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2011-01-26softirqs: Account ksoftirqd time as cpustat softirqVenkatesh Pallipadi
softirq time in ksoftirqd context is not accounted in ns granularity per cpu softirq stats, as we want that to be a part of ksoftirqd exec_runtime. Accounting them as softirq on /proc/stat separately. Tested-by: Shaun Ruffell <sruffell@digium.com> Signed-off-by: Venkatesh Pallipadi <venki@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1292980144-28796-6-git-send-email-venki@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-26sched: Export ns irqtimes through /proc/statVenkatesh Pallipadi
CONFIG_IRQ_TIME_ACCOUNTING adds ns granularity irq time on each CPU. This info is already used in scheduler to do proper task chargeback (earlier patches). This patch retro-fits this ns granularity hardirq and softirq information to /proc/stat irq and softirq fields. The update is still done on timer tick, where we look at accumulated ns hardirq/softirq time and account the tick to user/system/irq/hardirq/guest accordingly. No new interface added. Earlier versions looked at adding this as new fields in some /proc files. This one seems to be the best in terms of impact to existing apps, even though it has somewhat more kernel code than earlier versions. Tested-by: Shaun Ruffell <sruffell@digium.com> Signed-off-by: Venkatesh Pallipadi <venki@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1292980144-28796-5-git-send-email-venki@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-26sched: Refactor account_system_time separating id-updateVenkatesh Pallipadi
Refactor account_system_time, to separate out the logic of identifying the update needed and code that does actual update. This is used by following patch for IRQ_TIME_ACCOUNTING, which has different identification logic and same update logic. Tested-by: Shaun Ruffell <sruffell@digium.com> Signed-off-by: Venkatesh Pallipadi <venki@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1292980144-28796-4-git-send-email-venki@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-26softirqs: Free up pf flag PF_KSOFTIRQDVenkatesh Pallipadi
Cleanup patch, freeing up PF_KSOFTIRQD and use per_cpu ksoftirqd pointer instead, as suggested by Eric Dumazet. Tested-by: Shaun Ruffell <sruffell@digium.com> Signed-off-by: Venkatesh Pallipadi <venki@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1292980144-28796-2-git-send-email-venki@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-26sched: Avoid expensive initial update_cfs_load()Paul Turner
Since cfs->{load_stamp,load_last} are zero-initalized the initial load update will consider the delta to be 'since the beginning of time'. This results in a lot of pointless divisions to bring this large period to be within the sysctl_sched_shares_window. Fix this by initializing load_stamp to be 1 at cfs_rq initialization, this allows for an initial load_stamp > load_last which then lets standard idle truncation proceed. We avoid spinning (and slightly improve consistency) by fixing delta to be [period - 1] in this path resulting in a slightly more predictable shares ramp. (Previously the amount of idle time preserved by the overflow would range between [period/2,period-1].) Signed-off-by: Paul Turner <pjt@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20110122044852.102126037@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-26sched: Simplify update_cfs_shares parametersPaul Turner
Re-visiting this: Since update_cfs_shares will now only ever re-weight an entity that is a relative parent of the current entity in enqueue_entity; we can safely issue the account_entity_enqueue relative to that cfs_rq and avoid the requirement for special handling of the enqueue case in update_cfs_shares. Signed-off-by: Paul Turner <pjt@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20110122044851.915214637@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-20Merge branch 'sched-fixes-for-linus' of ↵Linus Torvalds
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, cgroup: Use exit hook to avoid use-after-free crash sched: Fix signed unsigned comparison in check_preempt_tick() sched: Replace rq->bkl_count with rq->rq_sched_info.bkl_count sched, autogroup: Fix CONFIG_RT_GROUP_SCHED sched_setscheduler() failure sched: Display autogroup names in /proc/sched_debug sched: Reinstate group names in /proc/sched_debug sched: Update effective_load() to use global share weights
2011-01-19sched, cgroup: Use exit hook to avoid use-after-free crashPeter Zijlstra
By not notifying the controller of the on-exit move back to init_css_set, we fail to move the task out of the previous cgroup's cfs_rq. This leads to an opportunity for a cgroup-destroy to come in and free the cgroup (there are no active tasks left in it after all) to which the not-quite dead task is still enqueued. Reported-by: Miklos Vajna <vmiklos@frugalware.org> Fixed-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: <stable@kernel.org> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by: Ingo Molnar <mingo@elte.hu> LKML-Reference: <1293206353.29444.205.camel@laptop>
2011-01-18sched: Replace rq->bkl_count with rq->rq_sched_info.bkl_countYong Zhang
Now rq->rq_sched_info.bkl_count is not used for rq, scroll rq->bkl_count into it. Thus we can save some space for rq. Signed-off-by: Yong Zhang <yong.zhang0@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1294991859-13246-1-git-send-email-yong.zhang0@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-18sched, autogroup: Fix CONFIG_RT_GROUP_SCHED sched_setscheduler() failureMike Galbraith
If CONFIG_RT_GROUP_SCHED is set, __sched_setscheduler() fails due to autogroup not allocating rt_runtime. Free unused/unusable rt_se and rt_rq, redirect RT tasks to the root task group, and tell __sched_setscheduler() that it's ok. Reported-and-tested-by: Bharata B Rao <bharata@linux.vnet.ibm.com> Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1294890890.8089.39.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-13Merge branch 'for-next' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial * 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (43 commits) Documentation/trace/events.txt: Remove obsolete sched_signal_send. writeback: fix global_dirty_limits comment runtime -> real-time ppc: fix comment typo singal -> signal drivers: fix comment typo diable -> disable. m68k: fix comment typo diable -> disable. wireless: comment typo fix diable -> disable. media: comment typo fix diable -> disable. remove doc for obsolete dynamic-printk kernel-parameter remove extraneous 'is' from Documentation/iostats.txt Fix spelling milisec -> ms in snd_ps3 module parameter description Fix spelling mistakes in comments Revert conflicting V4L changes i7core_edac: fix typos in comments mm/rmap.c: fix comment sound, ca0106: Fix assignment to 'channel'. hrtimer: fix a typo in comment init/Kconfig: fix typo anon_inodes: fix wrong function name in comment fix comment typos concerning "consistent" poll: fix a typo in comment ... Fix up trivial conflicts in: - drivers/net/wireless/iwlwifi/iwl-core.c (moved to iwl-legacy.c) - fs/ext4/ext4.h Also fix missed 'diabled' typo in drivers/net/bnx2x/bnx2x.h while at it.
2011-01-07sched: Fix strncmp operationHillf Danton
One of the operands, buf, is incorrect, since it is stripped and the correct address for subsequent string comparing could change if leading white spaces, if any, are removed from buf. It is fixed by replacing buf with cmp. Signed-off-by: Hillf Danton <dhillf@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <AANLkTinOPuYsVovrZpbuCCmG5deEyc8WgA_A1RJx_YK7@mail.gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-07sched: Fix struct autogroup memory leakMike Galbraith
Seems I lost a change somewhere, leaking memory. sched: fix struct autogroup memory leak Add missing change to actually use autogroup_free(). Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1294222285.8369.2.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-07sched: Consolidate the name of root_task_group and init_task_groupYong Zhang
root_task_group is the leftover of USER_SCHED, now it's always same to init_task_group. But as Mike suggested, root_task_group is maybe the suitable name to keep for a tree. So in this patch: init_task_group --> root_task_group init_task_group_load --> root_task_group_load INIT_TASK_GROUP_LOAD --> ROOT_TASK_GROUP_LOAD Suggested-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Yong Zhang <yong.zhang0@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20110107071736.GA32635@windriver.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-06Merge branch 'sched-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (30 commits) sched: Change wait_for_completion_*_timeout() to return a signed long sched, autogroup: Fix reference leak sched, autogroup: Fix potential access to freed memory sched: Remove redundant CONFIG_CGROUP_SCHED ifdef sched: Fix interactivity bug by charging unaccounted run-time on entity re-weight sched: Move periodic share updates to entity_tick() printk: Use this_cpu_{read|write} api on printk_pending sched: Make pushable_tasks CONFIG_SMP dependant sched: Add 'autogroup' scheduling feature: automated per session task groups sched: Fix unregister_fair_sched_group() sched: Remove unused argument dest_cpu to migrate_task() mutexes, sched: Introduce arch_mutex_cpu_relax() sched: Add some clock info to sched_debug cpu: Remove incorrect BUG_ON cpu: Remove unused variable sched: Fix UP build breakage sched: Make task dump print all 15 chars of proc comm sched: Update tg->shares after cpu.shares write sched: Allow update_cfs_load() to update global load sched: Implement demand based update_cfs_load() ...
2011-01-06Merge branch 'perf-core-for-linus' of ↵Linus Torvalds
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: (146 commits) tools, perf: Documentation for the power events API perf: Add calls to suspend trace point perf script: Make some lists static perf script: Use the default lost event handler perf session: Warn about errors when processing pipe events too perf tools: Fix perf_event.h header usage perf test: Clarify some error reports in the open syscall test x86, NMI: Add touch_nmi_watchdog to io_check_error delay x86: Avoid calling arch_trigger_all_cpu_backtrace() at the same time x86: Only call smp_processor_id in non-preempt cases perf timechart: Adjust perf timechart to the new power events perf: Clean up power events by introducing new, more generic ones perf: Do not export power_frequency, but power_start event perf test: Add test for counting open syscalls perf evsel: Auto allocate resources needed for some methods perf evsel: Use {cpu,thread}_map to shorten list of parameters perf tools: Refactor all_tids to hold nr and the map perf tools: Refactor cpumap to hold nr and the map perf evsel: Introduce per cpu and per thread open helpers perf evsel: Steal the counter reading routines from stat ...
2011-01-05sched: Change wait_for_completion_*_timeout() to return a signed longNeilBrown
wait_for_completion_*_timeout() can return: 0: if the wait timed out -ve: if the wait was interrupted +ve: if the completion was completed. As they currently return an 'unsigned long', the last two cases are not easily distinguished which can easily result in buggy code, as is the case for the recently added wait_for_completion_interruptible_timeout() call in net/sunrpc/cache.c So change them both to return 'long'. As MAX_SCHEDULE_TIMEOUT is LONG_MAX, a large +ve return value should never overflow. Signed-off-by: NeilBrown <neilb@suse.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: J. Bruce Fields <bfields@fieldses.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <20110105125016.64ccab0e@notabene.brown> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-05Merge commit 'v2.6.37' into sched/coreIngo Molnar
Merge reason: Merge the final .37 tree. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-04sched: Remove redundant CONFIG_CGROUP_SCHED ifdefYong Zhang
CONFIG_[FAIR|RT]_GROUP_SCHED always means CONFIG_CGROUP_SCHED Signed-off-by: Yong Zhang <yong.zhang0@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <1293803938-8157-1-git-send-email-yong.zhang0@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-12-23Merge branch 'rcu/next' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu into core/rcu
2010-12-22Merge branch 'master' into for-nextJiri Kosina
Conflicts: MAINTAINERS arch/arm/mach-omap2/pm24xx.c drivers/scsi/bfa/bfa_fcpim.c Needed to update to apply fixes for which the old branch was too outdated.
2010-12-22Merge commit 'v2.6.37-rc7' into perf/coreIngo Molnar
Merge reason: Pick up the latest -rc. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-12-19sched: Remove debugging checkIngo Molnar
Linus reported that the new warning introduced by commit f26f9aff6aaf "Sched: fix skip_clock_update optimization" triggers. The need_resched flag can be set by other CPUs asynchronously so this debug check is bogus - remove it. Reported-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <AANLkTinJ8hAG1TpyC+CSYPR47p48+1=E7fiC45hMXT_1@mail.gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-12-16perf: Move perf_event_init() into main.cPeter Zijlstra
Currently we call perf_event_init() from sched_init(). In order to make it more obvious move it to the cannnonical location. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20101117222056.093629821@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-12-16sched: Fix the irqtime code for 32bitPeter Zijlstra
Since the irqtime accounting is using non-atomic u64 and can be read from remote cpus (writes are strictly cpu local, reads are not) we have to deal with observing partial updates. When we do observe partial updates the clock movement (in particular, ->clock_task movement) will go funny (in either direction), a subsequent clock update (observing the full update) will make it go funny in the oposite direction. Since we rely on these clocks to be strictly monotonic we cannot suffer backwards motion. One possible solution would be to simply ignore all backwards deltas, but that will lead to accounting artefacts, most notable: clock_task + irq_time != clock, this inaccuracy would end up in user visible stats. Therefore serialize the reads using a seqcount. Reviewed-by: Venkatesh Pallipadi <venki@google.com> Reported-by: Mikael Pettersson <mikpe@it.uu.se> Tested-by: Mikael Pettersson <mikpe@it.uu.se> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1292242434.6803.200.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-12-16sched: Fix the irqtime code to deal with u64 wrapsPeter Zijlstra
Some ARM systems have a short sched_clock() [ which needs to be fixed too ], but this exposed a bug in the irq_time code as well, it doesn't deal with wraps at all. Fix the irq_time code to deal with u64 wraps by re-writing the code to only use delta increments, which avoids the whole issue. Reviewed-by: Venkatesh Pallipadi <venki@google.com> Reported-by: Mikael Pettersson <mikpe@it.uu.se> Tested-by: Mikael Pettersson <mikpe@it.uu.se> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1292242433.6803.199.camel@twins> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-12-13sched: Remove unlikely() from ttwu_post_activationSteven Rostedt
The unlikely() used in ttwu_post_activation() tests if the rq->idle_stamp is set. But since this is for a wakeup, and wakeups happen when tasks block on IO, and blocking tasks on IO may put the system into idle, this can actually be a common occurence. Running the annotated branch profiler on an average desktop running firefox, evolution, xchat and distcc, the report shows: correct incorrect % Function File Line ------- --------- - -------- ---- ---- 34884862 146110926 80 ttwu_post_activation sched.c 2309 80% of the time, this unlikely is incorrect. Best not to assume what the result is, and just remove the branch annotation. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-12-13sched: Remove unlikely() from rt_policy() in sched.cSteven Rostedt
The rt_policy() has an unlikely() that the policy it is checking is of RT priority (SCHED_FIFO or SCHED_RR). According to the annotate branch profiler it is incorrect most of the time: correct incorrect % Function File Line ------- --------- - -------- ---- ---- 36667 654674 94 rt_policy sched.c 126 This makes sense because the rt_policy() is used by the sched_set_scheduler() and nice(). Although users may use sys_nice a bit, all RT users use the sched_set_scheduler() to set their RT priority, including kernel threads. The above numbers were from a normal desktop computer running firefox, evolution, xchat and was part of a distcc compile farm. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2010-12-08sched: Make pushable_tasks CONFIG_SMP dependantDario Faggioli
As noted by Peter Zijlstra at https://lkml.org/lkml/2010/11/10/391 (while reviewing other stuff, though), tracking pushable tasks only makes sense on SMP systems. Signed-off-by: Dario Faggioli <raistlin@linux.it> Acked-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Gregory Haskins <ghaskins@novell.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1291143093.2697.298.camel@Palantir> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-12-08Sched: fix skip_clock_update optimizationMike Galbraith
idle_balance() drops/retakes rq->lock, leaving the previous task vulnerable to set_tsk_need_resched(). Clear it after we return from balancing instead, and in setup_thread_stack() as well, so no successfully descheduled or never scheduled task has it set. Need resched confused the skip_clock_update logic, which assumes that the next call to update_rq_clock() will come nearly immediately after being set. Make the optimization robust against the waking a sleeper before it sucessfully deschedules case by checking that the current task has not been dequeued before setting the flag, since it is that useless clock update we're trying to save, and clear unconditionally in schedule() proper instead of conditionally in put_prev_task(). Signed-off-by: Mike Galbraith <efault@gmx.de> Reported-by: Bjoern B. Brandenburg <bbb.lst@gmail.com> Tested-by: Yong Zhang <yong.zhang0@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: stable@kernel.org LKML-Reference: <1291802742.1417.9.camel@marge.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-12-08sched: Cure more NO_HZ load average woesPeter Zijlstra
There's a long-running regression that proved difficult to fix and which is hitting certain people and is rather annoying in its effects. Damien reported that after 74f5187ac8 (sched: Cure load average vs NO_HZ woes) his load average is unnaturally high, he also noted that even with that patch reverted the load avgerage numbers are not correct. The problem is that the previous patch only solved half the NO_HZ problem, it addressed the part of going into NO_HZ mode, not of comming out of NO_HZ mode. This patch implements that missing half. When comming out of NO_HZ mode there are two important things to take care of: - Folding the pending idle delta into the global active count. - Correctly aging the averages for the idle-duration. So with this patch the NO_HZ interaction should be complete and behaviour between CONFIG_NO_HZ=[yn] should be equivalent. Furthermore, this patch slightly changes the load average computation by adding a rounding term to the fixed point multiplication. Reported-by: Damien Wyart <damien.wyart@free.fr> Reported-by: Tim McGrath <tmhikaru@gmail.com> Tested-by: Damien Wyart <damien.wyart@free.fr> Tested-by: Orion Poplawski <orion@cora.nwra.com> Tested-by: Kyle McMartin <kyle@mcmartin.ca> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: stable@kernel.org Cc: Chase Douglas <chase.douglas@canonical.com> LKML-Reference: <1291129145.32004.874.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-30sched: Add 'autogroup' scheduling feature: automated per session task groupsMike Galbraith
A recurring complaint from CFS users is that parallel kbuild has a negative impact on desktop interactivity. This patch implements an idea from Linus, to automatically create task groups. Currently, only per session autogroups are implemented, but the patch leaves the way open for enhancement. Implementation: each task's signal struct contains an inherited pointer to a refcounted autogroup struct containing a task group pointer, the default for all tasks pointing to the init_task_group. When a task calls setsid(), a new task group is created, the process is moved into the new task group, and a reference to the preveious task group is dropped. Child processes inherit this task group thereafter, and increase it's refcount. When the last thread of a process exits, the process's reference is dropped, such that when the last process referencing an autogroup exits, the autogroup is destroyed. At runqueue selection time, IFF a task has no cgroup assignment, its current autogroup is used. Autogroup bandwidth is controllable via setting it's nice level through the proc filesystem: cat /proc/<pid>/autogroup Displays the task's group and the group's nice level. echo <nice level> > /proc/<pid>/autogroup Sets the task group's shares to the weight of nice <level> task. Setting nice level is rate limited for !admin users due to the abuse risk of task group locking. The feature is enabled from boot by default if CONFIG_SCHED_AUTOGROUP=y is selected, but can be disabled via the boot option noautogroup, and can also be turned on/off on the fly via: echo [01] > /proc/sys/kernel/sched_autogroup_enabled ... which will automatically move tasks to/from the root task group. Signed-off-by: Mike Galbraith <efault@gmx.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Markus Trippelsdorf <markus@trippelsdorf.de> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Paul Turner <pjt@google.com> Cc: Oleg Nesterov <oleg@redhat.com> [ Removed the task_group_path() debug code, and fixed !EVENTFD build failure. ] Signed-off-by: Ingo Molnar <mingo@elte.hu> LKML-Reference: <1290281700.28711.9.camel@maggy.simson.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-30sched: Fix unregister_fair_sched_group()Paul Turner
In the flipping and flopping between calling unregister_fair_sched_group() on a per-cpu versus per-group basis we ended up in a bad state. Remove from the list for the passed cpu as opposed to some arbitrary index. ( This fixes explosions w/ autogroup as well as a group creation/destruction stress test. ) Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <20101130005740.080828123@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-29rcu,cleanup: move synchronize_sched_expedited() out of sched.cLai Jiangshan
The first version of synchronize_sched_expedited() used the migration code in the scheduler, and was therefore implemented in kernel/sched.c. However, the more recent version of this code no longer uses the migration code, so this commit moves it to the main RCU source files. Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2010-11-26sched: Remove unused argument dest_cpu to migrate_task()Nikanth Karthikesan
Remove unused argument, 'dest_cpu' of migrate_task(), and pass runqueue, as it is always known at the call site. Signed-off-by: Nikanth Karthikesan <knikanth@suse.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <201011261237.09187.knikanth@suse.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-26mutexes, sched: Introduce arch_mutex_cpu_relax()Gerald Schaefer
The spinning mutex implementation uses cpu_relax() in busy loops as a compiler barrier. Depending on the architecture, cpu_relax() may do more than needed in this specific mutex spin loops. On System z we also give up the time slice of the virtual cpu in cpu_relax(), which prevents effective spinning on the mutex. This patch replaces cpu_relax() in the spinning mutex code with arch_mutex_cpu_relax(), which can be defined by each architecture that selects HAVE_ARCH_MUTEX_CPU_RELAX. The default is still cpu_relax(), so this patch should not affect other architectures than System z for now. Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1290437256.7455.4.camel@thinkpad> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-26Merge commit 'v2.6.37-rc3' into sched/coreIngo Molnar
Merge reason: Pick up latest fixes. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-23sched: Make task dump print all 15 chars of proc commErik Gilling
Signed-off-by: Erik Gilling <konkers@android.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1290218934-8544-3-git-send-email-john.stultz@linaro.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-18sched: Update tg->shares after cpu.shares writePaul Turner
Formerly sched_group_set_shares would force a rebalance by overflowing domain share sums. Now that per-cpu averages are maintained we can set the true value by issuing an update_cfs_shares() following a tg->shares update. Also initialize tg se->load to 0 for consistency since we'll now set correct weights on enqueue. Signed-off-by: Paul Turner <pjt@google.com?> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20101115234938.465521344@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-18sched: Implement demand based update_cfs_load()Paul Turner
When the system is busy, dilation of rq->next_balance makes lb->update_shares() insufficiently frequent for threads which don't sleep (no dequeue/enqueue updates). Adjust for this by making demand based updates based on the accumulation of execution time sufficient to wrap our averaging window. Signed-off-by: Paul Turner <pjt@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20101115234938.291159744@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-18sched: Fix update_cfs_load() synchronizationPaul Turner
Using cfs_rq->nr_running is not sufficient to synchronize update_cfs_load with the put path since nr_running accounting occurs at deactivation. It's also not safe to make the removal decision based on load_avg as this fails with both high periods and low shares. Resolve this by clipping history after 4 periods without activity. Note: the above will always occur from update_shares() since in the last-task-sleep-case that task will still be cfs_rq->curr when update_cfs_load is called. Signed-off-by: Paul Turner <pjt@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20101115234937.933428187@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-18sched: Make tg_shares_up() walk on-demandPeter Zijlstra
Make tg_shares_up() use the active cgroup list, this means we cannot do a strict bottom-up walk of the hierarchy, but assuming its a very wide tree with a small number of active groups it should be a win. Signed-off-by: Paul Turner <pjt@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20101115234937.754159484@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-18sched: Implement on-demand (active) cfs_rq listPeter Zijlstra
Make certain load-balance actions scale per number of active cgroups instead of the number of existing cgroups. This makes wakeup/sleep paths more expensive, but is a win for systems where the vast majority of existing cgroups are idle. Signed-off-by: Paul Turner <pjt@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20101115234937.666535048@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-18sched: Rewrite tg_shares_up)Peter Zijlstra
By tracking a per-cpu load-avg for each cfs_rq and folding it into a global task_group load on each tick we can rework tg_shares_up to be strictly per-cpu. This should improve cpu-cgroup performance for smp systems significantly. [ Paul: changed to use queueing cfs_rq + bug fixes ] Signed-off-by: Paul Turner <pjt@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20101115234937.580480400@google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-18sched: Simplify cpu-hot-unplug task migrationPeter Zijlstra
While discussing the need for sched_idle_next(), Oleg remarked that since try_to_wake_up() ensures sleeping tasks will end up running on a sane cpu, we can do away with migrate_live_tasks(). If we then extend the existing hack of migrating current from CPU_DYING to migrating the full rq worth of tasks from CPU_DYING, the need for the sched_idle_next() abomination disappears as well, since idle will be the only possible thread left after the migration thread stops. This greatly simplifies the hot-unplug task migration path, as can be seen from the resulting code reduction (and about half the new lines are comments). Suggested-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1289851597.2109.547.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-18Merge commit 'v2.6.37-rc2' into sched/coreIngo Molnar
Merge reason: Move to a .37-rc base. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-11sched: Fix cross-sched-class wakeup preemptionPeter Zijlstra
Instead of dealing with sched classes inside each check_preempt_curr() implementation, pull out this logic into the generic wakeup preemption path. This fixes a hang in KVM (and others) where we are waiting for the stop machine thread to run ... Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de> Tested-by: Marcelo Tosatti <mtosatti@redhat.com> Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1288891946.2039.31.camel@laptop> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-10sched: Use group weight, idle cpu metrics to fix imbalances during idleSuresh Siddha
Currently we consider a sched domain to be well balanced when the imbalance is less than the domain's imablance_pct. As the number of cores and threads are increasing, current values of imbalance_pct (for example 25% for a NUMA domain) are not enough to detect imbalances like: a) On a WSM-EP system (two sockets, each having 6 cores and 12 logical threads), 24 cpu-hogging tasks get scheduled as 13 on one socket and 11 on another socket. Leading to an idle HT cpu. b) On a hypothetial 2 socket NHM-EX system (each socket having 8 cores and 16 logical threads), 16 cpu-hogging tasks can get scheduled as 9 on one socket and 7 on another socket. Leaving one core in a socket idle whereas in another socket we have a core having both its HT siblings busy. While this issue can be fixed by decreasing the domain's imbalance_pct (by making it a function of number of logical cpus in the domain), it can potentially cause more task migrations across sched groups in an overloaded case. Fix this by using imbalance_pct only during newly_idle and busy load balancing. And during idle load balancing, check if there is an imbalance in number of idle cpu's across the busiest and this sched_group or if the busiest group has more tasks than its weight that the idle cpu in this_group can pull. Reported-by: Nikhil Rao <ncrao@google.com> Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1284760952.2676.11.camel@sbsiddha-MOBL3.sc.intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-11-01tree-wide: fix comment/printk typosUwe Kleine-König
"gadget", "through", "command", "maintain", "maintain", "controller", "address", "between", "initiali[zs]e", "instead", "function", "select", "already", "equal", "access", "management", "hierarchy", "registration", "interest", "relative", "memory", "offset", "already", Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2010-10-29Merge branch 'sched-fixes-for-linus' of ↵Linus Torvalds
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_stat: Update sched_info_queue/dequeue() code comments sched, cgroup: Fixup broken cgroup movement
generated by cgit v1.2.3 (git 2.0.4) at 2025-08-13 01:41:28 +0000