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* workqueue, freezer: unify spelling of 'freeze' + 'able' to 'freezable'Tejun Heo2011-02-161-3/+3
| | | | | | | | | | | | | | | | | There are two spellings in use for 'freeze' + 'able' - 'freezable' and 'freezeable'. The former is the more prominent one. The latter is mostly used by workqueue and in a few other odd places. Unify the spelling to 'freezable'. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Acked-by: Dmitry Torokhov <dtor@mail.ru> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Alex Dubov <oakad@yahoo.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Steven Whitehouse <swhiteho@redhat.com>
* PM / Wakeup: Replace pm_check_wakeup_events() with pm_wakeup_pending()Rafael J. Wysocki2010-12-241-1/+1
| | | | | | | | | To avoid confusion with the meaning and return value of pm_check_wakeup_events() replace it with pm_wakeup_pending() that will work the other way around (ie. return true when system-wide power transition should be aborted). Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* Freezer: Fix a race during freezing of TASK_STOPPED tasksTejun Heo2010-12-241-0/+6
| | | | | | | | | | | | | | | | | | After calling freeze_task(), try_to_freeze_tasks() see whether the task is stopped or traced and if so, considers it to be frozen; however, nothing guarantees that either the task being frozen sees TIF_FREEZE or the freezer sees TASK_STOPPED -> TASK_RUNNING transition. The task being frozen may wake up and not see TIF_FREEZE while the freezer fails to notice the transition and believes the task is still stopped. This patch fixes the race by making freeze_task() always go through fake_signal_wake_up() for applicable tasks. The function goes through the target task's scheduler lock and thus guarantees that either the target sees TIF_FREEZE or try_to_freeze_task() sees TASK_RUNNING. Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM: Allow wakeup events to abort freezing of tasksRafael J. Wysocki2010-10-171-2/+9
| | | | | | | | | | | | If there is a wakeup event during the freezing of tasks, suspend or hibernation will fail anyway. Since try_to_freeze_tasks() can take up to 20 seconds to complete or fail, aborting it as soon as a wakeup event is detected improves the worst case wakeup latency. Based on a patch from Arve Hjønnevåg. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz>
* workqueue: reimplement workqueue freeze using max_activeTejun Heo2010-06-291-2/+19
| | | | | | | | | | | | | | | | | | | | | Currently, workqueue freezing is implemented by marking the worker freezeable and calling try_to_freeze() from dispatch loop. Reimplement it using cwq->limit so that the workqueue is frozen instead of the worker. * workqueue_struct->saved_max_active is added which stores the specified max_active on initialization. * On freeze, all cwq->max_active's are quenched to zero. Freezing is complete when nr_active on all cwqs reach zero. * On thaw, all cwq->max_active's are restored to wq->saved_max_active and the worklist is repopulated. This new implementation allows having single shared pool of workers per cpu. Signed-off-by: Tejun Heo <tj@kernel.org>
* Freezer: Fix buggy resume test for tasks frozen with cgroup freezerMatt Helsley2010-03-261-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the cgroup freezer is used to freeze tasks we do not want to thaw those tasks during resume. Currently we test the cgroup freezer state of the resuming tasks to see if the cgroup is FROZEN. If so then we don't thaw the task. However, the FREEZING state also indicates that the task should remain frozen. This also avoids a problem pointed out by Oren Ladaan: the freezer state transition from FREEZING to FROZEN is updated lazily when userspace reads or writes the freezer.state file in the cgroup filesystem. This means that resume will thaw tasks in cgroups which should be in the FROZEN state if there is no read/write of the freezer.state file to trigger this transition before suspend. NOTE: Another "simple" solution would be to always update the cgroup freezer state during resume. However it's a bad choice for several reasons: Updating the cgroup freezer state is somewhat expensive because it requires walking all the tasks in the cgroup and checking if they are each frozen. Worse, this could easily make resume run in N^2 time where N is the number of tasks in the cgroup. Finally, updating the freezer state from this code path requires trickier locking because of the way locks must be ordered. Instead of updating the freezer state we rely on the fact that lazy updates only manage the transition from FREEZING to FROZEN. We know that a cgroup with the FREEZING state may actually be FROZEN so test for that state too. This makes sense in the resume path even for partially-frozen cgroups -- those that really are FREEZING but not FROZEN. Reported-by: Oren Ladaan <orenl@cs.columbia.edu> Signed-off-by: Matt Helsley <matthltc@us.ibm.com> Cc: stable@kernel.org Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* Freezer: Only show the state of tasks refusing to freezeXiaotian Feng2010-03-261-2/+1
| | | | | | | | | | | show_state will dump all tasks state, so if freezer failed to freeze any task, kernel will dump all tasks state and flood the dmesg log. This patch makes freezer only show state of tasks refusing to freeze. Signed-off-by: Xiaotian Feng <dfeng@redhat.com> Acked-by: Pavel Machek <pavel@ucw.cz> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* PM / freezer: Don't get over-anxious while waitingTejun Heo2009-10-281-4/+10
| | | | | | | | | | | | Freezing isn't exactly the most latency sensitive operation and there's no reason to burn cpu cycles and power waiting for it to complete. msleep(10) instead of yield(). This should improve reliability of emergency hibernation. [rjw: Modified the comment next to the msleep(10).] Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* oom: move oom_killer_enable()/oom_killer_disable to where they belongAlexey Dobriyan2009-09-221-0/+1
| | | | | | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: David Rientjes <rientjes@google.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm, PM/Freezer: Disable OOM killer when tasks are frozenRafael J. Wysocki2009-06-171-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, the following scenario appears to be possible in theory: * Tasks are frozen for hibernation or suspend. * Free pages are almost exhausted. * Certain piece of code in the suspend code path attempts to allocate some memory using GFP_KERNEL and allocation order less than or equal to PAGE_ALLOC_COSTLY_ORDER. * __alloc_pages_internal() cannot find a free page so it invokes the OOM killer. * The OOM killer attempts to kill a task, but the task is frozen, so it doesn't die immediately. * __alloc_pages_internal() jumps to 'restart', unsuccessfully tries to find a free page and invokes the OOM killer. * No progress can be made. Although it is now hard to trigger during hibernation due to the memory shrinking carried out by the hibernation code, it is theoretically possible to trigger during suspend after the memory shrinking has been removed from that code path. Moreover, since memory allocations are going to be used for the hibernation memory shrinking, it will be even more likely to happen during hibernation. To prevent it from happening, introduce the oom_killer_disabled switch that will cause __alloc_pages_internal() to fail in the situations in which the OOM killer would have been called and make the freezer set this switch after tasks have been successfully frozen. [akpm@linux-foundation.org: be nicer to the namespace] Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Fengguang Wu <fengguang.wu@gmail.com> Cc: David Rientjes <rientjes@google.com> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* container freezer: skip frozen cgroups during power management resumeMatt Helsley2008-10-201-0/+3
| | | | | | | | | | | | | | | | When a system is resumed after a suspend, it will also unfreeze frozen cgroups. This patchs modifies the resume sequence to skip the tasks which are part of a frozen control group. Signed-off-by: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Matt Helsley <matthltc@us.ibm.com> Acked-by: Serge E. Hallyn <serue@us.ibm.com> Tested-by: Matt Helsley <matthltc@us.ibm.com> Acked-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* container freezer: make refrigerator always availableMatt Helsley2008-10-201-116/+0
| | | | | | | | | | | | | | | | | Now that the TIF_FREEZE flag is available in all architectures, extract the refrigerator() and freeze_task() from kernel/power/process.c and make it available to all. The refrigerator() can now be used in a control group subsystem implementing a control group freezer. Signed-off-by: Cedric Le Goater <clg@fr.ibm.com> Signed-off-by: Matt Helsley <matthltc@us.ibm.com> Acked-by: Serge E. Hallyn <serue@us.ibm.com> Tested-by: Matt Helsley <matthltc@us.ibm.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pm: fix try_to_freeze_tasks()'s use of do_div()David Howells2008-07-241-1/+1
| | | | | | | | | | | | | | | | | Fix try_to_freeze_tasks()'s use of do_div() on an s64 by making elapsed_csecs64 a u64 instead and dividing that. Possibly this should be guarded lest the interval calculation turn up negative, but the possible negativity of the result of the division is cast away anyway. This was introduced by patch 438e2ce68dfd4af4cfcec2f873564fb921db4bb5. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Freezer: Introduce PF_FREEZER_NOSIGRafael J. Wysocki2008-07-161-55/+42
| | | | | | | | | | | | | | | | | | | | | The freezer currently attempts to distinguish kernel threads from user space tasks by checking if their mm pointer is unset and it does not send fake signals to kernel threads. However, there are kernel threads, mostly related to networking, that behave like user space tasks and may want to be sent a fake signal to be frozen. Introduce the new process flag PF_FREEZER_NOSIG that will be set by default for all kernel threads and make the freezer only send fake signals to the tasks having PF_FREEZER_NOSIG unset. Provide the set_freezable_with_signal() function to be called by the kernel threads that want to be sent a fake signal for freezing. This patch should not change the freezer's observable behavior. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Andi Kleen <ak@linux.intel.com> Acked-by: Pavel Machek <pavel@suse.cz> Signed-off-by: Len Brown <len.brown@intel.com>
* freezer vs stopped or tracedRoland McGrath2008-03-041-17/+12
| | | | | | | | | | | | | | | | | | | | | | | | This changes the "freezer" code used by suspend/hibernate in its treatment of tasks in TASK_STOPPED (job control stop) and TASK_TRACED (ptrace) states. As I understand it, the intent of the "freezer" is to hold all tasks from doing anything significant. For this purpose, TASK_STOPPED and TASK_TRACED are "frozen enough". It's possible the tasks might resume from ptrace calls (if the tracer were unfrozen) or from signals (including ones that could come via timer interrupts, etc). But this doesn't matter as long as they quickly block again while "freezing" is in effect. Some minor adjustments to the signal.c code make sure that try_to_freeze() very shortly follows all wakeups from both kinds of stop. This lets the freezer code safely leave stopped tasks unmolested. Changing this fixes the longstanding bug of seeing after resuming from suspend/hibernate your shell report "[1] Stopped" and the like for all your jobs stopped by ^Z et al, as if you had freshly fg'd and ^Z'd them. It also removes from the freezer the arcane special case treatment for ptrace'd tasks, which relied on intimate knowledge of ptrace internals. Signed-off-by: Roland McGrath <roland@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* power: Use task_is_*Matthew Wilcox2007-12-061-3/+3
| | | | Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
* freezer: measure freezing timeRafael J. Wysocki2007-10-181-3/+15
| | | | | | | | | Measure the time of the freezing of tasks, even if it doesn't fail. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* freezer: be more verboseRafael J. Wysocki2007-10-181-6/+9
| | | | | | | | | | | Increase the freezer's verbosity a bit, so that it's easier to read problem reports related to it. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Nigel Cunningham <nigel@nigel.suspend2.net> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* freezer: do not send signals to kernel threadsRafael J. Wysocki2007-10-181-33/+74
| | | | | | | | | | | | | | | | | | The freezer should not send signals to kernel threads, since that may lead to subtle problems. In particular, commit b74d0deb968e1f85942f17080eace015ce3c332c has changed recalc_sigpending_tsk() so that it doesn't clear TIF_SIGPENDING. For this reason, if the freezer continues to send fake signals to kernel threads and the freezing of kernel threads fails, some of them may be running with TIF_SIGPENDING set forever. Accordingly, recalc_sigpending_tsk() shouldn't set the task's TIF_SIGPENDING flag if TIF_FREEZE is set. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Nigel Cunningham <nigel@nigel.suspend2.net> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* freezer: do not sync filesystems from freeze_processesRafael J. Wysocki2007-10-181-1/+0
| | | | | | | | | | | | | | | | | The syncing of filesystems from within the freezer is generally not needed. Also, if there's an ext3 filesystem loopback-mounted from a FUSE one, the syncing results in writes to it and deadlocks. Similarly, it will deadlock if FUSE implements sync. Change freeze_processes() so that it doesn't execute sys_sync() and make the suspend and hibernation code path sync filesystems independently of the freezer. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Nigel Cunningham <nigel@nigel.suspend2.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Freezer: remove redundant check in try_to_freeze_tasksRafael J. Wysocki2007-07-191-1/+1
| | | | | | | | | | | | | We don't need to check if todo is positive before calling time_after() in try_to_freeze_tasks(), because if todo is zero at this point, the loop will be broken anyway due to the while () condition being false. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Freezer: return int from freeze_processesRafael J. Wysocki2007-07-191-12/+9
| | | | | | | | | | | | | Make try_to_freeze_tasks() and freeze_processes() return -EBUSY on failure instead of the number of unfrozen tasks (none of the callers actually uses this number). Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Freezer: use __set_current_state in refrigeratorRafael J. Wysocki2007-07-191-1/+1
| | | | | | | | | | | | Use __set_current_state() as appropriate in refrigerator() instead of accessing current->state directly. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Freezer: avoid freezing kernel threads prematurelyRafael J. Wysocki2007-07-191-31/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Kernel threads should not have TIF_FREEZE set when user space processes are being frozen, since otherwise some of them might be frozen prematurely. To prevent this from happening we can (1) make exit_mm() unset TIF_FREEZE unconditionally just after clearing tsk->mm and (2) make try_to_freeze_tasks() check if p->mm is different from zero and PF_BORROWED_MM is unset in p->flags when user space processes are to be frozen. Namely, when user space processes are being frozen, we only should set TIF_FREEZE for tasks that have p->mm different from NULL and don't have PF_BORROWED_MM set in p->flags. For this reason task_lock() must be used to prevent try_to_freeze_tasks() from racing with use_mm()/unuse_mm(), in which p->mm and p->flags.PF_BORROWED_MM are changed under task_lock(p). Also, we need to prevent the following scenario from happening: * daemonize() is called by a task spawned from a user space code path * freezer checks if the task has p->mm set and the result is positive * task enters exit_mm() and clears its TIF_FREEZE * freezer sets TIF_FREEZE for the task * task calls try_to_freeze() and goes to the refrigerator, which is wrong at that point This requires us to acquire task_lock(p) before p->flags.PF_BORROWED_MM and p->mm are examined and release it after TIF_FREEZE is set for p (or it turns out that TIF_FREEZE should not be set). Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Nigel Cunningham <nigel@nigel.suspend2.net> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* freezer: run show_state() when freezing times outAndrew Morton2007-07-191-0/+1
| | | | | | | | | | To see which tasks are stuck where. Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* recalc_sigpending_tsk fixesRoland McGrath2007-05-241-1/+1
| | | | | | | | | | | | | | | | | | | Steve Hawkes discovered a problem where recalc_sigpending_tsk was called in do_sigaction but no signal_wake_up call was made, preventing later signals from waking up blocked threads with TIF_SIGPENDING already set. In fact, the few other calls to recalc_sigpending_tsk outside the signals code are also subject to this problem in other race conditions. This change makes recalc_sigpending_tsk private to the signals code. It changes the outside calls, as well as do_sigaction, to use the new recalc_sigpending_and_wake instead. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: <Steve.Hawkes@motorola.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* freezer: move frozen_process() to kernel/power/process.cGautham R Shenoy2007-05-241-1/+13
| | | | | | | | | | | | | | | | Other than refrigerator, no one else calls frozen_process(). So move it from include/linux/freezer.h to kernel/power/process.c. Also, since a task can be marked as frozen by itself, we don't need to pass the (struct task_struct *p) parameter to frozen_process(). Signed-off-by: Gautham R Shenoy <ego@in.ibm.com> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* freezer: take kernel_execve into considerationRafael J. Wysocki2007-05-241-2/+2
| | | | | | | | | | | | | | | | | Kernel threads can become userland processes by calling kernel_execve(). In particular, this may happen right after the try_to_freeze_tasks() called with FREEZER_USER_SPACE has returned, so try_to_freeze_tasks() needs to take userspace processes into consideration even if it is called with FREEZER_KERNEL_THREADS. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* freezer: fix vfork problemRafael J. Wysocki2007-05-241-20/+9
| | | | | | | | | | | | | | | | | | | Currently try_to_freeze_tasks() has to wait until all of the vforked processes exit and for this reason every user can make it fail. To fix this problem we can introduce the additional process flag PF_FREEZER_SKIP to be used by tasks that do not want to be counted as freezable by the freezer and want to have TIF_FREEZE set nevertheless. Then, this flag can be set by tasks using sys_vfork() before they call wait_for_completion(&vfork) and cleared after they have woken up. After clearing it, the tasks should call try_to_freeze() as soon as possible. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* freezer: close potential race between refrigerator and thaw_tasksRafael J. Wysocki2007-05-241-1/+11
| | | | | | | | | | | | | | | | | | | | | If the freezing of tasks fails and a task is preempted in refrigerator() before calling frozen_process(), then thaw_tasks() may run before this task is frozen. In that case the task will freeze and no one will thaw it. To fix this race we can call freezing(current) in refrigerator() along with frozen_process(current) under the task_lock() which also should be taken in the error path of try_to_freeze_tasks() as well as in thaw_process(). Moreover, if thaw_process() additionally clears TIF_FREEZE for tasks that are not frozen, we can be sure that all tasks are thawed and there are no pending "freeze" requests after thaw_tasks() has run. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* header cleaning: don't include smp_lock.h when not usedRandy Dunlap2007-05-081-1/+0
| | | | | | | | | | | | Remove includes of <linux/smp_lock.h> where it is not used/needed. Suggested by Al Viro. Builds cleanly on x86_64, i386, alpha, ia64, powerpc, sparc, sparc64, and arm (all 59 defconfigs). Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* freezer: task->exit_state should be treated as boleanOleg Nesterov2007-05-081-3/+2
| | | | | | | | | | | | | Except for BUG_ON() checks, we should not use EXIT_XXXX defines outside of exit/wait paths. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Cc: Ingo Molnar <mingo@elte.hu> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fix refrigerator() vs thaw_process() raceOleg Nesterov2007-05-071-2/+4
| | | | | | | | | | | refrigerator() can miss a wakeup, "wait event" loop needs a proper memory ordering. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] PM: Fix SMP races in the freezerRafael J. Wysocki2006-12-131-7/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, to tell a task that it should go to the refrigerator, we set the PF_FREEZE flag for it and send a fake signal to it. Unfortunately there are two SMP-related problems with this approach. First, a task running on another CPU may be updating its flags while the freezer attempts to set PF_FREEZE for it and this may leave the task's flags in an inconsistent state. Second, there is a potential race between freeze_process() and refrigerator() in which freeze_process() running on one CPU is reading a task's PF_FREEZE flag while refrigerator() running on another CPU has just set PF_FROZEN for the same task and attempts to reset PF_FREEZE for it. If the refrigerator wins the race, freeze_process() will state that PF_FREEZE hasn't been set for the task and will set it unnecessarily, so the task will go to the refrigerator once again after it's been thawed. To solve first of these problems we need to stop using PF_FREEZE to tell tasks that they should go to the refrigerator. Instead, we can introduce a special TIF_*** flag and use it for this purpose, since it is allowed to change the other tasks' TIF_*** flags and there are special calls for it. To avoid the freeze_process()-refrigerator() race we can make freeze_process() to always check the task's PF_FROZEN flag after it's read its "freeze" flag. We should also make sure that refrigerator() will always reset the task's "freeze" flag after it's set PF_FROZEN for it. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Russell King <rmk@arm.linux.org.uk> Cc: David Howells <dhowells@redhat.com> Cc: Andi Kleen <ak@muc.de> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] PM: Fix freezing of stopped tasksRafael J. Wysocki2006-12-131-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | Currently, if a task is stopped (ie. it's in the TASK_STOPPED state), it is considered by the freezer as unfreezeable. However, there may be a race between the freezer and the delivery of the continuation signal to the task resulting in the task running after we have finished freezing the other tasks. This, in turn, may lead to undesirable effects up to and including data corruption. To prevent this from happening we first need to make the freezer consider stopped tasks as freezeable. For this purpose we need to make freezeable() stop returning 0 for these tasks and we need to force them to enter the refrigerator. However, if there's no continuation signal in the meantime, the stopped tasks should remain stopped after all processes have been thawed, so we need to send an additional SIGSTOP to each of them before waking it up. Also, a stopped task that has just been woken up should first check if there's a freezing request for it and go to the refrigerator if that's the case. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] swsusp: Untangle freeze_processesRafael J. Wysocki2006-12-071-30/+54
| | | | | | | | | | | | Move the loop from freeze_processes() to a separate function and call it independently for user space processes and kernel threads so that the order of freezing tasks is clearly visible. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Cc: Nigel Cunningham <nigel@suspend2.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] swsusp: Untangle thaw_processesRafael J. Wysocki2006-12-071-22/+27
| | | | | | | | | | | | | | Move the loop from thaw_processes() to a separate function and call it independently for kernel threads and user space processes so that the order of thawing tasks is clearly visible. Drop thaw_kernel_threads() which is never used. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Cc: Nigel Cunningham <nigel@suspend2.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] suspend to disk fails if gdb is suspended with a traced childRafael J. Wysocki2006-12-071-1/+3
| | | | | | | | | | | | | Fix http://bugzilla.kernel.org/show_bug.cgi?id=7534 Fix the freezing of processes so that it won't fail if there is a traced process the parent of which has been stopped. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: maurice barnum <pixi+kbug@burble.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] swsusp: thaw userspace and kernel space separatelyNigel Cunningham2006-12-071-7/+18
| | | | | | | | | | | | | Modify process thawing so that we can thaw kernel space without thawing userspace, and thaw kernelspace first. This will be useful in later patches, where I intend to get swsusp thawing kernel threads only before seeking to free memory. Signed-off-by: Nigel Cunningham <nigel@suspend2.net> Cc: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] swsusp: clean up whitespace in freezer outputNigel Cunningham2006-12-071-8/+8
| | | | | | | | | | Minor whitespace and formatting modifications for the freezer. Signed-off-by: Nigel Cunningham <nigel@suspend2.net> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] swsusp: quieten Freezer if !CONFIG_PM_DEBUGNigel Cunningham2006-12-071-1/+0
| | | | | | | | | | | | | | | The freezer currently prints an '=' for every process that is frozen. This is pretty pointless, as the equals sign says nothing about which process is frozen, and makes logs look messier (especially if there were a large number of processes running). All we really need to know is that we started trying to freeze processes and what processes (if any) failed to freeze, or that we succeeded. Signed-off-by: Nigel Cunningham <nigel@suspend2.net> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Add include/linux/freezer.h and move definitions from sched.hNigel Cunningham2006-12-071-0/+1
| | | | | | | | | | | | | Move process freezing functions from include/linux/sched.h to freezer.h, so that modifications to the freezer or the kernel configuration don't require recompiling just about everything. [akpm@osdl.org: fix ueagle driver] Signed-off-by: Nigel Cunningham <nigel@suspend2.net> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Make suspend possible with a traced process at a breakpointRafael J. Wysocki2006-08-061-8/+18
| | | | | | | | | | | | | | | It should be possible to suspend, either to RAM or to disk, if there's a traced process that has just reached a breakpoint. However, this is a special case, because its parent process might have been frozen already and then we are unable to deliver the "freeze" signal to the traced process. If this happens, it's better to cancel the freezing of the traced process. Ref. http://bugzilla.kernel.org/show_bug.cgi?id=6787 Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Fix suspend with traced tasksPavel Machek2006-03-311-2/+1
| | | | | | | | | | | strace /bin/bash misbehaves after resume; this fixes it. (akpm: it's scary calling refrigerator() in state TASK_TRACED, but it seems to do the right thing). Signed-off-by: Pavel Machek <pavel@suse.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] swsusp: freeze user space processes firstRafael J. Wysocki2006-03-231-15/+46
| | | | | | | | | | | | | Allow swsusp to freeze processes successfully under heavy load by freezing userspace processes before kernel threads. [Thanks to Nigel Cunningham <nigel@suspend2.net> for suggesting the way to go.] Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@suse.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] swsusp: documentation updatesPavel Machek2006-03-231-1/+1
| | | | | | | | | | | | | | | | | | | Update suspend-to-RAM documentation with new machines, and makes message when processes can't be stopped little clearer. (In one case, waiting longer actually did help). From: "Rafael J. Wysocki" <rjw@sisk.pl> Warn in the documentation that data may be lost if there are some filesystems mounted from USB devices before suspend. [Thanks to Alan Stern for providing the answer to the question in the Q:-A: part.] Signed-off-by: Pavel Machek <pavel@suse.cz> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] pm: fix process freezingPavel Machek2005-09-051-2/+22
| | | | | | | | | | If process freezing fails, some processes are frozen, and rest are left in "were asked to be frozen" state. Thats wrong, we should leave it in some consistent state. Signed-off-by: Pavel Machek <pavel@suse.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] remove busywait in refrigeratorPavel Machek2005-09-051-2/+3
| | | | | | | | | This should make refrigerator sleep properly, not busywait after the first schedule() returns. Signed-off-by: Pavel Machek <pavel@suse.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] pm: clean up process.cPavel Machek2005-07-081-4/+2
| | | | | | | | | freezeable() already tests for TRACED/STOPPED processes, no need to do it twice. Signed-off-by: Pavel Machek <pavel@suse.cz> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Cleanup patch for process freezingChristoph Lameter2005-06-261-16/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 1. Establish a simple API for process freezing defined in linux/include/sched.h: frozen(process) Check for frozen process freezing(process) Check if a process is being frozen freeze(process) Tell a process to freeze (go to refrigerator) thaw_process(process) Restart process frozen_process(process) Process is frozen now 2. Remove all references to PF_FREEZE and PF_FROZEN from all kernel sources except sched.h 3. Fix numerous locations where try_to_freeze is manually done by a driver 4. Remove the argument that is no longer necessary from two function calls. 5. Some whitespace cleanup 6. Clear potential race in refrigerator (provides an open window of PF_FREEZE cleared before setting PF_FROZEN, recalc_sigpending does not check PF_FROZEN). This patch does not address the problem of freeze_processes() violating the rule that a task may only modify its own flags by setting PF_FREEZE. This is not clean in an SMP environment. freeze(process) is therefore not SMP safe! Signed-off-by: Christoph Lameter <christoph@lameter.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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