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* Merge remote-tracking branch 'kernelorg/linux-3.0.y' into 3_0_64Andrew Dodd2013-02-271-24/+57
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/arm/Kconfig arch/arm/include/asm/hwcap.h arch/arm/kernel/smp.c arch/arm/plat-samsung/adc.c drivers/gpu/drm/i915/i915_reg.h drivers/gpu/drm/i915/intel_drv.h drivers/mmc/core/sd.c drivers/net/tun.c drivers/net/usb/usbnet.c drivers/regulator/max8997.c drivers/usb/core/hub.c drivers/usb/host/xhci.h drivers/usb/serial/qcserial.c fs/jbd2/transaction.c include/linux/migrate.h kernel/sys.c kernel/time/timekeeping.c lib/genalloc.c mm/memory-failure.c mm/memory_hotplug.c mm/mempolicy.c mm/page_alloc.c mm/vmalloc.c mm/vmscan.c mm/vmstat.c scripts/Kbuild.include Change-Id: I91e2d85c07320c7ccfc04cf98a448e89bed6ade6
| * CPU hotplug, cpusets, suspend: Don't modify cpusets during suspend/resumeSrivatsa S. Bhat2012-10-131-4/+36
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit d35be8bab9b0ce44bed4b9453f86ebf64062721e upstream. In the event of CPU hotplug, the kernel modifies the cpusets' cpus_allowed masks as and when necessary to ensure that the tasks belonging to the cpusets have some place (online CPUs) to run on. And regular CPU hotplug is destructive in the sense that the kernel doesn't remember the original cpuset configurations set by the user, across hotplug operations. However, suspend/resume (which uses CPU hotplug) is a special case in which the kernel has the responsibility to restore the system (during resume), to exactly the same state it was in before suspend. In order to achieve that, do the following: 1. Don't modify cpusets during suspend/resume. At all. In particular, don't move the tasks from one cpuset to another, and don't modify any cpuset's cpus_allowed mask. So, simply ignore cpusets during the CPU hotplug operations that are carried out in the suspend/resume path. 2. However, cpusets and sched domains are related. We just want to avoid altering cpusets alone. So, to keep the sched domains updated, build a single sched domain (containing all active cpus) during each of the CPU hotplug operations carried out in s/r path, effectively ignoring the cpusets' cpus_allowed masks. (Since userspace is frozen while doing all this, it will go unnoticed.) 3. During the last CPU online operation during resume, build the sched domains by looking up the (unaltered) cpusets' cpus_allowed masks. That will bring back the system to the same original state as it was in before suspend. Ultimately, this will not only solve the cpuset problem related to suspend resume (ie., restores the cpusets to exactly what it was before suspend, by not touching it at all) but also speeds up suspend/resume because we avoid running cpuset update code for every CPU being offlined/onlined. Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20120524141611.3692.20155.stgit@srivatsabhat.in.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * sched: Fix race in task_group()Peter Zijlstra2012-10-021-14/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 8323f26ce3425460769605a6aece7a174edaa7d1 upstream. Stefan reported a crash on a kernel before a3e5d1091c1 ("sched: Don't call task_group() too many times in set_task_rq()"), he found the reason to be that the multiple task_group() invocations in set_task_rq() returned different values. Looking at all that I found a lack of serialization and plain wrong comments. The below tries to fix it using an extra pointer which is updated under the appropriate scheduler locks. Its not pretty, but I can't really see another way given how all the cgroup stuff works. Reported-and-tested-by: Stefan Bader <stefan.bader@canonical.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1340364965.18025.71.camel@twins Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * sched: Fix the relax_domain_level boot parameterDimitri Sivanich2012-06-171-6/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit a841f8cef4bb124f0f5563314d0beaf2e1249d72 upstream. It does not get processed because sched_domain_level_max is 0 at the time that setup_relax_domain_level() is run. Simply accept the value as it is, as we don't know the value of sched_domain_level_max until sched domain construction is completed. Fix sched_relax_domain_level in cpuset. The build_sched_domain() routine calls the set_domain_attribute() routine prior to setting the sd->level, however, the set_domain_attribute() routine relies on the sd->level to decide whether idle load balancing will be off/on. Signed-off-by: Dimitri Sivanich <sivanich@sgi.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20120605184436.GA15668@sgi.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | Merge linux-3.0.31 from korg into jellybeancodeworkx2012-09-181-27/+26
|\ \ | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/arm/mm/proc-v7.S drivers/base/core.c drivers/gpu/drm/i915/i915_gem_execbuffer.c drivers/gpu/drm/i915/intel_display.c drivers/gpu/drm/i915/intel_lvds.c drivers/gpu/drm/radeon/evergreen.c drivers/gpu/drm/radeon/r100.c drivers/gpu/drm/radeon/radeon_connectors.c drivers/gpu/drm/radeon/rs600.c drivers/usb/core/hub.c drivers/usb/host/xhci-pci.c drivers/usb/host/xhci.c drivers/usb/serial/qcserial.c fs/proc/base.c Change-Id: Ia98b35db3f8c0bfd95817867d3acb85be8e5e772
| * sched: Fix nohz load accounting -- again!Peter Zijlstra2012-05-071-27/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit c308b56b5398779cd3da0f62ab26b0453494c3d4 upstream. [ backported to 3.0 by Kerin Millar <kerframil@gmail.com>] Various people reported nohz load tracking still being wrecked, but Doug spotted the actual problem. We fold the nohz remainder in too soon, causing us to loose samples and under-account. So instead of playing catch-up up-front, always do a single load-fold with whatever state we encounter and only then fold the nohz remainder and play catch-up. Reported-by: Doug Smythies <dsmythies@telus.net> Reported-by: LesÅ=82aw Kope=C4=87 <leslaw.kopec@nasza-klasa.pl> Reported-by: Aman Gupta <aman@tmm1.net> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-4v31etnhgg9kwd6ocgx3rxl8@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Kerin Millar <kerframil@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
* | samsung update 1codeworkx2012-06-021-4/+112
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* posix-cpu-timers: Cure SMP wobblesPeter Zijlstra2011-10-161-24/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit d670ec13178d0fd8680e6742a2bc6e04f28f87d8 upstream. David reported: Attached below is a watered-down version of rt/tst-cpuclock2.c from GLIBC. Just build it with "gcc -o test test.c -lpthread -lrt" or similar. Run it several times, and you will see cases where the main thread will measure a process clock difference before and after the nanosleep which is smaller than the cpu-burner thread's individual thread clock difference. This doesn't make any sense since the cpu-burner thread is part of the top-level process's thread group. I've reproduced this on both x86-64 and sparc64 (using both 32-bit and 64-bit binaries). For example: [davem@boricha build-x86_64-linux]$ ./test process: before(0.001221967) after(0.498624371) diff(497402404) thread: before(0.000081692) after(0.498316431) diff(498234739) self: before(0.001223521) after(0.001240219) diff(16698) [davem@boricha build-x86_64-linux]$ The diff of 'process' should always be >= the diff of 'thread'. I make sure to wrap the 'thread' clock measurements the most tightly around the nanosleep() call, and that the 'process' clock measurements are the outer-most ones. --- #include <unistd.h> #include <stdio.h> #include <stdlib.h> #include <time.h> #include <fcntl.h> #include <string.h> #include <errno.h> #include <pthread.h> static pthread_barrier_t barrier; static void *chew_cpu(void *arg) { pthread_barrier_wait(&barrier); while (1) __asm__ __volatile__("" : : : "memory"); return NULL; } int main(void) { clockid_t process_clock, my_thread_clock, th_clock; struct timespec process_before, process_after; struct timespec me_before, me_after; struct timespec th_before, th_after; struct timespec sleeptime; unsigned long diff; pthread_t th; int err; err = clock_getcpuclockid(0, &process_clock); if (err) return 1; err = pthread_getcpuclockid(pthread_self(), &my_thread_clock); if (err) return 1; pthread_barrier_init(&barrier, NULL, 2); err = pthread_create(&th, NULL, chew_cpu, NULL); if (err) return 1; err = pthread_getcpuclockid(th, &th_clock); if (err) return 1; pthread_barrier_wait(&barrier); err = clock_gettime(process_clock, &process_before); if (err) return 1; err = clock_gettime(my_thread_clock, &me_before); if (err) return 1; err = clock_gettime(th_clock, &th_before); if (err) return 1; sleeptime.tv_sec = 0; sleeptime.tv_nsec = 500000000; nanosleep(&sleeptime, NULL); err = clock_gettime(th_clock, &th_after); if (err) return 1; err = clock_gettime(my_thread_clock, &me_after); if (err) return 1; err = clock_gettime(process_clock, &process_after); if (err) return 1; diff = process_after.tv_nsec - process_before.tv_nsec; printf("process: before(%lu.%.9lu) after(%lu.%.9lu) diff(%lu)\n", process_before.tv_sec, process_before.tv_nsec, process_after.tv_sec, process_after.tv_nsec, diff); diff = th_after.tv_nsec - th_before.tv_nsec; printf("thread: before(%lu.%.9lu) after(%lu.%.9lu) diff(%lu)\n", th_before.tv_sec, th_before.tv_nsec, th_after.tv_sec, th_after.tv_nsec, diff); diff = me_after.tv_nsec - me_before.tv_nsec; printf("self: before(%lu.%.9lu) after(%lu.%.9lu) diff(%lu)\n", me_before.tv_sec, me_before.tv_nsec, me_after.tv_sec, me_after.tv_nsec, diff); return 0; } This is due to us using p->se.sum_exec_runtime in thread_group_cputime() where we iterate the thread group and sum all data. This does not take time since the last schedule operation (tick or otherwise) into account. We can cure this by using task_sched_runtime() at the cost of having to take locks. This also means we can (and must) do away with thread_group_sched_runtime() since the modified thread_group_cputime() is now more accurate and would deadlock when called from thread_group_sched_runtime(). Aside of that it makes the function safe on 32 bit systems. The old code added t->se.sum_exec_runtime unprotected. sum_exec_runtime is a 64bit value and could be changed on another cpu at the same time. Reported-by: David Miller <davem@davemloft.net> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1314874459.7945.22.camel@twins Tested-by: David Miller <davem@davemloft.net> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sched: Fix up wchan borkageSimon Kirby2011-10-161-1/+1
| | | | | | | | | | | | | | | | commit 6ebbe7a07b3bc40b168d2afc569a6543c020d2e3 upstream. Commit c259e01a1ec ("sched: Separate the scheduler entry for preemption") contained a boo-boo wrecking wchan output. It forgot to put the new schedule() function in the __sched section and thereby doesn't get properly ignored for things like wchan. Tested-by: Simon Kirby <sim@hostway.ca> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110923000346.GA25425@hostway.ca Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sched: Fix a memory leak in __sdt_free()WANG Cong2011-10-031-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit feff8fa0075bdfd43c841e9d689ed81adda988d6 upstream. This patch fixes the following memory leak: unreferenced object 0xffff880107266800 (size 512): comm "sched-powersave", pid 3718, jiffies 4323097853 (age 27495.450s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<ffffffff81133940>] create_object+0x187/0x28b [<ffffffff814ac103>] kmemleak_alloc+0x73/0x98 [<ffffffff811232ba>] __kmalloc_node+0x104/0x159 [<ffffffff81044b98>] kzalloc_node.clone.97+0x15/0x17 [<ffffffff8104cb90>] build_sched_domains+0xb7/0x7f3 [<ffffffff8104d4df>] partition_sched_domains+0x1db/0x24a [<ffffffff8109ee4a>] do_rebuild_sched_domains+0x3b/0x47 [<ffffffff810a00c7>] rebuild_sched_domains+0x10/0x12 [<ffffffff8104d5ba>] sched_power_savings_store+0x6c/0x7b [<ffffffff8104d5df>] sched_mc_power_savings_store+0x16/0x18 [<ffffffff8131322c>] sysdev_class_store+0x20/0x22 [<ffffffff81193876>] sysfs_write_file+0x108/0x144 [<ffffffff81135b10>] vfs_write+0xaf/0x102 [<ffffffff81135d23>] sys_write+0x4d/0x74 [<ffffffff814c8a42>] system_call_fastpath+0x16/0x1b [<ffffffffffffffff>] 0xffffffffffffffff Signed-off-by: WANG Cong <amwang@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1313671017-4112-1-git-send-email-amwang@redhat.com Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sched: Move blk_schedule_flush_plug() out of __schedule()Thomas Gleixner2011-10-031-10/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | commit 9c40cef2b799f9b5e7fa5de4d2ad3a0168ba118c upstream. There is no real reason to run blk_schedule_flush_plug() with interrupts and preemption disabled. Move it into schedule() and call it when the task is going voluntarily to sleep. There might be false positives when the task is woken between that call and actually scheduling, but that's not really different from being woken immediately after switching away. This fixes a deadlock in the scheduler where the blk_schedule_flush_plug() callchain enables interrupts and thereby allows a wakeup to happen of the task that's going to sleep. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-dwfxtra7yg1b5r65m32ywtct@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* sched: Separate the scheduler entry for preemptionThomas Gleixner2011-10-031-5/+10
| | | | | | | | | | | | | | | | | | | | | | | | commit c259e01a1ec90063042f758e409cd26b2a0963c8 upstream. Block-IO and workqueues call into notifier functions from the scheduler core code with interrupts and preemption disabled. These calls should be made before entering the scheduler core. To simplify this, separate the scheduler core code into __schedule(). __schedule() is directly called from the places which set PREEMPT_ACTIVE and from schedule(). This allows us to add the work checks into schedule(), so they are only called when a task voluntary goes to sleep. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Tejun Heo <tj@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20110622174918.813258321@linutronix.de Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
* Merge branch 'core-urgent-for-linus' of ↵Linus Torvalds2011-07-201-6/+38
|\ | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: signal: align __lock_task_sighand() irq disabling and RCU softirq,rcu: Inform RCU of irq_exit() activity sched: Add irq_{enter,exit}() to scheduler_ipi() rcu: protect __rcu_read_unlock() against scheduler-using irq handlers rcu: Streamline code produced by __rcu_read_unlock() rcu: Fix RCU_BOOST race handling current->rcu_read_unlock_special rcu: decrease rcu_report_exp_rnp coupling with scheduler
| * Merge branch 'rcu/urgent' of ↵Ingo Molnar2011-07-201-6/+38
| |\ | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-2.6-rcu into core/urgent
| | * sched: Add irq_{enter,exit}() to scheduler_ipi()Peter Zijlstra2011-07-201-6/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Ensure scheduler_ipi() calls irq_{enter,exit} when it does some actual work. Traditionally we never did any actual work from the resched IPI and all magic happened in the return from interrupt path. Now that we do do some work, we need to ensure irq_{enter,exit} are called so that we don't confuse things. This affects things like timekeeping, NO_HZ and RCU, basically everything with a hook in irq_enter/exit. Explicit examples of things going wrong are: sched_clock_cpu() -- has a callback when leaving NO_HZ state to take a new reading from GTOD and TSC. Without this callback, time is stuck in the past. RCU -- needs in_irq() to work in order to avoid some nasty deadlocks Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
* | | sched: Avoid creating superfluous NUMA domains on non-NUMA systemsPeter Zijlstra2011-07-201-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When creating sched_domains, stop when we've covered the entire target span instead of continuing to create domains, only to later find they're redundant and throw them away again. This avoids single node systems from touching funny NUMA sched_domain creation code and reduces the risks of the new SD_OVERLAP code. Requested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Anton Blanchard <anton@samba.org> Cc: mahesh@linux.vnet.ibm.com Cc: benh@kernel.crashing.org Cc: linuxppc-dev@lists.ozlabs.org Link: http://lkml.kernel.org/r/1311180177.29152.57.camel@twins Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | sched: Allow for overlapping sched_domain spansPeter Zijlstra2011-07-201-29/+128
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Allow for sched_domain spans that overlap by giving such domains their own sched_group list instead of sharing the sched_groups amongst each-other. This is needed for machines with more than 16 nodes, because sched_domain_node_span() will generate a node mask from the 16 nearest nodes without regard if these masks have any overlap. Currently sched_domains have a sched_group that maps to their child sched_domain span, and since there is no overlap we share the sched_group between the sched_domains of the various CPUs. If however there is overlap, we would need to link the sched_group list in different ways for each cpu, and hence sharing isn't possible. In order to solve this, allocate private sched_groups for each CPU's sched_domain but have the sched_groups share a sched_group_power structure such that we can uniquely track the power. Reported-and-tested-by: Anton Blanchard <anton@samba.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-08bxqw9wis3qti9u5inifh3y@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | sched: Break out cpu_power from the sched_group structurePeter Zijlstra2011-07-201-6/+26
|/ / | | | | | | | | | | | | | | | | | | | | | | In order to prepare for non-unique sched_groups per domain, we need to carry the cpu_power elsewhere, so put a level of indirection in. Reported-and-tested-by: Anton Blanchard <anton@samba.org> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-qkho2byuhe4482fuknss40ad@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | sched: Fix 32bit racePeter Zijlstra2011-07-151-0/+3
|/ | | | | | | | | | | | | | | Commit 3fe1698b7fe0 ("sched: Deal with non-atomic min_vruntime reads on 32bit") forgot to initialize min_vruntime_copy which could lead to an infinite while loop in task_waking_fair() under some circumstances (early boot, lucky timing). [ This bug was also reported by others that blamed it on the RCU initialization problems ] Reported-and-tested-by: Bruno Wolff III <bruno@wolff.to> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* sched, cgroups: Fix MIN_SHARES on 64-bit boxenMike Galbraith2011-07-011-6/+3
| | | | | | | | | | | | Commit c8b28116 ("sched: Increase SCHED_LOAD_SCALE resolution") intended to have no user-visible effect, but allows setting cpu.shares to < MIN_SHARES, which the user then sees. Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Nikhil Rao <ncrao@google.com> Link: http://lkml.kernel.org/r/1307192600.8618.3.camel@marge.simson.net Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Fix/clarify set_task_cpu() locking rulesPeter Zijlstra2011-06-071-5/+16
| | | | | | | | | | | | | | | Sergey reported a CONFIG_PROVE_RCU warning in push_rt_task where set_task_cpu() was called with both relevant rq->locks held, which should be sufficient for running tasks since holding its rq->lock will serialize against sched_move_task(). Update the comments and fix the task_group() lockdep test. Reported-and-tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1307115427.2353.3456.camel@twins Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Fix schedstat.nr_wakeups_migratePeter Zijlstra2011-05-311-4/+7
| | | | | | | | | | | | | While looking over the code I found that with the ttwu rework the nr_wakeups_migrate test broke since we now switch cpus prior to calling ttwu_stat(), hence the test is always true. Cure this by passing the migration state in wake_flags. Also move the whole test under CONFIG_SMP, its hard to migrate tasks on UP :-) Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-pwwxl7gdqs5676f1d4cx6pj7@git.kernel.org Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Fix cross-cpu clock sync on remote wakeupsPeter Zijlstra2011-05-311-0/+1
| | | | | | | | | | | | | | | | | | Markus reported that commit 317f394160e ("sched: Move the second half of ttwu() to the remote cpu") caused some accounting funnies on his AMD Phenom II X4, such as weird 'top' results. It turns out that this is due to non-synced TSC and the queued remote wakeups stopped coupeling the two relevant cpu clocks, which leads to wakeups seeing time jumps, which in turn lead to skewed runtime stats. Add an explicit call to sched_clock_cpu() to couple the per-cpu clocks to restore the normal flow of time. Reported-and-tested-by: Markus Trippelsdorf <markus@trippelsdorf.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1306835745.2353.3.camel@twins Signed-off-by: Ingo Molnar <mingo@elte.hu>
* cpuset: Fix cpuset_cpus_allowed_fallback(), don't update tsk->rt.nr_cpus_allowedKOSAKI Motohiro2011-05-281-7/+12
| | | | | | | | | | | The rule is, we have to update tsk->rt.nr_cpus_allowed if we change tsk->cpus_allowed. Otherwise RT scheduler may confuse. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/4DD4B3FA.5060901@jp.fujitsu.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
* sched: Fix ttwu() for __ARCH_WANT_INTERRUPTS_ON_CTXSWPeter Zijlstra2011-05-281-9/+28
| | | | | | | | | | | | | | | | | | | | | | | Marc reported that e4a52bcb9 (sched: Remove rq->lock from the first half of ttwu()) broke his ARM-SMP machine. Now ARM is one of the few __ARCH_WANT_INTERRUPTS_ON_CTXSW users, so that exception in the ttwu() code was suspect. Yong found that the interrupt could hit after context_switch() changes current but before it clears p->on_cpu, if that interrupt were to attempt a wake-up of p we would indeed find ourselves spinning in IRQ context. Fix this by reverting to the old behaviour for this situation and perform a full remote wake-up. Cc: Frank Rowand <frank.rowand@am.sony.com> Cc: Yong Zhang <yong.zhang0@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Reported-by: Marc Zyngier <Marc.Zyngier@arm.com> Tested-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* cgroups: add per-thread subsystem callbacksBen Blum2011-05-261-35/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Add cgroup subsystem callbacks for per-thread attachment in atomic contexts Add can_attach_task(), pre_attach(), and attach_task() as new callbacks for cgroups's subsystem interface. Unlike can_attach and attach, these are for per-thread operations, to be called potentially many times when attaching an entire threadgroup. Also, the old "bool threadgroup" interface is removed, as replaced by this. All subsystems are modified for the new interface - of note is cpuset, which requires from/to nodemasks for attach to be globally scoped (though per-cpuset would work too) to persist from its pre_attach to attach_task and attach. This is a pre-patch for cgroup-procs-writable.patch. Signed-off-by: Ben Blum <bblum@andrew.cmu.edu> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Cc: Matt Helsley <matthltc@us.ibm.com> Reviewed-by: Paul Menage <menage@google.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2011-05-231-12/+27
|\ | | | | | | | | | | | | | | | | 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: sched: Increase SCHED_LOAD_SCALE resolution sched: Introduce SCHED_POWER_SCALE to scale cpu_power calculations sched: Cleanup set_load_weight()
| * sched: Increase SCHED_LOAD_SCALE resolutionNikhil Rao2011-05-201-8/+20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce SCHED_LOAD_RESOLUTION, which scales is added to SCHED_LOAD_SHIFT and increases the resolution of SCHED_LOAD_SCALE. This patch sets the value of SCHED_LOAD_RESOLUTION to 10, scaling up the weights for all sched entities by a factor of 1024. With this extra resolution, we can handle deeper cgroup hiearchies and the scheduler can do better shares distribution and load load balancing on larger systems (especially for low weight task groups). This does not change the existing user interface, the scaled weights are only used internally. We do not modify prio_to_weight values or inverses, but use the original weights when calculating the inverse which is used to scale execution time delta in calc_delta_mine(). This ensures we do not lose accuracy when accounting time to the sched entities. Thanks to Nikunj Dadhania for fixing an bug in c_d_m() that broken fairness. Below is some analysis of the performance costs/improvements of this patch. 1. Micro-arch performance costs: Experiment was to run Ingo's pipe_test_100k 200 times with the task pinned to one cpu. I measured instruction, cycles and stalled-cycles for the runs. See: http://thread.gmane.org/gmane.linux.kernel/1129232/focus=1129389 for more info. -tip (baseline): Performance counter stats for '/root/load-scale/pipe-test-100k' (200 runs): 964,991,769 instructions # 0.82 insns per cycle # 0.33 stalled cycles per insn # ( +- 0.05% ) 1,171,186,635 cycles # 0.000 GHz ( +- 0.08% ) 306,373,664 stalled-cycles-backend # 26.16% backend cycles idle ( +- 0.28% ) 314,933,621 stalled-cycles-frontend # 26.89% frontend cycles idle ( +- 0.34% ) 1.122405684 seconds time elapsed ( +- 0.05% ) -tip+patches: Performance counter stats for './load-scale/pipe-test-100k' (200 runs): 963,624,821 instructions # 0.82 insns per cycle # 0.33 stalled cycles per insn # ( +- 0.04% ) 1,175,215,649 cycles # 0.000 GHz ( +- 0.08% ) 315,321,126 stalled-cycles-backend # 26.83% backend cycles idle ( +- 0.28% ) 316,835,873 stalled-cycles-frontend # 26.96% frontend cycles idle ( +- 0.29% ) 1.122238659 seconds time elapsed ( +- 0.06% ) With this patch, instructions decrease by ~0.10% and cycles increase by 0.27%. This doesn't look statistically significant. The number of stalled cycles in the backend increased from 26.16% to 26.83%. This can be attributed to the shifts we do in c_d_m() and other places. The fraction of stalled cycles in the frontend remains about the same, at 26.96% compared to 26.89% in -tip. 2. Balancing low-weight task groups Test setup: run 50 tasks with random sleep/busy times (biased around 100ms) in a low weight container (with cpu.shares = 2). Measure %idle as reported by mpstat over a 10s window. -tip (baseline): 06:47:48 PM CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle intr/s 06:47:49 PM all 94.32 0.00 0.06 0.00 0.00 0.00 0.00 0.00 5.62 15888.00 06:47:50 PM all 94.57 0.00 0.62 0.00 0.00 0.00 0.00 0.00 4.81 16180.00 06:47:51 PM all 94.69 0.00 0.06 0.00 0.00 0.00 0.00 0.00 5.25 15966.00 06:47:52 PM all 95.81 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.19 16053.00 06:47:53 PM all 94.88 0.06 0.00 0.00 0.00 0.00 0.00 0.00 5.06 15984.00 06:47:54 PM all 93.31 0.00 0.00 0.00 0.00 0.00 0.00 0.00 6.69 15806.00 06:47:55 PM all 94.19 0.00 0.06 0.00 0.00 0.00 0.00 0.00 5.75 15896.00 06:47:56 PM all 92.87 0.00 0.00 0.00 0.00 0.00 0.00 0.00 7.13 15716.00 06:47:57 PM all 94.88 0.00 0.00 0.00 0.00 0.00 0.00 0.00 5.12 15982.00 06:47:58 PM all 95.44 0.00 0.00 0.00 0.00 0.00 0.00 0.00 4.56 16075.00 Average: all 94.49 0.01 0.08 0.00 0.00 0.00 0.00 0.00 5.42 15954.60 -tip+patches: 06:47:03 PM CPU %usr %nice %sys %iowait %irq %soft %steal %guest %idle intr/s 06:47:04 PM all 100.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 16630.00 06:47:05 PM all 99.69 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.31 16580.20 06:47:06 PM all 99.69 0.00 0.06 0.00 0.00 0.00 0.00 0.00 0.25 16596.00 06:47:07 PM all 99.20 0.00 0.74 0.00 0.00 0.06 0.00 0.00 0.00 17838.61 06:47:08 PM all 100.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 16540.00 06:47:09 PM all 100.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 16575.00 06:47:10 PM all 100.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 16614.00 06:47:11 PM all 99.94 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.06 16588.00 06:47:12 PM all 99.94 0.00 0.06 0.00 0.00 0.00 0.00 0.00 0.00 16593.00 06:47:13 PM all 99.94 0.00 0.06 0.00 0.00 0.00 0.00 0.00 0.00 16551.00 Average: all 99.84 0.00 0.09 0.00 0.00 0.01 0.00 0.00 0.06 16711.58 We see an improvement in idle% on the system (drops from 5.42% on -tip to 0.06% with the patches). We see an improvement in idle% on the system (drops from 5.42% on -tip to 0.06% with the patches). Signed-off-by: Nikhil Rao <ncrao@google.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Nikunj A. Dadhania <nikunj@linux.vnet.ibm.com> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Stephan Barwolf <stephan.baerwolf@tu-ilmenau.de> Cc: Mike Galbraith <efault@gmx.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/1305754668-18792-1-git-send-email-ncrao@google.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Introduce SCHED_POWER_SCALE to scale cpu_power calculationsNikhil Rao2011-05-201-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | SCHED_LOAD_SCALE is used to increase nice resolution and to scale cpu_power calculations in the scheduler. This patch introduces SCHED_POWER_SCALE and converts all uses of SCHED_LOAD_SCALE for scaling cpu_power to use SCHED_POWER_SCALE instead. This is a preparatory patch for increasing the resolution of SCHED_LOAD_SCALE, and there is no need to increase resolution for cpu_power calculations. Signed-off-by: Nikhil Rao <ncrao@google.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Nikunj A. Dadhania <nikunj@linux.vnet.ibm.com> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Stephan Barwolf <stephan.baerwolf@tu-ilmenau.de> Cc: Mike Galbraith <efault@gmx.de> Link: http://lkml.kernel.org/r/1305738580-9924-3-git-send-email-ncrao@google.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * sched: Cleanup set_load_weight()Nikhil Rao2011-05-201-4/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Avoid using long repetitious names; make this simpler and nicer to read. No functional change introduced in this patch. Signed-off-by: Nikhil Rao <ncrao@google.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Nikunj A. Dadhania <nikunj@linux.vnet.ibm.com> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Stephan Barwolf <stephan.baerwolf@tu-ilmenau.de> Cc: Mike Galbraith <efault@gmx.de> Link: http://lkml.kernel.org/r/1305738580-9924-2-git-send-email-ncrao@google.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next-2.6Linus Torvalds2011-05-221-1/+1
|\ \ | |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc-next-2.6: (28 commits) sparc32: fix build, fix missing cpu_relax declaration SCHED_TTWU_QUEUE is not longer needed since sparc32 now implements IPI sparc32,leon: Remove unnecessary page_address calls in LEON DMA API. sparc: convert old cpumask API into new one sparc32, sun4d: Implemented SMP IPIs support for SUN4D machines sparc32, sun4m: Implemented SMP IPIs support for SUN4M machines sparc32,leon: Implemented SMP IPIs for LEON CPU sparc32: implement SMP IPIs using the generic functions sparc32,leon: SMP power down implementation sparc32,leon: added some SMP comments sparc: add {read,write}*_be routines sparc32,leon: don't rely on bootloader to mask IRQs sparc32,leon: operate on boot-cpu IRQ controller registers sparc32: always define boot_cpu_id sparc32: removed unused code, implemented by generic code sparc32: avoid build warning at mm/percpu.c:1647 sparc32: always register a PROM based early console sparc32: probe for cpu info only during startup sparc: consolidate show_cpuinfo in cpu.c sparc32,leon: implement genirq CPU affinity ...
| * SCHED_TTWU_QUEUE is not longer needed since sparc32 now implements IPIDaniel Hellstrom2011-05-201-1/+1
| | | | | | | | | | | | | | Signed-off-by: Daniel Hellstrom <daniel@gaisler.com> Reported-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: David S. Miller <davem@davemloft.net>
| * Merge commit '317f394160e9beb97d19a84c39b7e5eb3d7815a8'David S. Miller2011-05-201-278/+349
| |\ | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/sparc/kernel/smp_32.c With merge conflict help from Daniel Hellstrom. Signed-off-by: David S. Miller <davem@davemloft.net>
* | | sched: Fix and optimise calculation of the weight-inverseStephan Baerwolf2011-05-161-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If the inverse loadweight should be zero, function "calc_delta_mine" calculates the inverse of "lw->weight" (in 32bit integer ops). This calculation is actually a little bit impure (because it is inverting something around "lw-weight"+1), especially when "lw->weight" becomes smaller. The correct inverse would be 1/lw->weight multiplied by "WMULT_CONST" for fixcomma-scaling it into integers. (So WMULT_CONST/lw->weight ...) The old, impure algorithm took two divisions for inverting lw->weight, the new, more exact one only takes one and an additional unlikely-if. Signed-off-by: Stephan Baerwolf <stephan.baerwolf@tu-ilmenau.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-0pz0wnyalr4tk4ln11xwumdx@git.kernel.org [ This could explain some aritmetical issues for small shares but nothing concrete has been reported yet so we are not confident enough to queue this up in sched/urgent and for -stable backport. But if anyone finds this commit and sees it to fix some badness then we can certainly change our mind! ] Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | sched: Avoid going ahead if ->cpus_allowed is not changedYong Zhang2011-05-161-2/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If cpumask_equal(&p->cpus_allowed, new_mask) is true, seems there is no reason to prevent set_cpus_allowed_ptr() return directly. Signed-off-by: Yong Zhang <yong.zhang0@gmail.com> Acked-by: Hillf Danton <dhillf@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110509140705.GA2219@zhy Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | sched, rt: Update rq clock when unthrottling of an otherwise idle CPUMike Galbraith2011-05-161-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If an RT task is awakened while it's rt_rq is throttled, the time between wakeup/enqueue and unthrottle/selection may be accounted as rt_time if the CPU is idle. Set rq->skip_clock_update negative upon throttle release to tell put_prev_task() that we need a clock update. Reported-by: Thomas Giesel <skoe@directbox.com> Signed-off-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1304059010.7472.1.camel@marge.simson.net Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | sched: Remove unused parameters from sched_fork() and wake_up_new_task()Samir Bellabes2011-05-121-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | sched_fork() and wake_up_new_task() are defined with a parameter 'unsigned long clone_flags', which is unused. This patch removes the parameters. Signed-off-by: Samir Bellabes <sam@synack.fr> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1305130685-1047-1-git-send-email-sam@synack.fr Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | sched: Shorten the construction of the span cpu mask of sched domainHillf Danton2011-05-061-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For a given node, when constructing the cpumask for its sched_domain to span, if there is no best node available after searching, further efforts could be saved, based on small change in the return value of find_next_best_node(). Signed-off-by: Hillf Danton <dhillf@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Yong Zhang <yong.zhang0@gmail.com> Link: http://lkml.kernel.org/r/BANLkTi%3DqPWxRAa6%2BdT3ohEP6Z%3D0v%2Be4EXA@mail.gmail.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | sched: Wrap the 'cfs_rq->nr_spread_over' field with CONFIG_SCHED_DEBUGRakib Mullick2011-05-061-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | cfs_rq->nr_spread_over is only used when CONFIG_SCHED_DEBUG is set. So wrap it with CONFIG_SCHED_DEBUG. Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1304528026.15681.3.camel@localhost.localdomain Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | sched: Remove noop in alloc_rt_sched_group()Hillf Danton2011-04-261-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The rq varible, though computed for each possible cpu, has nothing to do in the function, so it can be removed. This also eliminates a build warning. Signed-off-by: Hillf Danton <dhillf@gmail.com> Reviewed-by: Yong Zhang <yong.zhang0@gmail.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/BANLkTin-FfQfqW5ym1iuEmrk8s777Y1LAg@mail.gmail.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | sched: Get rid of lock_depthJonathan Corbet2011-04-241-10/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Neil Brown pointed out that lock_depth somehow escaped the BKL removal work. Let's get rid of it now. Note that the perf scripting utilities still have a bunch of code for dealing with common_lock_depth in tracepoints; I have left that in place in case anybody wants to use that code with older kernels. Suggested-by: Neil Brown <neilb@suse.de> Signed-off-by: Jonathan Corbet <corbet@lwn.net> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20110422111910.456c0e84@bike.lwn.net Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | sched: Remove obsolete comment from scheduler_tick()Rakib Mullick2011-04-211-3/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | scheduler_tick() is no longer called by fork code - this got discarded a long time ago by commit bc947631d1d532 ("sched: improve efficiency of sched_fork()"). So, remove the comment which still claims otherwise. Signed-off-by: Rakib Mullick <rakib.mullick@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/BANLkTimO4iGP0QpaHO1HHF1QOnVcQpc0cw@mail.gmail.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | Merge commit 'v2.6.39-rc4' into sched/coreIngo Molnar2011-04-211-1/+1
|\ \ \ | |/ / | | | | | | | | | | | | Merge reason: Pick up upstream fixes. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | block: let io_schedule() flush the plug inlineJens Axboe2011-04-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Linus correctly observes that the most important dispatch cases are now done from kblockd, this isn't ideal for latency reasons. The original reason for switching dispatches out-of-line was to avoid too deep a stack, so by _only_ letting the "accidental" flush directly in schedule() be guarded by offload to kblockd, we should be able to get the best of both worlds. So add a blk_schedule_flush_plug() that offloads to kblockd, and only use that from the schedule() path. Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
* | | sched: Fix sched_domain iterations vs. RCUPeter Zijlstra2011-04-191-3/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Vladis Kletnieks reported a new RCU debug warning in the scheduler. Since commit dce840a08702b ("sched: Dynamically allocate sched_domain/ sched_group data-structures") the sched_domain trees are protected by RCU instead of RCU-sched. This means that we need to include rcu_read_lock() protection when we iterate them since disabling preemption doesn't suffice anymore. Reported-by: Valdis.Kletnieks@vt.edu Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1302882741.2388.241.camel@twins Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | | Merge branch 'sched/locking' into sched/coreIngo Molnar2011-04-181-297/+353
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | Merge reason: the rq locking changes are stable, propagate them into the .40 queue. Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | | sched: Remove need_migrate_task()Peter Zijlstra2011-04-141-16/+1
| | |/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Oleg noticed that need_migrate_task() doesn't need the ->on_cpu check now that ttwu() doesn't do remote enqueues for !->on_rq && ->on_cpu, so remove the helper and replace the single instance with a direct ->on_rq test. Suggested-by: Oleg Nesterov <oleg@redhat.com> Reviewed-by: Frank Rowand <frank.rowand@am.sony.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/20110405152729.556674812@chello.nl Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * | sched: Move the second half of ttwu() to the remote cpuPeter Zijlstra2011-04-141-0/+56
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that we've removed the rq->lock requirement from the first part of ttwu() and can compute placement without holding any rq->lock, ensure we execute the second half of ttwu() on the actual cpu we want the task to run on. This avoids having to take rq->lock and doing the task enqueue remotely, saving lots on cacheline transfers. As measured using: http://oss.oracle.com/~mason/sembench.c $ for i in /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor ; do echo performance > $i; done $ echo 4096 32000 64 128 > /proc/sys/kernel/sem $ ./sembench -t 2048 -w 1900 -o 0 unpatched: run time 30 seconds 647278 worker burns per second patched: run time 30 seconds 816715 worker burns per second Reviewed-by: Frank Rowand <frank.rowand@am.sony.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110405152729.515897185@chello.nl
| * | sched: Restructure ttwu() some morePeter Zijlstra2011-04-141-33/+58
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Factor our helper functions to make the inner workings of try_to_wake_up() more obvious, this also allows for adding remote queues. Reviewed-by: Frank Rowand <frank.rowand@am.sony.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110405152729.475848012@chello.nl
| * | sched: Rename ttwu_post_activation() to ttwu_do_wakeup()Peter Zijlstra2011-04-141-3/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The ttwu_post_activation() code does the core wakeup, it sets TASK_RUNNING and performs wakeup-preemption, so give is a more descriptive name. Reviewed-by: Frank Rowand <frank.rowand@am.sony.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Nick Piggin <npiggin@kernel.dk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110405152729.434609705@chello.nl
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