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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>
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>
2009-12-16Merge branch 'linus' into sched/urgentIngo Molnar1-114/+117
Conflicts: kernel/sched_idletask.c Merge reason: resolve the conflicts, pick up latest changes. Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-14sched: Convert pi_lock to raw_spinlockThomas Gleixner1-6/+6
Convert locks which cannot be sleeping locks in preempt-rt to raw_spinlocks. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Ingo Molnar <mingo@elte.hu>
2009-12-14sched: Convert rt_runtime_lock to raw_spinlockThomas Gleixner1-14/+14
Convert locks which cannot be sleeping locks in preempt-rt to raw_spinlocks. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Ingo Molnar <mingo@elte.hu>
2009-12-14sched: Convert rq->lock to raw_spinlockThomas Gleixner1-90/+93
Convert locks which cannot be sleeping locks in preempt-rt to raw_spinlocks. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Ingo Molnar <mingo@elte.hu>
2009-12-14locking: Further name space cleanupsThomas Gleixner1-1/+1
The name space hierarchy for the internal lock functions is now a bit backwards. raw_spin* functions map to _spin* which use __spin*, while we would like to have _raw_spin* and __raw_spin*. _raw_spin* is already used by lock debugging, so rename those funtions to do_raw_spin* to free up the _raw_spin* name space. No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Ingo Molnar <mingo@elte.hu>
2009-12-14locking: Implement new raw_spinlockThomas Gleixner1-1/+1
Now that the raw_spin name space is freed up, we can implement raw_spinlock and the related functions which are used to annotate the locks which are not converted to sleeping spinlocks in preempt-rt. A side effect is that only such locks can be used with the low level lock fsunctions which circumvent lockdep. For !rt spin_* functions are mapped to the raw_spin* implementations. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Ingo Molnar <mingo@elte.hu>
2009-12-14Merge branch 'for-linus' of ↵Linus Torvalds1-4/+4
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: (34 commits) m68k: rename global variable vmalloc_end to m68k_vmalloc_end percpu: add missing per_cpu_ptr_to_phys() definition for UP percpu: Fix kdump failure if booted with percpu_alloc=page percpu: make misc percpu symbols unique percpu: make percpu symbols in ia64 unique percpu: make percpu symbols in powerpc unique percpu: make percpu symbols in x86 unique percpu: make percpu symbols in xen unique percpu: make percpu symbols in cpufreq unique percpu: make percpu symbols in oprofile unique percpu: make percpu symbols in tracer unique percpu: make percpu symbols under kernel/ and mm/ unique percpu: remove some sparse warnings percpu: make alloc_percpu() handle array types vmalloc: fix use of non-existent percpu variable in put_cpu_var() this_cpu: Use this_cpu_xx in trace_functions_graph.c this_cpu: Use this_cpu_xx for ftrace this_cpu: Use this_cpu_xx in nmi handling this_cpu: Use this_cpu operations in RCU this_cpu: Use this_cpu ops for VM statistics ... Fix up trivial (famous last words) global per-cpu naming conflicts in arch/x86/kvm/svm.c mm/slab.c
2009-12-14sched: Use rcu in sched_get_rr_param()Thomas Gleixner1-3/+3
read_lock(&tasklist_lock) does not protect sys_sched_get_rr_param() against a concurrent update of the policy or scheduler parameters as do_sched_scheduler() does not take the tasklist_lock. The access to task->sched_class->get_rr_interval is protected by task_rq_lock(task). Use rcu_read_lock() to protect find_task_by_vpid() and prevent the task struct from going away. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20091209100706.862897167@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-14sched: Use rcu in sched_get/set_affinity()Thomas Gleixner1-10/+6
tasklist_lock is held read locked to protect the find_task_by_vpid() call and to prevent the task going away. sched_setaffinity acquires a task struct ref and drops tasklist lock right away. The access to the cpus_allowed mask is protected by rq->lock. rcu_read_lock() provides the same protection here. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20091209100706.789059966@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-14sched: Use rcu in sys_sched_getscheduler/sys_sched_getparam()Thomas Gleixner1-5/+5
read_lock(&tasklist_lock) does not protect sys_sched_getscheduler and sys_sched_getparam() against a concurrent update of the policy or scheduler parameters as do_sched_setscheduler() does not take the tasklist_lock. The accessed integers can be retrieved w/o locking and are snapshots anyway. Using rcu_read_lock() to protect find_task_by_vpid() and prevent the task struct from going away is not changing the above situation. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20091209100706.753790977@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-13sched: Use pr_fmt() and pr_<level>()Joe Perches1-52/+42
- Convert printk(KERN_<level> to pr_<level> (not KERN_DEBUG) - Add #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt - Coalesce long format strings - Add missing \n to "ERROR: !SD_LOAD_BALANCE domain has parent" Signed-off-by: Joe Perches <joe@perches.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1260655047.2637.7.camel@Joe-Laptop.home> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-13sched: Make wakeup side and atomic variants of completion API irq safeRafael J. Wysocki1-4/+6
Alan Stern noticed that all the wakeup side (and atomic) variants of the completion APIs should be irq safe, but the newly introduced completion_done() and try_wait_for_completion() aren't. The use of the irq unsafe variants in IRQ contexts can cause crashes/hangs. Fix the problem by making them use spin_lock_irqsave() and spin_lock_irqrestore(). Reported-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Zhang Rui <rui.zhang@intel.com> Cc: pm list <linux-pm@lists.linux-foundation.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: David Chinner <david@fromorbit.com> Cc: Lachlan McIlroy <lachlan@sgi.com> LKML-Reference: <200912130007.30541.rjw@sisk.pl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-12Merge branch 'sched-fixes-for-linus' of ↵Linus Torvalds1-104/+114
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: (21 commits) sched: Remove forced2_migrations stats sched: Fix memory leak in two error corner cases sched: Fix build warning in get_update_sysctl_factor() sched: Update normalized values on user updates via proc sched: Make tunable scaling style configurable sched: Fix missing sched tunable recalculation on cpu add/remove sched: Fix task priority bug sched: cgroup: Implement different treatment for idle shares sched: Remove unnecessary RCU exclusion sched: Discard some old bits sched: Clean up check_preempt_wakeup() sched: Move update_curr() in check_preempt_wakeup() to avoid redundant call sched: Sanitize fork() handling sched: Clean up ttwu() rq locking sched: Remove rq->clock coupling from set_task_cpu() sched: Consolidate select_task_rq() callers sched: Remove sysctl.sched_features sched: Protect sched_rr_get_param() access to task->sched_class sched: Protect task->cpus_allowed access in sched_getaffinity() sched: Fix balance vs hotplug race ... Fixed up conflicts in kernel/sysctl.c (due to sysctl cleanup)
2009-12-10sched: Remove forced2_migrations statsIngo Molnar1-6/+0
This build warning: kernel/sched.c: In function 'set_task_cpu': kernel/sched.c:2070: warning: unused variable 'old_rq' Made me realize that the forced2_migrations stat looks pretty pointless (and a misnomer) - remove it. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-10sched: Fix memory leak in two error corner casesPhil Carmody1-2/+6
If the second in each of these pairs of allocations fails, then the first one will not be freed in the error route out. Found by a static code analysis tool. Signed-off-by: Phil Carmody <ext-phil.2.carmody@nokia.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1260448177-28448-1-git-send-email-ext-phil.2.carmody@nokia.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-12-10sched: Fix build warning in get_update_sysctl_factor()Mike Galbraith1-1/+1
Signed-off-by: Mike Galbraith <efault@gmx.de> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu> LKML-Reference: <new-submission>
2009-12-09sched: Update normalized values on user updates via procChristian Ehrhardt1-2/+10
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>
2009-12-09sched: Make tunable scaling style configurableChristian Ehrhardt1-1/+14
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>
2009-12-09sched: Fix missing sched tunable recalculation on cpu add/removeChristian Ehrhardt1-13/+16
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>
2009-12-09sched: Fix task priority bugPeter Zijlstra1-6/+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>
2009-12-09sched: cgroup: Implement different treatment for idle sharesPeter Zijlstra1-2/+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>
2009-12-09sched: Discard some old bitsPeter Zijlstra1-10/+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>
2009-12-09sched: Sanitize fork() handlingPeter Zijlstra1-29/+18
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>
2009-12-09sched: Clean up ttwu() rq lockingPeter Zijlstra1-8/+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>
2009-12-09sched: Remove rq->clock coupling from set_task_cpu()Peter Zijlstra1-12/+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>
2009-12-09sched: Consolidate select_task_rq() callersPeter Zijlstra1-3/+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>
2009-12-09sched: Protect sched_rr_get_param() access to task->sched_classThomas Gleixner1-1/+5
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>
2009-12-09sched: Protect task->cpus_allowed access in sched_getaffinity()Thomas Gleixner1-0/+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>
2009-12-08Merge git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/sysctl-2.6Linus Torvalds1-3/+2
* git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/sysctl-2.6: (43 commits) security/tomoyo: Remove now unnecessary handling of security_sysctl. security/tomoyo: Add a special case to handle accesses through the internal proc mount. sysctl: Drop & in front of every proc_handler. sysctl: Remove CTL_NONE and CTL_UNNUMBERED sysctl: kill dead ctl_handler definitions. sysctl: Remove the last of the generic binary sysctl support sysctl net: Remove unused binary sysctl code sysctl security/tomoyo: Don't look at ctl_name sysctl arm: Remove binary sysctl support sysctl x86: Remove dead binary sysctl support sysctl sh: Remove dead binary sysctl support sysctl powerpc: Remove dead binary sysctl support sysctl ia64: Remove dead binary sysctl support sysctl s390: Remove dead sysctl binary support sysctl frv: Remove dead binary sysctl support sysctl mips/lasat: Remove dead binary sysctl support sysctl drivers: Remove dead binary sysctl support sysctl crypto: Remove dead binary sysctl support sysctl security/keys: Remove dead binary sysctl support sysctl kernel: Remove binary sysctl logic ...
2009-12-08Merge branch 'for-linus' into for-nextTejun Heo1-11/+11
Conflicts: mm/percpu.c
2009-12-06sched: Fix balance vs hotplug racePeter Zijlstra1-15/+17
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>
2009-12-05Merge branch 'sched-core-for-linus' of ↵Linus Torvalds1-96/+174
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 ...
2009-12-05Merge branch 'core-rcu-for-linus' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (31 commits) rcu: Make RCU's CPU-stall detector be default rcu: Add expedited grace-period support for preemptible RCU rcu: Enable fourth level of TREE_RCU hierarchy rcu: Rename "quiet" functions rcu: Re-arrange code to reduce #ifdef pain rcu: Eliminate unneeded function wrapping rcu: Fix grace-period-stall bug on large systems with CPU hotplug rcu: Eliminate __rcu_pending() false positives rcu: Further cleanups of use of lastcomp rcu: Simplify association of forced quiescent states with grace periods rcu: Accelerate callback processing on CPUs not detecting GP end rcu: Mark init-time-only rcu_bootup_announce() as __init rcu: Simplify association of quiescent states with grace periods rcu: Rename dynticks_completed to completed_fqs rcu: Enable synchronize_sched_expedited() fastpath rcu: Remove inline from forward-referenced functions rcu: Fix note_new_gpnum() uses of ->gpnum rcu: Fix synchronization for rcu_process_gp_end() uses of ->completed counter rcu: Prepare for synchronization fixes: clean up for non-NO_HZ handling of ->completed counter rcu: Cleanup: balance rcu_irq_enter()/rcu_irq_exit() calls ...
2009-12-03mutex: Fix missing conditions to build mutex_spin_on_owner()Frederic Weisbecker1-1/+1
We don't need to build mutex_spin_on_owner() if we have CONFIG_DEBUG_MUTEXES or CONFIG_HAVE_DEFAULT_NO_SPIN_MUTEXES as it won't be used under such configs. Use CONFIG_MUTEX_SPIN_ON_OWNER as it gathers all the necessary checks before building it. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <1259783357-8542-2-git-send-regression-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org>
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