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path: root/drivers/cpufreq/cpufreq.c
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2008-04-28[CPUFREQ] expose cpufreq coordination requirements regardless of ↵Darrick J. Wong
coordination mechanism Currently, affected_cpus shows which CPUs need to have their frequency coordinated in software. When hardware coordination is in use, the contents of this file appear the same as when no coordination is required. This can lead to some confusion among user-space programs, for example, that do not know that extra coordination is required to force a CPU core to a particular speed to control power consumption. To fix this, create a "related_cpus" attribute that always displays the coordination map regardless of whatever coordination strategy the cpufreq driver uses (sw or hw). If the cpufreq driver does not provide a value, fall back to policy->cpus. Signed-off-by: Darrick J. Wong <djwong@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dave Jones <davej@redhat.com>
2008-04-28[CPUFREQ] Warn when cpufreq_register_notifier called before pure initcallsCesar Eduardo Barros
If cpufreq_register_notifier is called before pure initcalls, init_cpufreq_transition_notifier_list will overwrite whatever it did, causing notifiers to be ignored. Print some noise to the kernel log if that happens. Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net> Signed-off-by: Dave Jones <davej@codemonkey.org.uk>
2008-04-28[CPUFREQ] Refactor locking in cpufreq_add_devDave Jones
Simplify this by moving the unlocking out of the error paths into the exit path. Signed-off-by: Dave Jones <davej@codemonkey.org.uk>
2008-04-28[CPUFREQ] more CodingStyleDave Jones
void * p -> void *p no space between function parameters removed excess whitespace Signed-off-by: Dave Jones <davej@codemonkey.org.uk>
2008-04-28[CPUFREQ] CodingStyleDave Jones
return is not a function. Signed-off-by: Dave Jones <davej@redhat.com>
2008-04-28[CPUFREQ] Slightly shorten the error paths of cpufreq_suspend/cpufreq_resumeDave Jones
Signed-off-by: Dave Jones <davej@redhat.com>
2008-03-05[CPUFREQ] fix section mismatch warningsSam Ravnborg
Fix the following warnings: WARNING: vmlinux.o(.text+0xfe6711): Section mismatch in reference from the function cpufreq_unregister_driver() to the variable .cpuinit.data:cpufreq_cpu_notifier WARNING: vmlinux.o(.text+0xfe68af): Section mismatch in reference from the function cpufreq_register_driver() to the variable .cpuinit.data:cpufreq_cpu_notifier WARNING: vmlinux.o(.exit.text+0xc4fa): Section mismatch in reference from the function cpufreq_stats_exit() to the variable .cpuinit.data:cpufreq_stat_cpu_notifier The warnings were casued by references to unregister_hotcpu_notifier() from normal functions or exit functions. This is flagged by modpost as a potential error because it does not know that for the non HOTPLUG_CPU scenario the unregister_hotcpu_notifier() is a nop. Silence the warning by replacing the __initdata annotation with a __refdata annotation. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Dave Jones <davej@codemonkey.org.uk>
2008-03-05[CPUFREQ] Fix missing cpufreq_cpu_put() call in ->storeDave Jones
refactor to use gotos instead of explicit exit paths Signed-off-by: Dave Jones <davej@redhat.com>
2008-03-05[CPUFREQ] Fix missing cpufreq_cpu_put() call in ->showDave Jones
refactor to use gotos instead of explicit exit paths Signed-off-by: Dave Jones <davej@redhat.com>
2008-02-21cpufreq: fix kobject reference count handlingBalaji Rao
The cpufreq core should not take an extra kobject reference count for no reason, and then refuse to release it. This has been reported as keeping machines from properly powering down all the way. Signed-off-by: Balaji Rao <balajirrao@gmail.com> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Yi Yang <yi.y.yang@intel.com> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Frans Pop <elendil@planet.nl> Cc: Yinghai Lu <yhlu.kernel@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-02-06[CPUFREQ] Eliminate cpufreq_userspace scaling_setspeed deadlockVenki Pallipadi
Eliminate cpufreq_userspace scaling_setspeed deadlock. Luming Yu recently uncovered yet another cpufreq related deadlock. One thread that continuously switches the governors and the other thread that repeatedly cats the contents of cpufreq directory causes both these threads to go into a deadlock. Detailed examination of the deadlock showed the exact flow before the deadlock as: Thread 1 Thread 2 ________ ________ cats files under /sys/devices/.../cpufreq/ Set governor to userspace Adds a new sysfs entry for scaling_setspeed cats files under /sys/devices/.../cpufreq/ Set governor to performance Holds cpufreq_rw_sem in write mode Sends a STOP notify to userspace governor cat /sys/devices/.../cpufreq/scaling_setspeed Gets a handle on the above sysfs entry with sysfs_get_active Blocks while trying to get cpufreq_rw_sem in read mode Remove a sysfs entry for scaling_setspeed Blocks on sysfs_deactivate while waiting for earlier get_active (on other thread) to drain At this point both threads go into deadlock and any other thread that tries to do anything with sysfs cpufreq will also block. There seems to be no easy way to avoid this deadlock as long as cpufreq_userspace adds/removes the sysfs entry under same kobject as cpufreq. Below patch moves scaling_setspeed to cpufreq.c, keeping it always and calling back the governor on read/write. This is the cleanest fix I could think of, even though adding two callbacks in governor structure just for this seems unnecessary. Note that the change makes scaling_setspeed under /sys/.../cpufreq permanent and returns <unsupported> when governor is not userspace. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
2008-02-06[CPUFREQ] drivers/cpufreq: Add missing "space"Joe Perches
Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Dave Jones <davej@redhat.com>
2008-01-30cpufreq: fix obvious condition statement errorYi Yang
The function __cpufreq_set_policy in file drivers/cpufreq/cpufreq.c has a very obvious error: if (policy->min > data->min && policy->min > policy->max) { ret = -EINVAL; goto error_out; } This condtion statement is wrong because it returns -EINVAL only if policy->min is greater than policy->max (in this case, "policy->min > data->min" is true for ever.). In fact, it should return -EINVAL as well if policy->max is less than data->min. The correct condition should be: if (policy->min > data->max || policy->max < data->min) { The following test result testifies the above conclusion: Before applying this patch: [root@yangyi-dev /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies 2394000 1596000 [root@yangyi-dev /]# echo 1596000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq [root@yangyi-dev /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq 1596000 [root@yangyi-dev /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq 1596000 [root@yangyi-dev /]# echo "2000000" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq -bash: echo: write error: Invalid argument [root@yangyi-dev /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq 1596000 [root@yangyi-dev /]# echo "0" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq [root@yangyi-dev /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq 1596000 [root@yangyi-dev /]# echo "1595000" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq [root@yangyi-dev /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq 1596000 [root@yangyi-dev /]# After applying this patch: [root@yangyi-dev /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies 2394000 1596000 [root@yangyi-dev /]# echo 1596000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq [root@yangyi-dev /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq 1596000 [root@yangyi-dev /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq 1596000 [root@localhost /]# echo "2000000" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq -bash: echo: write error: Invalid argument [root@localhost /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq 1596000 [root@localhost /]# echo "0" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq -bash: echo: write error: Invalid argument [root@localhost /]# echo "1595000" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq -bash: echo: write error: Invalid argument [root@localhost /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq 1596000 [root@localhost /]# echo "1596000" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq [root@localhost /]# echo "2394000" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq [root@localhost /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq 2394000 [root@localhost /] Signed-off-by: Yi Yang <yi.y.yang@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-01-24Kobject: convert drivers/* from kobject_unregister() to kobject_put()Greg Kroah-Hartman
There is no need for kobject_unregister() anymore, thanks to Kay's kobject cleanup changes, so replace all instances of it with kobject_put(). Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-01-24Kobject: change drivers/cpufreq/cpufreq.c to use kobject_init_and_addGreg Kroah-Hartman
Stop using kobject_register, as this way we can control the sending of the uevent properly, after everything is properly initialized. Cc: Dominik Brodowski <linux@brodo.de> Cc: Ashok Raj <ashok.raj@intel.com> Cc: Jacob Shin <jacob.shin@amd.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-12-17cpufreq: fix missing unlocks in cpufreq_add_dev error paths.Dave Jones
Ingo hit some BUG_ONs that were probably caused by these missing unlocks causing an unbalance. He couldn't reproduce the bug reliably, so it's unknown that it's definitly fixing the problem he hit, but it's a fairly good chance, and this fixes an obvious bug. [ Dave: "Ingo followed up that he hit some lockdep related output with this applied, so it may not be right. I'll look at it after xmas if no-one has it figured out before then." Akpm: "It looks pretty correct to me though." ] Signed-off-by: Dave Jones <davej@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-12Merge master.kernel.org:/pub/scm/linux/kernel/git/gregkh/driver-2.6Linus Torvalds
* master.kernel.org:/pub/scm/linux/kernel/git/gregkh/driver-2.6: (75 commits) PM: merge device power-management source files sysfs: add copyrights kobject: update the copyrights kset: add some kerneldoc to help describe what these strange things are Driver core: rename ktype_edd and ktype_efivar Driver core: rename ktype_driver Driver core: rename ktype_device Driver core: rename ktype_class driver core: remove subsystem_init() sysfs: move sysfs file poll implementation to sysfs_open_dirent sysfs: implement sysfs_open_dirent sysfs: move sysfs_dirent->s_children into sysfs_dirent->s_dir sysfs: make sysfs_root a regular directory dirent sysfs: open code sysfs_attach_dentry() sysfs: make s_elem an anonymous union sysfs: make bin attr open get active reference of parent too sysfs: kill unnecessary NULL pointer check in sysfs_release() sysfs: kill unnecessary sysfs_get() in open paths sysfs: reposition sysfs_dirent->s_mode. sysfs: kill sysfs_update_file() ...
2007-10-12kobjects: fix up improper use of the kobject name fieldGreg Kroah-Hartman
A number of different drivers incorrect access the kobject name field directly. This is not correct as the name might not be in the array. Use the proper accessor function instead.
2007-10-09[CPUFREQ] Don't take semaphore in cpufreq_quick_get()Andi Kleen
I don't see any reason to take an expensive lock in cpufreq_quick_get() Reading policy->cur is a single atomic operation and after the lock is dropped again the state could change any time anyways. So don't take the lock in the first place. This also makes this function interrupt safe which is useful for some code of mine. Signed-off-by: Andi Kleen <ak@suse.de> Cc: "Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
2007-10-04[CPUFREQ] mark hotplug notifier callback as __cpuinitSatyam Sharma
The notifier_block is already __cpuinitdata, thereby allowing us to safely mark the callback function as __cpuinit also, thereby saving space when HOTPLUG_CPU=n. Signed-off-by: Satyam Sharma <satyam@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dave Jones <davej@redhat.com>
2007-10-04[CPUFREQ] Only check for transition latency on problematic governors ↵Thomas Renninger
(kconfig fix) Cc: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dave Jones <davej@redhat.com>
2007-10-04[CPUFREQ] allow ondemand and conservative cpufreq governors to be used as ↵Thomas Renninger
default Depending on the transition latency of the HW for cpufreq switches, the ondemand or conservative governor cannot be used with certain cpufreq drivers. Still the ondemand should be the default governor on a wide range of systems. This patch allows this and lets the governor fallback to the performance governor at cpufreq driver load time, if the driver does not support fast enough frequency switching. Main benefit is that on e.g. installation or other systems without userspace support a working dynamic cpufreq support can be achieved on most systems by simply loading the cpufreq driver. This is especially essential for recent x86(_64) laptop hardware which may rely on working dynamic cpufreq OS support. Signed-off-by: Thomas Renninger <trenn@suse.de> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Bryan Wu <bryan.wu@analog.com> Cc: Andi Kleen <ak@suse.de> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dave Jones <davej@redhat.com>
2007-10-04[CPUFREQ] move policy's governor initialisation out of low-level drivers ↵Thomas Renninger
into cpufreq core Signed-off-by: Thomas Renninger <trenn@suse.de> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Bryan Wu <bryan.wu@analog.com> Cc: Andi Kleen <ak@suse.de> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dave Jones <davej@redhat.com>
2007-07-13[CPUFREQ] Restore previously used governor on a hot-replugged CPUThomas Renninger
Negative side effect: needs NR_CPUs pointer array of memory in CONFIG_HOTPLUG_CPU case. Still needs userspace track keeping and rewriting of governors if governors change while a CPU is not active (always the governor at CPU remove time is restored). Move of policy->user_policy.governor assignment is just a minor cleanup. http://bugzilla.kernel.org/show_bug.cgi?id=8671 Signed-off-by: Thomas Renninger <trenn@suse.de> Signed-off-by: Mattia Dongili <malattia@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dave Jones <davej@redhat.com>
2007-07-13[CPUFREQ] bugfix cpufreq in combination with performance governorPeter Oruba
There is a frequency scaling issue that I encountered with the performance governor in combination with CPU hotplug. In cpufreq.c CPU frequency is reduced to its minimum before the CPU gets unregistered and set offline. Does that have a particular reason? Since the (k8-)governor does not monitor CPU frequency that setting also applies then to the remaining CPU as well and lets the system run on the lowest frequency although performance is chose as the policy. Signed-off-by: Peter Oruba <peter.oruba@amd.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dave Jones <davej@redhat.com>
2007-06-21[CPUFREQ] Fix sysfs_create_file return value handlingTobias Klauser
Commit 0a4b2ccc555fa2ca6873d60219047104e4805d45 in cpufreq.git eliminates the build warnings but does not pass on the error code of sysfs_create_file to the function calling cpufreq_add_dev. Instead some previous value of ret would be returned. Signed-off-by: Tobias Klauser <tklauser@distanz.ch> Signed-off-by: Dave Jones <davej@redhat.com>
2007-05-29[CPUFREQ] check return value of sysfs_create_fileThomas Renninger
Eliminate build warning (sysfs_create_file return value must be checked) Signed-off-by: Thomas Renninger <trenn@suse.de> Signed-off-by: Dave Jones <davej@redhat.com>
2007-05-09Add suspend-related notifications for CPU hotplugRafael J. Wysocki
Since nonboot CPUs are now disabled after tasks and devices have been frozen and the CPU hotplug infrastructure is used for this purpose, we need special CPU hotplug notifications that will help the CPU-hotplug-aware subsystems distinguish normal CPU hotplug events from CPU hotplug events related to a system-wide suspend or resume operation in progress. This patch introduces such notifications and causes them to be used during suspend and resume transitions. It also changes all of the CPU-hotplug-aware subsystems to take these notifications into consideration (for now they are handled in the same way as the corresponding "normal" ones). [oleg@tv-sign.ru: cleanups] Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-04-26[CPUFREQ] Remove deprecated /proc/acpi/processor/performance write supportThomas Renninger
Remove deprecated /proc/acpi/processor/performance write support Writing to /proc/acpi/processor/xy/performance interferes with sysfs cpufreq interface. Also removes buggy cpufreq_set_policy exported symbol. Signed-off-by: Thomas Renninger <trenn@suse.de> Signed-off-by: Dave Jones <davej@redhat.com>
2007-04-26[CPUFREQ] Fix limited cpufreq when booted on batteryThomas Renninger
References: https://bugzilla.novell.com/show_bug.cgi?id=231107 https://bugzilla.novell.com/show_bug.cgi?id=264077 Fix limited cpufreq when booted on battery If booted on battery: cpufreq_set_policy (evil) is invoked which calls verify_within_limits. max_freq gets lowered and therefore users_policy.max, which is used to restore higher freqs via update_policy later is set to the already limited frequency -> you can never go up again, even BIOS allows higher freqs later. Signed-off-by: Thomas Renninger <trenn@suse.de> Signed-off-by: Dave Jones <davej@redhat.com>
2007-03-27[PATCH] Fix maxcpus=1 trigerring BUG() in cpufreqVenki Pallipadi
Ingo reported it on lkml in the thread "2.6.21-rc5: maxcpus=1 crash in cpufreq: kernel BUG at drivers/cpufreq/cpufreq.c:82!" This check added to remove_dev is symmetric to one in add_dev and handles callbacks for offline cpus cleanly. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-26Revert "[CPUFREQ] constify cpufreq_driver where possible."Linus Torvalds
This reverts commit aeeddc1435c37fa3fc844f31d39c185b08de4158, which was half-baked and broken. It just resulted in compile errors, since cpufreq_register_driver() still changes the 'driver_data' by setting bits in the flags field. So claiming it is 'const' _really_ doesn't work. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-22[CPUFREQ] constify cpufreq_driver where possible.Dave Jones
Not all cases are possible due to ->flags being set at runtime on some drivers. Signed-off-by: Dave Jones <davej@redhat.com>
2007-02-10[CPUFREQ] Rewrite lock in cpufreq to eliminate cpufreq/hotplug related issuesVenkatesh Pallipadi
Yet another attempt to resolve cpufreq and hotplug locking issues. Patchset has 3 patches: * Rewrite the lock infrastructure of cpufreq using a per cpu rwsem. * Minor restructuring of work callback in ondemand driver. * Use the new cpufreq rwsem infrastructure in ondemand work. This patch: Convert policy->lock to rwsem and move it to per_cpu area. This rwsem will protect against both changing/accessing policy related parameters and CPU hot plug/unplug. [malattia@linux.it: fix oops in kref_put()] Cc: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Cc: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Mattia Dongili <malattia@linux.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dave Jones <davej@redhat.com>
2007-02-10[CPUFREQ] Remove hotplug cpu crapDave Jones
The hotplug CPU locking in cpufreq is horrendous. No-one seems to care enough to fix it, so just remove it so that the 99.9% of the real world users of this code can use cpufreq without being bothered by warnings. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dave Jones <davej@redhat.com>
2007-01-29[CPUFREQ] check sysfs_create_link return valueAhmed S. Darwish
Trivial patch to check sysfs_create_link return values. Fail gracefully if needed. Signed-off-by: Ahmed Darwish <darwish.07@gmail.com> Signed-off-by: Dave Jones <davej@redhat.com>
2006-12-13[CPUFREQ] fixes typo in cpufreq.cDhaval Giani
This patch fixes a typo in cpufreq.c From: Dhaval Giani <dhaval.giani@gmail.com> Signed-off-by: Dave Jones <davej@redhat.com>
2006-12-12Merge ../linusDave Jones
Conflicts: drivers/cpufreq/cpufreq.c
2006-12-07[PATCH] hotplug CPU: clean up hotcpu_notifier() useIngo Molnar
There was lots of #ifdef noise in the kernel due to hotcpu_notifier(fn, prio) not correctly marking 'fn' as used in the !HOTPLUG_CPU case, and thus generating compiler warnings of unused symbols, hence forcing people to add #ifdefs. the compiler can skip truly unused functions just fine: text data bss dec hex filename 1624412 728710 3674856 6027978 5bfaca vmlinux.before 1624412 728710 3674856 6027978 5bfaca vmlinux.after [akpm@osdl.org: topology.c fix] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-11-22WorkStruct: Pass the work_struct pointer instead of context dataDavid Howells
Pass the work_struct pointer to the work function rather than context data. The work function can use container_of() to work out the data. For the cases where the container of the work_struct may go away the moment the pending bit is cleared, it is made possible to defer the release of the structure by deferring the clearing of the pending bit. To make this work, an extra flag is introduced into the management side of the work_struct. This governs auto-release of the structure upon execution. Ordinarily, the work queue executor would release the work_struct for further scheduling or deallocation by clearing the pending bit prior to jumping to the work function. This means that, unless the driver makes some guarantee itself that the work_struct won't go away, the work function may not access anything else in the work_struct or its container lest they be deallocated.. This is a problem if the auxiliary data is taken away (as done by the last patch). However, if the pending bit is *not* cleared before jumping to the work function, then the work function *may* access the work_struct and its container with no problems. But then the work function must itself release the work_struct by calling work_release(). In most cases, automatic release is fine, so this is the default. Special initiators exist for the non-auto-release case (ending in _NAR). Signed-Off-By: David Howells <dhowells@redhat.com>
2006-11-20Add "pure_initcall" for static variable initializationLinus Torvalds
This is a quick hack to overcome the fact that SRCU currently does not allow static initializers, and we need to sometimes initialize those things before any other initializers (even "core" ones) can do so. Currently we don't allow this at all for modules, and the only user that needs is right now is cpufreq. As reported by Thomas Gleixner: "Commit b4dfdbb3c707474a2254c5b4d7e62be31a4b7da9 ("[PATCH] cpufreq: make the transition_notifier chain use SRCU breaks cpu frequency notification users, which register the callback > on core_init level." Cc: Thomas Gleixner <tglx@timesys.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Andrew Morton <akpm@osdl.org>, Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-11-06[CPUFREQ] Fix coding style issues in cpufreq.Gautham R Shenoy
Clean up cpufreq subsystem to fix coding style issues and to improve the readability. Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Dave Jones <davej@redhat.com>
2006-10-15[CPUFREQ][8/8] acpi-cpufreq: Add support for freq feedback from hardwareVenkatesh Pallipadi
Enable ondemand governor and acpi-cpufreq to use IA32_APERF and IA32_MPERF MSR to get active frequency feedback for the last sampling interval. This will make ondemand take right frequency decisions when hardware coordination of frequency is going on. Without APERF/MPERF, ondemand can take wrong decision at times due to underlying hardware coordination or TM2. Example: * CPU 0 and CPU 1 are hardware cooridnated. * CPU 1 running at highest frequency. * CPU 0 was running at highest freq. Now ondemand reduces it to some intermediate frequency based on utilization. * Due to underlying hardware coordination with other CPU 1, CPU 0 continues to run at highest frequency (as long as other CPU is at highest). * When ondemand samples CPU 0 again next time, without actual frequency feedback from APERF/MPERF, it will think that previous frequency change was successful and can go to wrong target frequency. This is because it thinks that utilization it has got this sampling interval is when running at intermediate frequency, rather than actual highest frequency. More information about IA32_APERF IA32_MPERF MSR: Refer to IA-32 Intel® Architecture Software Developer's Manual at http://developer.intel.com Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
2006-10-04[PATCH] cpufreq: make the transition_notifier chain use SRCUAlan Stern
This patch (as762) changes the cpufreq_transition_notifier_list from a blocking_notifier_head to an srcu_notifier_head. This will prevent errors caused attempting to call down_read() to access the notifier chain at a time when interrupts must remain disabled, during system suspend. It's not clear to me whether this is really necessary; perhaps the chain could be made into an atomic_notifier. However a couple of the callout routines do use blocking operations, so this approach seems safer. The head of the notifier chain needs to be initialized before use; this is done by an __init routine at core_initcall time. If this turns out not to be a good choice, it can easily be changed. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Cc: "Paul E. McKenney" <paulmck@us.ibm.com> Cc: Jesse Brandeburg <jesse.brandeburg@gmail.com> Cc: Dave Jones <davej@codemonkey.org.uk> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-26[CPUFREQ] Fix cut-n-paste bug in suspend printkDave Jones
Signed-off-by: Dave Jones <davej@redhat.com>
2006-08-11[CPUFREQ] Fix typo.Dave Jones
Signed-off-by: Dave Jones <davej@redhat.com>
2006-07-31[CPUFREQ] [2/2] demand load governor modules.Jeremy Fitzhardinge
Demand-load cpufreq governor modules if needed. Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Dave Jones <davej@redhat.com>
2006-07-31[CPUFREQ] [1/2] add __find_governor helper and clean up some error handling.Jeremy Fitzhardinge
Adds a __find_governor() helper function to look up a governor by name. Also restructures some error handling to conform to the "single-exit" model which is generally preferred for kernel code. Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Dave Jones <davej@redhat.com>
2006-07-31[CPUFREQ] return error when failing to set minfreqMattia Dongili
I just stumbled on this bug/feature, this is how to reproduce it: # echo 450000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq # echo 450000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq # echo powersave > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor # cpufreq-info -p 450000 450000 powersave # echo 1800000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq ; echo $? 0 # cpufreq-info -p 450000 450000 powersave Here it is. The kernel refuses to set a min_freq higher than the max_freq but it allows a max_freq lower than min_freq (lowering min_freq also). This behaviour is pretty straightforward (but undocumented) and it doesn't return an error altough failing to accomplish the requested action (set min_freq). The problem (IMO) is basically that userspace is not allowed to set a full policy atomically while the kernel always does that thus it must enforce an ordering on operations. The attached patch returns -EINVAL if trying to increase frequencies starting from scaling_min_freq and documents the correct ordering of writes. Signed-off-by: Mattia Dongili <malattia@linux.it> Signed-off-by: Dominik Brodowski <linux at dominikbrodowski.net> Signed-off-by: Dave Jones <davej@redhat.com> --
2006-07-26[PATCH] Reorganize the cpufreq cpu hotplug locking to not be totally bizareArjan van de Ven
The patch below moves the cpu hotplugging higher up in the cpufreq layering; this is needed to avoid recursive taking of the cpu hotplug lock and to otherwise detangle the mess. The new rules are: 1. you must do lock_cpu_hotplug() around the following functions: __cpufreq_driver_target __cpufreq_governor (for CPUFREQ_GOV_LIMITS operation only) __cpufreq_set_policy 2. governer methods (.governer) must NOT take the lock_cpu_hotplug() lock in any way; they are called with the lock taken already 3. if your governer spawns a thread that does things, like calling __cpufreq_driver_target, your thread must honor rule #1. 4. the policy lock and other cpufreq internal locks nest within the lock_cpu_hotplug() lock. I'm not entirely happy about how the __cpufreq_governor rule ended up (conditional locking rule depending on the argument) but basically all callers pass this as a constant so it's not too horrible. The patch also removes the cpufreq_governor() function since during the locking audit it turned out to be entirely unused (so no need to fix it) The patch works on my testbox, but it could use more testing (otoh... it can't be much worse than the current code) Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>