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* Merge branch 'for-2.6.38' of ↵Linus Torvalds2011-01-081-18/+18
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu * 'for-2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: (30 commits) gameport: use this_cpu_read instead of lookup x86: udelay: Use this_cpu_read to avoid address calculation x86: Use this_cpu_inc_return for nmi counter x86: Replace uses of current_cpu_data with this_cpu ops x86: Use this_cpu_ops to optimize code vmstat: User per cpu atomics to avoid interrupt disable / enable irq_work: Use per cpu atomics instead of regular atomics cpuops: Use cmpxchg for xchg to avoid lock semantics x86: this_cpu_cmpxchg and this_cpu_xchg operations percpu: Generic this_cpu_cmpxchg() and this_cpu_xchg support percpu,x86: relocate this_cpu_add_return() and friends connector: Use this_cpu operations xen: Use this_cpu_inc_return taskstats: Use this_cpu_ops random: Use this_cpu_inc_return fs: Use this_cpu_inc_return in buffer.c highmem: Use this_cpu_xx_return() operations vmstat: Use this_cpu_inc_return for vm statistics x86: Support for this_cpu_add, sub, dec, inc_return percpu: Generic support for this_cpu_add, sub, dec, inc_return ... Fixed up conflicts: in arch/x86/kernel/{apic/nmi.c, apic/x2apic_uv_x.c, process.c} as per Tejun.
| * core: Replace __get_cpu_var with __this_cpu_read if not used for an address.Christoph Lameter2010-12-171-18/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __get_cpu_var() can be replaced with this_cpu_read and will then use a single read instruction with implied address calculation to access the correct per cpu instance. However, the address of a per cpu variable passed to __this_cpu_read() cannot be determined (since it's an implied address conversion through segment prefixes). Therefore apply this only to uses of __get_cpu_var where the address of the variable is not used. Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Hugh Dickins <hughd@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Acked-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Christoph Lameter <cl@linux.com> Signed-off-by: Tejun Heo <tj@kernel.org>
* | Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2011-01-061-1/+1
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (30 commits) sched: Change wait_for_completion_*_timeout() to return a signed long sched, autogroup: Fix reference leak sched, autogroup: Fix potential access to freed memory sched: Remove redundant CONFIG_CGROUP_SCHED ifdef sched: Fix interactivity bug by charging unaccounted run-time on entity re-weight sched: Move periodic share updates to entity_tick() printk: Use this_cpu_{read|write} api on printk_pending sched: Make pushable_tasks CONFIG_SMP dependant sched: Add 'autogroup' scheduling feature: automated per session task groups sched: Fix unregister_fair_sched_group() sched: Remove unused argument dest_cpu to migrate_task() mutexes, sched: Introduce arch_mutex_cpu_relax() sched: Add some clock info to sched_debug cpu: Remove incorrect BUG_ON cpu: Remove unused variable sched: Fix UP build breakage sched: Make task dump print all 15 chars of proc comm sched: Update tg->shares after cpu.shares write sched: Allow update_cfs_load() to update global load sched: Implement demand based update_cfs_load() ...
| * \ Merge commit 'v2.6.37' into sched/coreIngo Molnar2011-01-051-1/+2
| |\ \ | | | | | | | | | | | | | | | | | | | | Merge reason: Merge the final .37 tree. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * \ \ Merge commit 'v2.6.37-rc2' into sched/coreIngo Molnar2010-11-181-1/+1
| |\ \ \ | | | |/ | | |/| | | | | | | | | | | | | Merge reason: Move to a .37-rc base. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | sched: Make sched_param argument static in sched_setscheduler() callersKOSAKI Motohiro2010-10-231-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Andrew Morton pointed out almost all sched_setscheduler() callers are using fixed parameters and can be converted to static. It reduces runtime memory use a little. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reported-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: James Morris <jmorris@namei.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | Merge commit 'v2.6.37' into perf/coreIngo Molnar2011-01-051-1/+2
|\ \ \ \ | | |_|/ | |/| | | | | | | | | | | | | | Merge reason: Add the final .37 tree. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | watchdog: Improve initialisation error message and documentationBen Hutchings2011-01-031-1/+2
| | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The error message 'NMI watchdog failed to create perf event...' does not make it clear that this is a fatal error for the watchdog. It also currently prints the error value as a pointer, rather than extracting the error code with PTR_ERR(). Fix that. Add a note to the description of the 'nowatchdog' kernel parameter to associate it with this message. Reported-by: Cesare Leonardi <celeonar@gmail.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Cc: 599368@bugs.debian.org Cc: 608138@bugs.debian.org Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: <stable@kernel.org> # .37.x and later LKML-Reference: <1294009362.3167.126.camel@localhost> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | x86, NMI: Add back unknown_nmi_panic and nmi_watchdog sysctlsDon Zickus2010-12-101-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Originally adapted from Huang Ying's patch which moved the unknown_nmi_panic to the traps.c file. Because the old nmi watchdog was deleted before this change happened, the unknown_nmi_panic sysctl was lost. This re-adds it. Also, the nmi_watchdog sysctl was re-implemented and its documentation updated accordingly. Patch-inspired-by: Huang Ying <ying.huang@intel.com> Signed-off-by: Don Zickus <dzickus@redhat.com> Reviewed-by: Cyrill Gorcunov <gorcunov@gmail.com> Acked-by: Yinghai Lu <yinghai@kernel.org> Cc: fweisbec@gmail.com LKML-Reference: <1291068437-5331-3-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | perf, arch: Cleanup perf-pmu init vs lockup-detectorPeter Zijlstra2010-11-261-4/+3
|/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The perf hardware pmu got initialized at various points in the boot, some before early_initcall() some after (notably arch_initcall). The problem is that the NMI lockup detector is ran from early_initcall() and expects the hardware pmu to be present. Sanitize this by moving all architecture hardware pmu implementations to initialize at early_initcall() and move the lockup detector to an explicit initcall right after that. Cc: paulus <paulus@samba.org> Cc: davem <davem@davemloft.net> Cc: Michael Cree <mcree@orcon.net.nz> Cc: Deng-Cheng Zhu <dengcheng.zhu@gmail.com> Acked-by: Paul Mundt <lethal@linux-sh.org> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1290707759.2145.119.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* / watchdog: Fix section mismatch and potential undefined behavior.David Daney2010-11-061-1/+1
|/ | | | | | | | | | | | | | Commit d9ca07a05ce1 ("watchdog: Avoid kernel crash when disabling watchdog") introduces a section mismatch. Now that we reference no_watchdog from non-__init code it can no longer be __initdata. Signed-off-by: David Daney <ddaney@caviumnetworks.com> Cc: Stephane Eranian <eranian@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'perf-core-for-linus' of ↵Linus Torvalds2010-10-211-26/+15
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (163 commits) tracing: Fix compile issue for trace_sched_wakeup.c [S390] hardirq: remove pointless header file includes [IA64] Move local_softirq_pending() definition perf, powerpc: Fix power_pmu_event_init to not use event->ctx ftrace: Remove recursion between recordmcount and scripts/mod/empty jump_label: Add COND_STMT(), reducer wrappery perf: Optimize sw events perf: Use jump_labels to optimize the scheduler hooks jump_label: Add atomic_t interface jump_label: Use more consistent naming perf, hw_breakpoint: Fix crash in hw_breakpoint creation perf: Find task before event alloc perf: Fix task refcount bugs perf: Fix group moving irq_work: Add generic hardirq context callbacks perf_events: Fix transaction recovery in group_sched_in() perf_events: Fix bogus AMD64 generic TLB events perf_events: Fix bogus context time tracking tracing: Remove parent recording in latency tracer graph options tracing: Use one prologue for the preempt irqs off tracer function tracers ...
| * perf events: Clean up pid passingMatt Helsley2010-09-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The kernel perf event creation path shouldn't use find_task_by_vpid() because a vpid exists in a specific namespace. find_task_by_vpid() uses current's pid namespace which isn't always the correct namespace to use for the vpid in all the places perf_event_create_kernel_counter() (and thus find_get_context()) is called. The goal is to clean up pid namespace handling and prevent bugs like: https://bugzilla.kernel.org/show_bug.cgi?id=17281 Instead of using pids switch find_get_context() to use task struct pointers directly. The syscall is responsible for resolving the pid to a task struct. This moves the pid namespace resolution into the syscall much like every other syscall that takes pid parameters. Signed-off-by: Matt Helsley <matthltc@us.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Robin Green <greenrd@greenrd.org> Cc: Prasad <prasad@linux.vnet.ibm.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Will Deacon <will.deacon@arm.com> Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com> LKML-Reference: <a134e5e392ab0204961fd1a62c84a222bf5874a9.1284407763.git.matthltc@us.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * watchdog: Avoid kernel crash when disabling watchdogStephane Eranian2010-09-151-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In case you boot with the watchdog disabled, i.e., nowatchdog, then, if you try to disable it via /proc/sys/kernel/watchdog, you get a kernel crash. The reason is that you are trying to cancel a hrtimer which has never been initialized. This patch fixes this by skipping execution of watchdog_disable_all_cpus() when the watchdog is marked disabled from boot. Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <4c8f7a23.cae9d80a.2c11.0bb4@mx.google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * Merge branch 'perf/urgent' into perf/coreIngo Molnar2010-09-091-5/+12
| |\ | | | | | | | | | | | | | | | Merge reason: Pick up pending fixes before applying dependent new changes. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | lockup_detector: Remove unused panic_notifierAkinobu Mita2010-09-011-15/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The panic notifer in lockup_detector just set did_panic to 1. But did_panic is not used anywhere so we can just remove it. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: peterz@infradead.org Cc: gorcunov@gmail.com Cc: fweisbec@gmail.com LKML-Reference: <1283310009-22168-4-git-send-email-dzickus@redhat.com> Signed-off-by: Don Zickus <dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | lockup_detector: Convert cpu notifier to return encapsulate errno valueAkinobu Mita2010-09-011-10/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | By the commit e6bde73b07edeb703d4c89c1daabc09c303de11f ("cpu-hotplug: return better errno on cpu hotplug failure"), the cpu notifier can return encapsulate errno value, resulting in more meaningful error codes for CPU hotplug failures. This converts the cpu notifier to return encapsulate errno value for the lockup_detector as well. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: peterz@infradead.org Cc: gorcunov@gmail.com Cc: fweisbec@gmail.com LKML-Reference: <1283310009-22168-3-git-send-email-dzickus@redhat.com> Signed-off-by: Don Zickus <dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | Merge branch 'linus' into core/lockingThomas Gleixner2010-10-121-5/+15
|\ \ \ | | |/ | |/| | | | | | | | | | Reason: Pull in the semaphore related changes Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | lockup_detector: Sync touch_*_watchdog back to old semanticsDon Zickus2010-09-011-5/+12
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | During my rewrite, the semantics of touch_nmi_watchdog and touch_softlockup_watchdog changed enough to break some drivers (mostly over preemptable regions). These are cases where long delays on one CPU (due to print_delay for example) can cause long delays on other CPUs - so we must 'touch' the nmi_watchdog flag of those other CPUs as well. This change brings those touch_*_watchdog() functions back in line with to how they used to work. Signed-off-by: Don Zickus <dzickus@redhat.com> Acked-by: Cyrill Gorcunov <gorcunov@openvz.org> Cc: peterz@infradead.org Cc: fweisbec@gmail.com LKML-Reference: <1283310009-22168-2-git-send-email-dzickus@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * watchdog: Don't throttle the watchdogPeter Zijlstra2010-08-231-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Stephane reported that when the machine locks up, the regular ticks, which are responsible to resetting the throttle count, stop too. Hence the NMI watchdog can end up being throttled before it reports on the locked up state, and we end up being sad.. Cure this by having the watchdog overflow reset its own throttle count. Reported-by: Stephane Eranian <eranian@google.com> Tested-by: Stephane Eranian <eranian@google.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1282215916.1926.4696.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | lockup_detector: Make callback function staticLin Ming2010-08-201-1/+1
|/ | | | | | | | | | watchdog_overflow_callback() is only used in kernel/watchdog.c. Signed-off-by: Lin Ming <ming.m.lin@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Don Zickus <dzickus@redhat.com> LKML-Reference: <1282273431.16443.32.camel@minggr.sh.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* kernel/watchdog: Initialize 'result'Kulikov Vasiliy2010-07-071-1/+1
| | | | | | | | | | | | | | | | | | | | | Variable on the stack is not initialized to zero, do it explicitly. This bug was found by a compiler warning: kernel/watchdog.c:463: warning: 'result' may be used uninitialized in this function Signed-off-by: Kulikov Vasiliy <segooon@gmail.com> Acked-by: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1278316854-28442-1-git-send-email-segooon@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockup_detector: Convert per_cpu to __get_cpu_var for readabilityDon Zickus2010-05-191-18/+17
| | | | | | | | | | | | | | | | Just a bunch of conversions as suggested by Frederic W. __get_cpu_var() provides preemption disabled checks. Plus it gives more readability as it makes it obvious we are dealing locally now with these vars. Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Don Zickus <dzickus@redhat.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> LKML-Reference: <1274133966-18415-2-git-send-email-dzickus@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* lockup_detector: Cross arch compile fixesDon Zickus2010-05-161-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | Combining the softlockup and hardlockup code causes watchdog.c to build even without the hardlockup detection support. So if an arch, that has the previous and the new nmi watchdog implementations cohabiting, wants to know if the generic one is in use, CONFIG_LOCKUP_DETECTOR is not a reliable check. We need to use CONFIG_HARDLOCKUP_DETECTOR instead. Fixes: kernel/built-in.o: In function `touch_nmi_watchdog': (.text+0x449bc): multiple definition of `touch_nmi_watchdog' arch/sparc/kernel/built-in.o:(.text+0x11b28): first defined here Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Don Zickus <dzickus@redhat.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com> LKML-Reference: <20100514151121.GR15159@redhat.com> [ use CONFIG_HARDLOCKUP_DETECTOR instead of CONFIG_PERF_EVENTS_NMI] Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* lockup_detector: Introduce CONFIG_HARDLOCKUP_DETECTORFrederic Weisbecker2010-05-161-7/+7
| | | | | | | | | | | | | | | | | | | | This new config is deemed to simplify even more the lockup detector dependencies and can make it easier to bring a smooth sorting between archs that support the new generic lockup detector and those that still have their own, especially for those that are in the middle of this migration. Instead of checking whether we have CONFIG_LOCKUP_DETECTOR + CONFIG_PERF_EVENTS_NMI each time an arch wants to know if it needs to build its own lockup detector, take a shortcut with this new config. It is enabled only if the hardlockup detection part of the whole lockup detector is on. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Don Zickus <dzickus@redhat.com> Cc: Cyrill Gorcunov <gorcunov@gmail.com>
* watchdog: Export touch_softlockup_watchdogIngo Molnar2010-05-131-0/+1
| | | | | | | | | | | | | There are modules that rely on it: ERROR: "touch_softlockup_watchdog" [drivers/video/nvidia/nvidiafb.ko] undefined! Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Cyrill Gorcunov <gorcunov@gmail.com> LKML-Reference: <1273713674-8434-1-git-send-regression-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* lockup_detector: Separate touch_nmi_watchdog code path from touch_watchdogDon Zickus2010-05-121-3/+4
| | | | | | | | | | | | | | | | | | | When I combined the nmi_watchdog (hardlockup) and softlockup code, I also combined the paths the touch_watchdog and touch_nmi_watchdog took. This may not be the best idea as pointed out by Frederic W., that the touch_watchdog case probably should not reset the hardlockup count. Therefore the patch below falls back to the previous idea of keeping the touch_nmi_watchdog a superset of the touch_watchdog case. Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Eric Paris <eparis@redhat.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> LKML-Reference: <1273266711-18706-9-git-send-email-dzickus@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* lockup_detector: Touch_softlockup cleanups and softlockup_tick removalDon Zickus2010-05-121-32/+3
| | | | | | | | | | | | | | | | | Just some code cleanup to make touch_softlockup clearer and remove the softlockup_tick function as it is no longer needed. Also remove the /proc softlockup_thres call as it has been changed to watchdog_thres. Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Eric Paris <eparis@redhat.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> LKML-Reference: <1273266711-18706-3-git-send-email-dzickus@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
* lockup_detector: Combine nmi_watchdog and softlockup detectorDon Zickus2010-05-121-0/+592
The new nmi_watchdog (which uses the perf event subsystem) is very similar in structure to the softlockup detector. Using Ingo's suggestion, I combined the two functionalities into one file: kernel/watchdog.c. Now both the nmi_watchdog (or hardlockup detector) and softlockup detector sit on top of the perf event subsystem, which is run every 60 seconds or so to see if there are any lockups. To detect hardlockups, cpus not responding to interrupts, I implemented an hrtimer that runs 5 times for every perf event overflow event. If that stops counting on a cpu, then the cpu is most likely in trouble. To detect softlockups, tasks not yielding to the scheduler, I used the previous kthread idea that now gets kicked every time the hrtimer fires. If the kthread isn't being scheduled neither is anyone else and the warning is printed to the console. I tested this on x86_64 and both the softlockup and hardlockup paths work. V2: - cleaned up the Kconfig and softlockup combination - surrounded hardlockup cases with #ifdef CONFIG_PERF_EVENTS_NMI - seperated out the softlockup case from perf event subsystem - re-arranged the enabling/disabling nmi watchdog from proc space - added cpumasks for hardlockup failure cases - removed fallback to soft events if no PMU exists for hard events V3: - comment cleanups - drop support for older softlockup code - per_cpu cleanups - completely remove software clock base hardlockup detector - use per_cpu masking on hard/soft lockup detection - #ifdef cleanups - rename config option NMI_WATCHDOG to LOCKUP_DETECTOR - documentation additions V4: - documentation fixes - convert per_cpu to __get_cpu_var - powerpc compile fixes V5: - split apart warn flags for hard and soft lockups TODO: - figure out how to make an arch-agnostic clock2cycles call (if possible) to feed into perf events as a sample period [fweisbec: merged conflict patch] Signed-off-by: Don Zickus <dzickus@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Cyrill Gorcunov <gorcunov@gmail.com> Cc: Eric Paris <eparis@redhat.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> LKML-Reference: <1273266711-18706-2-git-send-email-dzickus@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
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