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2010-03-11sched: Remove avg_overlapMike Galbraith1-33/+0
Both avg_overlap and avg_wakeup had an inherent problem in that their accuracy was detrimentally affected by cross-cpu wakeups, this because we are missing the necessary call to update_curr(). This can't be fixed without increasing overhead in our already too fat fastpath. Additionally, with recent load balancing changes making us prefer to place tasks in an idle cache domain (which is good for compute bound loads), communicating tasks suffer when a sync wakeup, which would enable affine placement, is turned into a non-sync wakeup by SYNC_LESS. With one task on the runqueue, wake_affine() rejects the affine wakeup request, leaving the unfortunate where placed, taking frequent cache misses. Remove it, and recover some fastpath cycles. Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1268301121.6785.30.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-11sched: Remove avg_wakeupMike Galbraith1-22/+4
Testing the load which led to this heuristic (nfs4 kbuild) shows that it has outlived it's usefullness. With intervening load balancing changes, I cannot see any difference with/without, so recover there fastpath cycles. Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1268301062.6785.29.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-11sched: Rate-limit nohzMike Galbraith1-0/+12
Entering nohz code on every micro-idle is costing ~10% throughput for netperf TCP_RR when scheduling cross-cpu. Rate limiting entry fixes this, but raises ticks a bit. On my Q6600, an idle box goes from ~85 interrupts/sec to 128. The higher the context switch rate, the more nohz entry costs. With this patch and some cycle recovery patches in my tree, max cross cpu context switch rate is improved by ~16%, a large portion of which of which is this ratelimiting. Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1268301003.6785.28.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-11sched: Implement group scheduler statistics in one structLucas De Marchi1-38/+9
Put all statistic fields of sched_entity in one struct, sched_statistics, and embed it into sched_entity. This change allows to memset the sched_statistics to 0 when needed (for instance when forking), avoiding bugs of non initialized fields. Signed-off-by: Lucas De Marchi <lucas.de.marchi@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1268275065-18542-1-git-send-email-lucas.de.marchi@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-11sched: Cleanup: remove unused variable in try_to_wake_up()Dan Carpenter1-2/+2
We haven't used the "orig_rq" variable since 055a00865d "Fix/add missing update_rq_clock() calls" Signed-off-by: Dan Carpenter <error27@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andreas Herrmann <andreas.herrmann3@amd.com> Cc: Gautham R Shenoy <ego@in.ibm.com> Cc: efault@gmx.de LKML-Reference: <20100306111752.GL4958@bicker> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-03-07sysdev: Pass attribute in sysdev_class attributes show/storeAndi Kleen1-0/+4
Passing the attribute to the low level IO functions allows all kinds of cleanups, by sharing low level IO code without requiring an own function for every piece of data. Also drivers can extend the attributes with own data fields and use that in the low level function. Similar to sysdev_attributes and normal attributes. This is a tree-wide sweep, converting everything in one go. No functional changes in this patch other than passing the new argument everywhere. Tested on x86, the non x86 parts are uncompiled. Signed-off-by: Andi Kleen <ak@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-03-06kernel core: use helpers for rlimitsJiri Slaby1-2/+2
Make sure compiler won't do weird things with limits. E.g. fetching them twice may return 2 different values after writable limits are implemented. I.e. either use rlimit helpers added in commit 3e10e716abf3 ("resource: add helpers for fetching rlimits") or ACCESS_ONCE if not applicable. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: john stultz <johnstul@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-03-03Merge branch 'for-linus' of ↵Linus Torvalds1-2/+2
git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/percpu: percpu: add __percpu sparse annotations to what's left percpu: add __percpu sparse annotations to fs percpu: add __percpu sparse annotations to core kernel subsystems local_t: Remove leftover local.h this_cpu: Remove pageset_notifier this_cpu: Page allocator conversion percpu, x86: Generic inc / dec percpu instructions local_t: Move local.h include to ringbuffer.c and ring_buffer_benchmark.c module: Use this_cpu_xx to dynamically allocate counters local_t: Remove cpu_local_xx macros percpu: refactor the code in pcpu_[de]populate_chunk() percpu: remove compile warnings caused by __verify_pcpu_ptr() percpu: make accessors check for percpu pointer in sparse percpu: add __percpu for sparse. percpu: make access macros universal percpu: remove per_cpu__ prefix.
2010-02-28Merge branch 'sched-core-for-linus' of ↵Linus Torvalds1-2009/+116
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: (25 commits) sched: Fix SCHED_MC regression caused by change in sched cpu_power sched: Don't use possibly stale sched_class kthread, sched: Remove reference to kthread_create_on_cpu sched: cpuacct: Use bigger percpu counter batch values for stats counters percpu_counter: Make __percpu_counter_add an inline function on UP sched: Remove member rt_se from struct rt_rq sched: Change usage of rt_rq->rt_se to rt_rq->tg->rt_se[cpu] sched: Remove unused update_shares_locked() sched: Use for_each_bit sched: Queue a deboosted task to the head of the RT prio queue sched: Implement head queueing for sched_rt sched: Extend enqueue_task to allow head queueing sched: Remove USER_SCHED sched: Fix the place where group powers are updated sched: Assume *balance is valid sched: Remove load_balance_newidle() sched: Unify load_balance{,_newidle}() sched: Add a lock break for PREEMPT=y sched: Remove from fwd decls sched: Remove rq_iterator from move_one_task ... Fix up trivial conflicts in kernel/sched.c
2010-02-28Merge branch 'sched-fixes-for-linus' of ↵Linus Torvalds1-28/+58
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: Fix race between ttwu() and task_rq_lock() sched: Fix SMT scheduler regression in find_busiest_queue() sched: Fix sched_mv_power_savings for !SMT kernel/sched.c: Suppress unused var warning
2010-02-28Merge branch 'perf-core-for-linus' of ↵Linus Torvalds1-3/+9
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: (172 commits) perf_event, amd: Fix spinlock initialization perf_event: Fix preempt warning in perf_clock() perf tools: Flush maps on COMM events perf_events, x86: Split PMU definitions into separate files perf annotate: Handle samples not at objdump output addr boundaries perf_events, x86: Remove superflous MSR writes perf_events: Simplify code by removing cpu argument to hw_perf_group_sched_in() perf_events, x86: AMD event scheduling perf_events: Add new start/stop PMU callbacks perf_events: Report the MMAP pgoff value in bytes perf annotate: Defer allocating sym_priv->hist array perf symbols: Improve debugging information about symtab origins perf top: Use a macro instead of a constant variable perf symbols: Check the right return variable perf/scripts: Tag syscall_name helper as not yet available perf/scripts: Add perf-trace-python Documentation perf/scripts: Remove unnecessary PyTuple resizes perf/scripts: Add syscall tracing scripts perf/scripts: Add Python scripting engine perf/scripts: Remove check-perf-trace from listed scripts ... Fix trivial conflict in tools/perf/util/probe-event.c
2010-02-25sched: Better name for for_each_domain_rdPaul E. McKenney1-2/+2
As suggested by Peter Ziljstra, make better choice of name for for_each_domain_rd(), containing "rcu_dereference", given that it is but a wrapper for rcu_dereference_check(). The name rcu_dereference_check_sched_domain() does that and provides a separate per-subsystem name space. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1266887105-1528-7-git-send-email-paulmck@linux.vnet.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-25sched: Use lockdep-based checking on rcu_dereference()Paul E. McKenney1-3/+8
Update the rcu_dereference() usages to take advantage of the new lockdep-based checking. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: mathieu.desnoyers@polymtl.ca Cc: josh@joshtriplett.org Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org Cc: Valdis.Kletnieks@vt.edu Cc: dhowells@redhat.com LKML-Reference: <1266887105-1528-6-git-send-email-paulmck@linux.vnet.ibm.com> [ -v2: fix allmodconfig missing symbol export build failure on x86 ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-17sched: Don't use possibly stale sched_classThomas Gleixner1-2/+4
setscheduler() saves task->sched_class outside of the rq->lock held region for a check after the setscheduler changes have become effective. That might result in checking a stale value. rtmutex_setprio() has the same problem, though it is protected by p->pi_lock against setscheduler(), but for correctness sake (and to avoid bad examples) it needs to be fixed as well. Retrieve task->sched_class inside of the rq->lock held region. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: stable@kernel.org
2010-02-17percpu: add __percpu sparse annotations to core kernel subsystemsTejun Heo1-2/+2
Add __percpu sparse annotations to core subsystems. These annotations are to make sparse consider percpu variables to be in a different address space and warn if accessed without going through percpu accessors. This patch doesn't affect normal builds. Signed-off-by: Tejun Heo <tj@kernel.org> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: linux-mm@kvack.org Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Dipankar Sarma <dipankar@in.ibm.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Eric Biederman <ebiederm@xmission.com>
2010-02-16Merge branch 'sched/urgent' into sched/coreThomas Gleixner1-27/+46
Conflicts: kernel/sched.c Necessary due to the urgent fixes which conflict with the code move from sched.c to sched_fair.c Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-02-16sched: Fix race between ttwu() and task_rq_lock()Peter Zijlstra1-27/+46
Thomas found that due to ttwu() changing a task's cpu without holding the rq->lock, task_rq_lock() might end up locking the wrong rq. Avoid this by serializing against TASK_WAKING. Reported-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1266241712.15770.420.camel@laptop> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-02-16sched: Fix SMT scheduler regression in find_busiest_queue()Suresh Siddha1-2/+13
Fix a SMT scheduler performance regression that is leading to a scenario where SMT threads in one core are completely idle while both the SMT threads in another core (on the same socket) are busy. This is caused by this commit (with the problematic code highlighted) commit bdb94aa5dbd8b55e75f5a50b61312fe589e2c2d1 Author: Peter Zijlstra <a.p.zijlstra@chello.nl> Date: Tue Sep 1 10:34:38 2009 +0200 sched: Try to deal with low capacity @@ -4203,15 +4223,18 @@ find_busiest_queue() ... for_each_cpu(i, sched_group_cpus(group)) { + unsigned long power = power_of(i); ... - wl = weighted_cpuload(i); + wl = weighted_cpuload(i) * SCHED_LOAD_SCALE; + wl /= power; - if (rq->nr_running == 1 && wl > imbalance) + if (capacity && rq->nr_running == 1 && wl > imbalance) continue; On a SMT system, power of the HT logical cpu will be 589 and the scheduler load imbalance (for scenarios like the one mentioned above) can be approximately 1024 (SCHED_LOAD_SCALE). The above change of scaling the weighted load with the power will result in "wl > imbalance" and ultimately resulting in find_busiest_queue() return NULL, causing load_balance() to think that the load is well balanced. But infact one of the tasks can be moved to the idle core for optimal performance. We don't need to use the weighted load (wl) scaled by the cpu power to compare with imabalance. In that condition, we already know there is only a single task "rq->nr_running == 1" and the comparison between imbalance, wl is to make sure that we select the correct priority thread which matches imbalance. So we really need to compare the imabalnce with the original weighted load of the cpu and not the scaled load. But in other conditions where we want the most hammered(busiest) cpu, we can use scaled load to ensure that we consider the cpu power in addition to the actual load on that cpu, so that we can move the load away from the guy that is getting most hammered with respect to the actual capacity, as compared with the rest of the cpu's in that busiest group. Fix it. Reported-by: Ma Ling <ling.ma@intel.com> Initial-Analysis-by: Zhang, Yanmin <yanmin_zhang@linux.intel.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1266023662.2808.118.camel@sbs-t61.sc.intel.com> Cc: stable@kernel.org [2.6.32.x] Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-02-08sched: cpuacct: Use bigger percpu counter batch values for stats countersAnton Blanchard1-1/+19
When CONFIG_VIRT_CPU_ACCOUNTING and CONFIG_CGROUP_CPUACCT are enabled we can call cpuacct_update_stats with values much larger than percpu_counter_batch. This means the call to percpu_counter_add will always add to the global count which is protected by a spinlock and we end up with a global spinlock in the scheduler. Based on an idea by KOSAKI Motohiro, this patch scales the batch value by cputime_one_jiffy such that we have the same batch limit as we would if CONFIG_VIRT_CPU_ACCOUNTING was disabled. His patch did this once at boot but that initialisation happened too early on PowerPC (before time_init) and it was never updated at runtime as a result of a hotplug cpu add/remove. This patch instead scales percpu_counter_batch by cputime_one_jiffy at runtime, which keeps the batch correct even after cpu hotplug operations. We cap it at INT_MAX in case of overflow. For architectures that do not support CONFIG_VIRT_CPU_ACCOUNTING, cputime_one_jiffy is the constant 1 and gcc is smart enough to optimise min(s32 percpu_counter_batch, INT_MAX) to just percpu_counter_batch at least on x86 and PowerPC. So there is no need to add an #ifdef. On a 64 thread PowerPC box with CONFIG_VIRT_CPU_ACCOUNTING and CONFIG_CGROUP_CPUACCT enabled, a context switch microbenchmark is 234x faster and almost matches a CONFIG_CGROUP_CPUACCT disabled kernel: CONFIG_CGROUP_CPUACCT disabled: 16906698 ctx switches/sec CONFIG_CGROUP_CPUACCT enabled: 61720 ctx switches/sec CONFIG_CGROUP_CPUACCT + patch: 16663217 ctx switches/sec Tested with: wget http://ozlabs.org/~anton/junkcode/context_switch.c make context_switch for i in `seq 0 63`; do taskset -c $i ./context_switch & done vmstat 1 Signed-off-by: Anton Blanchard <anton@samba.org> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Tested-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-08Merge branch 'sched/urgent' into sched/coreIngo Molnar1-13/+31
Merge reason: Merge dependent fix, update to latest -rc. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-08kernel/sched.c: Suppress unused var warningAndrew Morton1-1/+1
On UP: kernel/sched.c: In function 'wake_up_new_task': kernel/sched.c:2631: warning: unused variable 'cpu' Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-04sched: Remove member rt_se from struct rt_rqYong Zhang1-2/+0
It's a duplicate of tg->rt_se[cpu] and the only usage is sched_rt_rq_dequeue() and sched_rt_rq_enqueue(). After the first patch to those two function. rt_se can be removed. Signed-off-by: Yong Zhang <yong.zhang0@gmail.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <2674af741001282258q38781619u653ca4a7dd267347@mail.gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-02-02sched: Remove unused update_shares_locked()Peter Zijlstra1-14/+0
Commit f492e12ef050e02bf0185b6b57874992591b9be1 ("sched: Remove load_balance_newidle()") removed the only user of this function, so remove it too. Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1265019219.24455.128.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-01-29Merge branch 'perf/urgent' into perf/coreIngo Molnar1-1/+4
Merge reason: We want to queue up a dependent patch. Also update to later -rc's. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-01-22sched: Queue a deboosted task to the head of the RT prio queueThomas Gleixner1-1/+1
rtmutex_set_prio() is used to implement priority inheritance for futexes. When a task is deboosted it gets enqueued at the tail of its RT priority list. This is violating the POSIX scheduling semantics: rt priority list X contains two runnable tasks A and B task A runs with priority X and holds mutex M task C preempts A and is blocked on mutex M -> task A is boosted to priority of task C (Y) task A unlocks the mutex M and deboosts itself -> A is dequeued from rt priority list Y -> A is enqueued to the tail of rt priority list X task C schedules away task B runs This is wrong as task A did not schedule away and therefor violates the POSIX scheduling semantics. Enqueue the task to the head of the priority list instead. Reported-by: Mathias Weber <mathias.weber.mw1@roche.com> Reported-by: Carsten Emde <cbe@osadl.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Tested-by: Carsten Emde <cbe@osadl.org> Tested-by: Mathias Weber <mathias.weber.mw1@roche.com> LKML-Reference: <20100120171629.809074113@linutronix.de>
2010-01-22sched: Extend enqueue_task to allow head queueingThomas Gleixner1-6/+7
The ability of enqueueing a task to the head of a SCHED_FIFO priority list is required to fix some violations of POSIX scheduling policy. Extend the related functions with a "head" argument. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Tested-by: Carsten Emde <cbe@osadl.org> Tested-by: Mathias Weber <mathias.weber.mw1@roche.com> LKML-Reference: <20100120171629.734886007@linutronix.de>
2010-01-21sched: Fix fork vs hotplug vs cpuset namespacesPeter Zijlstra1-12/+27
There are a number of issues: 1) TASK_WAKING vs cgroup_clone (cpusets) copy_process(): sched_fork() child->state = TASK_WAKING; /* waiting for wake_up_new_task() */ if (current->nsproxy != p->nsproxy) ns_cgroup_clone() cgroup_clone() mutex_lock(inode->i_mutex) mutex_lock(cgroup_mutex) cgroup_attach_task() ss->can_attach() ss->attach() [ -> cpuset_attach() ] cpuset_attach_task() set_cpus_allowed_ptr(); while (child->state == TASK_WAKING) cpu_relax(); will deadlock the system. 2) cgroup_clone (cpusets) vs copy_process So even if the above would work we still have: copy_process(): if (current->nsproxy != p->nsproxy) ns_cgroup_clone() cgroup_clone() mutex_lock(inode->i_mutex) mutex_lock(cgroup_mutex) cgroup_attach_task() ss->can_attach() ss->attach() [ -> cpuset_attach() ] cpuset_attach_task() set_cpus_allowed_ptr(); ... p->cpus_allowed = current->cpus_allowed over-writing the modified cpus_allowed. 3) fork() vs hotplug if we unplug the child's cpu after the sanity check when the child gets attached to the task_list but before wake_up_new_task() shit will meet with fan. Solve all these issues by moving fork cpu selection into wake_up_new_task(). Reported-by: Serge E. Hallyn <serue@us.ibm.com> Tested-by: Serge E. Hallyn <serue@us.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1264106190.4283.1314.camel@laptop> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-01-21sched: Remove USER_SCHEDDhaval Giani1-107/+7
Remove the USER_SCHED feature. It has been scheduled to be removed in 2.6.34 as per http://marc.info/?l=linux-kernel&m=125728479022976&w=2 Signed-off-by: Dhaval Giani <dhaval.giani@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1263990378.24844.3.camel@localhost> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-01-21sched: Remove the sched_class load_balance methodsPeter Zijlstra1-26/+0
Take out the sched_class methods for load-balancing. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-01-21sched: Move load balance code into sched_fair.cPeter Zijlstra1-1840/+79
Straight fwd code movement. Since non of the load-balance abstractions are used anymore, do away with them and simplify the code some. In preparation move the code around. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-01-21sched: Reassign prev and switch_count when reacquire_kernel_lock() failYong Zhang1-1/+4
Assume A->B schedule is processing, if B have acquired BKL before and it need reschedule this time. Then on B's context, it will go to need_resched_nonpreemptible for reschedule. But at this time, prev and switch_count are related to A. It's wrong and will lead to incorrect scheduler statistics. Signed-off-by: Yong Zhang <yong.zhang0@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <2674af741001102238w7b0ddcadref00d345e2181d11@mail.gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-01-13sched/perf: Make sure irqs are disabled for perf_event_task_sched_in()Jamie Iles1-0/+6
perf_event_task_sched_in() expects interrupts to be disabled, but on architectures with __ARCH_WANT_INTERRUPTS_ON_CTXSW defined, this isn't true. If this is defined, disable irqs around the call in finish_task_switch(). Signed-off-by: Jamie Iles <jamie.iles@picochip.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Russell King - ARM Linux <linux@arm.linux.org.uk> LKML-Reference: <1262964453-27370-1-git-send-email-jamie.iles@picochip.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-01-13Merge branch 'perf/urgent' into perf/coreIngo Molnar1-143/+164
Merge reason: queue up dependent patch, update to -rc4 Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-28sched: might_sleep(): Make file parameter const char *Simon Kagstrom1-1/+1
Fixes a warning when building with g++: warning: deprecated conversion from string constant to 'char*' And the file parameter use is constant, so mark it as such. Signed-off-by: Simon Kagstrom <simon.kagstrom@netinsight.net> Cc: peterz@infradead.org LKML-Reference: <20091223110818.442d848e@marrow.netinsight.se> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-28perf events: Remove arg from perf sched hooksPeter Zijlstra1-3/+3
Since we only ever schedule the local cpu, there is no need to pass the cpu number to the perf sched hooks. This micro-optimizes things a bit. Signed-off-by: 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: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-23sched: Revert 738d2be, simplify set_task_cpu()Peter Zijlstra1-5/+4
Effectively reverts 738d2be4301007f054541c5c4bf7fb6a361c9b3a. As demonstrated by Eric, we really need to call __set_task_cpu() early in the fork() path to properly initialize the various task state -- specifically the cgroup state through set_task_rq(). [ we could probably fix this by explicitly calling __set_task_cpu() from sched_fork(), but lets try that for the next cycle and simply revert to the old behaviour for now. ] Reported-by: Eric Paris <eparis@redhat.com> Tested-by: Eric Paris <eparis@redhat.com>, Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: efault@gmx.de LKML-Reference: <1261492999.4937.36.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-20sched: Fix hotplug hangPeter Zijlstra1-1/+1
The hot-unplug kstopmachine usage does a wakeup after deactivating the cpu, hence we cannot use cpu_active() here but must rely on the good olde online. Reported-by: Sachin Sant <sachinp@in.ibm.com> Reported-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Tested-by: Jens Axboe <jens.axboe@oracle.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> LKML-Reference: <1261326987.4314.24.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-20sched: Restore printk sanityPeter Zijlstra1-40/+49
Revert the braindead pr_* crap. (Commit 663997d "sched: Use pr_fmt() and pr_<level>()") It's dumb and causes stupid "sched: " strings all over the place. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Mike Galbraith <efault@gmx.de> Cc: Joe Perches <joe@perches.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <1261315437.4314.6.camel@laptop> [ i dont mind the pr_*() patterns that much - but Peter dislikes them with a vengence. ] [ - v2: remove spurious diffstat from changelog :-/ ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-17sched: Fix broken assertionPeter Zijlstra1-1/+2
There's a preemption race in the set_task_cpu() debug check in that when we get preempted after setting task->state we'd still be on the rq proper, but fail the test. Check for preempted tasks, since those are always on the RQ. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20091217121830.137155561@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-17sched: Teach might_sleep() about preemptible RCUFrederic Weisbecker1-1/+1
In practice, it is harmless to voluntarily sleep in a rcu_read_lock() section if we are running under preempt rcu, but it is illegal if we build a kernel running non-preemptable rcu. Currently, might_sleep() doesn't notice sleepable operations under rcu_read_lock() sections if we are running under preemptable rcu because preempt_count() is left untouched after rcu_read_lock() in this case. But we want developers who test their changes under such config to notice the "sleeping while atomic" issues. So we add rcu_read_lock_nesting to prempt_count() in might_sleep() checks. [ v2: Handle rcu-tiny ] Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <1260991265-8451-1-git-send-regression-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-17sched: Make warning less noisyIngo Molnar1-1/+1
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <20091216170517.807938893@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-16sched: Simplify set_task_cpu()Peter Zijlstra1-8/+5
Rearrange code a bit now that its a simpler function. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <20091216170518.269101883@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-16sched: Remove the cfs_rq dependency from set_task_cpu()Peter Zijlstra1-5/+1
In order to remove the cfs_rq dependency from set_task_cpu() we need to ensure the task is cfs_rq invariant for all callsites. The simple approach is to substract cfs_rq->min_vruntime from se->vruntime on dequeue, and add cfs_rq->min_vruntime on enqueue. However, this has the downside of breaking FAIR_SLEEPERS since we loose the old vruntime as we only maintain the relative position. To solve this, we observe that we only migrate runnable tasks, we do this using deactivate_task(.sleep=0) and activate_task(.wakeup=0), therefore we can restrain the min_vruntime invariance to that state. The only other case is wakeup balancing, since we want to maintain the old vruntime we cannot make it relative on dequeue, but since we don't migrate inactive tasks, we can do so right before we activate it again. This is where we need the new pre-wakeup hook, we need to call this while still holding the old rq->lock. We could fold it into ->select_task_rq(), but since that has multiple callsites and would obfuscate the locking requirements, that seems like a fudge. This leaves the fork() case, simply make sure that ->task_fork() leaves the ->vruntime in a relative state. This covers all cases where set_task_cpu() gets called, and ensures it sees a relative vruntime. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <20091216170518.191697025@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-16sched: Add pre and post wakeup hooksPeter Zijlstra1-4/+8
As will be apparent in the next patch, we need a pre wakeup hook for sched_fair task migration, hence rename the post wakeup hook and one pre wakeup. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <20091216170518.114746117@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-16sched: Move kthread_bind() back to kthread.cPeter Zijlstra1-26/+0
Since kthread_bind() lost its dependencies on sched.c, move it back where it came from. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <20091216170518.039524041@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-16sched: Fix select_task_rq() vs hotplug issuesPeter Zijlstra1-35/+40
Since select_task_rq() is now responsible for guaranteeing ->cpus_allowed and cpu_active_mask, we need to verify this. select_task_rq_rt() can blindly return smp_processor_id()/task_cpu() without checking the valid masks, select_task_rq_fair() can do the same in the rare case that all SD_flags are disabled. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <20091216170517.961475466@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-16sched: Fix sched_exec() balancingPeter Zijlstra1-22/+23
Since we access ->cpus_allowed without holding rq->lock we need a retry loop to validate the result, this comes for near free when we merge sched_migrate_task() into sched_exec() since that already does the needed check. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <20091216170517.884743662@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-16sched: Ensure set_task_cpu() is never called on blocked tasksPeter Zijlstra1-19/+66
In order to clean up the set_task_cpu() rq dependencies we need to ensure it is never called on blocked tasks because such usage does not pair with consistent rq->lock usage. This puts the migration burden on ttwu(). Furthermore we need to close a race against changing ->cpus_allowed, since select_task_rq() runs with only preemption disabled. For sched_fork() this is safe because the child isn't in the tasklist yet, for wakeup we fix this by synchronizing set_cpus_allowed_ptr() against TASK_WAKING, which leaves sched_exec to be a problem This also closes a hole in (6ad4c1888 sched: Fix balance vs hotplug race) where ->select_task_rq() doesn't validate the result against the sched_domain/root_domain. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <20091216170517.807938893@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-16sched: Use TASK_WAKING for fork wakupsPeter Zijlstra1-9/+9
For later convenience use TASK_WAKING for fresh tasks. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <20091216170517.732561278@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-16sched: Fix task_hot() test orderPeter Zijlstra1-3/+3
Make sure not to access sched_fair fields before verifying it is indeed a sched_fair task. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> CC: stable@kernel.org LKML-Reference: <20091216170517.577998058@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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