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* sched: Fix user time incorrectly accounted as system time on 32-bitStanislaw Gruszka2010-09-151-4/+4
| | | | | | | | | | | | | | | | | | | | | We have 32-bit variable overflow possibility when multiply in task_times() and thread_group_times() functions. When the overflow happens then the scaled utime value becomes erroneously small and the scaled stime becomes i erroneously big. Reported here: https://bugzilla.redhat.com/show_bug.cgi?id=633037 https://bugzilla.kernel.org/show_bug.cgi?id=16559 Reported-by: Michael Chapman <redhat-bugzilla@very.puzzling.org> Reported-by: Ciriaco Garcia de Celis <sysman@etherpilot.com> Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: <stable@kernel.org> # 2.6.32.19+ (partially) and 2.6.33+ LKML-Reference: <20100914143513.GB8415@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Move sched_avg_update() to update_cpu_load()Suresh Siddha2010-09-091-0/+6
| | | | | | | | | | | | | | Currently sched_avg_update() (which updates rt_avg stats in the rq) is getting called from scale_rt_power() (in the load balance context) which doesn't take rq->lock. Fix it by moving the sched_avg_update() to more appropriate update_cpu_load() where the CFS load gets updated as well. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1282596171.2694.3.camel@sbsiddha-MOBL3> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* mutex: Improve the scalability of optimistic spinningTim Chen2010-08-231-1/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is a scalability issue for current implementation of optimistic mutex spin in the kernel. It is found on a 8 node 64 core Nehalem-EX system (HT mode). The intention of the optimistic mutex spin is to busy wait and spin on a mutex if the owner of the mutex is running, in the hope that the mutex will be released soon and be acquired, without the thread trying to acquire mutex going to sleep. However, when we have a large number of threads, contending for the mutex, we could have the mutex grabbed by other thread, and then another ……, and we will keep spinning, wasting cpu cycles and adding to the contention. One possible fix is to quit spinning and put the current thread on wait-list if mutex lock switch to a new owner while we spin, indicating heavy contention (see the patch included). I did some testing on a 8 socket Nehalem-EX system with a total of 64 cores. Using Ingo's test-mutex program that creates/delete files with 256 threads (http://lkml.org/lkml/2006/1/8/50) , I see the following speed up after putting in the mutex spin fix: ./mutex-test V 256 10 Ops/sec 2.6.34 62864 With fix 197200 Repeating the test with Aim7 fserver workload, again there is a speed up with the fix: Jobs/min 2.6.34 91657 With fix 149325 To look at the impact on the distribution of mutex acquisition time, I collected the mutex acquisition time on Aim7 fserver workload with some instrumentation. The average acquisition time is reduced by 48% and number of contentions reduced by 32%. #contentions Time to acquire mutex (cycles) 2.6.34 72973 44765791 With fix 49210 23067129 The histogram of mutex acquisition time is listed below. The acquisition time is in 2^bin cycles. We see that without the fix, the acquisition time is mostly around 2^26 cycles. With the fix, we the distribution get spread out a lot more towards the lower cycles, starting from 2^13. However, there is an increase of the tail distribution with the fix at 2^28 and 2^29 cycles. It seems a small price to pay for the reduced average acquisition time and also getting the cpu to do useful work. Mutex acquisition time distribution (acq time = 2^bin cycles): 2.6.34 With Fix bin #occurrence % #occurrence % 11 2 0.00% 120 0.24% 12 10 0.01% 790 1.61% 13 14 0.02% 2058 4.18% 14 86 0.12% 3378 6.86% 15 393 0.54% 4831 9.82% 16 710 0.97% 4893 9.94% 17 815 1.12% 4667 9.48% 18 790 1.08% 5147 10.46% 19 580 0.80% 6250 12.70% 20 429 0.59% 6870 13.96% 21 311 0.43% 1809 3.68% 22 255 0.35% 2305 4.68% 23 317 0.44% 916 1.86% 24 610 0.84% 233 0.47% 25 3128 4.29% 95 0.19% 26 63902 87.69% 122 0.25% 27 619 0.85% 286 0.58% 28 0 0.00% 3536 7.19% 29 0 0.00% 903 1.83% 30 0 0.00% 0 0.00% I've done similar experiments with 2.6.35 kernel on smaller boxes as well. One is on a dual-socket Westmere box (12 cores total, with HT). Another experiment is on an old dual-socket Core 2 box (4 cores total, no HT) On the 12-core Westmere box, I see a 250% increase for Ingo's mutex-test program with my mutex patch but no significant difference in aim7's fserver workload. On the 4-core Core 2 box, I see the difference with the patch for both mutex-test and aim7 fserver are negligible. So far, it seems like the patch has not caused regression on smaller systems. Signed-off-by: Tim Chen <tim.c.chen@linux.intel.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: <stable@kernel.org> # .35.x LKML-Reference: <1282168827.9542.72.camel@schen9-DESK> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2010-08-061-98/+293
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: (27 commits) sched: Use correct macro to display sched_child_runs_first in /proc/sched_debug sched: No need for bootmem special cases sched: Revert nohz_ratelimit() for now sched: Reduce update_group_power() calls sched: Update rq->clock for nohz balanced cpus sched: Fix spelling of sibling sched, cpuset: Drop __cpuexit from cpu hotplug callbacks sched: Fix the racy usage of thread_group_cputimer() in fastpath_timer_check() sched: run_posix_cpu_timers: Don't check ->exit_state, use lock_task_sighand() sched: thread_group_cputime: Simplify, document the "alive" check sched: Remove the obsolete exit_state/signal hacks sched: task_tick_rt: Remove the obsolete ->signal != NULL check sched: __sched_setscheduler: Read the RLIMIT_RTPRIO value lockless sched: Fix comments to make them DocBook happy sched: Fix fix_small_capacity powerpc: Exclude arch_sd_sibiling_asym_packing() on UP powerpc: Enable asymmetric SMT scheduling on POWER7 sched: Add asymmetric group packing option for sibling domain sched: Fix capacity calculations for SMT4 sched: Change nohz idle load balancing logic to push model ...
| * Merge branch 'sched/urgent' into sched/coreIngo Molnar2010-08-051-10/+0
| |\ | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: include/linux/sched.h Merge reason: Add the leftover .35 urgent bits, fix the conflict. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * sched: Revert nohz_ratelimit() for nowPeter Zijlstra2010-07-171-10/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Norbert reported that nohz_ratelimit() causes his laptop to burn about 4W (40%) extra. For now back out the change and see if we can adjust the power management code to make better decisions. Reported-by: Norbert Preining <preining@logic.at> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Mike Galbraith <efault@gmx.de> Cc: Arjan van de Ven <arjan@infradead.org> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | Merge branch 'linus' into sched/coreIngo Molnar2010-07-211-5/+17
| |\ \ | | |/ | | | | | | | | | | | | Merge reason: Move from the -rc3 to the almost-rc6 base. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: No need for bootmem special casesPekka Enberg2010-07-171-12/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | As of commit dcce284 ("mm: Extend gfp masking to the page allocator") and commit 7e85ee0 ("slab,slub: don't enable interrupts during early boot"), the slab allocator makes sure we don't attempt to sleep during boot. Therefore, remove bootmem special cases from the scheduler and use plain GFP_KERNEL instead. Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1279225102-2572-1-git-send-email-penberg@cs.helsinki.fi> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched, cpuset: Drop __cpuexit from cpu hotplug callbacksTejun Heo2010-06-221-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 3a101d05 (sched: adjust when cpu_active and cpuset configurations are updated during cpu on/offlining) added hotplug notifiers marked with __cpuexit; however, ia64 drops text in __cpuexit during link unlike x86. This means that functions which are referenced during init but used only for cpu hot unplugging afterwards shouldn't be marked with __cpuexit. Drop __cpuexit from those functions. Reported-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Tony Luck <tony.luck@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <4C1FDF5B.1040301@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: __sched_setscheduler: Read the RLIMIT_RTPRIO value locklessOleg Nesterov2010-06-181-6/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __sched_setscheduler() takes lock_task_sighand() to access task->signal. This is not needed since ea6d290c, ->signal can't go away. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20100610230944.GA25903@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Change nohz idle load balancing logic to push modelVenkatesh Pallipadi2010-06-091-3/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the new push model, all idle CPUs indeed go into nohz mode. There is still the concept of idle load balancer (performing the load balancing on behalf of all the idle cpu's in the system). Busy CPU kicks the nohz balancer when any of the nohz CPUs need idle load balancing. The kickee CPU does the idle load balancing on behalf of all idle CPUs instead of the normal idle balance. This addresses the below two problems with the current nohz ilb logic: * the idle load balancer continued to have periodic ticks during idle and wokeup frequently, even though it did not have any rebalancing to do on behalf of any of the idle CPUs. * On x86 and CPUs that have APIC timer stoppage on idle CPUs, this periodic wakeup can result in a periodic additional interrupt on a CPU doing the timer broadcast. Also currently we are migrating the unpinned timers from an idle to the cpu doing idle load balancing (when all the cpus in the system are idle, there is no idle load balancing cpu and timers get added to the same idle cpu where the request was made. So the existing optimization works only on semi idle system). And In semi idle system, we no longer have periodic ticks on the idle load balancer CPU. Using that cpu will add more delays to the timers than intended (as that cpu's timer base may not be uptodate wrt jiffies etc). This was causing mysterious slowdowns during boot etc. For now, in the semi idle case, use the nearest busy cpu for migrating timers from an idle cpu. This is good for power-savings anyway. Signed-off-by: Venkatesh Pallipadi <venki@google.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <1274486981.2840.46.camel@sbs-t61.sc.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Avoid side-effect of tickless idle on update_cpu_loadVenkatesh Pallipadi2010-06-091-5/+95
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | tickless idle has a negative side effect on update_cpu_load(), which in turn can affect load balancing behavior. update_cpu_load() is supposed to be called every tick, to keep track of various load indicies. With tickless idle, there are no scheduler ticks called on the idle CPUs. Idle CPUs may still do load balancing (with idle_load_balance CPU) using the stale cpu_load. It will also cause problems when all CPUs go idle for a while and become active again. In this case loads would not degrade as expected. This is how rq->nr_load_updates change looks like under different conditions: <cpu_num> <nr_load_updates change> All CPUS idle for 10 seconds (HZ=1000) 0 1621 10 496 11 139 12 875 13 1672 14 12 15 21 1 1472 2 2426 3 1161 4 2108 5 1525 6 701 7 249 8 766 9 1967 One CPU busy rest idle for 10 seconds 0 10003 10 601 11 95 12 966 13 1597 14 114 15 98 1 3457 2 93 3 6679 4 1425 5 1479 6 595 7 193 8 633 9 1687 All CPUs busy for 10 seconds 0 10026 10 10026 11 10026 12 10026 13 10025 14 10025 15 10025 1 10026 2 10026 3 10026 4 10026 5 10026 6 10026 7 10026 8 10026 9 10026 That is update_cpu_load works properly only when all CPUs are busy. If all are idle, all the CPUs get way lower updates. And when few CPUs are busy and rest are idle, only busy and ilb CPU does proper updates and rest of the idle CPUs will do lower updates. The patch keeps track of when a last update was done and fixes up the load avg based on current time. On one of my test system SPECjbb with warehouse 1..numcpus, patch improves throughput numbers by ~1% (average of 6 runs). On another test system (with different domain hierarchy) there is no noticable change in perf. Signed-off-by: Venkatesh Pallipadi <venki@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> LKML-Reference: <AANLkTilLtDWQsAUrIxJ6s04WTgmw9GuOODc5AOrYsaR5@mail.gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Simplify the reacquire_kernel_lock() logicOleg Nesterov2010-06-091-7/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Contrary to what 6d558c3a says, there is no need to reload prev = rq->curr after the context switch. You always schedule back to where you came from, prev must be equal to current even if cpu/rq was changed. - This also means reacquire_kernel_lock() can use prev instead of current. - No need to reassign switch_count if reacquire_kernel_lock() reports need_resched(), we can just move the initial assignment down, under the "need_resched_nonpreemptible:" label. - Try to update the comment after context_switch(). Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20100519125711.GA30199@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched_clock: Add local_clock() API and improve documentationPeter Zijlstra2010-06-091-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For people who otherwise get to write: cpu_clock(smp_processor_id()), there is now: local_clock(). Also, as per suggestion from Andrew, provide some documentation on the various clock interfaces, and minimize the unsigned long long vs u64 mess. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Jens Axboe <jaxboe@fusionio.com> LKML-Reference: <1275052414.1645.52.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | Merge branch 'sched-wq' of ↵Ingo Molnar2010-06-081-54/+151
| |\ \ | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq into sched/core
| | * | sched: add hooks for workqueueTejun Heo2010-06-081-2/+51
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Concurrency managed workqueue needs to know when workers are going to sleep and waking up. Using these two hooks, cmwq keeps track of the current concurrency level and throttles execution of new works if it's too high and wakes up another worker from the sleep hook if it becomes too low. This patch introduces PF_WQ_WORKER to identify workqueue workers and adds the following two hooks. * wq_worker_waking_up(): called when a worker is woken up. * wq_worker_sleeping(): called when a worker is going to sleep and may return a pointer to a local task which should be woken up. The returned task is woken up using try_to_wake_up_local() which is simplified ttwu which is called under rq lock and can only wake up local tasks. Both hooks are currently defined as noop in kernel/workqueue_sched.h. Later cmwq implementation will replace them with proper implementation. These hooks are hard coded as they'll always be enabled. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Ingo Molnar <mingo@elte.hu>
| | * | sched: refactor try_to_wake_up()Tejun Heo2010-06-081-34/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Factor ttwu_activate() and ttwu_woken_up() out of try_to_wake_up(). The factoring out doesn't affect try_to_wake_up() much code-generation-wise. Depending on configuration options, it ends up generating the same object code as before or slightly different one due to different register assignment. This is to help future implementation of try_to_wake_up_local(). Mike Galbraith suggested rename to ttwu_post_activation() from ttwu_woken_up() and comment update in try_to_wake_up(). Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Ingo Molnar <mingo@elte.hu>
| | * | sched: adjust when cpu_active and cpuset configurations are updated during ↵Tejun Heo2010-06-081-17/+50
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cpu on/offlining Currently, when a cpu goes down, cpu_active is cleared before CPU_DOWN_PREPARE starts and cpuset configuration is updated from a default priority cpu notifier. When a cpu is coming up, it's set before CPU_ONLINE but cpuset configuration again is updated from the same cpu notifier. For cpu notifiers, this presents an inconsistent state. Threads which a CPU_DOWN_PREPARE notifier expects to be bound to the CPU can be migrated to other cpus because the cpu is no more inactive. Fix it by updating cpu_active in the highest priority cpu notifier and cpuset configuration in the second highest when a cpu is coming up. Down path is updated similarly. This guarantees that all other cpu notifiers see consistent cpu_active and cpuset configuration. cpuset_track_online_cpus() notifier is converted to cpuset_update_active_cpus() which just updates the configuration and now called from cpuset_cpu_[in]active() notifiers registered from sched_init_smp(). If cpuset is disabled, cpuset_update_active_cpus() degenerates into partition_sched_domains() making separate notifier for !CONFIG_CPUSETS unnecessary. This problem is triggered by cmwq. During CPU_DOWN_PREPARE, hotplug callback creates a kthread and kthread_bind()s it to the target cpu, and the thread is expected to run on that cpu. * Ingo's test discovered __cpuinit/exit markups were incorrect. Fixed. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Menage <menage@google.com>
| | * | sched: define and use CPU_PRI_* enums for cpu notifier prioritiesTejun Heo2010-06-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of hardcoding priority 10 and 20 in sched and perf, collect them into CPU_PRI_* enums. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
* | | | Merge commit 'v2.6.35-rc4' into perf/coreIngo Molnar2010-07-051-2/+2
|\ \ \ \ | | |_|/ | |/| | | | | | | | | | | | | | Merge reason: Pick up the latest perf fixes Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | Merge branch 'sched-fixes-for-linus' of ↵Linus Torvalds2010-07-021-2/+2
| |\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sched: Cure nr_iowait_cpu() users init: Fix comment init, sched: Fix race between init and kthreadd
| | * | | sched: Cure nr_iowait_cpu() usersPeter Zijlstra2010-07-011-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 0224cf4c5e (sched: Intoduce get_cpu_iowait_time_us()) broke things by not making sure preemption was indeed disabled by the callers of nr_iowait_cpu() which took the iowait value of the current cpu. This resulted in a heap of preempt warnings. Cure this by making nr_iowait_cpu() take a cpu number and fix up the callers to pass in the right number. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Rafael J. Wysocki <rjw@sisk.pl> Cc: Maxim Levitsky <maximlevitsky@gmail.com> Cc: Len Brown <len.brown@intel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Jiri Slaby <jslaby@suse.cz> Cc: linux-pm@lists.linux-foundation.org LKML-Reference: <1277968037.1868.120.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | | | Merge branch 'linus' into perf/coreThomas Gleixner2010-06-281-59/+74
|\ \ \ \ \ | |/ / / / | | | | | | | | | | | | | | | | | | | | Reason: Further changes conflict with upstream fixes Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | Merge branch 'sched-fixes-for-linus' of ↵Linus Torvalds2010-06-281-59/+65
| |\ \ \ \ | | |/ / / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: sched: Prevent compiler from optimising the sched_avg_update() loop sched: Fix over-scheduling bug sched: Fix PROVE_RCU vs cpu_cgroup
| | * | | sched: Prevent compiler from optimising the sched_avg_update() loopWill Deacon2010-06-251-0/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | GCC 4.4.1 on ARM has been observed to replace the while loop in sched_avg_update with a call to uldivmod, resulting in the following build failure at link-time: kernel/built-in.o: In function `sched_avg_update': kernel/sched.c:1261: undefined reference to `__aeabi_uldivmod' kernel/sched.c:1261: undefined reference to `__aeabi_uldivmod' make: *** [.tmp_vmlinux1] Error 1 This patch introduces a fake data hazard to the loop body to prevent the compiler optimising the loop away. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: <stable@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | | sched: Fix over-scheduling bugAlex,Shi2010-06-181-3/+0
| | |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit e70971591 ("sched: Optimize unused cgroup configuration") introduced an imbalanced scheduling bug. If we do not use CGROUP, function update_h_load won't update h_load. When the system has a large number of tasks far more than logical CPU number, the incorrect cfs_rq[cpu]->h_load value will cause load_balance() to pull too many tasks to the local CPU from the busiest CPU. So the busiest CPU keeps going in a round robin. That will hurt performance. The issue was found originally by a scientific calculation workload that developed by Yanmin. With that commit, the workload performance drops about 40%. CPU before after 00 : 2 : 7 01 : 1 : 7 02 : 11 : 6 03 : 12 : 7 04 : 6 : 6 05 : 11 : 7 06 : 10 : 6 07 : 12 : 7 08 : 11 : 6 09 : 12 : 6 10 : 1 : 6 11 : 1 : 6 12 : 6 : 6 13 : 2 : 6 14 : 2 : 6 15 : 1 : 6 Reviewed-by: Yanmin zhang <yanmin.zhang@intel.com> Signed-off-by: Alex Shi <alex.shi@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1276754893.9452.5442.camel@debian> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * | sched: Fix PROVE_RCU vs cpu_cgroupPeter Zijlstra2010-06-081-56/+59
| | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | PROVE_RCU has a few issues with the cpu_cgroup because the scheduler typically holds rq->lock around the css rcu derefs but the generic cgroup code doesn't (and can't) know about that lock. Provide means to add extra checks to the css dereference and use that in the scheduler to annotate its users. The addition of rq->lock to these checks is correct because the cgroup_subsys::attach() method takes the rq->lock for each task it moves, therefore by holding that lock, we ensure the task is pinned to the current cgroup and the RCU derefence is valid. That leaves one genuine race in __sched_setscheduler() where we used task_group() without holding any of the required locks and thus raced with the cgroup code. Solve this by moving the check under the appropriate lock. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: silence PROVE_RCU in sched_fork()Peter Zijlstra2010-06-231-0/+9
| |/ | | | | | | | | | | | | | | | | | | | | | | | | Because cgroup_fork() is ran before sched_fork() [ from copy_process() ] and the child's pid is not yet visible the child is pinned to its cgroup. Therefore we can silence this warning. A nicer solution would be moving cgroup_fork() to right after dup_task_struct() and exclude PF_STARTING from task_subsys_state(). Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Reviewed-by: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* | Merge commit 'v2.6.35-rc3' into perf/coreIngo Molnar2010-06-181-18/+6
|\ \ | |/ | | | | Merge reason: Go from -rc1 base to -rc3 base, merge in fixes.
| * sched: Fix wake_affine() vs RT tasksPeter Zijlstra2010-06-011-18/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Mike reports that since e9e9250b (sched: Scale down cpu_power due to RT tasks), wake_affine() goes funny on RT tasks due to them still having a !0 weight and wake_affine() still subtracts that from the rq weight. Since nobody should be using se->weight for RT tasks, set the value to zero. Also, since we now use ->cpu_power to normalize rq weights to account for RT cpu usage, add that factor into the imbalance computation. Reported-by: Mike Galbraith <efault@gmx.de> Tested-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1275316109.27810.22969.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | Merge branch 'tip/perf/core-3' of ↵Ingo Molnar2010-06-081-3/+3
|\ \ | |/ |/| | | git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into perf/core
| * tracing/sched: Make preempt_schedule() notraceSteven Rostedt2010-06-031-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The function tracer code uses ftrace_preempt_disable() to disable preemption instead of normal preempt_disable(). But there's a slight race condition that may cause it to lose a preemption check. This was made to keep the function tracer from recursing on itself by disabling preemption then having the enable call the function tracer again, causing infinite recursion. The bug was assumed to happen if the call was just in schedule, but this is incorrect. The bug is caused by preempt_schedule() which is called by preempt_enable(). The calling of preempt_enable() when NEED_RESCHED was set would call preempt_schedule() which would call the function tracer again. By making the preempt_schedule() and add_preempt_count() notrace then this will prevent the inifinite recursion. This is because the add_preempt_count() would stop the preempt_enable() in the function tracer from calling preempt_schedule() again. The sub_preempt_count() is also made notrace just to keep it symmetric. Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
* | Merge branch 'for-linus' of ↵Linus Torvalds2010-05-301-0/+17
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client: ceph: clean up on forwarded aborted mds request ceph: fix leak of osd authorizer ceph: close out mds, osd connections before stopping auth ceph: make lease code DN specific fs/ceph: Use ERR_CAST ceph: renew auth tickets before they expire ceph: do not resend mon requests on auth ticket renewal ceph: removed duplicated #includes ceph: avoid possible null dereference ceph: make mds requests killable, not interruptible sched: add wait_for_completion_killable_timeout
| * sched: add wait_for_completion_killable_timeoutSage Weil2010-05-291-0/+17
| | | | | | | | | | | | | | | | | | | | | | | | Add missing _killable_timeout variant for wait_for_completion that will return when a timeout expires or the task is killed. CC: Ingo Molnar <mingo@elte.hu> CC: Andreas Herrmann <andreas.herrmann3@amd.com> CC: Thomas Gleixner <tglx@linutronix.de> CC: Mike Galbraith <efault@gmx.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Sage Weil <sage@newdream.net>
* | signals: kill the awful task_rq_unlock_wait() hackOleg Nesterov2010-05-271-8/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that task->signal can't go away we can revert the horrible hack added by ad474caca3e2a0550b7ce0706527ad5ab389a4d4 ("fix for account_group_exec_runtime(), make sure ->signal can't be freed under rq->lock"). And we can do more cleanups sched_stats.h/posix-cpu-timers.c later. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Alan Cox <alan@linux.intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Acked-by: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | Merge branch 'kdb-merge' of ↵Linus Torvalds2010-05-211-2/+5
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb * 'kdb-merge' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb: (25 commits) kdb,debug_core: Allow the debug core to receive a panic notification MAINTAINERS: update kgdb, kdb, and debug_core info debug_core,kdb: Allow the debug core to process a recursive debug entry printk,kdb: capture printk() when in kdb shell kgdboc,kdb: Allow kdb to work on a non open console port kgdb: Add the ability to schedule a breakpoint via a tasklet mips,kgdb: kdb low level trap catch and stack trace powerpc,kgdb: Introduce low level trap catching x86,kgdb: Add low level debug hook kgdb: remove post_primary_code references kgdb,docs: Update the kgdb docs to include kdb kgdboc,keyboard: Keyboard driver for kdb with kgdb kgdb: gdb "monitor" -> kdb passthrough sparc,sunzilog: Add console polling support for sunzilog serial driver sh,sh-sci: Use NO_POLL_CHAR in the SCIF polled console code kgdb,8250,pl011: Return immediately from console poll kgdb: core changes to support kdb kdb: core for kgdb back end (2 of 2) kdb: core for kgdb back end (1 of 2) kgdb,blackfin: Add in kgdb_arch_set_pc for blackfin ...
| * | kdb: core for kgdb back end (2 of 2)Jason Wessel2010-05-201-2/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch contains the hooks and instrumentation into kernel which live outside the kernel/debug directory, which the kdb core will call to run commands like lsmod, dmesg, bt etc... CC: linux-arch@vger.kernel.org Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Martin Hicks <mort@sgi.com>
* | | Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6Linus Torvalds2010-05-201-0/+1
|\ \ \ | |/ / |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb-2.6: (229 commits) USB: remove unused usb_buffer_alloc and usb_buffer_free macros usb: musb: update gfp/slab.h includes USB: ftdi_sio: fix legacy SIO-device header USB: kl5usb105: reimplement using generic framework USB: kl5usb105: minor clean ups USB: kl5usb105: fix memory leak USB: io_ti: use kfifo to implement write buffering USB: io_ti: remove unsused private counter USB: ti_usb: use kfifo to implement write buffering USB: ir-usb: fix incorrect write-buffer length USB: aircable: fix incorrect write-buffer length USB: safe_serial: straighten out read processing USB: safe_serial: reimplement read using generic framework USB: safe_serial: reimplement write using generic framework usb-storage: always print quirks USB: usb-storage: trivial debug improvements USB: oti6858: use port write fifo USB: oti6858: use kfifo to implement write buffering USB: cypress_m8: use kfifo to implement write buffering USB: cypress_m8: remove unused drain define ... Fix up conflicts (due to usb_buffer_alloc/free renaming) in drivers/input/tablet/acecad.c drivers/input/tablet/kbtab.c drivers/input/tablet/wacom_sys.c drivers/media/video/gspca/gspca.c sound/usb/usbaudio.c
| * | wait_event_interruptible_locked() interfaceMichal Nazarewicz2010-05-201-0/+1
| |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | New wait_event_interruptible{,_exclusive}_locked{,_irq} macros added. They work just like versions without _locked* suffix but require the wait queue's lock to be held. Also __wake_up_locked() is now exported as to pair it with the above macros. The use case of this new facility is when one uses wait queue's lock to protect a data structure. This may be advantageous if the structure needs to be protected by a spinlock anyway. In particular, with additional spinlock the following code has to be used to wait for a condition: spin_lock(&data.lock); ... for (ret = 0; !ret && !(condition); ) { spin_unlock(&data.lock); ret = wait_event_interruptible(data.wqh, (condition)); spin_lock(&data.lock); } ... spin_unlock(&data.lock); This looks bizarre plus wait_event_interruptible() locks the wait queue's lock anyway so there is a unlock+lock sequence where it could be avoided. To avoid those problems and benefit from wait queue's lock, a code similar to the following should be used: /* Waiting */ spin_lock(&data.wqh.lock); ... ret = wait_event_interruptible_locked(data.wqh, (condition)); ... spin_unlock(&data.wqh.lock); /* Waiting exclusively */ spin_lock(&data.whq.lock); ... ret = wait_event_interruptible_exclusive_locked(data.whq, (condition)); ... spin_unlock(&data.whq.lock); /* Waking up */ spin_lock(&data.wqh.lock); ... wake_up_locked(&data.wqh); ... spin_unlock(&data.wqh.lock); When spin_lock_irq() is used matching versions of macros need to be used (*_locked_irq()). Signed-off-by: Michal Nazarewicz <m.nazarewicz@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Takashi Iwai <tiwai@suse.de> Cc: David Howells <dhowells@redhat.com> Cc: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* | Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2010-05-181-463/+263
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: (49 commits) stop_machine: Move local variable closer to the usage site in cpu_stop_cpu_callback() sched, wait: Use wrapper functions sched: Remove a stale comment ondemand: Make the iowait-is-busy time a sysfs tunable ondemand: Solve a big performance issue by counting IOWAIT time as busy sched: Intoduce get_cpu_iowait_time_us() sched: Eliminate the ts->idle_lastupdate field sched: Fold updating of the last_update_time_info into update_ts_time_stats() sched: Update the idle statistics in get_cpu_idle_time_us() sched: Introduce a function to update the idle statistics sched: Add a comment to get_cpu_idle_time_us() cpu_stop: add dummy implementation for UP sched: Remove rq argument to the tracepoints rcu: need barrier() in UP synchronize_sched_expedited() sched: correctly place paranioa memory barriers in synchronize_sched_expedited() sched: kill paranoia check in synchronize_sched_expedited() sched: replace migration_thread with cpu_stop stop_machine: reimplement using cpu_stop cpu_stop: implement stop_cpu[s]() sched: Fix select_idle_sibling() logic in select_task_rq_fair() ...
| * | sched, wait: Use wrapper functionsChangli Gao2010-05-111-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | epoll should not touch flags in wait_queue_t. This patch introduces a new function __add_wait_queue_exclusive(), for the users, who use wait queue as a LIFO queue. __add_wait_queue_tail_exclusive() is introduced too instead of add_wait_queue_exclusive_locked(). remove_wait_queue_locked() is removed, as it is a duplicate of __remove_wait_queue(), disliked by users, and with less users. Signed-off-by: Changli Gao <xiaosuo@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Paul Menage <menage@google.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Davide Libenzi <davidel@xmailserver.org> Cc: <containers@lists.linux-foundation.org> LKML-Reference: <1273214006-2979-1-git-send-email-xiaosuo@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | Merge branch 'cpu_stop' of ↵Ingo Molnar2010-05-081-225/+60
| |\ \ | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc into sched/core
| | * | rcu: need barrier() in UP synchronize_sched_expedited()Paul E. McKenney2010-05-071-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If synchronize_sched_expedited() is ever to be called from within kernel/sched.c in a !SMP PREEMPT kernel, the !SMP implementation needs a barrier(). Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| | * | sched: correctly place paranioa memory barriers in synchronize_sched_expedited()Paul E. McKenney2010-05-061-10/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The memory barriers must be in the SMP case, not in the !SMP case. Also add a barrier after the atomic_inc() in order to ensure that other CPUs see post-synchronize_sched_expedited() actions as following the expedited grace period. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Tejun Heo <tj@kernel.org>
| | * | sched: kill paranoia check in synchronize_sched_expedited()Tejun Heo2010-05-061-37/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The paranoid check which verifies that the cpu_stop callback is actually called on all online cpus is completely superflous. It's guaranteed by cpu_stop facility and if it didn't work as advertised other things would go horribly wrong and trying to recover using synchronize_sched() wouldn't be very meaningful. Kill the paranoid check. Removal of this feature is done as a separate step so that it can serve as a bisection point if something actually goes wrong. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: Josh Triplett <josh@freedesktop.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Dimitri Sivanich <sivanich@sgi.com>
| | * | sched: replace migration_thread with cpu_stopTejun Heo2010-05-061-224/+91
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently migration_thread is serving three purposes - migration pusher, context to execute active_load_balance() and forced context switcher for expedited RCU synchronize_sched. All three roles are hardcoded into migration_thread() and determining which job is scheduled is slightly messy. This patch kills migration_thread and replaces all three uses with cpu_stop. The three different roles of migration_thread() are splitted into three separate cpu_stop callbacks - migration_cpu_stop(), active_load_balance_cpu_stop() and synchronize_sched_expedited_cpu_stop() - and each use case now simply asks cpu_stop to execute the callback as necessary. synchronize_sched_expedited() was implemented with private preallocated resources and custom multi-cpu queueing and waiting logic, both of which are provided by cpu_stop. synchronize_sched_expedited_count is made atomic and all other shared resources along with the mutex are dropped. synchronize_sched_expedited() also implemented a check to detect cases where not all the callback got executed on their assigned cpus and fall back to synchronize_sched(). If called with cpu hotplug blocked, cpu_stop already guarantees that and the condition cannot happen; otherwise, stop_machine() would break. However, this patch preserves the paranoid check using a cpumask to record on which cpus the stopper ran so that it can serve as a bisection point if something actually goes wrong theree. Because the internal execution state is no longer visible, rcu_expedited_torture_stats() is removed. This patch also renames cpu_stop threads to from "stopper/%d" to "migration/%d". The names of these threads ultimately don't matter and there's no reason to make unnecessary userland visible changes. With this patch applied, stop_machine() and sched now share the same resources. stop_machine() is faster without wasting any resources and sched migration users are much cleaner. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: Josh Triplett <josh@freedesktop.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Dimitri Sivanich <sivanich@sgi.com>
| * | | sched: Remove rq argument to the tracepointsPeter Zijlstra2010-05-071-4/+4
| |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | struct rq isn't visible outside of sched.o so its near useless to expose the pointer, also there are no users of it, so remove it. Acked-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1272997616.1642.207.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Pre-compute cpumask_weight(sched_domain_span(sd))Peter Zijlstra2010-04-231-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Dave reported that his large SPARC machines spend lots of time in hweight64(), try and optimize some of those needless cpumask_weight() invocations (esp. with the large offstack cpumasks these are very expensive indeed). Reported-by: David Miller <davem@davemloft.net> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Cure load average vs NO_HZ woesPeter Zijlstra2010-04-231-13/+67
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Chase reported that due to us decrementing calc_load_task prematurely (before the next LOAD_FREQ sample), the load average could be scewed by as much as the number of CPUs in the machine. This patch, based on Chase's patch, cures the problem by keeping the delta of the CPU going into NO_HZ idle separately and folding that in on the next LOAD_FREQ update. This restores the balance and we get strict LOAD_FREQ period samples. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Chase Douglas <chase.douglas@canonical.com> LKML-Reference: <1271934490.1776.343.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Fix UP update_avg() build warningMike Galbraith2010-04-151-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | update_avg() is only used for SMP builds, move it to the nearest SMP block. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <1271309399.14779.17.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>