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2011-05-02timerfd: Allow timers to be cancelled when clock was setThomas Gleixner
Some applications must be aware of clock realtime being set backward. A simple example is a clock applet which arms a timer for the next minute display. If clock realtime is set backward then the applet displays a stale time for the amount of time which the clock was set backwards. Due to that applications poll the time because we don't have an interface. Extend the timerfd interface by adding a flag which puts the timer onto a different internal realtime clock. All timers on this clock are expired whenever the clock was set. The timerfd core records the monotonic offset when the timer is created. When the timer is armed, then the current offset is compared to the previous recorded offset. When it has changed, then timerfd_settime returns -ECANCELED. When a timer is read the offset is compared and if it changed -ECANCELED returned to user space. Periodic timers are not rearmed in the cancelation case. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: John Stultz <johnstul@us.ibm.com> Cc: Chris Friesen <chris.friesen@genband.com> Tested-by: Kay Sievers <kay.sievers@vrfy.org> Cc: "Kirill A. Shutemov" <kirill@shutemov.name> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Davide Libenzi <davidel@xmailserver.org> Reviewed-by: Alexander Shishkin <virtuoso@slind.org> Link: http://lkml.kernel.org/r/%3Calpine.LFD.2.02.1104271359580.3323%40ionos%3E Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-05-02hrtimers: Prepare for cancel on clock was set timersThomas Gleixner
Make clock_was_set() unconditional and rename hres_timers_resume to hrtimers_resume. This is a preparatory patch for hrtimers which are cancelled when clock realtime was set. Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-05-02hrtimer: Make lookup table constMike Frysinger
Signed-off-by: Mike Frysinger <vapier@gentoo.org> Link: http://lkml.kernel.org/r/%3C1304364267-14489-1-git-send-email-vapier%40gentoo.org%3E Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-05-02Merge branch 'linus' into timers/coreThomas Gleixner
Reason: Pick up the hrtimer_clock_to_base_table fix from mainline Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-05-02timers: Fix alarmtimer build issues when CONFIG_RTC_CLASS=nJohn Stultz
Ingo pointed out that the alarmtimers won't build if CONFIG_RTC_CLASS=n. This patch adds proper ifdefs to the alarmtimer code to disable the rtc usage if it is not built in. Reported-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-05-02genirq: Fix typo CONFIG_GENIRC_IRQ_SHOW_LEVELGeert Uytterhoeven
commit ab7798ffcf98b11a9525cf65bacdae3fd58d357f ("genirq: Expand generic show_interrupts()") added the Kconfig option GENERIC_IRQ_SHOW_LEVEL to accomodate PowerPC, but this doesn't actually enable the functionality due to a typo in the #ifdef check. Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Linux/PPC Development <linuxppc-dev@lists.ozlabs.org> Link: http://lkml.kernel.org/r/%3Calpine.DEB.2.00.1104302251370.19068%40ayla.of.borg%3E Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-05-02genirq: Make generic irq chip depend on CONFIG_GENERIC_IRQ_CHIPThomas Gleixner
Only compile it in when there are users. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-arm-kernel@lists.infradead.org
2011-05-01Merge branch 'tip/perf/core' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core
2011-05-01Merge branch 'tip/perf/urgent' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core
2011-04-30Merge branch 'fixes-2.6.39' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq * 'fixes-2.6.39' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: fix deadlock in worker_maybe_bind_and_lock() workqueue: Document debugging tricks Fix up trivial spelling conflict in kernel/workqueue.c
2011-04-29ftrace: Consolidate the function match routines for normal and modsSteven Rostedt
The code used for matching functions is almost identical between normal selecting of functions and using the :mod: feature of set_ftrace_notrace. Consolidate the two users into one function. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-29ftrace: Consolidate updating of ftrace_trace_functionSteven Rostedt
There are three locations that perform almost identical functions in order to update the ftrace_trace_function (the ftrace function variable that gets called by mcount). Consolidate these into a single function called update_ftrace_function(). Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-29ftrace: Move record update for normal and modules into a separate functionSteven Rostedt
The updating of a function record is moved to a single function. This will allow us to add specific changes in one location for both modules and kernel functions. Later patches will determine if the function record itself needs to be updated (which enables the mcount caller), or just the ftrace_ops needs the update. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-29ftrace: Remove FTRACE_FL_CONVERTED flagSteven Rostedt
Since we disable all function tracer processing if we detect that a modification of a instruction had failed, we do not need to track that the record has failed. No more ftrace processing is allowed, and the FTRACE_FL_CONVERTED flag is pointless. The FTRACE_FL_CONVERTED flag was used to denote records that were successfully converted from mcount calls into nops. But if a single record fails, all of ftrace is disabled. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-29ftrace: Remove FTRACE_FL_FAILED flagSteven Rostedt
Since we disable all function tracer processing if we detect that a modification of a instruction had failed, we do not need to track that the record has failed. No more ftrace processing is allowed, and the FTRACE_FL_FAILED flag is pointless. Removing this flag simplifies some of the code, but some ftrace_disabled checks needed to be added or move around a little. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-29ftrace: Remove failures fileSteven Rostedt
The failures file in the debugfs tracing directory would list the functions that failed to convert when the old dead ftrace daemon tried to update code but failed. Since this code is now dead along with the daemon the failures file is useless. Remove it. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-29ftrace: Remove unnecessary disabling of irqsSteven Rostedt
The disabling of interrupts around ftrace_update_code() was used to protect against the evil ftrace daemon from years past. But that daemon has long been killed. It is safe to keep interrupts enabled while updating the initial mcount into nops. The ftrace_mutex is also held which keeps other users at bay. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-29ftrace: Make FTRACE_WARN_ON() work in if conditionSteven Rostedt
Let FTRACE_WARN_ON() be used as a stand alone statement or inside a conditional: if (FTRACE_WARN_ON(x)) Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-29ftrace: Only update the function code on write to filter filesSteven Rostedt
If function tracing is enabled, a read of the filter files will cause the call to stop_machine to update the function trace sites. It should only call stop_machine on write. Cc: stable@kernel.org Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2011-04-30PM / Runtime: Generic clock manipulation rountines for runtime PM (v6)Rafael J. Wysocki
Many different platforms and subsystems may want to disable device clocks during suspend and enable them during resume which is going to be done in a very similar way in all those cases. For this reason, provide generic routines for the manipulation of device clocks during suspend and resume. Convert the ARM shmobile platform to using the new routines. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
2011-04-29Merge branch 'perf-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: perf, x86, nmi: Move LVT un-masking into irq handlers perf events, x86: Work around the Nehalem AAJ80 erratum perf, x86: Fix BTS condition ftrace: Build without frame pointers on Microblaze
2011-04-29Merge branch 'timer-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'timer-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: hrtimer: Initialize CLOCK_ID to HRTIMER_BASE table statically rtc: max8925: Call dev_set_drvdata before rtc_device_register
2011-04-29workqueue: fix deadlock in worker_maybe_bind_and_lock()Tejun Heo
If a rescuer and stop_machine() bringing down a CPU race with each other, they may deadlock on non-preemptive kernel. The CPU won't accept a new task, so the rescuer can't migrate to the target CPU, while stop_machine() can't proceed because the rescuer is holding one of the CPU retrying migration. GCWQ_DISASSOCIATED is never cleared and worker_maybe_bind_and_lock() retries indefinitely. This problem can be reproduced semi reliably while the system is entering suspend. http://thread.gmane.org/gmane.linux.kernel/1122051 A lot of kudos to Thilo-Alexander for reporting this tricky issue and painstaking testing. stable: This affects all kernels with cmwq, so all kernels since and including v2.6.36 need this fix. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Thilo-Alexander Ginkel <thilo@ginkel.com> Tested-by: Thilo-Alexander Ginkel <thilo@ginkel.com> Cc: stable@kernel.org
2011-04-29hrtimer: Initialize CLOCK_ID to HRTIMER_BASE table staticallyThomas Gleixner
Sedat and Bruno reported RCU stalls which turned out to be caused by the following; sched_init() calls init_rt_bandwidth() which calls hrtimer_init() _BEFORE_ hrtimers_init() is called. While not entirely correct this worked because hrtimer_init() only accessed statically initialized data (hrtimer_bases.clock_base[CLOCK_MONOTONIC]) Commit e06383db9 (hrtimers: extend hrtimer base code to handle more then 2 clockids) added an indirection to the hrtimer_bases.clock_base lookup to avoid gap handling in the hot path. The table which is used for the translataion from CLOCK_ID to HRTIMER_BASE index is initialized at runtime in hrtimers_init(). So the early call of the scheduler code translates CLOCK_MONOTONIC to HRTIMER_BASE_REALTIME. Thus the rt_bandwith timer ends up on CLOCK_REALTIME. If the timer is armed and the wall clock time is set (e.g. ntpdate in the early boot process - which also gives the problem deterministic behaviour i.e. magic recovery after N hours), then the timer ends up with an expiry time far into the future. That breaks the RT throttler mechanism as rt runtime is accumulated and never cleared, so the rt throttler detects a false cpu hog condition and blocks all RT tasks until the timer finally expires. That in turn stalls the RCU thread of TINYRCU which leads to an huge amount of RCU callbacks piling up. Make the translation table statically initialized, so we are back to the status of <= 2.6.39. Reported-and-tested-by: Sedat Dilek <sedat.dilek@gmail.com> Reported-by: Bruno Prémont <bonbons@linux-vserver.org> Cc: John stultz <johnstul@us.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/%3Calpine.LFD.2.02.1104282353140.3005%40ionos%3E Reviewed-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2011-04-28timers: Remove delayed irqwork from alarmtimers implementationJohn Stultz
Thomas asked about the delayed irq work in the alarmtimers code, and I realized that it was a legacy from when the alarmtimer base lock was a mutex (due to concerns that we'd be interacting with the RTC device, which is protected by mutexes). Since the alarmtimer base is now protected by a spinlock, we can simply execute alarmtimer functions directly from the hrtimer callback. Should any future alarmtimer functions sleep, they can simply manage scheduling any delayed work themselves. CC: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-04-28timers: Improve alarmtimer comments and minor fixesJohn Stultz
This patch addresses a number of minor comment improvements and other minor issues from Thomas' review of the alarmtimers code. CC: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-04-28kernel/watchdog.c: disable nmi perf event in the error path of enabling watchdogHillf Danton
In corner cases where softlockup watchdog is not setup successfully, the relevant nmi perf event for hardlockup watchdog could be disabled, then the status of the underlying hardware remains unchanged. Also, if the kthread doesn't start then the hrtimer won't run and the hardlockup detector will falsely fire. Signed-off-by: Hillf Danton <dhillf@gmail.com> Signed-off-by: Don Zickus <dzickus@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-04-28signal: cleanup sys_sigprocmask()Oleg Nesterov
Cleanup. Remove the unneeded goto's, we can simply read blocked.sig[0] unconditionally and then copy-to-user it if oset != NULL. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>
2011-04-28signal: rename signandsets() to sigandnsets()Oleg Nesterov
As Tejun and Linus pointed out, "nand" is the wrong name for "x & ~y", it should be "andn". Rename signandsets() as suggested. Suggested-by: Tejun Heo <tj@kernel.org> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Tejun Heo <tj@kernel.org>
2011-04-28signal: do_sigtimedwait() needs retarget_shared_pending()Oleg Nesterov
do_sigtimedwait() changes current->blocked and thus it needs set_current_blocked()->retarget_shared_pending(). We could use set_current_blocked() directly. It is fine to change ->real_blocked from all-zeroes to ->blocked and vice versa lockless, but this is not immediately clear, looks racy, and needs a huge comment to explain why this is correct. To keep the things simple this patch adds the new static helper, __set_task_blocked() which should be called with ->siglock held. This way we can change both ->real_blocked and ->blocked atomically under ->siglock as the current code does. This is more understandable. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>
2011-04-28signal: introduce do_sigtimedwait() to factor out compat/native codeOleg Nesterov
Factor out the common code in sys_rt_sigtimedwait/compat_sys_rt_sigtimedwait to the new helper, do_sigtimedwait(). Add the comment to document the extra tick we add to timespec_to_jiffies(ts), thanks to Linus who explained this to me. Perhaps it would be better to move compat_sys_rt_sigtimedwait() into signal.c under CONFIG_COMPAT, then we can make do_sigtimedwait() static. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>
2011-04-28signal: sys_rt_sigtimedwait: simplify the timeout logicOleg Nesterov
No functional changes, cleanup compat_sys_rt_sigtimedwait() and sys_rt_sigtimedwait(). Calculate the timeout before we take ->siglock, this simplifies and lessens the code. Use timespec_valid() to check the timespec. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Tejun Heo <tj@kernel.org> Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com>
2011-04-28signal: cleanup sys_rt_sigprocmask()Oleg Nesterov
sys_rt_sigprocmask() looks unnecessarily complicated, simplify it. We can just read current->blocked lockless unconditionally before anything else and then copy-to-user it if needed. At worst we copy 4 words on mips. We could copy-to-user the old mask first and simplify the code even more, but the patch tries to keep the current behaviour: we change current->block even if copy_to_user(oset) fails. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com> Acked-by: Tejun Heo <tj@kernel.org>
2011-04-28signal: sigprocmask() should do retarget_shared_pending()Oleg Nesterov
In short, almost every changing of current->blocked is wrong, or at least can lead to the unexpected results. For example. Two threads T1 and T2, T1 sleeps in sigtimedwait/pause/etc. kill(tgid, SIG) can pick T2 for TIF_SIGPENDING. If T2 calls sigprocmask() and blocks SIG before it notices the pending signal, nobody else can handle this pending shared signal. I am not sure this is bug, but at least this looks strange imho. T1 should not sleep forever, there is a signal which should wake it up. This patch moves the code which actually changes ->blocked into the new helper, set_current_blocked() and changes this code to call retarget_shared_pending() as exit_signals() does. We should only care about the signals we just blocked, we use "newset & ~current->blocked" as a mask. We do not check !sigisemptyset(newblocked), retarget_shared_pending() is cheap unless mask & shared_pending. Note: for this particular case we could simply change sigprocmask() to return -EINTR if signal_pending(), but then we should change other callers and, more importantly, if we need this fix then set_current_blocked() will have more callers and some of them can't restart. See the next patch as a random example. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com> Acked-by: Tejun Heo <tj@kernel.org>
2011-04-28signal: sigprocmask: narrow the scope of ->siglockOleg Nesterov
No functional changes, preparation to simplify the review of the next change. 1. We can read current->block lockless, nobody else can ever change this mask. 2. Calculate the resulting sigset_t outside of ->siglock into the temporary variable, then take ->siglock and change ->blocked. Also, kill the stale comment about BKL. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com> Acked-by: Tejun Heo <tj@kernel.org>
2011-04-28signal: retarget_shared_pending: optimize while_each_thread() loopOleg Nesterov
retarget_shared_pending() blindly does recalc_sigpending_and_wake() for every sub-thread, this is suboptimal. We can check t->blocked and stop looping once every bit in shared_pending has the new target. Note: we do not take task_is_stopped_or_traced(t) into account, we are not trying to speed up the signal delivery or to avoid the unnecessary (but harmless) signal_wake_up(0) in this unlikely case. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com> Acked-by: Tejun Heo <tj@kernel.org>
2011-04-28signal: retarget_shared_pending: consider shared/unblocked signals onlyOleg Nesterov
exit_signals() checks signal_pending() before retarget_shared_pending() but this is suboptimal. We can avoid the while_each_thread() loop in case when there are no shared signals visible to us. Add the "shared_pending.signal & ~blocked" check. We don't use tsk->blocked directly but pass ~blocked as an argument, this is needed for the next patch. Note: we can optimize this more. while_each_thread(t) can check t->blocked into account and stop after every pending signal has the new target, see the next patch. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com> Acked-by: Tejun Heo <tj@kernel.org>
2011-04-28signal: introduce retarget_shared_pending()Oleg Nesterov
No functional changes. Move the notify-other-threads code from exit_signals() to the new helper, retarget_shared_pending(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Matt Fleming <matt.fleming@linux.intel.com> Acked-by: Tejun Heo <tj@kernel.org>
2011-04-28watchdog, hung_task_timeout: Add Kconfig configurable defaultJeff Mahoney
This patch allows the default value for sysctl_hung_task_timeout_secs to be set at build time. The feature carries virtually no overhead, so it makes sense to keep it enabled. On heavily loaded systems, though, it can end up triggering stack traces when there is no bug other than the system being underprovisioned. We use this patch to keep the hung task facility available but disabled at boot-time. The default of 120 seconds is preserved. As a note, commit e162b39a may have accidentally reverted commit fb822db4, which raised the default from 120 seconds to 480 seconds. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Acked-by: Mandeep Singh Baines <msb@google.com> Link: http://lkml.kernel.org/r/4DB8600C.8080000@suse.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-27audit: acquire creds selectively to reduce atomic op overheadTony Jones
Commit c69e8d9c01db ("CRED: Use RCU to access another task's creds and to release a task's own creds") added calls to get_task_cred and put_cred in audit_filter_rules. Profiling with a large number of audit rules active on the exit chain shows that we are spending upto 48% in this routine for syscall intensive tests, most of which is in the atomic ops. 1. The code should be accessing tsk->cred rather than tsk->real_cred. 2. Since tsk is current (or tsk is being created by copy_process) access to tsk->cred without rcu read lock is possible. At the request of the audit maintainer, a new flag has been added to audit_filter_rules in order to make this explicit and guide future code. Signed-off-by: Tony Jones <tonyj@suse.de> Acked-by: Eric Paris <eparis@redhat.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2011-04-27Merge branch 'tip/perf/core' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core Conflicts: include/linux/perf_event.h Merge reason: pick up the latest jump-label enhancements, they are cooked ready. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-27Merge branch 'tip/perf/urgent' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/urgent
2011-04-26timers: Posix interface for alarm-timersJohn Stultz
This patch exposes alarm-timers to userland via the posix clock and timers interface, using two new clockids: CLOCK_REALTIME_ALARM and CLOCK_BOOTTIME_ALARM. Both clockids behave identically to CLOCK_REALTIME and CLOCK_BOOTTIME, respectively, but timers set against the _ALARM suffixed clockids will wake the system if it is suspended. Some background can be found here: https://lwn.net/Articles/429925/ The concept for Alarm-timers was inspired by the Android Alarm driver (by Arve Hjønnevåg) found in the Android kernel tree. See: http://android.git.kernel.org/?p=kernel/common.git;a=blob;f=drivers/rtc/alarm.c;h=1250edfbdf3302f5e4ea6194847c6ef4bb7beb1c;hb=android-2.6.36 While the in-kernel interface is pretty similar between alarm-timers and Android alarm driver, the user-space interface for the Android alarm driver is via ioctls to a new char device. As mentioned above, I've instead chosen to export this functionality via the posix interface, as it seemed a little simpler and avoids creating duplicate interfaces to things like CLOCK_REALTIME and CLOCK_MONOTONIC under alternate names (ie:ANDROID_ALARM_RTC and ANDROID_ALARM_SYSTEMTIME). The semantics of the Android alarm driver are different from what this posix interface provides. For instance, threads other then the thread waiting on the Android alarm driver are able to modify the alarm being waited on. Also this interface does not allow the same wakelock semantics that the Android driver provides (ie: kernel takes a wakelock on RTC alarm-interupt, and holds it through process wakeup, and while the process runs, until the process either closes the char device or calls back in to wait on a new alarm). One potential way to implement similar semantics may be via the timerfd infrastructure, but this needs more research. There may also need to be some sort of sysfs system level policy hooks that allow alarm timers to be disabled to keep them from firing at inappropriate times (ie: laptop in a well insulated bag, mid-flight). CC: Arve Hjønnevåg <arve@android.com> CC: Thomas Gleixner <tglx@linutronix.de> CC: Alessandro Zummo <a.zummo@towertech.it> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-04-26timers: Introduce in-kernel alarm-timer interfaceJohn Stultz
This provides the in kernel interface and infrastructure for alarm-timers. Alarm-timers are a hybrid style timer, similar to hrtimers, but when the system is suspended, the RTC device is set to fire and wake the system for when the soonest alarm-timer expires. The concept for Alarm-timers was inspired by the Android Alarm driver (by Arve Hjønnevåg) found in the Android kernel tree. See: http://android.git.kernel.org/?p=kernel/common.git;a=blob;f=drivers/rtc/alarm.c;h=1250edfbdf3302f5e4ea6194847c6ef4bb7beb1c;hb=android-2.6.36 This in-kernel interface should be fairly compatible with the Android alarm driver in-kernel interface, but has the advantage of utilizing the new RTC timerqueue code instead of doing direct RTC manipulation. CC: Arve Hjønnevåg <arve@android.com> CC: Thomas Gleixner <tglx@linutronix.de> CC: Alessandro Zummo <a.zummo@towertech.it> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-04-26time: Add timekeeping_inject_sleeptimeJohn Stultz
Some platforms cannot implement read_persistent_clock, as their RTC devices are only accessible when interrupts are enabled. This keeps them from being used by the timekeeping code on resume to measure the time in suspend. The RTC layer tries to work around this, by calling do_settimeofday on resume after irqs are reenabled to set the time properly. However, this only corrects CLOCK_REALTIME, and does not properly adjust the sleep time value. This causes btime in /proc/stat to be incorrect as well as making the new CLOCK_BOTTTIME inaccurate. This patch resolves the issue by introducing a new timekeeping hook to allow the RTC layer to inject the sleep time on resume. The code also checks to make sure that read_persistent_clock is nonfunctional before setting the sleep time, so that should the RTC's HCTOSYS option be configured in on a system that does support read_persistent_clock we will not increase the total_sleep_time twice. CC: Arve Hjønnevåg <arve@android.com> CC: Thomas Gleixner <tglx@linutronix.de> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: John Stultz <john.stultz@linaro.org>
2011-04-26sched: Remove noop in alloc_rt_sched_group()Hillf Danton
The rq varible, though computed for each possible cpu, has nothing to do in the function, so it can be removed. This also eliminates a build warning. Signed-off-by: Hillf Danton <dhillf@gmail.com> Reviewed-by: Yong Zhang <yong.zhang0@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/BANLkTin-FfQfqW5ym1iuEmrk8s777Y1LAg@mail.gmail.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-04-26Merge branch 'master' into for-nextJiri Kosina
Fast-forwarded to current state of Linus' tree as there are patches to be applied for files that didn't exist on the old branch.
2011-04-25modules: Enabled dynamic debugging for staging modulesRoland Vossen
Driver modules from the staging directory are marked 'tainted' by module.c. Subsequently, tainted modules are denied dynamic debugging. This is unwanted behavior, since staging modules should be able to use the dynamic debugging mechanism. Please merge this also into the staging-linus branch. Signed-off-by: Roland Vossen <rvossen@broadcom.com> Acked-by: Jason Baron <jbaron@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-25params.c: Use new strtobool function to process boolean inputsJonathan Cameron
No functional changes. Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2011-04-25ptrace: Prepare to fix racy accesses on task breakpointsFrederic Weisbecker
When a task is traced and is in a stopped state, the tracer may execute a ptrace request to examine the tracee state and get its task struct. Right after, the tracee can be killed and thus its breakpoints released. This can happen concurrently when the tracer is in the middle of reading or modifying these breakpoints, leading to dereferencing a freed pointer. Hence, to prepare the fix, create a generic breakpoint reference holding API. When a reference on the breakpoints of a task is held, the breakpoints won't be released until the last reference is dropped. After that, no more ptrace request on the task's breakpoints can be serviced for the tracer. Reported-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Will Deacon <will.deacon@arm.com> Cc: Prasad <prasad@linux.vnet.ibm.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: v2.6.33.. <stable@kernel.org> Link: http://lkml.kernel.org/r/1302284067-7860-2-git-send-email-fweisbec@gmail.com