diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/DocBook/kgdb.tmpl | 8 | ||||
| -rw-r--r-- | Documentation/cgroups.txt | 4 | ||||
| -rw-r--r-- | Documentation/feature-removal-schedule.txt | 8 | ||||
| -rw-r--r-- | Documentation/filesystems/Locking | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.txt | 4 | ||||
| -rw-r--r-- | Documentation/hwmon/adt7473 | 3 | ||||
| -rw-r--r-- | Documentation/i2c/functionality | 95 | ||||
| -rw-r--r-- | Documentation/i2c/smbus-protocol | 81 | ||||
| -rw-r--r-- | Documentation/kernel-parameters.txt | 5 | ||||
| -rw-r--r-- | Documentation/memory-barriers.txt | 12 | ||||
| -rw-r--r-- | Documentation/s390/CommonIO | 11 | ||||
| -rw-r--r-- | Documentation/scheduler/sched-design.txt | 165 | ||||
| -rw-r--r-- | Documentation/video4linux/CARDLIST.cx23885 | 2 | ||||
| -rw-r--r-- | Documentation/video4linux/CARDLIST.em28xx | 2 |
14 files changed, 130 insertions, 272 deletions
diff --git a/Documentation/DocBook/kgdb.tmpl b/Documentation/DocBook/kgdb.tmpl index 97618bed4d6..028a8444d95 100644 --- a/Documentation/DocBook/kgdb.tmpl +++ b/Documentation/DocBook/kgdb.tmpl @@ -72,7 +72,7 @@ kgdb is a source level debugger for linux kernel. It is used along with gdb to debug a linux kernel. The expectation is that gdb can be used to "break in" to the kernel to inspect memory, variables - and look through a cal stack information similar to what an + and look through call stack information similar to what an application developer would use gdb for. It is possible to place breakpoints in kernel code and perform some limited execution stepping. @@ -93,8 +93,10 @@ <chapter id="CompilingAKernel"> <title>Compiling a kernel</title> <para> - To enable <symbol>CONFIG_KGDB</symbol>, look under the "Kernel debugging" - and then select "KGDB: kernel debugging with remote gdb". + To enable <symbol>CONFIG_KGDB</symbol> you should first turn on + "Prompt for development and/or incomplete code/drivers" + (CONFIG_EXPERIMENTAL) in "General setup", then under the + "Kernel debugging" select "KGDB: kernel debugging with remote gdb". </para> <para> Next you should choose one of more I/O drivers to interconnect debugging diff --git a/Documentation/cgroups.txt b/Documentation/cgroups.txt index c298a6690e0..824fc027447 100644 --- a/Documentation/cgroups.txt +++ b/Documentation/cgroups.txt @@ -310,8 +310,8 @@ and then start a subshell 'sh' in that cgroup: cd /dev/cgroup mkdir Charlie cd Charlie - /bin/echo 2-3 > cpus - /bin/echo 1 > mems + /bin/echo 2-3 > cpuset.cpus + /bin/echo 1 > cpuset.mems /bin/echo $$ > tasks sh # The subshell 'sh' is now running in cgroup Charlie diff --git a/Documentation/feature-removal-schedule.txt b/Documentation/feature-removal-schedule.txt index 3c35d452b1a..5b3f31faed5 100644 --- a/Documentation/feature-removal-schedule.txt +++ b/Documentation/feature-removal-schedule.txt @@ -289,6 +289,14 @@ Who: Glauber Costa <gcosta@redhat.com> --------------------------- +What: old style serial driver for ColdFire (CONFIG_SERIAL_COLDFIRE) +When: 2.6.28 +Why: This driver still uses the old interface and has been replaced + by CONFIG_SERIAL_MCF. +Who: Sebastian Siewior <sebastian@breakpoint.cc> + +--------------------------- + What: /sys/o2cb symlink When: January 2010 Why: /sys/fs/o2cb is the proper location for this information - /sys/o2cb diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index c2992bc54f2..8b22d7d8b99 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -92,7 +92,6 @@ prototypes: void (*destroy_inode)(struct inode *); void (*dirty_inode) (struct inode *); int (*write_inode) (struct inode *, int); - void (*put_inode) (struct inode *); void (*drop_inode) (struct inode *); void (*delete_inode) (struct inode *); void (*put_super) (struct super_block *); @@ -115,7 +114,6 @@ alloc_inode: no no no destroy_inode: no dirty_inode: no (must not sleep) write_inode: no -put_inode: no drop_inode: no !!!inode_lock!!! delete_inode: no put_super: yes yes no diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index 81e5be6e6e3..b7522c6cbae 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -205,7 +205,6 @@ struct super_operations { void (*dirty_inode) (struct inode *); int (*write_inode) (struct inode *, int); - void (*put_inode) (struct inode *); void (*drop_inode) (struct inode *); void (*delete_inode) (struct inode *); void (*put_super) (struct super_block *); @@ -246,9 +245,6 @@ or bottom half). inode to disc. The second parameter indicates whether the write should be synchronous or not, not all filesystems check this flag. - put_inode: called when the VFS inode is removed from the inode - cache. - drop_inode: called when the last access to the inode is dropped, with the inode_lock spinlock held. diff --git a/Documentation/hwmon/adt7473 b/Documentation/hwmon/adt7473 index 22d8b19046a..2126de34c71 100644 --- a/Documentation/hwmon/adt7473 +++ b/Documentation/hwmon/adt7473 @@ -69,7 +69,8 @@ point2: Set the pwm speed at a higher temperature bound. The ADT7473 will scale the pwm between the lower and higher pwm speed when the temperature is between the two temperature boundaries. PWM values range -from 0 (off) to 255 (full speed). +from 0 (off) to 255 (full speed). Fan speed will be set to maximum when the +temperature sensor associated with the PWM control exceeds temp#_max. Notes ----- diff --git a/Documentation/i2c/functionality b/Documentation/i2c/functionality index 60cca249e45..42c17c1fb3c 100644 --- a/Documentation/i2c/functionality +++ b/Documentation/i2c/functionality @@ -51,26 +51,38 @@ A few combinations of the above flags are also defined for your convenience: the transparent emulation layer) -ALGORITHM/ADAPTER IMPLEMENTATION --------------------------------- +ADAPTER IMPLEMENTATION +---------------------- -When you write a new algorithm driver, you will have to implement a -function callback `functionality', that gets an i2c_adapter structure -pointer as its only parameter: +When you write a new adapter driver, you will have to implement a +function callback `functionality'. Typical implementations are given +below. - struct i2c_algorithm { - /* Many other things of course; check <linux/i2c.h>! */ - u32 (*functionality) (struct i2c_adapter *); +A typical SMBus-only adapter would list all the SMBus transactions it +supports. This example comes from the i2c-piix4 driver: + + static u32 piix4_func(struct i2c_adapter *adapter) + { + return I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE | + I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | + I2C_FUNC_SMBUS_BLOCK_DATA; } -A typically implementation is given below, from i2c-algo-bit.c: +A typical full-I2C adapter would use the following (from the i2c-pxa +driver): - static u32 bit_func(struct i2c_adapter *adap) + static u32 i2c_pxa_functionality(struct i2c_adapter *adap) { - return I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR | - I2C_FUNC_PROTOCOL_MANGLING; + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; } +I2C_FUNC_SMBUS_EMUL includes all the SMBus transactions (with the +addition of I2C block transactions) which i2c-core can emulate using +I2C_FUNC_I2C without any help from the adapter driver. The idea is +to let the client drivers check for the support of SMBus functions +without having to care whether the said functions are implemented in +hardware by the adapter, or emulated in software by i2c-core on top +of an I2C adapter. CLIENT CHECKING @@ -78,36 +90,33 @@ CLIENT CHECKING Before a client tries to attach to an adapter, or even do tests to check whether one of the devices it supports is present on an adapter, it should -check whether the needed functionality is present. There are two functions -defined which should be used instead of calling the functionality hook -in the algorithm structure directly: - - /* Return the functionality mask */ - extern u32 i2c_get_functionality (struct i2c_adapter *adap); - - /* Return 1 if adapter supports everything we need, 0 if not. */ - extern int i2c_check_functionality (struct i2c_adapter *adap, u32 func); +check whether the needed functionality is present. The typical way to do +this is (from the lm75 driver): -This is a typical way to use these functions (from the writing-clients -document): - int foo_detect_client(struct i2c_adapter *adapter, int address, - unsigned short flags, int kind) + static int lm75_detect(...) { - /* Define needed variables */ - - /* As the very first action, we check whether the adapter has the - needed functionality: we need the SMBus read_word_data, - write_word_data and write_byte functions in this example. */ - if (!i2c_check_functionality(adapter,I2C_FUNC_SMBUS_WORD_DATA | - I2C_FUNC_SMBUS_WRITE_BYTE)) - goto ERROR0; - - /* Now we can do the real detection */ - - ERROR0: - /* Return an error */ + (...) + if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | + I2C_FUNC_SMBUS_WORD_DATA)) + goto exit; + (...) } +Here, the lm75 driver checks if the adapter can do both SMBus byte data +and SMBus word data transactions. If not, then the driver won't work on +this adapter and there's no point in going on. If the check above is +successful, then the driver knows that it can call the following +functions: i2c_smbus_read_byte_data(), i2c_smbus_write_byte_data(), +i2c_smbus_read_word_data() and i2c_smbus_write_word_data(). As a rule of +thumb, the functionality constants you test for with +i2c_check_functionality() should match exactly the i2c_smbus_* functions +which you driver is calling. + +Note that the check above doesn't tell whether the functionalities are +implemented in hardware by the underlying adapter or emulated in +software by i2c-core. Client drivers don't have to care about this, as +i2c-core will transparently implement SMBus transactions on top of I2C +adapters. CHECKING THROUGH /DEV @@ -116,19 +125,19 @@ CHECKING THROUGH /DEV If you try to access an adapter from a userspace program, you will have to use the /dev interface. You will still have to check whether the functionality you need is supported, of course. This is done using -the I2C_FUNCS ioctl. An example, adapted from the lm_sensors i2cdetect -program, is below: +the I2C_FUNCS ioctl. An example, adapted from the i2cdetect program, is +below: int file; - if (file = open("/dev/i2c-0",O_RDWR) < 0) { + if (file = open("/dev/i2c-0", O_RDWR) < 0) { /* Some kind of error handling */ exit(1); } - if (ioctl(file,I2C_FUNCS,&funcs) < 0) { + if (ioctl(file, I2C_FUNCS, &funcs) < 0) { /* Some kind of error handling */ exit(1); } - if (! (funcs & I2C_FUNC_SMBUS_QUICK)) { + if (!(funcs & I2C_FUNC_SMBUS_QUICK)) { /* Oops, the needed functionality (SMBus write_quick function) is not available! */ exit(1); diff --git a/Documentation/i2c/smbus-protocol b/Documentation/i2c/smbus-protocol index 8a653c60d25..03f08fb491c 100644 --- a/Documentation/i2c/smbus-protocol +++ b/Documentation/i2c/smbus-protocol @@ -1,5 +1,6 @@ SMBus Protocol Summary ====================== + The following is a summary of the SMBus protocol. It applies to all revisions of the protocol (1.0, 1.1, and 2.0). Certain protocol features which are not supported by @@ -8,6 +9,7 @@ this package are briefly described at the end of this document. Some adapters understand only the SMBus (System Management Bus) protocol, which is a subset from the I2C protocol. Fortunately, many devices use only the same subset, which makes it possible to put them on an SMBus. + If you write a driver for some I2C device, please try to use the SMBus commands if at all possible (if the device uses only that subset of the I2C protocol). This makes it possible to use the device driver on both @@ -15,7 +17,12 @@ SMBus adapters and I2C adapters (the SMBus command set is automatically translated to I2C on I2C adapters, but plain I2C commands can not be handled at all on most pure SMBus adapters). -Below is a list of SMBus commands. +Below is a list of SMBus protocol operations, and the functions executing +them. Note that the names used in the SMBus protocol specifications usually +don't match these function names. For some of the operations which pass a +single data byte, the functions using SMBus protocol operation names execute +a different protocol operation entirely. + Key to symbols ============== @@ -35,17 +42,16 @@ Count (8 bits): A data byte containing the length of a block operation. [..]: Data sent by I2C device, as opposed to data sent by the host adapter. -SMBus Write Quick -================= +SMBus Quick Command: i2c_smbus_write_quick() +============================================= This sends a single bit to the device, at the place of the Rd/Wr bit. -There is no equivalent Read Quick command. A Addr Rd/Wr [A] P -SMBus Read Byte -=============== +SMBus Receive Byte: i2c_smbus_read_byte() +========================================== This reads a single byte from a device, without specifying a device register. Some devices are so simple that this interface is enough; for @@ -55,17 +61,17 @@ the previous SMBus command. S Addr Rd [A] [Data] NA P -SMBus Write Byte -================ +SMBus Send Byte: i2c_smbus_write_byte() +======================================== -This is the reverse of Read Byte: it sends a single byte to a device. -See Read Byte for more information. +This operation is the reverse of Receive Byte: it sends a single byte +to a device. See Receive Byte for more information. S Addr Wr [A] Data [A] P -SMBus Read Byte Data -==================== +SMBus Read Byte: i2c_smbus_read_byte_data() +============================================ This reads a single byte from a device, from a designated register. The register is specified through the Comm byte. @@ -73,30 +79,30 @@ The register is specified through the Comm byte. S Addr Wr [A] Comm [A] S Addr Rd [A] [Data] NA P -SMBus Read Word Data -==================== +SMBus Read Word: i2c_smbus_read_word_data() +============================================ -This command is very like Read Byte Data; again, data is read from a +This operation is very like Read Byte; again, data is read from a device, from a designated register that is specified through the Comm byte. But this time, the data is a complete word (16 bits). S Addr Wr [A] Comm [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P -SMBus Write Byte Data -===================== +SMBus Write Byte: i2c_smbus_write_byte_data() +============================================== This writes a single byte to a device, to a designated register. The register is specified through the Comm byte. This is the opposite of -the Read Byte Data command. +the Read Byte operation. S Addr Wr [A] Comm [A] Data [A] P -SMBus Write Word Data -===================== +SMBus Write Word: i2c_smbus_write_word_data() +============================================== -This is the opposite operation of the Read Word Data command. 16 bits +This is the opposite of the Read Word operation. 16 bits of data is written to a device, to the designated register that is specified through the Comm byte. @@ -113,8 +119,8 @@ S Addr Wr [A] Comm [A] DataLow [A] DataHigh [A] S Addr Rd [A] [DataLow] A [DataHigh] NA P -SMBus Block Read -================ +SMBus Block Read: i2c_smbus_read_block_data() +============================================== This command reads a block of up to 32 bytes from a device, from a designated register that is specified through the Comm byte. The amount @@ -124,8 +130,8 @@ S Addr Wr [A] Comm [A] S Addr Rd [A] [Count] A [Data] A [Data] A ... A [Data] NA P -SMBus Block Write -================= +SMBus Block Write: i2c_smbus_write_block_data() +================================================ The opposite of the Block Read command, this writes up to 32 bytes to a device, to a designated register that is specified through the @@ -134,10 +140,11 @@ Comm byte. The amount of data is specified in the Count byte. S Addr Wr [A] Comm [A] Count [A] Data [A] Data [A] ... [A] Data [A] P -SMBus Block Process Call -======================== +SMBus Block Write - Block Read Process Call +=========================================== -SMBus Block Process Call was introduced in Revision 2.0 of the specification. +SMBus Block Write - Block Read Process Call was introduced in +Revision 2.0 of the specification. This command selects a device register (through the Comm byte), sends 1 to 31 bytes of data to it, and reads 1 to 31 bytes of data in return. @@ -159,13 +166,16 @@ alerting device's address. Packet Error Checking (PEC) =========================== + Packet Error Checking was introduced in Revision 1.1 of the specification. -PEC adds a CRC-8 error-checking byte to all transfers. +PEC adds a CRC-8 error-checking byte to transfers using it, immediately +before the terminating STOP. Address Resolution Protocol (ARP) ================================= + The Address Resolution Protocol was introduced in Revision 2.0 of the specification. It is a higher-layer protocol which uses the messages above. @@ -177,14 +187,17 @@ require PEC checksums. I2C Block Transactions ====================== + The following I2C block transactions are supported by the SMBus layer and are described here for completeness. +They are *NOT* defined by the SMBus specification. + I2C block transactions do not limit the number of bytes transferred but the SMBus layer places a limit of 32 bytes. -I2C Block Read -============== +I2C Block Read: i2c_smbus_read_i2c_block_data() +================================================ This command reads a block of bytes from a device, from a designated register that is specified through the Comm byte. @@ -203,8 +216,8 @@ S Addr Wr [A] Comm1 [A] Comm2 [A] S Addr Rd [A] [Data] A [Data] A ... A [Data] NA P -I2C Block Write -=============== +I2C Block Write: i2c_smbus_write_i2c_block_data() +================================================== The opposite of the Block Read command, this writes bytes to a device, to a designated register that is specified through the @@ -212,5 +225,3 @@ Comm byte. Note that command lengths of 0, 2, or more bytes are supported as they are indistinguishable from data. S Addr Wr [A] Comm [A] Data [A] Data [A] ... [A] Data [A] P - - diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index a3c35446e75..cdd5b934f43 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1094,9 +1094,6 @@ and is between 256 and 4096 characters. It is defined in the file mac5380= [HW,SCSI] Format: <can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags> - mac53c9x= [HW,SCSI] Format: - <num_esps>,<disconnect>,<nosync>,<can_queue>,<cmd_per_lun>,<sg_tablesize>,<hostid>,<use_tags> - machvec= [IA64] Force the use of a particular machine-vector (machvec) in a generic kernel. Example: machvec=hpzx1_swiotlb @@ -1525,6 +1522,8 @@ and is between 256 and 4096 characters. It is defined in the file This is normally done in pci_enable_device(), so this option is a temporary workaround for broken drivers that don't call it. + skip_isa_align [X86] do not align io start addr, so can + handle more pci cards firmware [ARM] Do not re-enumerate the bus but instead just use the configuration from the bootloader. This is currently used on diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt index e5a819a4f0c..f5b7127f54a 100644 --- a/Documentation/memory-barriers.txt +++ b/Documentation/memory-barriers.txt @@ -994,7 +994,17 @@ The Linux kernel has eight basic CPU memory barriers: DATA DEPENDENCY read_barrier_depends() smp_read_barrier_depends() -All CPU memory barriers unconditionally imply compiler barriers. +All memory barriers except the data dependency barriers imply a compiler +barrier. Data dependencies do not impose any additional compiler ordering. + +Aside: In the case of data dependencies, the compiler would be expected to +issue the loads in the correct order (eg. `a[b]` would have to load the value +of b before loading a[b]), however there is no guarantee in the C specification +that the compiler may not speculate the value of b (eg. is equal to 1) and load +a before b (eg. tmp = a[1]; if (b != 1) tmp = a[b]; ). There is also the +problem of a compiler reloading b after having loaded a[b], thus having a newer +copy of b than a[b]. A consensus has not yet been reached about these problems, +however the ACCESS_ONCE macro is a good place to start looking. SMP memory barriers are reduced to compiler barriers on uniprocessor compiled systems because it is assumed that a CPU will appear to be self-consistent, diff --git a/Documentation/s390/CommonIO b/Documentation/s390/CommonIO index 8fbc0a85287..bf0baa19ec2 100644 --- a/Documentation/s390/CommonIO +++ b/Documentation/s390/CommonIO @@ -8,17 +8,6 @@ Command line parameters Enable logging of debug information in case of ccw device timeouts. - -* cio_msg = yes | no - - Determines whether information on found devices and sensed device - characteristics should be shown during startup or when new devices are - found, i. e. messages of the types "Detected device 0.0.4711 on subchannel - 0.0.0042" and "SenseID: Device 0.0.4711 reports: ...". - - Default is off. - - * cio_ignore = {all} | {<device> | <range of devices>} | {!<device> | !<range of devices>} diff --git a/Documentation/scheduler/sched-design.txt b/Documentation/scheduler/sched-design.txt deleted file mode 100644 index 1605bf0cba8..00000000000 --- a/Documentation/scheduler/sched-design.txt +++ /dev/null @@ -1,165 +0,0 @@ - Goals, Design and Implementation of the - new ultra-scalable O(1) scheduler - - - This is an edited version of an email Ingo Molnar sent to - lkml on 4 Jan 2002. It describes the goals, design, and - implementation of Ingo's new ultra-scalable O(1) scheduler. - Last Updated: 18 April 2002. - - -Goal -==== - -The main goal of the new scheduler is to keep all the good things we know -and love about the current Linux scheduler: - - - good interactive performance even during high load: if the user - types or clicks then the system must react instantly and must execute - the user tasks smoothly, even during considerable background load. - - - good scheduling/wakeup performance with 1-2 runnable processes. - - - fairness: no process should stay without any timeslice for any - unreasonable amount of time. No process should get an unjustly high - amount of CPU time. - - - priorities: less important tasks can be started with lower priority, - more important tasks with higher priority. - - - SMP efficiency: no CPU should stay idle if there is work to do. - - - SMP affinity: processes which run on one CPU should stay affine to - that CPU. Processes should not bounce between CPUs too frequently. - - - plus additional scheduler features: RT scheduling, CPU binding. - -and the goal is also to add a few new things: - - - fully O(1) scheduling. Are you tired of the recalculation loop - blowing the L1 cache away every now and then? Do you think the goodness - loop is taking a bit too long to finish if there are lots of runnable - processes? This new scheduler takes no prisoners: wakeup(), schedule(), - the timer interrupt are all O(1) algorithms. There is no recalculation - loop. There is no goodness loop either. - - - 'perfect' SMP scalability. With the new scheduler there is no 'big' - runqueue_lock anymore - it's all per-CPU runqueues and locks - two - tasks on two separate CPUs can wake up, schedule and context-switch - completely in parallel, without any interlocking. All - scheduling-relevant data is structured for maximum scalability. - - - better SMP affinity. The old scheduler has a particular weakness that - causes the random bouncing of tasks between CPUs if/when higher - priority/interactive tasks, this was observed and reported by many - people. The reason is that the timeslice recalculation loop first needs - every currently running task to consume its timeslice. But when this - happens on eg. an 8-way system, then this property starves an - increasing number of CPUs from executing any process. Once the last - task that has a timeslice left has finished using up that timeslice, - the recalculation loop is triggered and other CPUs can start executing - tasks again - after having idled around for a number of timer ticks. - The more CPUs, the worse this effect. - - Furthermore, this same effect causes the bouncing effect as well: - whenever there is such a 'timeslice squeeze' of the global runqueue, - idle processors start executing tasks which are not affine to that CPU. - (because the affine tasks have finished off their timeslices already.) - - The new scheduler solves this problem by distributing timeslices on a - per-CPU basis, without having any global synchronization or - recalculation. - - - batch scheduling. A significant proportion of computing-intensive tasks - benefit from batch-scheduling, where timeslices are long and processes - are roundrobin scheduled. The new scheduler does such batch-scheduling - of the lowest priority tasks - so nice +19 jobs will get - 'batch-scheduled' automatically. With this scheduler, nice +19 jobs are - in essence SCHED_IDLE, from an interactiveness point of view. - - - handle extreme loads more smoothly, without breakdown and scheduling - storms. - - - O(1) RT scheduling. For those RT folks who are paranoid about the - O(nr_running) property of the goodness loop and the recalculation loop. - - - run fork()ed children before the parent. Andrea has pointed out the - advantages of this a few months ago, but patches for this feature - do not work with the old scheduler as well as they should, - because idle processes often steal the new child before the fork()ing - CPU gets to execute it. - - -Design -====== - -The core of the new scheduler contains the following mechanisms: - - - *two* priority-ordered 'priority arrays' per CPU. There is an 'active' - array and an 'expired' array. The active array contains all tasks that - are affine to this CPU and have timeslices left. The expired array - contains all tasks which have used up their timeslices - but this array - is kept sorted as well. The active and expired array is not accessed - directly, it's accessed through two pointers in the per-CPU runqueue - structure. If all active tasks are used up then we 'switch' the two - pointers and from now on the ready-to-go (former-) expired array is the - active array - and the empty active array serves as the new collector - for expired tasks. - - - there is a 64-bit bitmap cache for array indices. Finding the highest - priority task is thus a matter of two x86 BSFL bit-search instructions. - -the split-array solution enables us to have an arbitrary number of active -and expired tasks, and the recalculation of timeslices can be done -immediately when the timeslice expires. Because the arrays are always -access through the pointers in the runqueue, switching the two arrays can -be done very quickly. - -this is a hybride priority-list approach coupled with roundrobin -scheduling and the array-switch method of distributing timeslices. - - - there is a per-task 'load estimator'. - -one of the toughest things to get right is good interactive feel during -heavy system load. While playing with various scheduler variants i found -that the best interactive feel is achieved not by 'boosting' interactive -tasks, but by 'punishing' tasks that want to use more CPU time than there -is available. This method is also much easier to do in an O(1) fashion. - -to establish the actual 'load' the task contributes to the system, a -complex-looking but pretty accurate method is used: there is a 4-entry -'history' ringbuffer of the task's activities during the last 4 seconds. -This ringbuffer is operated without much overhead. The entries tell the -scheduler a pretty accurate load-history of the task: has it used up more -CPU time or less during the past N seconds. [the size '4' and the interval -of 4x 1 seconds was found by lots of experimentation - this part is -flexible and can be changed in both directions.] - -the penalty a task gets for generating more load than the CPU can handle -is a priority decrease - there is a maximum amount to this penalty -relative to their static priority, so even fully CPU-bound tasks will -observe each other's priorities, and will share the CPU accordingly. - -the SMP load-balancer can be extended/switched with additional parallel -computing and cache hierarchy concepts: NUMA scheduling, multi-core CPUs -can be supported easily by changing the load-balancer. Right now it's -tuned for my SMP systems. - -i skipped the prev->mm == next->mm advantage - no workload i know of shows -any sensitivity to this. It can be added back by sacrificing O(1) -schedule() [the current and one-lower priority list can be searched for a -that->mm == current->mm condition], but costs a fair number of cycles -during a number of important workloads, so i wanted to avoid this as much -as possible. - -- the SMP idle-task startup code was still racy and the new scheduler -triggered this. So i streamlined the idle-setup code a bit. We do not call -into schedule() before all processors have started up fully and all idle -threads are in place. - -- the patch also cleans up a number of aspects of sched.c - moves code -into other areas of the kernel where it's appropriate, and simplifies -certain code paths and data constructs. As a result, the new scheduler's -code is smaller than the old one. - - Ingo diff --git a/Documentation/video4linux/CARDLIST.cx23885 b/Documentation/video4linux/CARDLIST.cx23885 index 929b90c8387..191194ea1e2 100644 --- a/Documentation/video4linux/CARDLIST.cx23885 +++ b/Documentation/video4linux/CARDLIST.cx23885 @@ -5,6 +5,6 @@ 4 -> DViCO FusionHDTV5 Express [18ac:d500] 5 -> Hauppauge WinTV-HVR1500Q [0070:7790,0070:7797] 6 -> Hauppauge WinTV-HVR1500 [0070:7710,0070:7717] - 7 -> Hauppauge WinTV-HVR1200 [0070:71d1] + 7 -> Hauppauge WinTV-HVR1200 [0070:71d1,0070:71d3] 8 -> Hauppauge WinTV-HVR1700 [0070:8101] 9 -> Hauppauge WinTV-HVR1400 [0070:8010] diff --git a/Documentation/video4linux/CARDLIST.em28xx b/Documentation/video4linux/CARDLIST.em28xx index f40e09296f3..1d6a245c828 100644 --- a/Documentation/video4linux/CARDLIST.em28xx +++ b/Documentation/video4linux/CARDLIST.em28xx @@ -14,4 +14,4 @@ 13 -> Terratec Prodigy XS (em2880) [0ccd:0047] 14 -> Pixelview Prolink PlayTV USB 2.0 (em2820/em2840) 15 -> V-Gear PocketTV (em2800) - 16 -> Hauppauge WinTV HVR 950 (em2880) [2040:6513] + 16 -> Hauppauge WinTV HVR 950 (em2880) [2040:6513,2040:6517,2040:651b,2040:651f] |