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* sched: Update normalized values on user updates via procChristian Ehrhardt2009-12-093-8/+29
| | | | | | | | | | | | | | | | | The normalized values are also recalculated in case the scaling factor changes. This patch updates the internally used scheduler tuning values that are normalized to one cpu in case a user sets new values via sysfs. Together with patch 2 of this series this allows to let user configured values scale (or not) to cpu add/remove events taking place later. Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1259579808-11357-4-git-send-email-ehrhardt@linux.vnet.ibm.com> [ v2: fix warning ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Make tunable scaling style configurableChristian Ehrhardt2009-12-094-1/+51
| | | | | | | | | | | | | | | | | As scaling now takes place on all kind of cpu add/remove events a user that configures values via proc should be able to configure if his set values are still rescaled or kept whatever happens. As the comments state that log2 was just a second guess that worked the interface is not just designed for on/off, but to choose a scaling type. Currently this allows none, log and linear, but more important it allwos us to keep the interface even if someone has an even better idea how to scale the values. Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1259579808-11357-3-git-send-email-ehrhardt@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Fix missing sched tunable recalculation on cpu add/removeChristian Ehrhardt2009-12-092-13/+32
| | | | | | | | | | | Based on Peter Zijlstras patch suggestion this enables recalculation of the scheduler tunables in response of a change in the number of cpus. It also adds a max of eight cpus that are considered in that scaling. Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1259579808-11357-2-git-send-email-ehrhardt@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Fix task priority bugPeter Zijlstra2009-12-091-6/+0
| | | | | | | | | | | | | | | | 83f9ac removed a call to effective_prio() in wake_up_new_task(), which leads to tasks running at MAX_PRIO. This is caused by the idle thread being set to MAX_PRIO before forking off init. O(1) used that to make sure idle was always preempted, CFS uses check_preempt_curr_idle() for that so we can savely remove this bit of legacy code. 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: <1259754383.4003.610.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: cgroup: Implement different treatment for idle sharesPeter Zijlstra2009-12-091-2/+6
| | | | | | | | | | | | | | | | | | | | When setting the weight for a per-cpu task-group, we have to put in a phantom weight when there is no work on that cpu, otherwise we'll not service that cpu when new work gets placed there until we again update the per-cpu weights. We used to add these phantom weights to the total, so that the idle per-cpu shares don't get inflated, this however causes the non-idle parts to get deflated, causing unexpected weight distibutions. Reverse this, so that the non-idle shares are correct but the idle shares are inflated. Reported-by: Yasunori Goto <y-goto@jp.fujitsu.com> Tested-by: Yasunori Goto <y-goto@jp.fujitsu.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1257934048.23203.76.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Remove unnecessary RCU exclusionPeter Zijlstra2009-12-091-7/+2
| | | | | | | | | | | | | | | As Nick pointed out, and realized by myself when doing: sched: Fix balance vs hotplug race the patch: sched: for_each_domain() vs RCU is wrong, sched_domains are freed after synchronize_sched(), which means disabling preemption is enough. Reported-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Discard some old bitsPeter Zijlstra2009-12-094-19/+7
| | | | | | | | | WAKEUP_RUNNING was an experiment, not sure why that ever ended up being merged... Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Clean up check_preempt_wakeup()Peter Zijlstra2009-12-091-40/+33
| | | | | | | | | Streamline the wakeup preemption code a bit, unifying the preempt path so that they all do the same. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Move update_curr() in check_preempt_wakeup() to avoid redundant callJupyung Lee2009-12-091-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | If a RT task is woken up while a non-RT task is running, check_preempt_wakeup() is called to check whether the new task can preempt the old task. The function returns quickly without going deeper because it is apparent that a RT task can always preempt a non-RT task. In this situation, check_preempt_wakeup() always calls update_curr() to update vruntime value of the currently running task. However, the function call is unnecessary and redundant at that moment because (1) a non-RT task can always be preempted by a RT task regardless of its vruntime value, and (2) update_curr() will be called shortly when the context switch between two occurs. By moving update_curr() in check_preempt_wakeup(), we can avoid redundant call to update_curr(), slightly reducing the time taken to wake up RT tasks. Signed-off-by: Jupyung Lee <jupyung@gmail.com> [ Place update_curr() right before the wake_preempt_entity() call, which is the only thing that relies on the updated vruntime ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1258451500-6714-1-git-send-email-jupyung@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Sanitize fork() handlingPeter Zijlstra2009-12-092-42/+33
| | | | | | | | | | | | | | | Currently we try to do task placement in wake_up_new_task() after we do the load-balance pass in sched_fork(). This yields complicated semantics in that we have to deal with tasks on different RQs and the set_task_cpu() calls in copy_process() and sched_fork() Rename ->task_new() to ->task_fork() and call it from sched_fork() before the balancing, this gives the policy a clear point to place the task. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Clean up ttwu() rq lockingPeter Zijlstra2009-12-091-8/+5
| | | | | | | | | | | Since set_task_clock() doesn't rely on rq->clock anymore we can simplyfy the mess in ttwu(). Optimize things a bit by not fiddling with the IRQ state there. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Remove rq->clock coupling from set_task_cpu()Peter Zijlstra2009-12-091-12/+1
| | | | | | | | | | | | | | | | | set_task_cpu() should be rq invariant and only touch task state, it currently fails to do so, which opens up a few races, since not all callers hold both rq->locks. Remove the relyance on rq->clock, as any site calling set_task_cpu() should also do a remote clock update, which should ensure the observed time between these two cpus is monotonic, as per kernel/sched_clock.c:sched_clock_remote(). Therefore we can simply remove the clock_offset bits and be happy. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Consolidate select_task_rq() callersPeter Zijlstra2009-12-091-3/+11
| | | | | | | | | Small cleanup. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> [ v2: build fix ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Remove sysctl.sched_featuresPeter Zijlstra2009-12-091-8/+0
| | | | | | | | | | Since we've had a much saner debugfs interface to this, remove the sysctl one. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> [ v2: build fix ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Protect sched_rr_get_param() access to task->sched_classThomas Gleixner2009-12-094-8/+8
| | | | | | | | | | | | | | | | sched_rr_get_param calls task->sched_class->get_rr_interval(task) without protection against a concurrent sched_setscheduler() call which modifies task->sched_class. Serialize the access with task_rq_lock(task) and hand the rq pointer into get_rr_interval() as it's needed at least in the sched_fair implementation. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <alpine.LFD.2.00.0912090930120.3089@localhost.localdomain> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Protect task->cpus_allowed access in sched_getaffinity()Thomas Gleixner2009-12-091-0/+4
| | | | | | | | | | | | sched_getaffinity() is not protected against a concurrent modification of the tasks affinity. Serialize the access with task_rq_lock(task). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20091208202026.769251187@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Fix balance vs hotplug racePeter Zijlstra2009-12-063-27/+39
| | | | | | | | | | | | | | | | | | | | | | | Since (e761b77: cpu hotplug, sched: Introduce cpu_active_map and redo sched domain managment) we have cpu_active_mask which is suppose to rule scheduler migration and load-balancing, except it never (fully) did. The particular problem being solved here is a crash in try_to_wake_up() where select_task_rq() ends up selecting an offline cpu because select_task_rq_fair() trusts the sched_domain tree to reflect the current state of affairs, similarly select_task_rq_rt() trusts the root_domain. However, the sched_domains are updated from CPU_DEAD, which is after the cpu is taken offline and after stop_machine is done. Therefore it can race perfectly well with code assuming the domains are right. Cure this by building the domains from cpu_active_mask on CPU_DOWN_PREPARE. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* cpumask: Fix generate_sched_domains() for UPGeert Uytterhoeven2009-12-061-1/+1
| | | | | | | | | | | | | | | | Commit acc3f5d7cabbfd6cec71f0c1f9900621fa2d6ae7 ("cpumask: Partition_sched_domains takes array of cpumask_var_t") changed the function signature of generate_sched_domains() for the CONFIG_SMP=y case, but forgot to update the corresponding function for the CONFIG_SMP=n case, causing: kernel/cpuset.c:2073: warning: passing argument 1 of 'generate_sched_domains' from incompatible pointer type Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <alpine.DEB.2.00.0912062038070.5693@ayla.of.borg> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2009-12-0610-177/+330
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: (35 commits) sched, cputime: Introduce thread_group_times() sched, cputime: Cleanups related to task_times() Revert "sched, x86: Optimize branch hint in __switch_to()" sched: Fix isolcpus boot option sched: Revert 498657a478c60be092208422fefa9c7b248729c2 sched, time: Define nsecs_to_jiffies() sched: Remove task_{u,s,g}time() sched: Introduce task_times() to replace task_{u,s}time() pair sched: Limit the number of scheduler debug messages sched.c: Call debug_show_all_locks() when dumping all tasks sched, x86: Optimize branch hint in __switch_to() sched: Optimize branch hint in context_switch() sched: Optimize branch hint in pick_next_task_fair() sched_feat_write(): Update ppos instead of file->f_pos sched: Sched_rt_periodic_timer vs cpu hotplug sched, kvm: Fix race condition involving sched_in_preempt_notifers sched: More generic WAKE_AFFINE vs select_idle_sibling() sched: Cleanup select_task_rq_fair() sched: Fix granularity of task_u/stime() sched: Fix/add missing update_rq_clock() calls ...
| * sched, cputime: Introduce thread_group_times()Hidetoshi Seto2009-12-024-21/+64
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a real fix for problem of utime/stime values decreasing described in the thread: http://lkml.org/lkml/2009/11/3/522 Now cputime is accounted in the following way: - {u,s}time in task_struct are increased every time when the thread is interrupted by a tick (timer interrupt). - When a thread exits, its {u,s}time are added to signal->{u,s}time, after adjusted by task_times(). - When all threads in a thread_group exits, accumulated {u,s}time (and also c{u,s}time) in signal struct are added to c{u,s}time in signal struct of the group's parent. So {u,s}time in task struct are "raw" tick count, while {u,s}time and c{u,s}time in signal struct are "adjusted" values. And accounted values are used by: - task_times(), to get cputime of a thread: This function returns adjusted values that originates from raw {u,s}time and scaled by sum_exec_runtime that accounted by CFS. - thread_group_cputime(), to get cputime of a thread group: This function returns sum of all {u,s}time of living threads in the group, plus {u,s}time in the signal struct that is sum of adjusted cputimes of all exited threads belonged to the group. The problem is the return value of thread_group_cputime(), because it is mixed sum of "raw" value and "adjusted" value: group's {u,s}time = foreach(thread){{u,s}time} + exited({u,s}time) This misbehavior can break {u,s}time monotonicity. Assume that if there is a thread that have raw values greater than adjusted values (e.g. interrupted by 1000Hz ticks 50 times but only runs 45ms) and if it exits, cputime will decrease (e.g. -5ms). To fix this, we could do: group's {u,s}time = foreach(t){task_times(t)} + exited({u,s}time) But task_times() contains hard divisions, so applying it for every thread should be avoided. This patch fixes the above problem in the following way: - Modify thread's exit (= __exit_signal()) not to use task_times(). It means {u,s}time in signal struct accumulates raw values instead of adjusted values. As the result it makes thread_group_cputime() to return pure sum of "raw" values. - Introduce a new function thread_group_times(*task, *utime, *stime) that converts "raw" values of thread_group_cputime() to "adjusted" values, in same calculation procedure as task_times(). - Modify group's exit (= wait_task_zombie()) to use this introduced thread_group_times(). It make c{u,s}time in signal struct to have adjusted values like before this patch. - Replace some thread_group_cputime() by thread_group_times(). This replacements are only applied where conveys the "adjusted" cputime to users, and where already uses task_times() near by it. (i.e. sys_times(), getrusage(), and /proc/<PID>/stat.) This patch have a positive side effect: - Before this patch, if a group contains many short-life threads (e.g. runs 0.9ms and not interrupted by ticks), the group's cputime could be invisible since thread's cputime was accumulated after adjusted: imagine adjustment function as adj(ticks, runtime), {adj(0, 0.9) + adj(0, 0.9) + ....} = {0 + 0 + ....} = 0. After this patch it will not happen because the adjustment is applied after accumulated. v2: - remove if()s, put new variables into signal_struct. Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Spencer Candland <spencer@bluehost.com> Cc: Americo Wang <xiyou.wangcong@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> LKML-Reference: <4B162517.8040909@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched, cputime: Cleanups related to task_times()Hidetoshi Seto2009-12-022-10/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Remove if({u,s}t)s because no one call it with NULL now. - Use cputime_{add,sub}(). - Add ifndef-endif for prev_{u,s}time since they are used only when !VIRT_CPU_ACCOUNTING. Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Spencer Candland <spencer@bluehost.com> Cc: Americo Wang <xiyou.wangcong@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> LKML-Reference: <4B1624C7.7040302@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Fix isolcpus boot optionRusty Russell2009-12-021-1/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Anton Blanchard wrote: > We allocate and zero cpu_isolated_map after the isolcpus > __setup option has run. This means cpu_isolated_map always > ends up empty and if CPUMASK_OFFSTACK is enabled we write to a > cpumask that hasn't been allocated. I introduced this regression in 49557e620339cb13 (sched: Fix boot crash by zalloc()ing most of the cpu masks). Use the bootmem allocator if they set isolcpus=, otherwise allocate and zero like normal. Reported-by: Anton Blanchard <anton@samba.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: peterz@infradead.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: <stable@kernel.org> LKML-Reference: <200912021409.17013.rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu> Tested-by: Anton Blanchard <anton@samba.org>
| * sched: Revert 498657a478c60be092208422fefa9c7b248729c2Tejun Heo2009-12-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 498657a478c60be092208422fefa9c7b248729c2 incorrectly assumed that preempt wasn't disabled around context_switch() and thus was fixing imaginary problem. It also broke KVM because it depended on ->sched_in() to be called with irq enabled so that it can do smp calls from there. Revert the incorrect commit and add comment describing different contexts under with the two callbacks are invoked. Avi: spotted transposed in/out in the added comment. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Avi Kivity <avi@redhat.com> Cc: peterz@infradead.org Cc: efault@gmx.de Cc: rusty@rustcorp.com.au LKML-Reference: <1259726212-30259-2-git-send-email-tj@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched, time: Define nsecs_to_jiffies()Hidetoshi Seto2009-11-262-2/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Use of msecs_to_jiffies() for nsecs_to_cputime() have some problems: - The type of msecs_to_jiffies()'s argument is unsigned int, so it cannot convert msecs greater than UINT_MAX = about 49.7 days. - msecs_to_jiffies() returns MAX_JIFFY_OFFSET if MSB of argument is set, assuming that input was negative value. So it cannot convert msecs greater than INT_MAX = about 24.8 days too. This patch defines a new function nsecs_to_jiffies() that can deal greater values, and that can deal all incoming values as unsigned. Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Spencer Candland <spencer@bluehost.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Amrico Wang <xiyou.wangcong@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: John Stultz <johnstul@linux.vnet.ibm.com> LKML-Reference: <4B0E16E7.5070307@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Remove task_{u,s,g}time()Hidetoshi Seto2009-11-262-32/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now all task_{u,s}time() pairs are replaced by task_times(). And task_gtime() is too simple to be an inline function. Cleanup them all. Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Spencer Candland <spencer@bluehost.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Americo Wang <xiyou.wangcong@gmail.com> LKML-Reference: <4B0E16D1.70902@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Introduce task_times() to replace task_{u,s}time() pairHidetoshi Seto2009-11-263-24/+41
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Functions task_{u,s}time() are called in pair in almost all cases. However task_stime() is implemented to call task_utime() from its inside, so such paired calls run task_utime() twice. It means we do heavy divisions (div_u64 + do_div) twice to get utime and stime which can be obtained at same time by one set of divisions. This patch introduces a function task_times(*tsk, *utime, *stime) to retrieve utime and stime at once in better, optimized way. Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Spencer Candland <spencer@bluehost.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Americo Wang <xiyou.wangcong@gmail.com> LKML-Reference: <4B0E16AE.906@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * Merge branch 'sched/urgent' into sched/coreIngo Molnar2009-11-2623-193/+373
| |\ | | | | | | | | | | | | | | | Merge reason: Pick up fixes that did not make it into .32.0 Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * sched: Sched_rt_periodic_timer vs cpu hotplugPeter Zijlstra2009-11-161-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Heiko reported a case where a timer interrupt managed to reference a root_domain structure that was already freed by a concurrent hot-un-plug operation. Solve this like the regular sched_domain stuff is also synchronized, by adding a synchronize_sched() stmt to the free path, this ensures that a root_domain stays present for any atomic section that could have observed it. Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Gregory Haskins <ghaskins@novell.com> Cc: Siddha Suresh B <suresh.b.siddha@intel.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> LKML-Reference: <1258363873.26714.83.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * sched, kvm: Fix race condition involving sched_in_preempt_notifersTejun Heo2009-11-151-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In finish_task_switch(), fire_sched_in_preempt_notifiers() is called after finish_lock_switch(). However, depending on architecture, preemption can be enabled after finish_lock_switch() which breaks the semantics of preempt notifiers. So move it before finish_arch_switch(). This also makes the in- notifiers symmetric to out- notifiers in terms of locking - now both are called under rq lock. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Avi Kivity <avi@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <4AFD2801.7020900@kernel.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| | * sched: Fix/add missing update_rq_clock() callsMike Galbraith2009-11-121-5/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | kthread_bind(), migrate_task() and sched_fork were missing updates, and try_to_wake_up() was updating after having already used the stale clock. Aside from preventing potential latency hits, there' a side benefit in that early boot printk time stamps become monotonic. Signed-off-by: Mike Galbraith <efault@gmx.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1258020464.6491.2.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu> LKML-Reference: <new-submission>
| * | sched: Limit the number of scheduler debug messagesMike Travis2009-11-261-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Remove the verbose scheduler debug messages unless kernel parameter "sched_debug" set. /proc/sched_debug unchanged. Signed-off-by: Mike Travis <travis@sgi.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Roland Dreier <rdreier@cisco.com> Cc: Randy Dunlap <rdunlap@xenotime.net> Cc: Tejun Heo <tj@kernel.org> Cc: Andi Kleen <andi@firstfloor.org> Cc: Greg Kroah-Hartman <gregkh@suse.de> Cc: Yinghai Lu <yhlu.kernel@gmail.com> Cc: David Rientjes <rientjes@google.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: Jack Steiner <steiner@sgi.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <20091118002221.489305000@alcatraz.americas.sgi.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched.c: Call debug_show_all_locks() when dumping all tasksShmulik Ladkani2009-11-251-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In commit v2.6.21-691-g39bc89f ("make SysRq-T show all tasks again") the interface of show_state_filter() was changed: zero valued 'state_filter' specifies "dump all tasks" (instead of -1). However, the condition for calling debug_show_all_locks() ("show locks if all tasks are dumped") was not updated accordingly. Signed-off-by: Shmulik Ladkani <shmulik.ladkani@gmail.com> Cc: peterz@infradead.org LKML-Reference: <4b0d2fe4.0ab6660a.6437.3cfc@mx.google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Optimize branch hint in context_switch()Tim Blechmann2009-11-241-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Branch hint profiling on my nehalem machine showed over 90% incorrect branch hints: 10420275 170645395 94 context_switch sched.c 3043 10408421 171098521 94 context_switch sched.c 3050 Signed-off-by: Tim Blechmann <tim@klingt.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4B0BBB9F.6080304@klingt.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Optimize branch hint in pick_next_task_fair()Tim Blechmann2009-11-241-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Branch hint profiling on my nehalem machine showed 90% incorrect branch hints: 15728471 158903754 90 pick_next_task_fair sched_fair.c 1555 Signed-off-by: Tim Blechmann <tim@klingt.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> LKML-Reference: <4B0BBBB1.2050100@klingt.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched_feat_write(): Update ppos instead of file->f_posJan Blunck2009-11-231-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | sched_feat_write() should update ppos instead of file->f_pos. (This reduces some BKL dependencies of this code.) Signed-off-by: Jan Blunck <jblunck@suse.de> Cc: jkacur@redhat.com Cc: Arnd Bergmann <arnd@arndb.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jamie Lokier <jamie@shareable.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> LKML-Reference: <1258735245-25826-8-git-send-email-jblunck@suse.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: More generic WAKE_AFFINE vs select_idle_sibling()Peter Zijlstra2009-11-131-17/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Instead of only considering SD_WAKE_AFFINE | SD_PREFER_SIBLING domains also allow all SD_PREFER_SIBLING domains below a SD_WAKE_AFFINE domain to change the affinity target. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <20091112145610.909723612@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Cleanup select_task_rq_fair()Peter Zijlstra2009-11-131-22/+51
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Clean up the new affine to idle sibling bits while trying to grok them. Should not have any function differences. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <20091112145610.832503781@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Fix granularity of task_u/stime()Hidetoshi Seto2009-11-121-9/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Originally task_s/utime() were designed to return clock_t but later changed to return cputime_t by following commit: commit efe567fc8281661524ffa75477a7c4ca9b466c63 Author: Christian Borntraeger <borntraeger@de.ibm.com> Date: Thu Aug 23 15:18:02 2007 +0200 It only changed the type of return value, but not the implementation. As the result the granularity of task_s/utime() is still that of clock_t, not that of cputime_t. So using task_s/utime() in __exit_signal() makes values accumulated to the signal struct to be rounded and coarse grained. This patch removes casts to clock_t in task_u/stime(), to keep granularity of cputime_t over the calculation. v2: Use div_u64() to avoid error "undefined reference to `__udivdi3`" on some 32bit systems. Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: xiyou.wangcong@gmail.com Cc: Spencer Candland <spencer@bluehost.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> LKML-Reference: <4AFB9029.9000208@jp.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Make sure task has correct sched_class after policy changePeter Zijlstra2009-11-101-12/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | From the code in rt_mutex_setprio(), it is evident that the intention is that task's with a RT 'prio' value as a consequence of receiving a PI boost also have their 'sched_class' field set to '&rt_sched_class'. However, Peter noticed that the code in __setscheduler() could result in this intention being frustrated. Fix it. Reported-by: Peter Williams <pwil3058@bigpond.net.au> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <1257880321.4108.457.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Fix and clean up rate-limit newidle codeMike Galbraith2009-11-101-13/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 1b9508f, "Rate-limit newidle" has been confirmed to fix the netperf UDP loopback regression reported by Alex Shi. This is a cleanup and a fix: - moved to a more out of the way spot - fix to ensure that balancing doesn't try to balance runqueues which haven't gone online yet, which can mess up CPU enumeration during boot. Reported-by: Alex Shi <alex.shi@intel.com> Reported-by: Zhang, Yanmin <yanmin_zhang@linux.intel.com> Signed-off-by: Mike Galbraith <efault@gmx.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: <stable@kernel.org> # .32.x: a1f84a3: sched: Check for an idle shared cache Cc: <stable@kernel.org> # .32.x: 1b9508f: sched: Rate-limit newidle Cc: <stable@kernel.org> # .32.x: fd21073: sched: Fix affinity logic Cc: <stable@kernel.org> # .32.x LKML-Reference: <1257821402.5648.17.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched, no_hz: Remove unused rq->last_tick_seen fieldLai Jiangshan2009-11-081-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In 15934a37324f32e0fda633dc7984a671ea81cd75, field last_tick_seen is added to struct rq. But it is unused now. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Cc: Guillaume Chazarain <guichaz@yahoo.fr> LKML-Reference: <4AE6A513.6010100@cn.fujitsu.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Fix affinity logic in select_task_rq_fair()Mike Galbraith2009-11-051-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ingo Molnar reported: [ 26.804000] BUG: using smp_processor_id() in preemptible [00000000] code: events/1/10 [ 26.808000] caller is vmstat_update+0x26/0x70 [ 26.812000] Pid: 10, comm: events/1 Not tainted 2.6.32-rc5 #6887 [ 26.816000] Call Trace: [ 26.820000] [<c1924a24>] ? printk+0x28/0x3c [ 26.824000] [<c13258a0>] debug_smp_processor_id+0xf0/0x110 [ 26.824000] mount used greatest stack depth: 1464 bytes left [ 26.828000] [<c111d086>] vmstat_update+0x26/0x70 [ 26.832000] [<c1086418>] worker_thread+0x188/0x310 [ 26.836000] [<c10863b7>] ? worker_thread+0x127/0x310 [ 26.840000] [<c108d310>] ? autoremove_wake_function+0x0/0x60 [ 26.844000] [<c1086290>] ? worker_thread+0x0/0x310 [ 26.848000] [<c108cf0c>] kthread+0x7c/0x90 [ 26.852000] [<c108ce90>] ? kthread+0x0/0x90 [ 26.856000] [<c100c0a7>] kernel_thread_helper+0x7/0x10 [ 26.860000] BUG: using smp_processor_id() in preemptible [00000000] code: events/1/10 [ 26.864000] caller is vmstat_update+0x3c/0x70 Because this commit: a1f84a3: sched: Check for an idle shared cache in select_task_rq_fair() broke ->cpus_allowed. Signed-off-by: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: arjan@infradead.org Cc: <stable@kernel.org> LKML-Reference: <1257415066.12867.1.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Rate-limit newidleMike Galbraith2009-11-042-1/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Rate limit newidle to migration_cost. It's a win for all stages of sysbench oltp tests. Signed-off-by: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Check for an idle shared cache in select_task_rq_fair()Mike Galbraith2009-11-041-4/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When waking affine, check for an idle shared cache, and if found, wake to that CPU/sibling instead of the waker's CPU. This improves pgsql+oltp ramp up by roughly 8%. Possibly more for other loads, depending on overlap. The trade-off is a roughly 1% peak downturn if tasks are truly synchronous. Signed-off-by: Mike Galbraith <efault@gmx.de> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: <stable@kernel.org> LKML-Reference: <1256654138.17752.7.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | cpumask: Partition_sched_domains takes array of cpumask_var_tRusty Russell2009-11-042-32/+55
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently partition_sched_domains() takes a 'struct cpumask *doms_new' which is a kmalloc'ed array of cpumask_t. You can't have such an array if 'struct cpumask' is undefined, as we plan for CONFIG_CPUMASK_OFFSTACK=y. So, we make this an array of cpumask_var_t instead: this is the same for the CONFIG_CPUMASK_OFFSTACK=n case, but requires multiple allocations for the CONFIG_CPUMASK_OFFSTACK=y case. Hence we add alloc_sched_domains() and free_sched_domains() functions. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <200911031453.40668.rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | cpumask: Simplify sched_rt.cRusty Russell2009-11-041-37/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | find_lowest_rq() wants to call pick_optimal_cpu() on the intersection of sched_domain_span(sd) and lowest_mask. Rather than doing a cpus_and into a temporary, we can open-code it. This actually makes the code slightly clearer, IMHO. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Acked-by: Gregory Haskins <ghaskins@novell.com> Cc: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <200911031453.15350.rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Remove unused cpu_nr_migrations()Hiroshi Shimamoto2009-11-041-11/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | cpu_nr_migrations() is not used, remove it. Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <4AF12A66.6020609@ct.jp.nec.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Remove unused __schedule() declarationHiroshi Shimamoto2009-11-041-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | __schedule() had been removed. Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <4AF129C8.3030008@ct.jp.nec.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched, cpuacct: Fix niced guest time accountingRyota Ozaki2009-10-251-2/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | CPU time of a guest is always accounted in 'user' time without concern for the nice value of its counterpart process although the guest is scheduled under the nice value. This patch fixes the defect and accounts cpu time of a niced guest in 'nice' time as same as a niced process. And also the patch adds 'guest_nice' to cpuacct. The value provides niced guest cpu time which is like 'nice' to 'user'. The original discussions can be found here: http://www.mail-archive.com/kvm@vger.kernel.org/msg23982.html http://www.mail-archive.com/kvm@vger.kernel.org/msg23860.html Signed-off-by: Ryota Ozaki <ozaki.ryota@gmail.com> Acked-by: Avi Kivity <avi@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1256314810-7897-1-git-send-email-ozaki.ryota@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | Merge branch 'linus' into sched/coreIngo Molnar2009-10-2597-8402/+8993
| |\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: fs/proc/array.c Merge reason: resolve conflict and queue up dependent patch. Signed-off-by: Ingo Molnar <mingo@elte.hu>
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