sched_load_balance' flag of a cpuset with non-empty CPUs changes, + - or CPUs come or go from a cpuset with this flag enabled, + - or 'sched_relax_domain_level' value of a cpuset with non-empty CPUs + and with this flag enabled changes, + - or a cpuset with non-empty CPUs and with this flag enabled is removed, + - or a cpu is offlined/onlined. This partition exactly defines what sched domains the scheduler should -setup - one sched domain for each element (cpumask_t) in the partition. +setup - one sched domain for each element (struct cpumask) in the +partition. The scheduler remembers the currently active sched domain partitions. When the scheduler routine partition_sched_domains() is invoked from @@ -559,7 +568,7 @@ domain, the largest value among those is used. Be careful, if one requests 0 and others are -1 then 0 is used. Note that modifying this file will have both good and bad effects, -and whether it is acceptable or not will be depend on your situation. +and whether it is acceptable or not depends on your situation. Don't modify this file if you are not sure. If your situation is: @@ -600,19 +609,15 @@ to allocate a page of memory for that task. If a cpuset has its 'cpus' modified, then each task in that cpuset will have its allowed CPU placement changed immediately. Similarly, -if a tasks pid is written to a cpusets 'tasks' file, in either its -current cpuset or another cpuset, then its allowed CPU placement is -changed immediately. If such a task had been bound to some subset -of its cpuset using the sched_setaffinity() call, the task will be -allowed to run on any CPU allowed in its new cpuset, negating the -affect of the prior sched_setaffinity() call. +if a tasks pid is written to another cpusets 'tasks' file, then its +allowed CPU placement is changed immediately. If such a task had been +bound to some subset of its cpuset using the sched_setaffinity() call, +the task will be allowed to run on any CPU allowed in its new cpuset, +negating the effect of the prior sched_setaffinity() call. In summary, the memory placement of a task whose cpuset is changed is updated by the kernel, on the next allocation of a page for that task, -but the processor placement is not updated, until that tasks pid is -rewritten to the 'tasks' file of its cpuset. This is done to avoid -impacting the scheduler code in the kernel with a check for changes -in a tasks processor placement. +and the processor placement is updated immediately. Normally, once a page is allocated (given a physical page of main memory) then that page stays on whatever node it @@ -681,10 +686,14 @@ and then start a subshell 'sh' in that cpuset: # The next line should display '/Charlie' cat /proc/self/cpuset -In the future, a C library interface to cpusets will likely be -available. For now, the only way to query or modify cpusets is -via the cpuset file system, using the various cd, mkdir, echo, cat, -rmdir commands from the shell, or their equivalent from C. +There are ways to query or modify cpusets: + - via the cpuset file system directly, using the various cd, mkdir, echo, + cat, rmdir commands from the shell, or their equivalent from C. + - via the C library libcpuset. + - via the C library libcgroup. + (http://sourceforge.net/proects/libcg/) + - via the python application cset. + (http://developer.novell.com/wiki/index.php/Cpuset) The sched_setaffinity calls can also be done at the shell prompt using SGI's runon or Robert Love's taskset. The mbind and set_mempolicy @@ -756,7 +765,7 @@ mount -t cpuset X /dev/cpuset is equivalent to -mount -t cgroup -ocpuset X /dev/cpuset +mount -t cgroup -ocpuset,noprefix X /dev/cpuset echo "/sbin/cpuset_release_agent" > /dev/cpuset/release_agent 2.2 Adding/removing cpus diff --git a/Documentation/connector/cn_test.c b/Documentation/connector/cn_test.c index be7af146dd3..6977c178729 100644 --- a/Documentation/connector/cn_test.c +++ b/Documentation/connector/cn_test.c @@ -137,7 +137,7 @@ static void cn_test_timer_func(unsigned long __data) memcpy(m + 1, data, m->len); - cn_netlink_send(m, 0, gfp_any()); + cn_netlink_send(m, 0, GFP_ATOMIC); kfree(m); } @@ -160,10 +160,8 @@ static int cn_test_init(void) goto err_out; } - init_timer(&cn_test_timer); - cn_test_timer.function = cn_test_timer_func; + setup_timer(&cn_test_timer, cn_test_timer_func, 0); cn_test_timer.expires = jiffies + HZ; - cn_test_timer.data = 0; add_timer(&cn_test_timer); return 0; diff --git a/Documentation/cpu-freq/user-guide.txt b/Documentation/cpu-freq/user-guide.txt index e3443ddcfb8..917918f84fc 100644 --- a/Documentation/cpu-freq/user-guide.txt +++ b/Documentation/cpu-freq/user-guide.txt @@ -195,19 +195,3 @@ scaling_setspeed. By "echoing" a new frequency into this you can change the speed of the CPU, but only within the limits of scaling_min_freq and scaling_max_freq. - - -3.2 Deprecated Interfaces -------------------------- - -Depending on your kernel configuration, you might find the following -cpufreq-related files: -/proc/cpufreq -/proc/sys/cpu/*/speed -/proc/sys/cpu/*/speed-min -/proc/sys/cpu/*/speed-max - -These are files for deprecated interfaces to cpufreq, which offer far -less functionality. Because of this, these interfaces aren't described -here. - diff --git a/Documentation/driver-model/device.txt b/Documentation/driver-model/device.txt index a05ec50f800..a7cbfff40d0 100644 --- a/Documentation/driver-model/device.txt +++ b/Documentation/driver-model/device.txt @@ -127,9 +127,11 @@ void unlock_device(struct device * dev); Attributes ~~~~~~~~~~ struct device_attribute { - struct attribute attr; - ssize_t (*show)(struct device * dev, char * buf, size_t count, loff_t off); - ssize_t (*store)(struct device * dev, const char * buf, size_t count, loff_t off); + struct attribute attr; + ssize_t (*show)(struct device *dev, struct device_attribute *attr, + char *buf); + ssize_t (*store)(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count); }; Attributes of devices can be exported via drivers using a simple diff --git a/Documentation/dvb/README.flexcop b/Documentation/dvb/README.flexcop deleted file mode 100644 index 5515469de7c..00000000000 --- a/Documentation/dvb/README.flexcop +++ /dev/null @@ -1,205 +0,0 @@ -This README escorted the skystar2-driver rewriting procedure. It describes the -state of the new flexcop-driver set and some internals are written down here -too. - -This document hopefully describes things about the flexcop and its -device-offsprings. Goal was to write an easy-to-write and easy-to-read set of -drivers based on the skystar2.c and other information. - -Remark: flexcop-pci.c was a copy of skystar2.c, but every line has been -touched and rewritten. - -History & News -============== - 2005-04-01 - correct USB ISOC transfers (thanks to Vadim Catana) - - - - -General coding processing -========================= - -We should proceed as follows (as long as no one complains): - -0) Think before start writing code! - -1) rewriting the skystar2.c with the help of the flexcop register descriptions -and splitting up the files to a pci-bus-part and a flexcop-part. -The new driver will be called b2c2-flexcop-pci.ko/b2c2-flexcop-usb.ko for the -device-specific part and b2c2-flexcop.ko for the common flexcop-functions. - -2) Search for errors in the leftover of flexcop-pci.c (compare with pluto2.c -and other pci drivers) - -3) make some beautification (see 'Improvements when rewriting (refactoring) is -done') - -4) Testing the new driver and maybe substitute the skystar2.c with it, to reach -a wider tester audience. - -5) creating an usb-bus-part using the already written flexcop code for the pci -card. - -Idea: create a kernel-object for the flexcop and export all important -functions. This option saves kernel-memory, but maybe a lot of functions have -to be exported to kernel namespace. - - -Current situation -================= - -0) Done :) -1) Done (some minor issues left) -2) Done -3) Not ready yet, more information is necessary -4) next to be done (see the table below) -5) USB driver is working (yes, there are some minor issues) - -What seems to be ready? ------------------------ - -1) Rewriting -1a) i2c is cut off from the flexcop-pci.c and seems to work -1b) moved tuner and demod stuff from flexcop-pci.c to flexcop-tuner-fe.c -1c) moved lnb and diseqc stuff from flexcop-pci.c to flexcop-tuner-fe.c -1e) eeprom (reading MAC address) -1d) sram (no dynamic sll size detection (commented out) (using default as JJ told me)) -1f) misc. register accesses for reading parameters (e.g. resetting, revision) -1g) pid/mac filter (flexcop-hw-filter.c) -1i) dvb-stuff initialization in flexcop.c (done) -1h) dma stuff (now just using the size-irq, instead of all-together, to be done) -1j) remove flexcop initialization from flexcop-pci.c completely (done) -1l) use a well working dma IRQ method (done, see 'Known bugs and problems and TODO') -1k) cleanup flexcop-files (remove unused EXPORT_SYMBOLs, make static from -non-static where possible, moved code to proper places) - -2) Search for errors in the leftover of flexcop-pci.c (partially done) -5a) add MAC address reading -5c) feeding of ISOC data to the software demux (format of the isochronous data -and speed optimization, no real error) (thanks to Vadim Catana) - -What to do in the near future? --------------------------------------- -(no special order here) - -5) USB driver -5b) optimize isoc-transfer (submitting/killing isoc URBs when transfer is starting) - -Testing changes ---------------- - -O = item is working -P = item is partially working -X = item is not working -N = item does not apply here -<empty field> = item need to be examined - - | PCI | USB -item | mt352 | nxt2002 | stv0299 | mt312 | mt352 | nxt2002 | stv0299 | mt312 --------+-------+---------+---------+-------+-------+---------+---------+------- -1a) | O | | | | N | N | N | N -1b) | O | | | | | | O | -1c) | N | N | | | N | N | O | -1d) | O | O -1e) | O | O -1f) | P -1g) | O -1h) | P | -1i) | O | N -1j) | O | N -1l) | O | N -2) | O | N -5a) | N | O -5b)* | N | -5c) | N | O - -* - not done yet - -Known bugs and problems and TODO --------------------------------- - -1g/h/l) when pid filtering is enabled on the pci card - -DMA usage currently: - The DMA is splitted in 2 equal-sized subbuffers. The Flexcop writes to first - address and triggers an IRQ when it's full and starts writing to the second - address. When the second address is full, the IRQ is triggered again, and - the flexcop writes to first address again, and so on. - The buffersize of each address is currently 640*188 bytes. - - Problem is, when using hw-pid-filtering and doing some low-bandwidth - operation (like scanning) the buffers won't be filled enough to trigger - the IRQ. That's why: - - When PID filtering is activated, the timer IRQ is used. Every 1.97 ms the IRQ - is triggered. Is the current write address of DMA1 different to the one - during the last IRQ, then the data is passed to the demuxer. - - There is an additional DMA-IRQ-method: packet count IRQ. This isn't - implemented correctly yet. - - The solution is to disable HW PID filtering, but I don't know how the DVB - API software demux behaves on slow systems with 45MBit/s TS. - -Solved bugs :) --------------- -1g) pid-filtering (somehow pid index 4 and 5 (EMM_PID and ECM_PID) aren't -working) -SOLUTION: also index 0 was affected, because net_translation is done for -these indexes by default - -5b) isochronous transfer does only work in the first attempt (for the Sky2PC -USB, Air2PC is working) SOLUTION: the flexcop was going asleep and never really -woke up again (don't know if this need fixes, see -flexcop-fe-tuner.c:flexcop_sleep) - -NEWS: when the driver is loaded and unloaded and loaded again (w/o doing -anything in the while the driver is loaded the first time), no transfers take -place anymore. - -Improvements when rewriting (refactoring) is done -================================================= - -- split sleeping of the flexcop (misc_204.ACPI3_sig = 1;) from lnb_control - (enable sleeping for other demods than dvb-s) -- add support for CableStar (stv0297 Microtune 203x/ALPS) (almost done, incompatibilities with the Nexus-CA) - -Debugging ---------- -- add verbose debugging to skystar2.c (dump the reg_dw_data) and compare it - with this flexcop, this is important, because i2c is now using the - flexcop_ibi_value union from flexcop-reg.h (do you have a better idea for - that, please tell us so). - -Everything which is identical in the following table, can be put into a common -flexcop-module. - - PCI USB -------------------------------------------------------------------------------- -Different: -Register access: accessing IO memory USB control message -I2C bus: I2C bus of the FC USB control message -Data transfer: DMA isochronous transfer -EEPROM transfer: through i2c bus not clear yet - -Identical: -Streaming: accessing registers -PID Filtering: accessing registers -Sram destinations: accessing registers -Tuner/Demod: I2C bus -DVB-stuff: can be written for common use - -Acknowledgements (just for the rewriting part) -================ - -Bjarne Steinsbo thought a lot in the first place of the pci part for this code -sharing idea. - -Andreas Oberritter for providing a recent PCI initialization template -(pluto2.c). - -Boleslaw Ciesielski for pointing out a problem with firmware loader. - -Vadim Catana for correcting the USB transfer. - -comments, critics and ideas to linux-dvb@linuxtv.org. diff --git a/Documentation/dvb/technisat.txt b/Documentation/dvb/technisat.txt index cdf6ee4b2da..3f435ffb289 100644 --- a/Documentation/dvb/technisat.txt +++ b/Documentation/dvb/technisat.txt @@ -1,5 +1,5 @@ -How to set up the Technisat devices -=================================== +How to set up the Technisat/B2C2 Flexcop devices +================================================ 1) Find out what device you have ================================ @@ -16,54 +16,60 @@ DVB: registering frontend 0 (Conexant CX24123/CX24109)... If the Technisat is the only TV device in your box get rid of unnecessary modules and check this one: "Multimedia devices" => "Customise analog and hybrid tuner modules to build" -In this directory uncheck every driver which is activated there. +In this directory uncheck every driver which is activated there (except "Simple tuner support" for case 9 only). Then please activate: 2a) Main module part: a.)"Multimedia devices" => "DVB/ATSC adapters" => "Technisat/B2C2 FlexcopII(b) and FlexCopIII adapters" -b.)"Multimedia devices" => "DVB/ATSC adapters" => "Technisat/B2C2 FlexcopII(b) and FlexCopIII adapters" => "Technisat/B2C2 Air/Sky/Cable2PC PCI" in case of a PCI card OR +b.)"Multimedia devices" => "DVB/ATSC adapters" => "Technisat/B2C2 FlexcopII(b) and FlexCopIII adapters" => "Technisat/B2C2 Air/Sky/Cable2PC PCI" in case of a PCI card +OR c.)"Multimedia devices" => "DVB/ATSC adapters" => "Technisat/B2C2 FlexcopII(b) and FlexCopIII adapters" => "Technisat/B2C2 Air/Sky/Cable2PC USB" in case of an USB 1.1 adapter d.)"Multimedia devices" => "DVB/ATSC adapters" => "Technisat/B2C2 FlexcopII(b) and FlexCopIII adapters" => "Enable debug for the B2C2 FlexCop drivers" Notice: d.) is helpful for troubleshooting 2b) Frontend module part: -1.) Revision 2.3: +1.) SkyStar DVB-S Revision 2.3: a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build" b.)"Multimedia devices" => "Customise DVB frontends" => "Zarlink VP310/MT312/ZL10313 based" -2.) Revision 2.6: +2.) SkyStar DVB-S Revision 2.6: a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build" b.)"Multimedia devices" => "Customise DVB frontends" => "ST STV0299 based" -3.) Revision 2.7: +3.) SkyStar DVB-S Revision 2.7: a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build" b.)"Multimedia devices" => "Customise DVB frontends" => "Samsung S5H1420 based" c.)"Multimedia devices" => "Customise DVB frontends" => "Integrant ITD1000 Zero IF tuner for DVB-S/DSS" d.)"Multimedia devices" => "Customise DVB frontends" => "ISL6421 SEC controller" -4.) Revision 2.8: +4.) SkyStar DVB-S Revision 2.8: a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build" b.)"Multimedia devices" => "Customise DVB frontends" => "Conexant CX24113/CX24128 tuner for DVB-S/DSS" c.)"Multimedia devices" => "Customise DVB frontends" => "Conexant CX24123 based" d.)"Multimedia devices" => "Customise DVB frontends" => "ISL6421 SEC controller" -5.) DVB-T card: +5.) AirStar DVB-T card: a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build" b.)"Multimedia devices" => "Customise DVB frontends" => "Zarlink MT352 based" -6.) DVB-C card: +6.) CableStar DVB-C card: a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build" b.)"Multimedia devices" => "Customise DVB frontends" => "ST STV0297 based" -7.) ATSC card 1st generation: +7.) AirStar ATSC card 1st generation: a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build" b.)"Multimedia devices" => "Customise DVB frontends" => "Broadcom BCM3510" -8.) ATSC card 2nd generation: +8.) AirStar ATSC card 2nd generation: a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build" b.)"Multimedia devices" => "Customise DVB frontends" => "NxtWave Communications NXT2002/NXT2004 based" -c.)"Multimedia devices" => "Customise DVB frontends" => "LG Electronics LGDT3302/LGDT3303 based" +c.)"Multimedia devices" => "Customise DVB frontends" => "Generic I2C PLL based tuners" -Author: Uwe Bugla <uwe.bugla@gmx.de> December 2008 +9.) AirStar ATSC card 3rd generation: +a.)"Multimedia devices" => "Customise DVB frontends" => "Customise the frontend modules to build" +b.)"Multimedia devices" => "Customise DVB frontends" => "LG Electronics LGDT3302/LGDT3303 based" +c.)"Multimedia devices" => "Customise analog and hybrid tuner modules to build" => "Simple tuner support" + +Author: Uwe Bugla <uwe.bugla@gmx.de> February 2009 diff --git a/Documentation/filesystems/sysfs-pci.txt b/Documentation/filesystems/sysfs-pci.txt index 68ef48839c0..9f8740ca3f3 100644 --- a/Documentation/filesystems/sysfs-pci.txt +++ b/Documentation/filesystems/sysfs-pci.txt @@ -9,6 +9,7 @@ that support it. For example, a given bus might look like this: | |-- class | |-- config | |-- device + | |-- enable | |-- irq | |-- local_cpus | |-- resource @@ -32,6 +33,7 @@ files, each with their own function. class PCI class (ascii, ro) config PCI config space (binary, rw) device PCI device (ascii, ro) + enable Whether the device is enabled (ascii, rw) irq IRQ number (ascii, ro) local_cpus nearby CPU mask (cpumask, ro) resource PCI resource host addresses (ascii, ro) @@ -57,10 +59,19 @@ used to do actual device programming from userspace. Note that some platforms don't support mmapping of certain resources, so be sure to check the return value from any attempted mmap. +The 'enable' file provides a counter that indicates how many times the device +has been enabled. If the 'enable' file currently returns '4', and a '1' is +echoed into it, it will then return '5'. Echoing a '0' into it will decrease +the count. Even when it returns to 0, though, some of the initialisation +may not be reversed. + The 'rom' file is special in that it provides read-only access to the device's ROM file, if available. It's disabled by default, however, so applications should write the string "1" to the file to enable it before attempting a read -call, and disable it following the access by writing "0" to the file. +call, and disable it following the access by writing "0" to the file. Note +that the device must be enabled for a rom read to return data succesfully. +In the event a driver is not bound to the device, it can be enabled using the +'enable' file, documented above. Accessing legacy resources through sysfs ---------------------------------------- diff --git a/Documentation/filesystems/sysfs.txt b/Documentation/filesystems/sysfs.txt index 9e9c348275a..7e81e37c0b1 100644 --- a/Documentation/filesystems/sysfs.txt +++ b/Documentation/filesystems/sysfs.txt @@ -2,8 +2,10 @@ sysfs - _The_ filesystem for exporting kernel objects. Patrick Mochel <mochel@osdl.org> +Mike Murphy <mamurph@cs.clemson.edu> -10 January 2003 +Revised: 22 February 2009 +Original: 10 January 2003 What it is: @@ -64,12 +66,13 @@ An attribute definition is simply: struct attribute { char * name; + struct module *owner; mode_t mode; }; -int sysfs_create_file(struct kobject * kobj, struct attribute * attr); -void sysfs_remove_file(struct kobject * kobj, struct attribute * attr); +int sysfs_create_file(struct kobject * kobj, const struct attribute * attr); +void sysfs_remove_file(struct kobject * kobj, const struct attribute * attr); A bare attribute contains no means to read or write the value of the @@ -80,9 +83,11 @@ a specific object type. For example, the driver model defines struct device_attribute like: struct device_attribute { - struct attribute attr; - ssize_t (*show)(struct device * dev, char * buf); - ssize_t (*store)(struct device * dev, const char * buf); + struct attribute attr; + ssize_t (*show)(struct device *dev, struct device_attribute *attr, + char *buf); + ssize_t (*store)(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count); }; int device_create_file(struct device *, struct device_attribute *); @@ -90,12 +95,8 @@ void device_remove_file(struct device *, struct device_attribute *); It also defines this helper for defining device attributes: -#define DEVICE_ATTR(_name, _mode, _show, _store) \ -struct device_attribute dev_attr_##_name = { \ - .attr = {.name = __stringify(_name) , .mode = _mode }, \ - .show = _show, \ - .store = _store, \ -}; +#define DEVICE_ATTR(_name, _mode, _show, _store) \ +struct device_attribute dev_attr_##_name = __ATTR(_name, _mode, _show, _store) For example, declaring @@ -107,9 +108,9 @@ static struct device_attribute dev_attr_foo = { .attr = { .name = "foo", .mode = S_IWUSR | S_IRUGO, + .show = show_foo, + .store = store_foo, }, - .show = show_foo, - .store = store_foo, }; @@ -161,10 +162,12 @@ To read or write attributes, show() or store() methods must be specified when declaring the attribute. The method types should be as simple as those defined for device attributes: - ssize_t (*show)(struct device * dev, char * buf); - ssize_t (*store)(struct device * dev, const char * buf); +ssize_t (*show)(struct device * dev, struct device_attribute * attr, + char * buf); +ssize_t (*store)(struct device * dev, struct device_attribute * attr, + const char * buf); -IOW, they should take only an object and a buffer as parameters. +IOW, they should take only an object, an attribute, and a buffer as parameters. sysfs allocates a buffer of size (PAGE_SIZE) and passes it to the @@ -299,14 +302,16 @@ The following interface layers currently exist in sysfs: Structure: struct device_attribute { - struct attribute attr; - ssize_t (*show)(struct device * dev, char * buf); - ssize_t (*store)(struct device * dev, const char * buf); + struct attribute attr; + ssize_t (*show)(struct device *dev, struct device_attribute *attr, + char *buf); + ssize_t (*store)(struct device *dev, struct device_attribute *attr, + const char *buf, size_t count); }; Declaring: -DEVICE_ATTR(_name, _str, _mode, _show, _store); +DEVICE_ATTR(_name, _mode, _show, _store); Creation/Removal: @@ -342,7 +347,8 @@ Structure: struct driver_attribute { struct attribute attr; ssize_t (*show)(struct device_driver *, char * buf); - ssize_t (*store)(struct device_driver *, const char * buf); + ssize_t (*store)(struct device_driver *, const char * buf, + size_t count); }; Declaring: diff --git a/Documentation/ftrace.txt b/Documentation/ftrace.txt index 803b1318b13..2041ee951c1 100644 --- a/Documentation/ftrace.txt +++ b/Documentation/ftrace.txt @@ -15,31 +15,31 @@ Introduction Ftrace is an internal tracer designed to help out developers and designers of systems to find what is going on inside the kernel. -It can be used for debugging or analyzing latencies and performance -issues that take place outside of user-space. +It can be used for debugging or analyzing latencies and +performance issues that take place outside of user-space. Although ftrace is the function tracer, it also includes an -infrastructure that allows for other types of tracing. Some of the -tracers that are currently in ftrace include a tracer to trace -context switches, the time it takes for a high priority task to -run after it was woken up, the time interrupts are disabled, and -more (ftrace allows for tracer plugins, which means that the list of -tracers can always grow). +infrastructure that allows for other types of tracing. Some of +the tracers that are currently in ftrace include a tracer to +trace context switches, the time it takes for a high priority +task to run after it was woken up, the time interrupts are +disabled, and more (ftrace allows for tracer plugins, which +means that the list of tracers can always grow). The File System --------------- -Ftrace uses the debugfs file system to hold the control files as well -as the files to display output. +Ftrace uses the debugfs file system to hold the control files as +well as the files to display output. To mount the debugfs system: # mkdir /debug # mount -t debugfs nodev /debug -(Note: it is more common to mount at /sys/kernel/debug, but for simplicity - this document will use /debug) +( Note: it is more common to mount at /sys/kernel/debug, but for + simplicity this document will use /debug) That's it! (assuming that you have ftrace configured into your kernel) @@ -50,90 +50,124 @@ of ftrace. Here is a list of some of the key files: Note: all time values are in microseconds. - current_tracer: This is used to set or display the current tracer - that is configured. - - available_tracers: This holds the different types of tracers that - have been compiled into the kernel. The tracers - listed here can be configured by echoing their name - into current_tracer. - - tracing_enabled: This sets or displays whether the current_tracer - is activated and tracing or not. Echo 0 into this - file to disable the tracer or 1 to enable it. - - trace: This file holds the output of the trace in a human readable - format (described below). - - latency_trace: This file shows the same trace but the information - is organized more to display possible latencies - in the system (described below). - - trace_pipe: The output is the same as the "trace" file but this - file is meant to be streamed with live tracing. - Reads from this file will block until new data - is retrieved. Unlike the "trace" and "latency_trace" - files, this file is a consumer. This means reading - from this file causes sequential reads to display - more current data. Once data is read from this - file, it is consumed, and will not be read - again with a sequential read. The "trace" and - "latency_trace" files are static, and if the - tracer is not adding more data, they will display - the same information every time they are read. - - trace_options: This file lets the user control the amount of data - that is displayed in one of the above output - files. - - trace_max_latency: Some of the tracers record the max latency. - For example, the time interrupts are disabled. - This time is saved in this file. The max trace - will also be stored, and displayed by either - "trace" or "latency_trace". A new max trace will - only be recorded if the latency is greater than - the value in this file. (in microseconds) - - buffer_size_kb: This sets or displays the number of kilobytes each CPU - buffer can hold. The tracer buffers are the same size - for each CPU. The displayed number is the size of the - CPU buffer and not total size of all buffers. The - trace buffers are allocated in pages (blocks of memory - that the kernel uses for allocation, usually 4 KB in size). - If the last page allocated has room for more bytes - than requested, the rest of the page will be used, - making the actual allocation bigger than requested. - (Note, the size may not be a multiple of the page size due - to buffer managment overhead.) - - This can only be updated when the current_tracer - is set to "nop". - - tracing_cpumask: This is a mask that lets the user only trace - on specified CPUS. The format is a hex string - representing the CPUS. - - set_ftrace_filter: When dynamic ftrace is configured in (see the - section below "dynamic ftrace"), the code is dynamically - modified (code text rewrite) to disable calling of the - function profiler (mcount). This lets tracing be configured - in with practically no overhead in performance. This also - has a side effect of enabling or disabling specific functions - to be traced. Echoing names of functions into this file - will limit the trace to only those functions. - - set_ftrace_notrace: This has an effect opposite to that of - set_ftrace_filter. Any function that is added here will not - be traced. If a function exists in both set_ftrace_filter - and set_ftrace_notrace, the function will _not_ be traced. - - set_ftrace_pid: Have the function tracer only trace a single thread. - - available_filter_functions: This lists the functions that ftrace - has processed and can trace. These are the function - names that you can pass to "set_ftrace_filter" or - "set_ftrace_notrace". (See the section "dynamic ftrace" - below for more details.) + current_tracer: + + This is used to set or display the current tracer + that is configured. + + available_tracers: + + This holds the different types of tracers that + have been compiled into the kernel. The + tracers listed here can be configured by + echoing their name into current_tracer. + + tracing_enabled: + + This sets or displays whether the current_tracer + is activated and tracing or not. Echo 0 into this + file to disable the tracer or 1 to enable it. + + trace: + + This file holds the output of the trace in a human + readable format (described below). + + latency_trace: + + This file shows the same trace but the information + is organized more to display possible latencies + in the system (described below). + + trace_pipe: + + The output is the same as the "trace" file but this + file is meant to be streamed with live tracing. + Reads from this file will block until new data + is retrieved. Unlike the "trace" and "latency_trace" + files, this file is a consumer. This means reading + from this file causes sequential reads to display + more current data. Once data is read from this + file, it is consumed, and will not be read + again with a sequential read. The "trace" and + "latency_trace" files are static, and if the + tracer is not adding more data, they will display + the same information every time they are read. + + trace_options: + + This file lets the user control the amount of data + that is displayed in one of the above output + files. + + trace_max_latency: + + Some of the tracers record the max latency. + For example, the time interrupts are disabled. + This time is saved in this file. The max trace + will also be stored, and displayed by either + "trace" or "latency_trace". A new max trace will + only be recorded if the latency is greater than + the value in this file. (in microseconds) + + buffer_size_kb: + + This sets or displays the number of kilobytes each CPU + buffer can hold. The tracer buffers are the same size + for each CPU. The displayed number is the size of the + CPU buffer and not total size of all buffers. The + trace buffers are allocated in pages (blocks of memory + that the kernel uses for allocation, usually 4 KB in size). + If the last page allocated has room for more bytes + than requested, the rest of the page will be used, + making the actual allocation bigger than requested. + ( Note, the size may not be a multiple of the page size + due to buffer managment overhead. ) + + This can only be updated when the current_tracer + is set to "nop". + + tracing_cpumask: + + This is a mask that lets the user only trace + on specified CPUS. The format is a hex string + representing the CPUS. + + set_ftrace_filter: + + When dynamic ftrace is configured in (see the + section below "dynamic ftrace"), the code is dynamically + modified (code text rewrite) to disable calling of the + function profiler (mcount). This lets tracing be configured + in with practically no overhead in performance. This also + has a side effect of enabling or disabling specific functions + to be traced. Echoing names of functions into this file + will limit the trace to only those functions. + + set_ftrace_notrace: + + This has an effect opposite to that of + set_ftrace_filter. Any function that is added here will not + be traced. If a function exists in both set_ftrace_filter + and set_ftrace_notrace, the function will _not_ be traced. + + set_ftrace_pid: + + Have the function tracer only trace a single thread. + + set_graph_function: + + Set a "trigger" function where tracing should start + with the function graph tracer (See the section + "dynamic ftrace" for more details). + + available_filter_functions: + + This lists the functions that ftrace + has processed and can trace. These are the function + names that you can pass to "set_ftrace_filter" or + "set_ftrace_notrace". (See the section "dynamic ftrace" + below for more details.) The Tracers @@ -141,36 +175,66 @@ The Tracers Here is the list of current tracers that may be configured. - function - function tracer that uses mcount to trace all functions. + "function" + + Function call tracer to trace all kernel functions. + + "function_graph_tracer" + + Similar to the function tracer except that the + function tracer probes the functions on their entry + whereas the function graph tracer traces on both entry + and exit of the functions. It then provides the ability + to draw a graph of function calls similar to C code + source. - sched_switch - traces the context switches between tasks. + "sched_switch" - irqsoff - traces the areas that disable interrupts and saves - the trace with the longest max latency. - See tracing_max_latency. When a new max is recorded, - it replaces the old trace. It is best to view this - trace via the latency_trace file. + Traces the context switches and wakeups between tasks. - preemptoff - Similar to irqsoff but traces and records the amount of - time for which preemption is disabled. + "irqsoff" - preemptirqsoff - Similar to irqsoff and preemptoff, but traces and - records the largest time for which irqs and/or preemption - is disabled. + Traces the areas that disable interrupts and saves + the trace with the longest max latency. + See tracing_max_latency. When a new max is recorded, + it replaces the old trace. It is best to view this + trace via the latency_trace file. - wakeup - Traces and records the max latency that it takes for - the highest priority task to get scheduled after - it has been woken up. + "preemptoff" - nop - This is not a tracer. To remove all tracers from tracing - simply echo "nop" into current_tracer. + Similar to irqsoff but traces and records the amount of + time for which preemption is disabled. + + "preemptirqsoff" + + Similar to irqsoff and preemptoff, but traces and + records the largest time for which irqs and/or preemption + is disabled. + + "wakeup" + + Traces and records the max latency that it takes for + the highest priority task to get scheduled after + it has been woken up. + + "hw-branch-tracer" + + Uses the BTS CPU feature on x86 CPUs to traces all + branches executed. + + "nop" + + This is the "trace nothing" tracer. To remove all + tracers from tracing simply echo "nop" into + current_tracer. Examples of using the tracer ---------------------------- -Here are typical examples of using the tracers when controlling them only -with the debugfs interface (without using any user-land utilities). +Here are typical examples of using the tracers when controlling +them only with the debugfs interface (without using any +user-land utilities). Output format: -------------- @@ -187,16 +251,16 @@ Here is an example of the output format of the file "trace" bash-4251 [01] 10152.583855: _atomic_dec_and_lock <-dput -------- -A header is printed with the tracer name that is represented by the trace. -In this case the tracer is "function". Then a header showing the format. Task -name "bash", the task PID "4251", the CPU that it was running on -"01", the timestamp in <secs>.<usecs> format, the function name that was -traced "path_put" and the parent function that called this function -"path_walk". The timestamp is the time at which the function was -entered. +A header is printed with the tracer name that is represented by +the trace. In this case the tracer is "function". Then a header +showing the format. Task name "bash", the task PID "4251", the +CPU that it was running on "01", the timestamp in <secs>.<usecs> +format, the function name that was traced "path_put" and the +parent function that called this function "path_walk". The +timestamp is the time at which the function was entered. -The sched_switch tracer also includes tracing of task wakeups and -context switches. +The sched_switch tracer also includes tracing of task wakeups +and context switches. ksoftirqd/1-7 [01] 1453.070013: 7:115:R + 2916:115:S ksoftirqd/1-7 [01] 1453.070013: 7:115:R + 10:115:S @@ -205,8 +269,8 @@ context switches. kondemand/1-2916 [01] 1453.070013: 2916:115:S ==> 7:115:R ksoftirqd/1-7 [01] 1453.070013: 7:115:S ==> 0:140:R -Wake ups are represented by a "+" and the context switches are shown as -"==>". The format is: +Wake ups are represented by a "+" and the context switches are +shown as "==>". The format is: Context switches: @@ -220,19 +284,20 @@ Wake ups are represented by a "+" and the context switches are shown as <pid>:<prio>:<state> + <pid>:<prio>:<state> -The prio is the internal kernel priority, which is the inverse of the -priority that is usually displayed by user-space tools. Zero represents -the highest priority (99). Prio 100 starts the "nice" priorities with -100 being equal to nice -20 and 139 being nice 19. The prio "140" is -reserved for the idle task which is the lowest priority thread (pid 0). +The prio is the internal kernel priority, which is the inverse +of the priority that is usually displayed by user-space tools. +Zero represents the highest priority (99). Prio 100 starts the +"nice" priorities with 100 being equal to nice -20 and 139 being +nice 19. The prio "140" is reserved for the idle task which is +the lowest priority thread (pid 0). Latency trace format -------------------- -For traces that display latency times, the latency_trace file gives -somewhat more information to see why a latency happened. Here is a typical -trace. +For traces that display latency times, the latency_trace file +gives somewhat more information to see why a latency happened. +Here is a typical trace. # tracer: irqsoff # @@ -259,20 +324,20 @@ irqsoff latency trace v1.1.5 on 2.6.26-rc8 <idle>-0 0d.s1 98us : trace_hardirqs_on (do_softirq) +This shows that the current tracer is "irqsoff" tracing the time +for which interrupts were disabled. It gives the trace version +and the version of the kernel upon which this was executed on +(2.6.26-rc8). Then it displays the max latency in microsecs (97 +us). The number of trace entries displayed and the total number +recorded (both are three: #3/3). The type of preemption that was +used (PREEMPT). VP, KP, SP, and HP are always zero and are +reserved for later use. #P is the number of online CPUS (#P:2). -This shows that the current tracer is "irqsoff" tracing the time for which -interrupts were disabled. It gives the trace version and the version -of the kernel upon which this was executed on (2.6.26-rc8). Then it displays -the max latency in microsecs (97 us). The number of trace entries displayed -and the total number recorded (both are three: #3/3). The type of -preemption that was used (PREEMPT). VP, KP, SP, and HP are always zero -and are reserved for later use. #P is the number of online CPUS (#P:2). - -The task is the process that was running when the latency occurred. -(swapper pid: 0). +The task is the process that was running when the latency +occurred. (swapper pid: 0). -The start and stop (the functions in which the interrupts were disabled and -enabled respectively) that caused the latencies: +The start and stop (the functions in which the interrupts were +disabled and enabled respectively) that caused the latencies: apic_timer_interrupt is where the interrupts were disabled. do_softirq is where they were enabled again. @@ -308,12 +373,12 @@ The above is mostly meaningful for kernel developers. latency_trace file is relative to the start of the trace. delay: This is just to help catch your eye a bit better. And - needs to be fixed to be only relative to the same CPU. - The marks are determined by the difference between this - current trace and the next trace. - '!' - greater than preempt_mark_thresh (default 100) - '+' - greater than 1 microsecond - ' ' - less than or equal to 1 microsecond. + needs to be fixed to be only relative to the same CPU. + The marks are determined by the difference between this + current trace and the next trace. + '!' - greater than preempt_mark_thresh (default 100) + '+' - greater than 1 microsecond + ' ' - less than or equal to 1 microsecond. The rest is the same as the 'trace' file. @@ -321,14 +386,15 @@ The above is mostly meaningful for kernel developers. trace_options ------------- -The trace_options file is used to control what gets printed in the trace -output. To see what is available, simply cat the file: +The trace_options file is used to control what gets printed in +the trace output. To see what is available, simply cat the file: cat /debug/tracing/trace_options print-parent nosym-offset nosym-addr noverbose noraw nohex nobin \ - noblock nostacktrace nosched-tree nouserstacktrace nosym-userobj + noblock nostacktrace nosched-tree nouserstacktrace nosym-userobj -To disable one of the options, echo in the option prepended with "no". +To disable one of the options, echo in the option prepended with +"no". echo noprint-parent > /debug/tracing/trace_options @@ -338,8 +404,8 @@ To enable an option, leave off the "no". Here are the available options: - print-parent - On function traces, display the calling function - as well as the function being traced. + print-parent - On function traces, display the calling (parent) + function as well as the function being traced. print-parent: bash-4000 [01] 1477.606694: simple_strtoul <-strict_strtoul @@ -348,15 +414,16 @@ Here are the available options: bash-4000 [01] 1477.606694: simple_strtoul - sym-offset - Display not only the function name, but also the offset - in the function. For example, instead of seeing just - "ktime_get", you will see "ktime_get+0xb/0x20". + sym-offset - Display not only the function name, but also the + offset in the function. For example, instead of + seeing just "ktime_get", you will see + "ktime_get+0xb/0x20". sym-offset: bash-4000 [01] 1477.606694: simple_strtoul+0x6/0xa0 - sym-addr - this will also display the function address as well as - the function name. + sym-addr - this will also display the function address as well + as the function name. sym-addr: bash-4000 [01] 1477.606694: simple_strtoul <c0339346> @@ -366,35 +433,41 @@ Here are the available options: bash 4000 1 0 00000000 00010a95 [58127d26] 1720.415ms \ (+0.000ms): simple_strtoul (strict_strtoul) - raw - This will display raw numbers. This option is best for use with - user applications that can translate the raw numbers better than - having it done in the kernel. + raw - This will display raw numbers. This option is best for + use with user applications that can translate the raw + numbers better than having it done in the kernel. - hex - Similar to raw, but the numbers will be in a hexadecimal format. + hex - Similar to raw, but the numbers will be in a hexadecimal + format. bin - This will print out the formats in raw binary. block - TBD (needs update) - stacktrace - This is one of the options that changes the trace itself. - When a trace is recorded, so is the stack of functions. - This allows for back traces of trace sites. + stacktrace - This is one of the options that changes the trace + itself. When a trace is recorded, so is the stack + of functions. This allows for back traces of + trace sites. - userstacktrace - This option changes the trace. - It records a stacktrace of the current userspace thread. + userstacktrace - This option changes the trace. It records a + stacktrace of the current userspace thread. - sym-userobj - when user stacktrace are enabled, look up which object the - address belongs to, and print a relative address - This is especially useful when ASLR is on, otherwise you don't - get a chance to resolve the address to object/file/line after the app is no - longer running + sym-userobj - when user stacktrace are enabled, look up which + object the address belongs to, and print a + relative address. This is especially useful when + ASLR is on, otherwise you don't get a chance to + resolve the address to object/file/line after + the app is no longer running - The lookup is performed when you read trace,trace_pipe,latency_trace. Example: + The lookup is performed when you read + trace,trace_pipe,latency_trace. Example: a.out-1623 [000] 40874.465068: /root/a.out[+0x480] <-/root/a.out[+0 x494] <- /root/a.out[+0x4a8] <- /lib/libc-2.7.so[+0x1e1a6] - sched-tree - TBD (any users??) + sched-tree - trace all tasks that are on the runqueue, at + every scheduling event. Will add overhead if + there's a lot of tasks running at once. sched_switch @@ -431,18 +504,19 @@ of how to use it. [...] -As we have discussed previously about this format, the header shows -the name of the trace and points to the options. The "FUNCTION" -is a misnomer since here it represents the wake ups and context -switches. +As we have discussed previously about this format, the header +shows the name of the trace and points to the options. The +"FUNCTION" is a misnomer since here it represents the wake ups +and context switches. -The sched_switch file only lists the wake ups (represented with '+') -and context switches ('==>') with the previous task or current task -first followed by the next task or task waking up. The format for both -of these is PID:KERNEL-PRIO:TASK-STATE. Remember that the KERNEL-PRIO -is the inverse of the actual priority with zero (0) being the highest -priority and the nice values starting at 100 (nice -20). Below is -a quick chart to map the kernel priority to user land priorities. +The sched_switch file only lists the wake ups (represented with +'+') and context switches ('==>') with the previous task or +current task first followed by the next task or task waking up. +The format for both of these is PID:KERNEL-PRIO:TASK-STATE. +Remember that the KERNEL-PRIO is the inverse of the actual +priority with zero (0) being the highest priority and the nice +values starting at 100 (nice -20). Below is a quick chart to map +the kernel priority to user land priorities. Kernel priority: 0 to 99 ==> user RT priority 99 to 0 Kernel priority: 100 to 139 ==> user nice -20 to 19 @@ -463,10 +537,10 @@ The task states are: ftrace_enabled -------------- -The following tracers (listed below) give different output depending -on whether or not the sysctl ftrace_enabled is set. To set ftrace_enabled, -one can either use the sysctl function or set it via the proc -file system interface. +The following tracers (listed below) give different output +depending on whether or not the sysctl ftrace_enabled is set. To +set ftrace_enabled, one can either use the sysctl function or +set it via the proc file system interface. sysctl kernel.ftrace_enabled=1 @@ -474,12 +548,12 @@ file system interface. echo 1 > /proc/sys/kernel/ftrace_enabled -To disable ftrace_enabled simply replace the '1' with '0' in -the above commands. +To disable ftrace_enabled simply replace the '1' with '0' in the +above commands. -When ftrace_enabled is set the tracers will also record the functions -that are within the trace. The descriptions of the tracers -will also show an example with ftrace enabled. +When ftrace_enabled is set the tracers will also record the +functions that are within the trace. The descriptions of the +tracers will also show an example with ftrace enabled. irqsoff @@ -487,17 +561,18 @@ irqsoff When interrupts are disabled, the CPU can not react to any other external event (besides NMIs and SMIs). This prevents the timer -interrupt from triggering or the mouse interrupt from letting the -kernel know of a new mouse event. The result is a latency with the -reaction time. +interrupt from triggering or the mouse interrupt from letting +the kernel know of a new mouse event. The result is a latency +with the reaction time. -The irqsoff tracer tracks the time for which interrupts are disabled. -When a new maximum latency is hit, the tracer saves the trace leading up -to that latency point so that every time a new maximum is reached, the old -saved trace is discarded and the new trace is saved. +The irqsoff tracer tracks the time for which interrupts are +disabled. When a new maximum latency is hit, the tracer saves +the trace leading up to that latency point so that every time a +new maximum is reached, the old saved trace is discarded and the +new trace is saved. -To reset the maximum, echo 0 into tracing_max_latency. Here is an -example: +To reset the maximum, echo 0 into tracing_max_latency. Here is +an example: # echo irqsoff > /debug/tracing/current_tracer # echo 0 > /debug/tracing/tracing_max_latency @@ -532,10 +607,11 @@ irqsoff latency trace v1.1.5 on 2.6.26 Here we see that that we had a latency of 12 microsecs (which is -very good). The _write_lock_irq in sys_setpgid disabled interrupts. -The difference between the 12 and the displayed timestamp 14us occurred -because the clock was incremented between the time of recording the max -latency and the time of recording the function that had that latency. +very good). The _write_lock_irq in sys_setpgid disabled +interrupts. The difference between the 12 and the displayed +timestamp 14us occurred because the clock was incremented +between the time of recording the max latency and the time of +recording the function that had that latency. Note the above example had ftrace_enabled not set. If we set the ftrace_enabled, we get a much larger output: @@ -586,24 +662,24 @@ irqsoff latency trace v1.1.5 on 2.6.26-rc8 Here we traced a 50 microsecond latency. But we also see all the -functions that were called during that time. Note that by enabling -function tracing, we incur an added overhead. This overhead may -extend the latency times. But nevertheless, this trace has provided -some very helpful debugging information. +functions that were called during that time. Note that by +enabling function tracing, we incur an added overhead. This +overhead may extend the latency times. But nevertheless, this +trace has provided some very helpful debugging information. preemptoff ---------- -When preemption is disabled, we may be able to receive interrupts but -the task cannot be preempted and a higher priority task must wait -for preemption to be enabled again before it can preempt a lower -priority task. +When preemption is disabled, we may be able to receive +interrupts but the task cannot be preempted and a higher +priority task must wait for preemption to be enabled again +before it can preempt a lower priority task. The preemptoff tracer traces the places that disable preemption. -Like the irqsoff tracer, it records the maximum latency for which preemption -was disabled. The control of preemptoff tracer is much like the irqsoff -tracer. +Like the irqsoff tracer, it records the maximum latency for +which preemption was disabled. The control of preemptoff tracer +is much like the irqsoff tracer. # echo preemptoff > /debug/tracing/current_tracer # echo 0 > /debug/tracing/tracing_max_latency @@ -637,11 +713,12 @@ preemptoff latency trace v1.1.5 on 2.6.26-rc8 sshd-4261 0d.s1 30us : trace_preempt_on (__do_softirq) -This has some more changes. Preemption was disabled when an interrupt -came in (notice the 'h'), and was enabled while doing a softirq. -(notice the 's'). But we also see that interrupts have been disabled -when entering the preempt off section and leaving it (the 'd'). -We do not know if interrupts were enabled in the mean time. +This has some more changes. Preemption was disabled when an +interrupt came in (notice the 'h'), and was enabled while doing +a softirq. (notice the 's'). But we also see that interrupts +have been disabled when entering the preempt off section and +leaving it (the 'd'). We do not know if interrupts were enabled +in the mean time. # tracer: preemptoff # @@ -700,28 +777,30 @@ preemptoff latency trace v1.1.5 on 2.6.26-rc8 sshd-4261 0d.s1 64us : trace_preempt_on (__do_softirq) -The above is an example of the preemptoff trace with ftrace_enabled -set. Here we see that interrupts were disabled the entire time. -The irq_enter code lets us know that we entered an interrupt 'h'. -Before that, the functions being traced still show that it is not -in an interrupt, but we can see from the functions themselves that -this is not the case. +The above is an example of the preemptoff trace with +ftrace_enabled set. Here we see that interrupts were disabled +the entire time. The irq_enter code lets us know that we entered +an interrupt 'h'. Before that, the functions being traced still +show that it is not in an interrupt, but we can see from the +functions themselves that this is not the case. -Notice that __do_softirq when called does not have a preempt_count. -It may seem that we missed a preempt enabling. What really happened -is that the preempt count is held on the thread's stack and we -switched to the softirq stack (4K stacks in effect). The code -does not copy the preempt count, but because interrupts are disabled, -we do not need to worry about it. Having a tracer like this is good -for letting people know what really happens inside the kernel. +Notice that __do_softirq when called does not have a +preempt_count. It may seem that we missed a preempt enabling. +What really happened is that the preempt count is held on the +thread's stack and we switched to the softirq stack (4K stacks +in effect). The code does not copy the preempt count, but +because interrupts are disabled, we do not need to worry about +it. Having a tracer like this is good for letting people know +what really happens inside the kernel. preemptirqsoff -------------- -Knowing the locations that have interrupts disabled or preemption -disabled for the longest times is helpful. But sometimes we would -like to know when either preemption and/or interrupts are disabled. +Knowing the locations that have interrupts disabled or +preemption disabled for the longest times is helpful. But +sometimes we would like to know when either preemption and/or +interrupts are disabled. Consider the following code: @@ -741,11 +820,13 @@ The preemptoff tracer will record the total length of call_function_with_irqs_and_preemption_off() and call_function_with_preemption_off(). -But neither will trace the time that interrupts and/or preemption -is disabled. This total time is the time that we can not schedule. -To record this time, use the preemptirqsoff tracer. +But neither will trace the time that interrupts and/or +preemption is disabled. This total time is the time that we can +not schedule. To record this time, use the preemptirqsoff +tracer. -Again, using this trace is much like the irqsoff and preemptoff tracers. +Again, using this trace is much like the irqsoff and preemptoff +tracers. # echo preemptirqsoff > /debug/tracing/current_tracer # echo 0 > /debug/tracing/tracing_max_latency @@ -781,9 +862,10 @@ preemptirqsoff latency trace v1.1.5 on 2.6.26-rc8 The trace_hardirqs_off_thunk is called from assembly on x86 when -interrupts are disabled in the assembly code. Without the function -tracing, we do not know if interrupts were enabled within the preemption -points. We do see that it started with preemption enabled. +interrupts are disabled in the assembly code. Without the +function tracing, we do not know if interrupts were enabled +within the preemption points. We do see that it started with +preemption enabled. Here is a trace with ftrace_enabled set: @@ -871,40 +953,42 @@ preemptirqsoff latency trace v1.1.5 on 2.6.26-rc8 sshd-4261 0d.s1 105us : trace_preempt_on (__do_softirq) -This is a very interesting trace. It started with the preemption of -the ls task. We see that the task had the "need_resched" bit set -via the 'N' in the trace. Interrupts were disabled before the spin_lock -at the beginning of the trace. We see that a schedule took place to run -sshd. When the interrupts were enabled, we took an interrupt. -On return from the interrupt handler, the softirq ran. We took another -interrupt while running the softirq as we see from the capital 'H'. +This is a very interesting trace. It started with the preemption +of the ls task. We see that the task had the "need_resched" bit +set via the 'N' in the trace. Interrupts were disabled before +the spin_lock at the beginning of the trace. We see that a +schedule took place to run sshd. When the interrupts were +enabled, we took an interrupt. On return from the interrupt +handler, the softirq ran. We took another interrupt while +running the softirq as we see from the capital 'H'. wakeup ------ -In a Real-Time environment it is very important to know the wakeup -time it takes for the highest priority task that is woken up to the -time that it executes. This is also known as "schedule latency". -I stress the point that this is about RT tasks. It is also important -to know the scheduling latency of non-RT tasks, but the average -schedule latency is better for non-RT tasks. Tools like -LatencyTop are more appropriate for such measurements. +In a Real-Time environment it is very important to know the +wakeup time it takes for the highest priority task that is woken +up to the time that it executes. This is also known as "schedule +latency". I stress the point that this is about RT tasks. It is +also important to know the scheduling latency of non-RT tasks, +but the average schedule latency is better for non-RT tasks. +Tools like LatencyTop are more appropriate for such +measurements. Real-Time environments are interested in the worst case latency. -That is the longest latency it takes for something to happen, and -not the average. We can have a very fast scheduler that may only -have a large latency once in a while, but that would not work well -with Real-Time tasks. The wakeup tracer was designed to record -the worst case wakeups of RT tasks. Non-RT tasks are not recorded -because the tracer only records one worst case and tracing non-RT -tasks that are unpredictable will overwrite the worst case latency -of RT tasks. - -Since this tracer only deals with RT tasks, we will run this slightly -differently than we did with the previous tracers. Instead of performing -an 'ls', we will run 'sleep 1' under 'chrt' which changes the -priority of the task. +That is the longest latency it takes for something to happen, +and not the average. We can have a very fast scheduler that may +only have a large latency once in a while, but that would not +work well with Real-Time tasks. The wakeup tracer was designed +to record the worst case wakeups of RT tasks. Non-RT tasks are +not recorded because the tracer only records one worst case and +tracing non-RT tasks that are unpredictable will overwrite the +worst case latency of RT tasks. + +Since this tracer only deals with RT tasks, we will run this +slightly differently than we did with the previous tracers. +Instead of performing an 'ls', we will run 'sleep 1' under +'chrt' which changes the priority of the task. # echo wakeup > /debug/tracing/current_tracer # echo 0 > /debug/tracing/tracing_max_latency @@ -934,17 +1018,16 @@ wakeup latency trace v1.1.5 on 2.6.26-rc8 <idle>-0 1d..4 4us : schedule (cpu_idle) +Running this on an idle system, we see that it only took 4 +microseconds to perform the task switch. Note, since the trace +marker in the schedule is before the actual "switch", we stop +the tracing when the recorded task is about to schedule in. This +may change if we add a new marker at the end of the scheduler. -Running this on an idle system, we see that it only took 4 microseconds -to perform the task switch. Note, since the trace marker in the -schedule is before the actual "switch", we stop the tracing when -the recorded task is about to schedule in. This may change if -we add a new marker at the end of the scheduler. - -Notice that the recorded task is 'sleep' with the PID of 4901 and it -has an rt_prio of 5. This priority is user-space priority and not -the internal kernel priority. The policy is 1 for SCHED_FIFO and 2 -for SCHED_RR. +Notice that the recorded task is 'sleep' with the PID of 4901 +and it has an rt_prio of 5. This priority is user-space priority +and not the internal kernel priority. The policy is 1 for +SCHED_FIFO and 2 for SCHED_RR. Doing the same with chrt -r 5 and ftrace_enabled set. @@ -1001,24 +1084,25 @@ ksoftirq-7 1d..6 49us : _spin_unlock (tracing_record_cmdline) ksoftirq-7 1d..6 49us : sub_preempt_count (_spin_unlock) ksoftirq-7 1d..4 50us : schedule (__cond_resched) -The interrupt went off while running ksoftirqd. This task runs at -SCHED_OTHER. Why did not we see the 'N' set early? This may be -a harmless bug with x86_32 and 4K stacks. On x86_32 with 4K stacks -configured, the interrupt and softirq run with their own stack. -Some information is held on the top of the task's stack (need_resched -and preempt_count are both stored there). The setting of the NEED_RESCHED -bit is done directly to the task's stack, but the reading of the -NEED_RESCHED is done by looking at the current stack, which in this case -is the stack for the hard interrupt. This hides the fact that NEED_RESCHED -has been set. We do not see the 'N' until we switch back to the task's +The interrupt went off while running ksoftirqd. This task runs +at SCHED_OTHER. Why did not we see the 'N' set early? This may +be a harmless bug with x86_32 and 4K stacks. On x86_32 with 4K +stacks configured, the interrupt and softirq run with their own +stack. Some information is held on the top of the task's stack +(need_resched and preempt_count are both stored there). The +setting of the NEED_RESCHED bit is done directly to the task's +stack, but the reading of the NEED_RESCHED is done by looking at +the current stack, which in this case is the stack for the hard +interrupt. This hides the fact that NEED_RESCHED has been set. +We do not see the 'N' until we switch back to the task's assigned stack. function -------- This tracer is the function tracer. Enabling the function tracer -can be done from the debug file system. Make sure the ftrace_enabled is -set; otherwise this tracer is a nop. +can be done from the debug file system. Make sure the +ftrace_enabled is set; otherwise this tracer is a nop. # sysctl kernel.ftrace_enabled=1 # echo function > /debug/tracing/current_tracer @@ -1048,14 +1132,15 @@ set; otherwise this tracer is a nop. [...] -Note: function tracer uses ring buffers to store the above entries. -The newest data may overwrite the oldest data. Sometimes using echo to -stop the trace is not sufficient because the tracing could have overwritten -the data that you wanted to record. For this reason, it is sometimes better to -disable tracing directly from a program. This allows you to stop the -tracing at the point that you hit the part that you are interested in. -To disable the tracing directly from a C program, something like following -code snippet can be used: +Note: function tracer uses ring buffers to store the above +entries. The newest data may overwrite the oldest data. +Sometimes using echo to stop the trace is not sufficient because +the tracing could have overwritten the data that you wanted to +record. For this reason, it is sometimes better to disable +tracing directly from a program. This allows you to stop the +tracing at the point that you hit the part that you are +interested in. To disable the tracing directly from a C program, +something like following code snippet can be used: int trace_fd; [...] @@ -1070,10 +1155,10 @@ int main(int argc, char *argv[]) { } Note: Here we hard coded the path name. The debugfs mount is not -guaranteed to be at /debug (and is more commonly at /sys/kernel/debug). -For simple one time traces, the above is sufficent. For anything else, -a search through /proc/mounts may be needed to find where the debugfs -file-system is mounted. +guaranteed to be at /debug (and is more commonly at +/sys/kernel/debug). For simple one time traces, the above is +sufficent. For anything else, a search through /proc/mounts may +be needed to find where the debugfs file-system is mounted. Single thread tracing @@ -1152,49 +1237,297 @@ int main (int argc, char **argv) return 0; } + +hw-branch-tracer (x86 only) +--------------------------- + +This tracer uses the x86 last branch tracing hardware feature to +collect a branch trace on all cpus with relatively low overhead. + +The tracer uses a fixed-size circular buffer per cpu and only +traces ring 0 branches. The trace file dumps that buffer in the +following format: + +# tracer: hw-branch-tracer +# +# CPU# TO <- FROM + 0 scheduler_tick+0xb5/0x1bf <- task_tick_idle+0x5/0x6 + 2 run_posix_cpu_timers+0x2b/0x72a <- run_posix_cpu_timers+0x25/0x72a + 0 scheduler_tick+0x139/0x1bf <- scheduler_tick+0xed/0x1bf + 0 scheduler_tick+0x17c/0x1bf <- scheduler_tick+0x148/0x1bf + 2 run_posix_cpu_timers+0x9e/0x72a <- run_posix_cpu_timers+0x5e/0x72a + 0 scheduler_tick+0x1b6/0x1bf <- scheduler_tick+0x1aa/0x1bf + + +The tracer may be used to dump the trace for the oops'ing cpu on +a kernel oops into the system log. To enable this, +ftrace_dump_on_oops must be set. To set ftrace_dump_on_oops, one +can either use the sysctl function or set it via the proc system +interface. + + sysctl kernel.ftrace_dump_on_oops=1 + +or + + echo 1 > /proc/sys/kernel/ftrace_dump_on_oops + + +Here's an example of such a dump after a null pointer +dereference in a kernel module: + +[57848.105921] BUG: unable to handle kernel NULL pointer dereference at 0000000000000000 +[57848.106019] IP: [<ffffffffa0000006>] open+0x6/0x14 [oops] +[57848.106019] PGD 2354e9067 PUD 2375e7067 PMD 0 +[57848.106019] Oops: 0002 [#1] SMP +[57848.106019] last sysfs file: /sys/devices/pci0000:00/0000:00:1e.0/0000:20:05.0/local_cpus +[57848.106019] Dumping ftrace buffer: +[57848.106019] --------------------------------- +[...] +[57848.106019] 0 chrdev_open+0xe6/0x165 <- cdev_put+0x23/0x24 +[57848.106019] 0 chrdev_open+0x117/0x165 <- chrdev_open+0xfa/0x165 +[57848.106019] 0 chrdev_open+0x120/0x165 <- chrdev_open+0x11c/0x165 +[57848.106019] 0 chrdev_open+0x134/0x165 <- chrdev_open+0x12b/0x165 +[57848.106019] 0 open+0x0/0x14 [oops] <- chrdev_open+0x144/0x165 +[57848.106019] 0 page_fault+0x0/0x30 <- open+0x6/0x14 [oops] +[57848.106019] 0 error_entry+0x0/0x5b <- page_fault+0x4/0x30 +[57848.106019] 0 error_kernelspace+0x0/0x31 <- error_entry+0x59/0x5b +[57848.106019] 0 error_sti+0x0/0x1 <- error_kernelspace+0x2d/0x31 +[57848.106019] 0 page_fault+0x9/0x30 <- error_sti+0x0/0x1 +[57848.106019] 0 do_page_fault+0x0/0x881 <- page_fault+0x1a/0x30 +[...] +[57848.106019] 0 do_page_fault+0x66b/0x881 <- is_prefetch+0x1ee/0x1f2 +[57848.106019] 0 do_page_fault+0x6e0/0x881 <- do_page_fault+0x67a/0x881 +[57848.106019] 0 oops_begin+0x0/0x96 <- do_page_fault+0x6e0/0x881 +[57848.106019] 0 trace_hw_branch_oops+0x0/0x2d <- oops_begin+0x9/0x96 +[...] +[57848.106019] 0 ds_suspend_bts+0x2a/0xe3 <- ds_suspend_bts+0x1a/0xe3 +[57848.106019] --------------------------------- +[57848.106019] CPU 0 +[57848.106019] Modules linked in: oops +[57848.106019] Pid: 5542, comm: cat Tainted: G W 2.6.28 #23 +[57848.106019] RIP: 0010:[<ffffffffa0000006>] [<ffffffffa0000006>] open+0x6/0x14 [oops] +[57848.106019] RSP: 0018:ffff880235457d48 EFLAGS: 00010246 +[...] + + +function graph tracer +--------------------------- + +This tracer is similar to the function tracer except that it +probes a function on its entry and its exit. This is done by +using a dynamically allocated stack of return addresses in each +task_struct. On function entry the tracer overwrites the return +address of each function traced to set a custom probe. Thus the +original return address is stored on the stack of return address +in the task_struct. + +Probing on both ends of a function leads to special features +such as: + +- measure of a function's time execution +- having a reliable call stack to draw function calls graph + +This tracer is useful in several situations: + +- you want to find the reason of a strange kernel behavior and + need to see what happens in detail on any areas (or specific + ones). + +- you are experiencing weird latencies but it's difficult to + find its origin. + +- you want to find quickly which path is taken by a specific + function + +- you just want to peek inside a working kernel and want to see + what happens there. + +# tracer: function_graph +# +# CPU DURATION FUNCTION CALLS +# | | | | | | | + + 0) | sys_open() { + 0) | do_sys_open() { + 0) | getname() { + 0) | kmem_cache_alloc() { + 0) 1.382 us | __might_sleep(); + 0) 2.478 us | } + 0) | strncpy_from_user() { + 0) | might_fault() { + 0) 1.389 us | __might_sleep(); + 0) 2.553 us | } + 0) 3.807 us | } + 0) 7.876 us | } + 0) | alloc_fd() { + 0) 0.668 us | _spin_lock(); + 0) 0.570 us | expand_files(); + 0) 0.586 us | _spin_unlock(); + + +There are several columns that can be dynamically +enabled/disabled. You can use every combination of options you +want, depending on your needs. + +- The cpu number on which the function executed is default + enabled. It is sometimes better to only trace one cpu (see + tracing_cpu_mask file) or you might sometimes see unordered + function calls while cpu tracing switch. + + hide: echo nofuncgraph-cpu > /debug/tracing/trace_options + show: echo funcgraph-cpu > /debug/tracing/trace_options + +- The duration (function's time of execution) is displayed on + the closing bracket line of a function or on the same line + than the current function in case of a leaf one. It is default + enabled. + + hide: echo nofuncgraph-duration > /debug/tracing/trace_options + show: echo funcgraph-duration > /debug/tracing/trace_options + +- The overhead field precedes the duration field in case of + reached duration thresholds. + + hide: echo nofuncgraph-overhead > /debug/tracing/trace_options + show: echo funcgraph-overhead > /debug/tracing/trace_options + depends on: funcgraph-duration + + ie: + + 0) | up_write() { + 0) 0.646 us | _spin_lock_irqsave(); + 0) 0.684 us | _spin_unlock_irqrestore(); + 0) 3.123 us | } + 0) 0.548 us | fput(); + 0) + 58.628 us | } + + [...] + + 0) | putname() { + 0) | kmem_cache_free() { + 0) 0.518 us | __phys_addr(); + 0) 1.757 us | } + 0) 2.861 us | } + 0) ! 115.305 us | } + 0) ! 116.402 us | } + + + means that the function exceeded 10 usecs. + ! means that the function exceeded 100 usecs. + + +- The task/pid field displays the thread cmdline and pid which + executed the function. It is default disabled. + + hide: echo nofuncgraph-proc > /debug/tracing/trace_options + show: echo funcgraph-proc > /debug/tracing/trace_options + + ie: + + # tracer: function_graph + # + # CPU TASK/PID DURATION FUNCTION CALLS + # | | | | | | | | | + 0) sh-4802 | | d_free() { + 0) sh-4802 | | call_rcu() { + 0) sh-4802 | | __call_rcu() { + 0) sh-4802 | 0.616 us | rcu_process_gp_end(); + 0) sh-4802 | 0.586 us | check_for_new_grace_period(); + 0) sh-4802 | 2.899 us | } + 0) sh-4802 | 4.040 us | } + 0) sh-4802 | 5.151 us | } + 0) sh-4802 | + 49.370 us | } + + +- The absolute time field is an absolute timestamp given by the + system clock since it started. A snapshot of this time is + given on each entry/exit of functions + + hide: echo nofuncgraph-abstime > /debug/tracing/trace_options + show: echo funcgraph-abstime > /debug/tracing/trace_options + + ie: + + # + # TIME CPU DURATION FUNCTION CALLS + # | | | | | | | | + 360.774522 | 1) 0.541 us | } + 360.774522 | 1) 4.663 us | } + 360.774523 | 1) 0.541 us | __wake_up_bit(); + 360.774524 | 1) 6.796 us | } + 360.774524 | 1) 7.952 us | } + 360.774525 | 1) 9.063 us | } + 360.774525 | 1) 0.615 us | journal_mark_dirty(); + 360.774527 | 1) 0.578 us | __brelse(); + 360.774528 | 1) | reiserfs_prepare_for_journal() { + 360.774528 | 1) | unlock_buffer() { + 360.774529 | 1) | wake_up_bit() { + 360.774529 | 1) | bit_waitqueue() { + 360.774530 | 1) 0.594 us | __phys_addr(); + + +You can put some comments on specific functions by using +ftrace_printk() For example, if you want to put a comment inside +the __might_sleep() function, you just have to include +<linux/ftrace.h> and call ftrace_printk() inside __might_sleep() + +ftrace_printk("I'm a comment!\n") + +will produce: + + 1) | __might_sleep() { + 1) | /* I'm a comment! */ + 1) 1.449 us | } + + +You might find other useful features for this tracer in the +following "dynamic ftrace" section such as tracing only specific +functions or tasks. + dynamic ftrace -------------- If CONFIG_DYNAMIC_FTRACE is set, the system will run with virtually no overhead when function tracing is disabled. The way this works is the mcount function call (placed at the start of -every kernel function, produced by the -pg switch in gcc), starts -of pointing to a simple return. (Enabling FTRACE will include the --pg switch in the compiling of the kernel.) +every kernel function, produced by the -pg switch in gcc), +starts of pointing to a simple return. (Enabling FTRACE will +include the -pg switch in the compiling of the kernel.) At compile time every C file object is run through the recordmcount.pl script (located in the scripts directory). This script will process the C object using objdump to find all the -locations in the .text section that call mcount. (Note, only -the .text section is processed, since processing other sections -like .init.text may cause races due to those sections being freed). +locations in the .text section that call mcount. (Note, only the +.text section is processed, since processing other sections like +.init.text may cause races due to those sections being freed). -A new section called "__mcount_loc" is created that holds references -to all the mcount call sites in the .text section. This section is -compiled back into the original object. The final linker will add -all these references into a single table. +A new section called "__mcount_loc" is created that holds +references to all the mcount call sites in the .text section. +This section is compiled back into the original object. The +final linker will add all these references into a single table. On boot up, before SMP is initialized, the dynamic ftrace code -scans this table and updates all the locations into nops. It also -records the locations, which are added to the available_filter_functions -list. Modules are processed as they are loaded and before they are -executed. When a module is unloaded, it also removes its functions from -the ftrace function list. This is automatic in the module unload -code, and the module author does not need to worry about it. - -When tracing is enabled, kstop_machine is called to prevent races -with the CPUS executing code being modified (which can cause the -CPU to do undesireable things), and the nops are patched back -to calls. But this time, they do not call mcount (which is just -a function stub). They now call into the ftrace infrastructure. +scans this table and updates all the locations into nops. It +also records the locations, which are added to the +available_filter_functions list. Modules are processed as they +are loaded and before they are executed. When a module is +unloaded, it also removes its functions from the ftrace function +list. This is automatic in the module unload code, and the +module author does not need to worry about it. + +When tracing is enabled, kstop_machine is called to prevent +races with the CPUS executing code being modified (which can +cause the CPU to do undesireable things), and the nops are +patched back to calls. But this time, they do not call mcount +(which is just a function stub). They now call into the ftrace +infrastructure. One special side-effect to the recording of the functions being traced is that we can now selectively choose which functions we -wish to trace and which ones we want the mcount calls to remain as -nops. +wish to trace and which ones we want the mcount calls to remain +as nops. -Two files are used, one for enabling and one for disabling the tracing -of specified functions. They are: +Two files are used, one for enabling and one for disabling the +tracing of specified functions. They are: set_ftrace_filter @@ -1202,8 +1535,8 @@ and set_ftrace_notrace -A list of available functions that you can add to these files is listed -in: +A list of available functions that you can add to these files is +listed in: available_filter_functions @@ -1240,8 +1573,8 @@ hrtimer_interrupt sys_nanosleep -Perhaps this is not enough. The filters also allow simple wild cards. -Only the following are currently available +Perhaps this is not enough. The filters also allow simple wild +cards. Only the following are currently available <match>* - will match functions that begin with <match> *<match> - will match functions that end with <match> @@ -1251,9 +1584,9 @@ These are the only wild cards which are supported. <match>*<match> will not work. -Note: It is better to use quotes to enclose the wild cards, otherwise - the shell may expand the parameters into names of files in the local - directory. +Note: It is better to use quotes to enclose the wild cards, + otherwise the shell may expand the parameters into names + of files in the local directory. # echo 'hrtimer_*' > /debug/tracing/set_ftrace_filter @@ -1299,7 +1632,8 @@ This is because the '>' and '>>' act just like they do in bash. To rewrite the filters, use '>' To append to the filters, use '>>' -To clear out a filter so that all functions will be recorded again: +To clear out a filter so that all functions will be recorded +again: # echo > /debug/tracing/set_ftrace_filter # cat /debug/tracing/set_ftrace_filter @@ -1331,7 +1665,8 @@ hrtimer_get_res hrtimer_init_sleeper -The set_ftrace_notrace prevents those functions from being traced. +The set_ftrace_notrace prevents those functions from being +traced. # echo '*preempt*' '*lock*' > /debug/tracing/set_ftrace_notrace @@ -1353,13 +1688,75 @@ Produces: We can see that there's no more lock or preempt tracing. + +Dynamic ftrace with the function graph tracer +--------------------------------------------- + +Although what has been explained above concerns both the +function tracer and the function-graph-tracer, there are some +special features only available in the function-graph tracer. + +If you want to trace only one function and all of its children, +you just have to echo its name into set_graph_function: + + echo __do_fault > set_graph_function + +will produce the following "expanded" trace of the __do_fault() +function: + + 0) | __do_fault() { + 0) | filemap_fault() { + 0) | find_lock_page() { + 0) 0.804 us | find_get_page(); + 0) | __might_sleep() { + 0) 1.329 us | } + 0) 3.904 us | } + 0) 4.979 us | } + 0) 0.653 us | _spin_lock(); + 0) 0.578 us | page_add_file_rmap(); + 0) 0.525 us | native_set_pte_at(); + 0) 0.585 us | _spin_unlock(); + 0) | unlock_page() { + 0) 0.541 us | page_waitqueue(); + 0) 0.639 us | __wake_up_bit(); + 0) 2.786 us | } + 0) + 14.237 us | } + 0) | __do_fault() { + 0) | filemap_fault() { + 0) | find_lock_page() { + 0) 0.698 us | find_get_page(); + 0) | __might_sleep() { + 0) 1.412 us | } + 0) 3.950 us | } + 0) 5.098 us | } + 0) 0.631 us | _spin_lock(); + 0) 0.571 us | page_add_file_rmap(); + 0) 0.526 us | native_set_pte_at(); + 0) 0.586 us | _spin_unlock(); + 0) | unlock_page() { + 0) 0.533 us | page_waitqueue(); + 0) 0.638 us | __wake_up_bit(); + 0) 2.793 us | } + 0) + 14.012 us | } + +You can also expand several functions at once: + + echo sys_open > set_graph_function + echo sys_close >> set_graph_function + +Now if you want to go back to trace all functions you can clear +this special filter via: + + echo > set_graph_function + + trace_pipe ---------- -The trace_pipe outputs the same content as the trace file, but the effect -on the tracing is different. Every read from trace_pipe is consumed. -This means that subsequent reads will be different. The trace -is live. +The trace_pipe outputs the same content as the trace file, but +the effect on the tracing is different. Every read from +trace_pipe is consumed. This means that subsequent reads will be +different. The trace is live. # echo function > /debug/tracing/current_tracer # cat /debug/tracing/trace_pipe > /tmp/trace.out & @@ -1387,38 +1784,45 @@ is live. bash-4043 [00] 41.267111: select_task_rq_rt <-try_to_wake_up -Note, reading the trace_pipe file will block until more input is added. -By changing the tracer, trace_pipe will issue an EOF. We needed -to set the function tracer _before_ we "cat" the trace_pipe file. +Note, reading the trace_pipe file will block until more input is +added. By changing the tracer, trace_pipe will issue an EOF. We +needed to set the function tracer _before_ we "cat" the +trace_pipe file. trace entries ------------- -Having too much or not enough data can be troublesome in diagnosing -an issue in the kernel. The file buffer_size_kb is used to modify -the size of the internal trace buffers. The number listed -is the number of entries that can be recorded per CPU. To know -the full size, multiply the number of possible CPUS with the -number of entries. +Having too much or not enough data can be troublesome in +diagnosing an issue in the kernel. The file buffer_size_kb is +used to modify the size of the internal trace buffers. The +number listed is the number of entries that can be recorded per +CPU. To know the full size, multiply the number of possible CPUS +with the number of entries. # cat /debug/tracing/buffer_size_kb 1408 (units kilobytes) -Note, to modify this, you must have tracing completely disabled. To do that, -echo "nop" into the current_tracer. If the current_tracer is not set -to "nop", an EINVAL error will be returned. +Note, to modify this, you must have tracing completely disabled. +To do that, echo "nop" into the current_tracer. If the +current_tracer is not set to "nop", an EINVAL error will be +returned. # echo nop > /debug/tracing/current_tracer # echo 10000 > /debug/tracing/buffer_size_kb # cat /debug/tracing/buffer_size_kb 10000 (units kilobytes) -The number of pages which will be allocated is limited to a percentage -of available memory. Allocating too much will produce an error. +The number of pages which will be allocated is limited to a +percentage of available memory. Allocating too much will produce +an error. # echo 1000000000000 > /debug/tracing/buffer_size_kb -bash: echo: write error: Cannot allocate memory # cat /debug/tracing/buffer_size_kb 85 +----------- + +More details can be found in the source code, in the +kernel/tracing/*.c files. diff --git a/Documentation/hwmon/hpfall.c b/Documentation/hwmon/hpfall.c new file mode 100644 index 00000000000..bbea1ccfd46 --- /dev/null +++ b/Documentation/hwmon/hpfall.c @@ -0,0 +1,101 @@ +/* Disk protection for HP machines. + * + * Copyright 2008 Eric Piel + * Copyright 2009 Pavel Machek <pavel@suse.cz> + * + * GPLv2. + */ + +#include <stdio.h> +#include <stdlib.h> +#include <unistd.h> +#include <fcntl.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <string.h> +#include <stdint.h> +#include <errno.h> +#include <signal.h> + +void write_int(char *path, int i) +{ + char buf[1024]; + int fd = open(path, O_RDWR); + if (fd < 0) { + perror("open"); + exit(1); + } + sprintf(buf, "%d", i); + if (write(fd, buf, strlen(buf)) != strlen(buf)) { + perror("write"); + exit(1); + } + close(fd); +} + +void set_led(int on) +{ + write_int("/sys/class/leds/hp::hddprotect/brightness", on); +} + +void protect(int seconds) +{ + write_int("/sys/block/sda/device/unload_heads", seconds*1000); +} + +int on_ac(void) +{ +// /sys/class/power_supply/AC0/online +} + +int lid_open(void) +{ +// /proc/acpi/button/lid/LID/state +} + +void ignore_me(void) +{ + protect(0); + set_led(0); + +} + +int main(int argc, char* argv[]) +{ + int fd, ret; + + fd = open("/dev/freefall", O_RDONLY); + if (fd < 0) { + perror("open"); + return EXIT_FAILURE; + } + + signal(SIGALRM, ignore_me); + + for (;;) { + unsigned char count; + + ret = read(fd, &count, sizeof(count)); + alarm(0); + if ((ret == -1) && (errno == EINTR)) { + /* Alarm expired, time to unpark the heads */ + continue; + } + + if (ret != sizeof(count)) { + perror("read"); + break; + } + + protect(21); + set_led(1); + if (1 || on_ac() || lid_open()) { + alarm(2); + } else { + alarm(20); + } + } + + close(fd); + return EXIT_SUCCESS; +} diff --git a/Documentation/hwmon/lis3lv02d b/Documentation/hwmon/lis3lv02d index 0fcfc4a7ccd..287f8c90265 100644 --- a/Documentation/hwmon/lis3lv02d +++ b/Documentation/hwmon/lis3lv02d @@ -33,6 +33,14 @@ rate - reports the sampling rate of the accelerometer device in HZ This driver also provides an absolute input class device, allowing the laptop to act as a pinball machine-esque joystick. +Another feature of the driver is misc device called "freefall" that +acts similar to /dev/rtc and reacts on free-fall interrupts received +from the device. It supports blocking operations, poll/select and +fasync operation modes. You must read 1 bytes from the device. The +result is number of free-fall interrupts since the last successful +read (or 255 if number of interrupts would not fit). + + Axes orientation ---------------- diff --git a/Documentation/kernel-doc-nano-HOWTO.txt b/Documentation/kernel-doc-nano-HOWTO.txt index d73fbd2b2b4..026ec7d5738 100644 --- a/Documentation/kernel-doc-nano-HOWTO.txt +++ b/Documentation/kernel-doc-nano-HOWTO.txt @@ -43,7 +43,8 @@ Only comments so marked will be considered by the kernel-doc scripts, and any comment so marked must be in kernel-doc format. Do not use "/**" to be begin a comment block unless the comment block contains kernel-doc formatted comments. The closing comment marker for -kernel-doc comments can be either "*/" or "**/". +kernel-doc comments can be either "*/" or "**/", but "*/" is +preferred in the Linux kernel tree. Kernel-doc comments should be placed just before the function or data structure being described. @@ -63,7 +64,7 @@ Example kernel-doc function comment: * comment lines. * * The longer description can have multiple paragraphs. - **/ + */ The first line, with the short description, must be on a single line. @@ -85,7 +86,7 @@ Example kernel-doc data structure comment. * perhaps with more lines and words. * * Longer description of this structure. - **/ + */ The kernel-doc function comments describe each parameter to the function, in order, with the @name lines. diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index d8362cf9909..d1cb2069e2f 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -49,6 +49,7 @@ parameter is applicable: ISAPNP ISA PnP code is enabled. ISDN Appropriate ISDN support is enabled. JOY Appropriate joystick support is enabled. + KMEMTRACE kmemtrace is enabled. LIBATA Libata driver is enabled LP Printer support is enabled. LOOP Loopback device support is enabled. @@ -114,7 +115,7 @@ In addition, the following text indicates that the option: Parameters denoted with BOOT are actually interpreted by the boot loader, and have no meaning to the kernel directly. Do not modify the syntax of boot loader parameters without extreme -need or coordination with <Documentation/x86/i386/boot.txt>. +need or coordination with <Documentation/x86/boot.txt>. There are also arch-specific kernel-parameters not documented here. See for example <Documentation/x86/x86_64/boot-options.txt>. @@ -134,7 +135,7 @@ and is between 256 and 4096 characters. It is defined in the file acpi= [HW,ACPI,X86-64,i386] Advanced Configuration and Power Interface - Format: { force | off | ht | strict | noirq } + Format: { force | off | ht | strict | noirq | rsdt } force -- enable ACPI if default was off off -- disable ACPI if default was on noirq -- do not use ACPI for IRQ routing @@ -868,8 +869,10 @@ and is between 256 and 4096 characters. It is defined in the file icn= [HW,ISDN] Format: <io>[,<membase>[,<icn_id>[,<icn_id2>]]] - ide= [HW] (E)IDE subsystem - Format: ide=nodma or ide=doubler + ide-core.nodma= [HW] (E)IDE subsystem + Format: =0.0 to prevent dma on hda, =0.1 hdb =1.0 hdc + .vlb_clock .pci_clock .noflush .noprobe .nowerr .cdrom + .chs .ignore_cable are additional options See Documentation/ide/ide.txt. idebus= [HW] (E)IDE subsystem - VLB/PCI bus speed @@ -937,6 +940,8 @@ and is between 256 and 4096 characters. It is defined in the file intel_iommu= [DMAR] Intel IOMMU driver (DMAR) option + on + Enable intel iommu driver. off Disable intel iommu driver. igfx_off [Default Off] @@ -1043,6 +1048,15 @@ and is between 256 and 4096 characters. It is defined in the file use the HighMem zone if it exists, and the Normal zone if it does not. + kmemtrace.enable= [KNL,KMEMTRACE] Format: { yes | no } + Controls whether kmemtrace is enabled + at boot-time. + + kmemtrace.subbufs=n [KNL,KMEMTRACE] Overrides the number of + subbufs kmemtrace's relay channel has. Set this + higher than default (KMEMTRACE_N_SUBBUFS in code) if + you experience buffer overruns. + movablecore=nn[KMG] [KNL,X86-32,IA-64,PPC,X86-64] This parameter is similar to kernelcore except it specifies the amount of memory used for migratable allocations. @@ -2447,7 +2461,7 @@ and is between 256 and 4096 characters. It is defined in the file See Documentation/fb/modedb.txt. vga= [BOOT,X86-32] Select a particular video mode - See Documentation/x86/i386/boot.txt and + See Documentation/x86/boot.txt and Documentation/svga.txt. Use vga=ask for menu. This is actually a boot loader parameter; the value is diff --git a/Documentation/scsi/cxgb3i.txt b/Documentation/scsi/cxgb3i.txt index 8141fa01978..7ac8032ee9b 100644 --- a/Documentation/scsi/cxgb3i.txt +++ b/Documentation/scsi/cxgb3i.txt @@ -4,7 +4,7 @@ Introduction ============ The Chelsio T3 ASIC based Adapters (S310, S320, S302, S304, Mezz cards, etc. -series of products) supports iSCSI acceleration and iSCSI Direct Data Placement +series of products) support iSCSI acceleration and iSCSI Direct Data Placement (DDP) where the hardware handles the expensive byte touching operations, such as CRC computation and verification, and direct DMA to the final host memory destination: @@ -31,9 +31,9 @@ destination: the TCP segments onto the wire. It handles TCP retransmission if needed. - On receving, S3 h/w recovers the iSCSI PDU by reassembling TCP + On receiving, S3 h/w recovers the iSCSI PDU by reassembling TCP segments, separating the header and data, calculating and verifying - the digests, then forwards the header to the host. The payload data, + the digests, then forwarding the header to the host. The payload data, if possible, will be directly placed into the pre-posted host DDP buffer. Otherwise, the payload data will be sent to the host too. @@ -68,9 +68,8 @@ The following steps need to be taken to accelerates the open-iscsi initiator: sure the ip address is unique in the network. 3. edit /etc/iscsi/iscsid.conf - The default setting for MaxRecvDataSegmentLength (131072) is too big, - replace "node.conn[0].iscsi.MaxRecvDataSegmentLength" to be a value no - bigger than 15360 (for example 8192): + The default setting for MaxRecvDataSegmentLength (131072) is too big; + replace with a value no bigger than 15360 (for example 8192): node.conn[0].iscsi.MaxRecvDataSegmentLength = 8192 diff --git a/Documentation/sysrq.txt b/Documentation/sysrq.txt index 9e592c718af..535aeb936db 100644 --- a/Documentation/sysrq.txt +++ b/Documentation/sysrq.txt @@ -113,6 +113,8 @@ On all - write a character to /proc/sysrq-trigger. e.g.: 'x' - Used by xmon interface on ppc/powerpc platforms. +'z' - Dump the ftrace buffer + '0'-'9' - Sets the console log level, controlling which kernel messages will be printed to your console. ('0', for example would make it so that only emergency messages like PANICs or OOPSes would diff --git a/Documentation/tracers/mmiotrace.txt b/Documentation/tracers/mmiotrace.txt index cde23b4a12a..5731c67abc5 100644 --- a/Documentation/tracers/mmiotrace.txt +++ b/Documentation/tracers/mmiotrace.txt @@ -78,12 +78,10 @@ to view your kernel log and look for "mmiotrace has lost events" warning. If events were lost, the trace is incomplete. You should enlarge the buffers and try again. Buffers are enlarged by first seeing how large the current buffers are: -$ cat /debug/tracing/trace_entries +$ cat /debug/tracing/buffer_size_kb gives you a number. Approximately double this number and write it back, for instance: -$ echo 0 > /debug/tracing/tracing_enabled -$ echo 128000 > /debug/tracing/trace_entries -$ echo 1 > /debug/tracing/tracing_enabled +$ echo 128000 > /debug/tracing/buffer_size_kb Then start again from the top. If you are doing a trace for a driver project, e.g. Nouveau, you should also diff --git a/Documentation/vm/kmemtrace.txt b/Documentation/vm/kmemtrace.txt new file mode 100644 index 00000000000..a956d9b7f94 --- /dev/null +++ b/Documentation/vm/kmemtrace.txt @@ -0,0 +1,126 @@ + kmemtrace - Kernel Memory Tracer + + by Eduard - Gabriel Munteanu + <eduard.munteanu@linux360.ro> + +I. Introduction +=============== + +kmemtrace helps kernel developers figure out two things: +1) how different allocators (SLAB, SLUB etc.) perform +2) how kernel code allocates memory and how much + +To do this, we trace every allocation and export information to the userspace +through the relay interface. We export things such as the number of requested +bytes, the number of bytes actually allocated (i.e. including internal +fragmentation), whether this is a slab allocation or a plain kmalloc() and so +on. + +The actual analysis is performed by a userspace tool (see section III for +details on where to get it from). It logs the data exported by the kernel, +processes it and (as of writing this) can provide the following information: +- the total amount of memory allocated and fragmentation per call-site +- the amount of memory allocated and fragmentation per allocation +- total memory allocated and fragmentation in the collected dataset +- number of cross-CPU allocation and frees (makes sense in NUMA environments) + +Moreover, it can potentially find inconsistent and erroneous behavior in +kernel code, such as using slab free functions on kmalloc'ed memory or +allocating less memory than requested (but not truly failed allocations). + +kmemtrace also makes provisions for tracing on some arch and analysing the +data on another. + +II. Design and goals +==================== + +kmemtrace was designed to handle rather large amounts of data. Thus, it uses +the relay interface to export whatever is logged to userspace, which then +stores it. Analysis and reporting is done asynchronously, that is, after the +data is collected and stored. By design, it allows one to log and analyse +on different machines and different arches. + +As of writing this, the ABI is not considered stable, though it might not +change much. However, no guarantees are made about compatibility yet. When +deemed stable, the ABI should still allow easy extension while maintaining +backward compatibility. This is described further in Documentation/ABI. + +Summary of design goals: + - allow logging and analysis to be done across different machines + - be fast and anticipate usage in high-load environments (*) + - be reasonably extensible + - make it possible for GNU/Linux distributions to have kmemtrace + included in their repositories + +(*) - one of the reasons Pekka Enberg's original userspace data analysis + tool's code was rewritten from Perl to C (although this is more than a + simple conversion) + + +III. Quick usage guide +====================== + +1) Get a kernel that supports kmemtrace and build it accordingly (i.e. enable +CONFIG_KMEMTRACE). + +2) Get the userspace tool and build it: +$ git-clone git://repo.or.cz/kmemtrace-user.git # current repository +$ cd kmemtrace-user/ +$ ./autogen.sh +$ ./configure +$ make + +3) Boot the kmemtrace-enabled kernel if you haven't, preferably in the +'single' runlevel (so that relay buffers don't fill up easily), and run +kmemtrace: +# '$' does not mean user, but root here. +$ mount -t debugfs none /sys/kernel/debug +$ mount -t proc none /proc +$ cd path/to/kmemtrace-user/ +$ ./kmemtraced +Wait a bit, then stop it with CTRL+C. +$ cat /sys/kernel/debug/kmemtrace/total_overruns # Check if we didn't + # overrun, should + # be zero. +$ (Optionally) [Run kmemtrace_check separately on each cpu[0-9]*.out file to + check its correctness] +$ ./kmemtrace-report + +Now you should have a nice and short summary of how the allocator performs. + +IV. FAQ and known issues +======================== + +Q: 'cat /sys/kernel/debug/kmemtrace/total_overruns' is non-zero, how do I fix +this? Should I worry? +A: If it's non-zero, this affects kmemtrace's accuracy, depending on how +large the number is. You can fix it by supplying a higher +'kmemtrace.subbufs=N' kernel parameter. +--- + +Q: kmemtrace_check reports errors, how do I fix this? Should I worry? +A: This is a bug and should be reported. It can occur for a variety of +reasons: + - possible bugs in relay code + - possible misuse of relay by kmemtrace + - timestamps being collected unorderly +Or you may fix it yourself and send us a patch. +--- + +Q: kmemtrace_report shows many errors, how do I fix this? Should I worry? +A: This is a known issue and I'm working on it. These might be true errors +in kernel code, which may have inconsistent behavior (e.g. allocating memory +with kmem_cache_alloc() and freeing it with kfree()). Pekka Enberg pointed +out this behavior may work with SLAB, but may fail with other allocators. + +It may also be due to lack of tracing in some unusual allocator functions. + +We don't want bug reports regarding this issue yet. +--- + +V. See also +=========== + +Documentation/kernel-parameters.txt +Documentation/ABI/testing/debugfs-kmemtrace + |