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2013-10-29sched: Fix cfs_bandwidth misuse of hrtimer_expires_remainingBen Segall
hrtimer_expires_remaining does not take internal hrtimer locks and thus must be guarded against concurrent __hrtimer_start_range_ns (but returning HRTIMER_RESTART is safe). Use cfs_b->lock to make it safe. Signed-off-by: Ben Segall <bsegall@google.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: pjt@google.com Link: http://lkml.kernel.org/r/20131016181617.22647.73829.stgit@sword-of-the-dawn.mtv.corp.google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-29sched: Fix race on toggling cfs_bandwidth_usedBen Segall
When we transition cfs_bandwidth_used to false, any currently throttled groups will incorrectly return false from cfs_rq_throttled. While tg_set_cfs_bandwidth will unthrottle them eventually, currently running code (including at least dequeue_task_fair and distribute_cfs_runtime) will cause errors. Fix this by turning off cfs_bandwidth_used only after unthrottling all cfs_rqs. Tested: toggle bandwidth back and forth on a loaded cgroup. Caused crashes in minutes without the patch, hasn't crashed with it. Signed-off-by: Ben Segall <bsegall@google.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: pjt@google.com Link: http://lkml.kernel.org/r/20131016181611.22647.80365.stgit@sword-of-the-dawn.mtv.corp.google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-29perf: Fix perf ring buffer memory orderingPeter Zijlstra
The PPC64 people noticed a missing memory barrier and crufty old comments in the perf ring buffer code. So update all the comments and add the missing barrier. When the architecture implements local_t using atomic_long_t there will be double barriers issued; but short of introducing more conditional barrier primitives this is the best we can do. Reported-by: Victor Kaplansky <victork@il.ibm.com> Tested-by: Victor Kaplansky <victork@il.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Cc: michael@ellerman.id.au Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Michael Neuling <mikey@neuling.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: anton@samba.org Cc: benh@kernel.crashing.org Link: http://lkml.kernel.org/r/20131025173749.GG19466@laptop.lan Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-29Merge branch 'perf/urgent' into perf/coreIngo Molnar
Conflicts: tools/perf/builtin-record.c tools/perf/builtin-top.c tools/perf/util/hist.h
2013-10-28sched: Remove extra put_online_cpus() inside sched_setaffinity()Michael wang
Commit 6acce3ef8: sched: Remove get_online_cpus() usage has left one extra put_online_cpus() inside sched_setaffinity(), remove it to fix the WARN: ------------[ cut here ]------------ WARNING: CPU: 0 PID: 3166 at kernel/cpu.c:84 put_online_cpus+0x43/0x70() ... [<ffffffff810c3fef>] put_online_cpus+0x43/0x70 [ [<ffffffff810efd59>] sched_setaffinity+0x7d/0x1f9 [ ... Reported-by: Fengguang Wu <fengguang.wu@intel.com> Tested-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Michael Wang <wangyun@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/526DD0EE.1090309@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-28genirq: Set the irq thread policy without checking CAP_SYS_NICEThomas Pfaff
In commit ee23871389 ("genirq: Set irq thread to RT priority on creation") we moved the assigment of the thread's priority from the thread's function into __setup_irq(). That function may run in user context for instance if the user opens an UART node and then driver calls requests in the ->open() callback. That user may not have CAP_SYS_NICE and so the irq thread won't run with the SCHED_OTHER policy. This patch uses sched_setscheduler_nocheck() so we omit the CAP_SYS_NICE check which is otherwise required for the SCHED_OTHER policy. [bigeasy: Rewrite the changelog] Signed-off-by: Thomas Pfaff <tpfaff@pcs.com> Cc: Ivo Sieben <meltedpianoman@gmail.com> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1381489240-29626-1-git-send-email-bigeasy@linutronix.de Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2013-10-27Merge branch 'timers-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fix from Ingo Molnar: "This tree contains a clockevents regression fix for certain ARM subarchitectures" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: clockevents: Sanitize ticks to nsec conversion
2013-10-27Merge branch 'perf-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull perf fixes from Ingo Molnar: "The tree contains three fixes: - Two tooling fixes - Reversal of the new 'MMAP2' extended mmap record ABI, introduced in this merge window. (Patches were proposed to fix it but it was all a bit late and we felt it's safer to just delay the ABI one more kernel release and do it right)" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf: Disable PERF_RECORD_MMAP2 support perf scripting perl: Fix build error on Fedora 12 perf probe: Fix to initialize fname always before use it
2013-10-27Merge branch 'core-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking fix from Ingo Molnar: "This tree fixes a boot crash in CONFIG_DEBUG_MUTEXES=y kernels, on kernels built with GCC 3.x (there are still such distros)" Side note: it's not just a fix for old gcc versions, it's also removing an incredibly broken/subtle check that LLVM had issues with, and that made no sense. * 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: mutex: Avoid gcc version dependent __builtin_constant_p() usage
2013-10-26sched/rt: Fix task_tick_rt() commentLi Bin
This issue was introduced by 454c79999f7e ("sched/rt: Fix SCHED_RR across cgroups") that missed the word 'not'. Fix it. Signed-off-by: Li Bin <huawei.libin@huawei.com> Cc: <guohanjun@huawei.com> Cc: <xiexiuqi@huawei.com> Cc: <peterz@infradead.org> Link: http://lkml.kernel.org/r/1382357743-54136-1-git-send-email-huawei.libin@huawei.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-26Merge tag 'pm+acpi-3.12-rc7' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull ACPI and power management fixes from "These fix two bugs in the intel_pstate driver, a hibernate bug leading to nasty resume failures sometimes and acpi-cpufreq initialization bug that causes problems to happen during module unload when intel_pstate is in use. Specifics: - Fix for rounding errors in intel_pstate causing CPU utilization to be underestimated from Brennan Shacklett. - intel_pstate fix to always use the correct max pstate value when computing the min pstate from Dirk Brandewie. - Hibernation fix for deadlocking resume in cases when the probing of the device containing the image is deferred from Russ Dill. - acpi-cpufreq fix to prevent the module from staying in memory when the driver cannot be registered and then attempting to unregister things that have never been registered on exit" * tag 'pm+acpi-3.12-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: acpi-cpufreq: Fail initialization if driver cannot be registered PM / hibernate: Move software_resume to late_initcall_sync intel_pstate: Correct calculation of min pstate value intel_pstate: Improve accuracy by not truncating until final result
2013-10-24PM / hibernate: Move software_resume to late_initcall_syncRuss Dill
software_resume is being called after deferred_probe_initcall in drivers base. If the probing of the device that contains the resume image is deferred, and the system has been instructed to wait for it to show up, this wait will occur in software_resume. This causes a deadlock. Move software_resume into late_initcall_sync so that it happens after all the other late_initcalls. Signed-off-by: Russ Dill <Russ.Dill@ti.com> Acked-by: Pavel Machek <Pavel@ucw.cz> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-10-24of/irq: simplify args to irq_create_of_mappingGrant Likely
All the callers of irq_create_of_mapping() pass the contents of a struct of_phandle_args structure to the function. Since all the callers already have an of_phandle_args pointer, why not pass it directly to irq_create_of_mapping()? Signed-off-by: Grant Likely <grant.likely@linaro.org> Acked-by: Michal Simek <monstr@monstr.eu> Acked-by: Tony Lindgren <tony@atomide.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Russell King <linux@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2013-10-23clockevents: Sanitize ticks to nsec conversionThomas Gleixner
Marc Kleine-Budde pointed out, that commit 77cc982 "clocksource: use clockevents_config_and_register() where possible" caused a regression for some of the converted subarchs. The reason is, that the clockevents core code converts the minimal hardware tick delta to a nanosecond value for core internal usage. This conversion is affected by integer math rounding loss, so the backwards conversion to hardware ticks will likely result in a value which is less than the configured hardware limitation. The affected subarchs used their own workaround (SIGH!) which got lost in the conversion. The solution for the issue at hand is simple: adding evt->mult - 1 to the shifted value before the integer divison in the core conversion function takes care of it. But this only works for the case where for the scaled math mult/shift pair "mult <= 1 << shift" is true. For the case where "mult > 1 << shift" we can apply the rounding add only for the minimum delta value to make sure that the backward conversion is not less than the given hardware limit. For the upper bound we need to omit the rounding add, because the backwards conversion is always larger than the original latch value. That would violate the upper bound of the hardware device. Though looking closer at the details of that function reveals another bogosity: The upper bounds check is broken as well. Checking for a resulting "clc" value greater than KTIME_MAX after the conversion is pointless. The conversion does: u64 clc = (latch << evt->shift) / evt->mult; So there is no sanity check for (latch << evt->shift) exceeding the 64bit boundary. The latch argument is "unsigned long", so on a 64bit arch the handed in argument could easily lead to an unnoticed shift overflow. With the above rounding fix applied the calculation before the divison is: u64 clc = (latch << evt->shift) + evt->mult - 1; So we need to make sure, that neither the shift nor the rounding add is overflowing the u64 boundary. [ukl: move assignment to rnd after eventually changing mult, fix build issue and correct comment with the right math] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Russell King - ARM Linux <linux@arm.linux.org.uk> Cc: Marc Kleine-Budde <mkl@pengutronix.de> Cc: nicolas.ferre@atmel.com Cc: Marc Pignat <marc.pignat@hevs.ch> Cc: john.stultz@linaro.org Cc: kernel@pengutronix.de Cc: Ronald Wahl <ronald.wahl@raritan.com> Cc: LAK <linux-arm-kernel@lists.infradead.org> Cc: Ludovic Desroches <ludovic.desroches@atmel.com> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/1380052223-24139-1-git-send-email-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2013-10-22Merge branch 'for-3.12-fixes' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup Pull cgroup fixes from Tejun Heo: "Two late fixes for cgroup. One fixes descendant walk introduced during this rc1 cycle. The other fixes a post 3.9 bug during task attach which can lead to hang. Both fixes are critical and the fixes are relatively straight-forward" * 'for-3.12-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: cgroup: fix to break the while loop in cgroup_attach_task() correctly cgroup: fix cgroup post-order descendant walk of empty subtree
2013-10-20Merge tag 'perf-urgent-for-mingo' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/urgent Pull perf/urgent fixes from Arnaldo Carvalho de Melo: " * Fix build error on Fedora 12. * Fix to initialize fname always before use it, bug introduced during this merge window, from Masami Hiramatsu. * Disable PERF_RECORD_MMAP2 support, from Stephane Eranian. " Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-19Merge 3.12-rc6 into driver-core-nextGreg Kroah-Hartman
We want these fixes here too. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-10-18time: Fix signedness bug in sysfs_get_uname() and its callersPatrick Palka
sysfs_get_uname() is erroneously declared as returning size_t even though it may return a negative value, specifically -EINVAL. Its callers then check whether its return value is less than zero and indeed that is never the case for size_t. This patch changes sysfs_get_uname() to return ssize_t and makes sure its callers use ssize_t accordingly. Signed-off-by: Patrick Palka <patrick@parcs.ath.cx> [jstultz: Didn't apply cleanly, as a similar partial fix was also applied so had to resolve the collisions] Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-10-18timekeeping: Fix some trivial typos in commentsXie XiuQi
Fix some typos in timekeeping comments. Signed-off-by: Xie XiuQi <xiexiuqi@huawei.com> [jstultz: Commit message tweaks] Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-10-18alarmtimer: return EINVAL instead of ENOTSUPP if rtcdev doesn't existKOSAKI Motohiro
Fedora Ruby maintainer reported latest Ruby doesn't work on Fedora Rawhide on ARM. (http://bugs.ruby-lang.org/issues/9008) Because of, commit 1c6b39ad3f (alarmtimers: Return -ENOTSUPP if no RTC device is present) intruduced to return ENOTSUPP when clock_get{time,res} can't find a RTC device. However this is incorrect. First, ENOTSUPP isn't exported to userland (ENOTSUP or EOPNOTSUP are the closest userland equivlents). Second, Posix and Linux man pages agree that clock_gettime and clock_getres should return EINVAL if clk_id argument is invalid. While the arugment that the clockid is valid, but just not supported on this hardware could be made, this is just a technicality that doesn't help userspace applicaitons, and only complicates error handling. Thus, this patch changes the code to use EINVAL. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: stable <stable@vger.kernel.org> #3.0 and up Reported-by: Vit Ondruch <v.ondruch@tiscali.cz> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> [jstultz: Tweaks to commit message to include full rational] Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-10-18mutex: Avoid gcc version dependent __builtin_constant_p() usageTetsuo Handa
Commit 040a0a37 ("mutex: Add support for wound/wait style locks") used "!__builtin_constant_p(p == NULL)" but gcc 3.x cannot handle such expression correctly, leading to boot failure when built with CONFIG_DEBUG_MUTEXES=y. Fix it by explicitly passing a bool which tells whether p != NULL or not. [ PeterZ: This is a sad patch, but provided it actually generates similar code I suppose its the best we can do bar whole sale deprecating gcc-3. ] Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Maarten Lankhorst <maarten.lankhorst@canonical.com> Cc: peterz@infradead.org Cc: imirkin@alum.mit.edu Cc: daniel.vetter@ffwll.ch Cc: robdclark@gmail.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/r/201310171945.AGB17114.FSQVtHOJFOOFML@I-love.SAKURA.ne.jp Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-18Merge branch 'rcu/next' of ↵Ingo Molnar
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/rcu Pull RCU updates from Paul E. McKenney. Major changes: " 1. Update RCU documentation. These were posted to LKML at http://article.gmane.org/gmane.linux.kernel/1566994. 2. Miscellaneous fixes. These were posted to LKML at http://article.gmane.org/gmane.linux.kernel/1567027. 3. Grace-period-related changes, primarily to aid in debugging, inspired by a -rt debugging session. These were posted to LKML at http://article.gmane.org/gmane.linux.kernel/1567076. 4. Idle entry/exit changes, primarily to address issues located by Tibor Billes. These were posted to LKML at http://article.gmane.org/gmane.linux.kernel/1567096. 5. Code reorganization moving RCU's source files from kernel to kernel/rcu. This was posted to LKML at http://article.gmane.org/gmane.linux.kernel/1577344." Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-17perf: Disable PERF_RECORD_MMAP2 supportStephane Eranian
For now, we disable the extended MMAP record support (MMAP2). We have identified cases where it would not report the correct mapping information, clone(VM_CLONE) but with separate pids. We will revisit the support once we find a solution for this case. The patch changes the kernel to return EINVAL if attr->mmap2 is set. The patch also modifies the perf tool to use regular PERF_RECORD_MMAP for synthetic events and it also prevents the tool from requesting attr->mmap2 mode because the kernel would reject it. The support will be revisited once the kenrel interface is updated. In V2, we reduce the patch to the strict minimum. In V3, we avoid calling perf_event_open() with mmap2 set because we know it will fail and require fallback retry. Signed-off-by: Stephane Eranian <eranian@google.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131017173215.GA8820@quad Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-10-16sysrq: Allow magic SysRq key functions to be disabled through KconfigBen Hutchings
Turn the initial value of sysctl kernel.sysrq (SYSRQ_DEFAULT_ENABLE) into a Kconfig variable. Original version by Bastian Blank <waldi@debian.org>. Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-10-16sched/wait: Introduce prepare_to_wait_event()Oleg Nesterov
Add the new helper, prepare_to_wait_event() which should only be used by ___wait_event(). prepare_to_wait_event() returns -ERESTARTSYS if signal_pending_state() is true, otherwise it does prepare_to_wait/exclusive. This allows to uninline the signal-pending checks in wait_event*() macros. Also, it can initialize wait->private/func. We do not care if they were already initialized, the values are the same. This also shaves a couple of insns from the inlined code. This obviously makes prepare_*() path a little bit slower, but we are likely going to sleep anyway, so I think it makes sense to shrink .text: text data bss dec hex filename =================================================== before: 5126092 2959248 10117120 18202460 115bf5c vmlinux after: 5124618 2955152 10117120 18196890 115a99a vmlinux on my build. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131007161824.GA29757@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-16sched: Remove get_online_cpus() usagePeter Zijlstra
Remove get_online_cpus() usage from the scheduler; there's 4 sites that use it: - sched_init_smp(); where its completely superfluous since we're in 'early' boot and there simply cannot be any hotplugging. - sched_getaffinity(); we already take a raw spinlock to protect the task cpus_allowed mask, this disables preemption and therefore also stabilizes cpu_online_mask as that's modified using stop_machine. However switch to active mask for symmetry with sched_setaffinity()/set_cpus_allowed_ptr(). We guarantee active mask stability by inserting sync_rcu/sched() into _cpu_down. - sched_setaffinity(); we don't appear to need get_online_cpus() either, there's two sites where hotplug appears relevant: * cpuset_cpus_allowed(); for the !cpuset case we use possible_mask, for the cpuset case we hold task_lock, which is a spinlock and thus for mainline disables preemption (might cause pain on RT). * set_cpus_allowed_ptr(); Holds all scheduler locks and thus has preemption properly disabled; also it already deals with hotplug races explicitly where it releases them. - migrate_swap(); we can make stop_two_cpus() do the heavy lifting for us with a little trickery. By adding a sync_sched/rcu() after the CPU_DOWN_PREPARE notifier we can provide preempt/rcu guarantees for cpu_active_mask. Use these to validate that both our cpus are active when queueing the stop work before we queue the stop_machine works for take_cpu_down(). Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Rik van Riel <riel@redhat.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Oleg Nesterov <oleg@redhat.com> Link: http://lkml.kernel.org/r/20131011123820.GV3081@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-16sched: Fix race in migrate_swap_stop()Peter Zijlstra
There is a subtle race in migrate_swap, when task P, on CPU A, decides to swap places with task T, on CPU B. Task P: - call migrate_swap Task T: - go to sleep, removing itself from the runqueue Task P: - double lock the runqueues on CPU A & B Task T: - get woken up, place itself on the runqueue of CPU C Task P: - see that task T is on a runqueue, and pretend to remove it from the runqueue on CPU B Now CPUs B & C both have corrupted scheduler data structures. This patch fixes it, by holding the pi_lock for both of the tasks involved in the migrate swap. This prevents task T from waking up, and placing itself onto another runqueue, until after migrate_swap has released all locks. This means that, when migrate_swap checks, task T will be either on the runqueue where it was originally seen, or not on any runqueue at all. Migrate_swap deals correctly with of those cases. Tested-by: Joe Mario <jmario@redhat.com> Acked-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: hannes@cmpxchg.org Cc: aarcange@redhat.com Cc: srikar@linux.vnet.ibm.com Cc: tglx@linutronix.de Cc: hpa@zytor.com Link: http://lkml.kernel.org/r/20131010181722.GO13848@laptop.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-16sched/rt: Add missing rmb()Peter Zijlstra
While discussing the proposed SCHED_DEADLINE patches which in parts mimic the existing FIFO code it was noticed that the wmb in rt_set_overloaded() didn't have a matching barrier. The only site using rt_overloaded() to test the rto_count is pull_rt_task() and we should issue a matching rmb before then assuming there's an rto_mask bit set. Without that smp_rmb() in there we could actually miss seeing the rto_mask bit. Also, change to using smp_[wr]mb(), even though this is SMP only code; memory barriers without smp_ always make me think they're against hardware of some sort. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: vincent.guittot@linaro.org Cc: luca.abeni@unitn.it Cc: bruce.ashfield@windriver.com Cc: dhaval.giani@gmail.com Cc: rostedt@goodmis.org Cc: hgu1972@gmail.com Cc: oleg@redhat.com Cc: fweisbec@gmail.com Cc: darren@dvhart.com Cc: johan.eker@ericsson.com Cc: p.faure@akatech.ch Cc: paulmck@linux.vnet.ibm.com Cc: raistlin@linux.it Cc: claudio@evidence.eu.com Cc: insop.song@gmail.com Cc: michael@amarulasolutions.com Cc: liming.wang@windriver.com Cc: fchecconi@gmail.com Cc: jkacur@redhat.com Cc: tommaso.cucinotta@sssup.it Cc: Juri Lelli <juri.lelli@gmail.com> Cc: harald.gustafsson@ericsson.com Cc: nicola.manica@disi.unitn.it Cc: tglx@linutronix.de Link: http://lkml.kernel.org/r/20131015103507.GF10651@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-15rcu: Move RCU-related source code to kernel/rcu directoryPaul E. McKenney
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Ingo Molnar <mingo@kernel.org>
2013-10-15Merge branch 'idle.2013.09.25a' into HEADPaul E. McKenney
idle.2013.09.25a: Topic branch for idle entry-/exit-related changes.
2013-10-15Merge branch 'gp.2013.09.25a' into HEADPaul E. McKenney
gp.2013.09.25a: Topic branch for grace-period updates.
2013-10-15Merge tag 'v3.12-rc5' into perf/coreIngo Molnar
Merge Linux v3.12-rc5, to pick up the latest fixes. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-14sched/fair: Fix trivial typos in commentsKamalesh Babulal
- 'load_icx' => 'load_idx' - 'calculcate_imbalance' => 'calculate_imbalance' Signed-off-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com> Cc: peterz@infradead.org Link: http://lkml.kernel.org/r/1381685775-3544-1-git-send-email-kamalesh@linux.vnet.ibm.com [ Also, don't capitalize 'idle' unnecessarily. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-13cgroup: fix to break the while loop in cgroup_attach_task() correctlyAnjana V Kumar
Both Anjana and Eunki reported a stall in the while_each_thread loop in cgroup_attach_task(). It's because, when we attach a single thread to a cgroup, if the cgroup is exiting or is already in that cgroup, we won't break the loop. If the task is already in the cgroup, the bug can lead to another thread being attached to the cgroup unexpectedly: # echo 5207 > tasks # cat tasks 5207 # echo 5207 > tasks # cat tasks 5207 5215 What's worse, if the task to be attached isn't the leader of the thread group, we might never exit the loop, hence cpu stall. Thanks for Oleg's analysis. This bug was introduced by commit 081aa458c38ba576bdd4265fc807fa95b48b9e79 ("cgroup: consolidate cgroup_attach_task() and cgroup_attach_proc()") [ lizf: - fixed the first continue, pointed out by Oleg, - rewrote changelog. ] Cc: <stable@vger.kernel.org> # 3.9+ Reported-by: Eunki Kim <eunki_kim@samsung.com> Reported-by: Anjana V Kumar <anjanavk12@gmail.com> Signed-off-by: Anjana V Kumar <anjanavk12@gmail.com> Signed-off-by: Li Zefan <lizefan@huawei.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2013-10-12sched: Remove bogus parameter in structured commentRamkumar Ramachandra
The balance parameter was removed by 23f0d20 ("sched: Factor out code to should_we_balance()", 2013-08-06). Signed-off-by: Ramkumar Ramachandra <artagnon@gmail.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1381400433-2030-1-git-send-email-artagnon@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-11Merge branch 'core/urgent' into sched/coreIngo Molnar
Merge in asm goto fix, to be able to apply the asm/rmwcc.h fix. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-10timer stats: Add a 'Collection: active/inactive' line to timer usage statisticsDong Zhu
We can enable/disable timer statistics collection via: echo [1|0] > /proc/timers_stats and it would be nice if apps had the ability to check what the current collection status is. This patch adds a 'Collection: active/inactive' line to display the current timer collection status. Also bump up the timer stats version to v0.3. Signed-off-by: Dong Zhu <bluezhudong@gmail.com> Cc: John Stultz <john.stultz@linaro.org> Link: http://lkml.kernel.org/r/20131010075618.GH2139@zhudong.nay.redhat.com [ Improved the changelog and the code. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-10Merge branch 'fortglx/3.13/time' of ↵Ingo Molnar
git://git.linaro.org/people/jstultz/linux into timers/core Pull more timekeeping items for v3.13 from John Stultz: * Small cleanup in the clocksource code. * Fix for rtc-pl031 to let it work with alarmtimers. * Move arm64 to using the generic sched_clock framework & resulting cleanup in the generic sched_clock code. Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-09sched_clock: Remove sched_clock_func() hookStephen Boyd
Nobody is using sched_clock_func() anymore now that sched_clock supports up to 64 bits. Remove the hook so that new code only uses sched_clock_register(). Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
2013-10-09sched/numa: Reflow task_numa_group() to avoid a compiler warningPeter Zijlstra
Reflow the function a bit because GCC gets confused: kernel/sched/fair.c: In function ‘task_numa_fault’: kernel/sched/fair.c:1448:3: warning: ‘my_grp’ may be used uninitialized in this function [-Wmaybe-uninitialized] kernel/sched/fair.c:1463:27: note: ‘my_grp’ was declared here Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-6ebt6x7u64pbbonq1khqu2z9@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-09sched/numa: Retry task_numa_migrate() periodicallyRik van Riel
Short spikes of CPU load can lead to a task being migrated away from its preferred node for temporary reasons. It is important that the task is migrated back to where it belongs, in order to avoid migrating too much memory to its new location, and generally disturbing a task's NUMA location. This patch fixes NUMA placement for 4 specjbb instances on a 4 node system. Without this patch, things take longer to converge, and processes are not always completely on their own node. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1381141781-10992-64-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-09sched/numa: Use unsigned longs for numa group fault statsMel Gorman
As Peter says "If you're going to hold locks you can also do away with all that atomic_long_*() nonsense". Lock aquisition moved slightly to protect the updates. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1381141781-10992-63-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-09sched/numa: Skip some page migrations after a shared faultRik van Riel
Shared faults can lead to lots of unnecessary page migrations, slowing down the system, and causing private faults to hit the per-pgdat migration ratelimit. This patch adds sysctl numa_balancing_migrate_deferred, which specifies how many shared page migrations to skip unconditionally, after each page migration that is skipped because it is a shared fault. This reduces the number of page migrations back and forth in shared fault situations. It also gives a strong preference to the tasks that are already running where most of the memory is, and to moving the other tasks to near the memory. Testing this with a much higher scan rate than the default still seems to result in fewer page migrations than before. Memory seems to be somewhat better consolidated than previously, with multi-instance specjbb runs on a 4 node system. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1381141781-10992-62-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-09mm: numa: Revert temporarily disabling of NUMA migrationRik van Riel
With the scan rate code working (at least for multi-instance specjbb), the large hammer that is "sched: Do not migrate memory immediately after switching node" can be replaced with something smarter. Revert temporarily migration disabling and all traces of numa_migrate_seq. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1381141781-10992-61-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-09sched/numa: Remove the numa_balancing_scan_period_reset sysctlMel Gorman
With scan rate adaptions based on whether the workload has properly converged or not there should be no need for the scan period reset hammer. Get rid of it. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1381141781-10992-60-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-09sched/numa: Adjust scan rate in task_numa_placementRik van Riel
Adjust numa_scan_period in task_numa_placement, depending on how much useful work the numa code can do. The more local faults there are in a given scan window the longer the period (and hence the slower the scan rate) during the next window. If there are excessive shared faults then the scan period will decrease with the amount of scaling depending on whether the ratio of shared/private faults. If the preferred node changes then the scan rate is reset to recheck if the task is properly placed. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1381141781-10992-59-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-09sched/numa: Take false sharing into account when adapting scan rateMel Gorman
Scan rate is altered based on whether shared/private faults dominated. task_numa_group() may detect false sharing but that information is not taken into account when adapting the scan rate. Take it into account. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1381141781-10992-58-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-09sched/numa: Be more careful about joining numa groupsRik van Riel
Due to the way the pid is truncated, and tasks are moved between CPUs by the scheduler, it is possible for the current task_numa_fault to group together tasks that do not actually share memory together. This patch adds a few easy sanity checks to task_numa_fault, joining tasks together if they share the same tsk->mm, or if the fault was on a page with an elevated mapcount, in a shared VMA. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1381141781-10992-57-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-09sched/numa: Avoid migrating tasks that are placed on their preferred nodePeter Zijlstra
This patch classifies scheduler domains and runqueues into types depending the number of tasks that are about their NUMA placement and the number that are currently running on their preferred node. The types are regular: There are tasks running that do not care about their NUMA placement. remote: There are tasks running that care about their placement but are currently running on a node remote to their ideal placement all: No distinction To implement this the patch tracks the number of tasks that are optimally NUMA placed (rq->nr_preferred_running) and the number of tasks running that care about their placement (nr_numa_running). The load balancer uses this information to avoid migrating idea placed NUMA tasks as long as better options for load balancing exists. For example, it will not consider balancing between a group whose tasks are all perfectly placed and a group with remote tasks. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Link: http://lkml.kernel.org/r/1381141781-10992-56-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-10-09sched/numa: Fix task or group comparisonRik van Riel
This patch separately considers task and group affinities when searching for swap candidates during NUMA placement. If tasks are part of the same group, or no group at all, the task weights are considered. Some hysteresis is added to prevent tasks within one group from getting bounced between NUMA nodes due to tiny differences. If tasks are part of different groups, the code compares group weights, in order to favor grouping task groups together. The patch also changes the group weight multiplier to be the same as the task weight multiplier, since the two are no longer added up like before. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1381141781-10992-55-git-send-email-mgorman@suse.de Signed-off-by: Ingo Molnar <mingo@kernel.org>