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| | * | | clocksource: tegra: Switch to sched_clock_register()Stephen Boyd2013-07-301-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The 32 bit sched_clock interface now supports 64 bits. Upgrade to the 64 bit function to allow us to remove the 32 bit registration interface. Cc: Stephen Warren <swarren@wwwdotorg.org> Acked-by: Stephen Warren <swarren@nvidia.com> Tested-by: Stephen Warren <swarren@nvidia.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
| | * | | clocksource: samsung_pwm_timer: Switch to sched_clock_register()Stephen Boyd2013-07-301-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The 32 bit sched_clock interface now supports 64 bits. Upgrade to the 64 bit function to allow us to remove the 32 bit registration interface. Cc: Tomasz Figa <t.figa@samsung.com> Cc: Kyungmin Park <kyungmin.park@samsung.com> Cc: Kukjin Kim <kgene.kim@samsung.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
| | * | | clocksource: nomadik: Switch to sched_clock_register()Stephen Boyd2013-07-301-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The 32 bit sched_clock interface now supports 64 bits. Upgrade to the 64 bit function to allow us to remove the 32 bit registration interface. Cc: Linus Walleij <linus.walleij@linaro.org> Acked-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
| | * | | clocksource: mxs_timer: Switch to sched_clock_register()Stephen Boyd2013-07-301-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The 32 bit sched_clock interface now supports 64 bits. Upgrade to the 64 bit function to allow us to remove the 32 bit registration interface. Cc: Shawn Guo <shawn.guo@linaro.org> Acked-by: Shawn Guo <shawn.guo@linaro.org> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
| | * | | clocksource: dw_apb_timer_of: Switch to sched_clock_register()Stephen Boyd2013-07-301-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The 32 bit sched_clock interface now supports 64 bits. Upgrade to the 64 bit function to allow us to remove the 32 bit registration interface. Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
| | * | | clocksource: dbx500-prcmu: Switch to sched_clock_register()Stephen Boyd2013-07-301-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The 32 bit sched_clock interface now supports 64 bits. Upgrade to the 64 bit function to allow us to remove the 32 bit registration interface. Cc: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com> Cc: Linus Walleij <linus.walleij@linaro.org> Acked-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
| | * | | clocksource: bcm2835: Switch to sched_clock_register()Stephen Boyd2013-07-301-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The 32 bit sched_clock interface now supports 64 bits. Upgrade to the 64 bit function to allow us to remove the 32 bit registration interface. Cc: Stephen Warren <swarren@wwwdotorg.org> Acked-by: Stephen Warren <swarren@wwwdotorg.org> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
| * | | | Merge branch 'timers/core' of ↵Ingo Molnar2013-10-034-2/+16
| |\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks into timers/core Merge updated full dynticks support from Frederic Weisbecker: - support 32-bit systems (full dynticks was 64-bit only before) - support ARM Signed-off-by: Ingo Molnar <mingo@kernel.org>
| | * | | | ARM: Kconfig: allow full nohz CPU accountingKevin Hilman2013-09-301-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With the 64-bit requirement removed from VIRT_CPU_ACCOUNTING_GEN, allow ARM platforms to enable it. Since VIRT_CPU_ACCOUNTING_GEN is a dependency for full NO_HZ, this allows ARM platforms to enable full NO_HZ as well. Signed-off-by: Kevin Hilman <khilman@linaro.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Arm Linux <linux-arm-kernel@lists.infradead.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
| | * | | | nohz: Drop generic vtime obsolete dependency on CONFIG_64BITKevin Hilman2013-09-302-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The CONFIG_64BIT requirement on vtime can finally be removed since we now depend on HAVE_VIRT_CPU_ACCOUNTING_GEN which already takes care of the arch ability to handle nsecs based cputime_t safely. Signed-off-by: Kevin Hilman <khilman@linaro.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Arm Linux <linux-arm-kernel@lists.infradead.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
| | * | | | vtime: Add HAVE_VIRT_CPU_ACCOUNTING_GEN KconfigKevin Hilman2013-09-303-0/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With VIRT_CPU_ACCOUNTING_GEN, cputime_t becomes 64-bit. In order to use that feature, arch code should be audited to ensure there are no races in concurrent read/write of cputime_t. For example, reading/writing 64-bit cputime_t on some 32-bit arches may require multiple accesses for low and high value parts, so proper locking is needed to protect against concurrent accesses. Therefore, add CONFIG_HAVE_VIRT_CPU_ACCOUNTING_GEN which arches can enable after they've been audited for potential races. This option is automatically enabled on 64-bit platforms. Feature requested by Frederic Weisbecker. Signed-off-by: Kevin Hilman <khilman@linaro.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Arm Linux <linux-arm-kernel@lists.infradead.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
| * | | | | Merge tag 'v3.12-rc3' into timers/coreIngo Molnar2013-10-03666-3519/+6406
| |\ \ \ \ \ | | |/ / / / | | | | / / | | |_|/ / | |/| | | | | | | | Merge Linux 3.12-rc3 - refresh the tree with the latest fixes before merging new bits. Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | Merge branch 'fortglx/3.12/time' into fortglx/3.13/timeJohn Stultz2013-09-163-5/+12
| |\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge in the timekeeping changes that missed 3.12 Signed-off-by: John Stultz <john.stultz@linaro.org>
| | * | | | ntp: Make periodic RTC update more reliableMiroslav Lichvar2013-08-221-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current code requires that the scheduled update of the RTC happens in the closest tick to the half of the second. This seems to be difficult to achieve reliably. The scheduled work may be missing the target time by a tick or two and be constantly rescheduled every second. Relax the limit to 10 ticks. As a typical RTC drifts in the 11-minute update interval by several milliseconds, this shouldn't affect the overall accuracy of the RTC much. Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
| | * | | | clocksource: Fix !CONFIG_CLOCKSOURCE_WATCHDOG compilePrarit Bhargava2013-07-221-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If I explicitly disable the clocksource watchdog in the x86 Kconfig, the x86 kernel will not compile unless this is properly defined. Cc: John Stultz <john.stultz@linaro.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: x86@kernel.org Signed-off-by: Prarit Bhargava <prarit@redhat.com> Signed-off-by: John Stultz <john.stultz@linaro.org>
| | * | | | rtc: Keep system awake until all expired RTC timers are handledZoran Markovic2013-07-221-4/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Current implementation of RTC interface allows for system suspend to occur in the following cases: (a) if a timer is set in the past and rtc_timer_do_work() is scheduled to handle it, and (b) if rtc_timer_do_work() is called to handle expired timers whose handlers implement a preemption point. A pending suspend request may be honoured in the above cases causing timer handling to be delayed until after the next resume. This is undesirable since timer handlers may have time-critical code to execute. This patch makes sure that the system stays awake until all expired timers are handled. Note that all calls to pm_stay_awake() are eventually paired with the single pm_relax() call in rtc_timer_do_work(), which is launched using schedule_work(). Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: John Stultz <john.stultz@linaro.org> Cc: Arve Hjonnevag <arve@android.com> Cc: Todd Poynor <toddpoynor@google.com> Signed-off-by: Zoran Markovic <zoran.markovic@linaro.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
| * | | | | Merge branch 'fortglx/3.12/sched-clock64-base' into fortglx/3.13/timeJohn Stultz2013-09-164-65/+95
| |\ \ \ \ \ | | | |_|/ / | | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge in 64bit sched_clock support that missed 3.12. Conflicts: kernel/time/sched_clock.c Signed-off-by: John.Stultz <john.stultz@linaro.org>
| | * | | | sched_clock: Add support for >32 bit sched_clockStephen Boyd2013-07-302-14/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The ARM architected system counter has at least 56 usable bits. Add support for counters with more than 32 bits to the generic sched_clock implementation so we can increase the time between wakeups due to dealing with wrap-around on these devices while benefiting from the irqtime accounting and suspend/resume handling that the generic sched_clock code already has. On my system using 56 bits over 32 bits changes the wraparound time from a few minutes to an hour. For faster running counters (GHz range) this is even more important because we may not be able to execute the timer in time to deal with the wraparound if only 32 bits are used. We choose a maxsec value of 3600 seconds because we assume no system will go idle for more than an hour. In the future we may need to increase this value. Note: All users should switch over to the 64-bit read function so we can remove setup_sched_clock() in favor of sched_clock_register(). Cc: Russell King <linux@arm.linux.org.uk> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
| | * | | | sched_clock: Use an hrtimer instead of timerStephen Boyd2013-07-301-17/+21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the next patch we're going to increase the number of bits that the generic sched_clock can handle to be greater than 32. With more than 32 bits the wraparound time can be larger than what can fit into the units that msecs_to_jiffies takes (unsigned int). Luckily, the wraparound is initially calculated in nanoseconds which we can easily use with hrtimers, so switch to using an hrtimer. Cc: Russell King <linux@arm.linux.org.uk> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> [jstultz: Fixup hrtimer intitialization order issue] Signed-off-by: John Stultz <john.stultz@linaro.org>
| | * | | | sched_clock: Use seqcount instead of rolling our ownStephen Boyd2013-07-301-19/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We're going to increase the cyc value to 64 bits in the near future. Doing that is going to break the custom seqcount implementation in the sched_clock code because 64 bit numbers aren't guaranteed to be atomic. Replace the cyc_copy with a seqcount to avoid this problem. Cc: Russell King <linux@arm.linux.org.uk> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
| | * | | | clocksource: Extract max nsec calculation into separate functionStephen Boyd2013-07-302-15/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We need to calculate the same number in the clocksource code and the sched_clock code, so extract this code into its own function. We also drop the min_t and just use min() because the two types are the same. Signed-off-by: Stephen Boyd <sboyd@codeaurora.org> Signed-off-by: John Stultz <john.stultz@linaro.org>
* | | | | | Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2013-11-12117-1594/+3569
|\ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler changes from Ingo Molnar: "The main changes in this cycle are: - (much) improved CONFIG_NUMA_BALANCING support from Mel Gorman, Rik van Riel, Peter Zijlstra et al. Yay! - optimize preemption counter handling: merge the NEED_RESCHED flag into the preempt_count variable, by Peter Zijlstra. - wait.h fixes and code reorganization from Peter Zijlstra - cfs_bandwidth fixes from Ben Segall - SMP load-balancer cleanups from Peter Zijstra - idle balancer improvements from Jason Low - other fixes and cleanups" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (129 commits) ftrace, sched: Add TRACE_FLAG_PREEMPT_RESCHED stop_machine: Fix race between stop_two_cpus() and stop_cpus() sched: Remove unnecessary iteration over sched domains to update nr_busy_cpus sched: Fix asymmetric scheduling for POWER7 sched: Move completion code from core.c to completion.c sched: Move wait code from core.c to wait.c sched: Move wait.c into kernel/sched/ sched/wait: Fix __wait_event_interruptible_lock_irq_timeout() sched: Avoid throttle_cfs_rq() racing with period_timer stopping sched: Guarantee new group-entities always have weight sched: Fix hrtimer_cancel()/rq->lock deadlock sched: Fix cfs_bandwidth misuse of hrtimer_expires_remaining sched: Fix race on toggling cfs_bandwidth_used sched: Remove extra put_online_cpus() inside sched_setaffinity() sched/rt: Fix task_tick_rt() comment sched/wait: Fix build breakage sched/wait: Introduce prepare_to_wait_event() sched/wait: Add ___wait_cond_timeout() to wait_event*_timeout() too sched: Remove get_online_cpus() usage sched: Fix race in migrate_swap_stop() ...
| * | | | | | ftrace, sched: Add TRACE_FLAG_PREEMPT_RESCHEDPeter Zijlstra2013-11-114-4/+25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since the introduction of PREEMPT_NEED_RESCHED in: f27dde8deef3 ("sched: Add NEED_RESCHED to the preempt_count") we need to be able to look at both TIF_NEED_RESCHED and PREEMPT_NEED_RESCHED to understand the full preemption behaviour. Add it to the trace output. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Fengguang Wu <fengguang.wu@intel.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Yuanhan Liu <yuanhan.liu@linux.intel.com> Link: http://lkml.kernel.org/r/20131004152826.GP3081@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | stop_machine: Fix race between stop_two_cpus() and stop_cpus()Rik van Riel2013-11-111-2/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There is a race between stop_two_cpus, and the global stop_cpus. It is possible for two CPUs to get their stopper functions queued "backwards" from one another, resulting in the stopper threads getting stuck, and the system hanging. This can happen because queuing up stoppers is not synchronized. This patch adds synchronization between stop_cpus (a rare operation), and stop_two_cpus. Reported-and-Tested-by: Prarit Bhargava <prarit@redhat.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Mel Gorman <mgorman@suse.de> Link: http://lkml.kernel.org/r/20131101104146.03d1e043@annuminas.surriel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | sched: Remove unnecessary iteration over sched domains to update nr_busy_cpusPreeti U Murthy2013-11-063-18/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | nr_busy_cpus parameter is used by nohz_kick_needed() to find out the number of busy cpus in a sched domain which has SD_SHARE_PKG_RESOURCES flag set. Therefore instead of updating nr_busy_cpus at every level of sched domain, since it is irrelevant, we can update this parameter only at the parent domain of the sd which has this flag set. Introduce a per-cpu parameter sd_busy which represents this parent domain. In nohz_kick_needed() we directly query the nr_busy_cpus parameter associated with the groups of sd_busy. By associating sd_busy with the highest domain which has SD_SHARE_PKG_RESOURCES flag set, we cover all lower level domains which could have this flag set and trigger nohz_idle_balancing if any of the levels have more than one busy cpu. sd_busy is irrelevant for asymmetric load balancing. However sd_asym has been introduced to represent the highest sched domain which has SD_ASYM_PACKING flag set so that it can be queried directly when required. While we are at it, we might as well change the nohz_idle parameter to be updated at the sd_busy domain level alone and not the base domain level of a CPU. This will unify the concept of busy cpus at just one level of sched domain where it is currently used. Signed-off-by: Preeti U Murthy<preeti@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: svaidy@linux.vnet.ibm.com Cc: vincent.guittot@linaro.org Cc: bitbucket@online.de Cc: benh@kernel.crashing.org Cc: anton@samba.org Cc: Morten.Rasmussen@arm.com Cc: pjt@google.com Cc: peterz@infradead.org Cc: mikey@neuling.org Link: http://lkml.kernel.org/r/20131030031252.23426.4417.stgit@preeti.in.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | sched: Fix asymmetric scheduling for POWER7Vaidyanathan Srinivasan2013-11-061-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Asymmetric scheduling within a core is a scheduler loadbalancing feature that is triggered when SD_ASYM_PACKING flag is set. The goal for the load balancer is to move tasks to lower order idle SMT threads within a core on a POWER7 system. In nohz_kick_needed(), we intend to check if our sched domain (core) is completely busy or we have idle cpu. The following check for SD_ASYM_PACKING: (cpumask_first_and(nohz.idle_cpus_mask, sched_domain_span(sd)) < cpu) already covers the case of checking if the domain has an idle cpu, because cpumask_first_and() will not yield any set bits if this domain has no idle cpu. Hence, nr_busy check against group weight can be removed. Reported-by: Michael Neuling <michael.neuling@au1.ibm.com> Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Tested-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: vincent.guittot@linaro.org Cc: bitbucket@online.de Cc: benh@kernel.crashing.org Cc: anton@samba.org Cc: Morten.Rasmussen@arm.com Cc: pjt@google.com Link: http://lkml.kernel.org/r/20131030031242.23426.13019.stgit@preeti.in.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | sched: Move completion code from core.c to completion.cPeter Zijlstra2013-11-064-286/+301
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Completions already have their own header file: linux/completion.h Move the implementation out of kernel/sched/core.c and into its own file: kernel/sched/completion.c. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-x2y49rmxu5dljt66ai2lcfuw@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | sched: Move wait code from core.c to wait.cPeter Zijlstra2013-11-062-105/+105
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For some reason only the wait part of the wait api lives in kernel/sched/wait.c and the wake part still lives in kernel/sched/core.c; ammend this. Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-ftycee88naznulqk7ei5mbci@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | sched: Move wait.c into kernel/sched/Peter Zijlstra2013-11-063-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-5q5yqvdaen0rmapwloeaotx3@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | sched/wait: Fix __wait_event_interruptible_lock_irq_timeout()Heiko Carstens2013-11-011-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __wait_event_interruptible_lock_irq_timeout() needs the timeout parameter passed instead of "ret". This magically compiled since the only user has a local ret variable. Luckily we got a build warning: CC drivers/s390/scsi/zfcp_qdio.o drivers/s390/scsi/zfcp_qdio.c: In function 'zfcp_qdio_sbal_get': include/linux/wait.h:780:15: warning: 'ret' may be used uninitialized Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20131031114814.GB5551@osiris Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | Merge branch 'linus' into sched/coreIngo Molnar2013-11-01506-2851/+4225
| |\ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Resolve cherry-picking conflicts: Conflicts: mm/huge_memory.c mm/memory.c mm/mprotect.c See this upstream merge commit for more details: 52469b4fcd4f Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | | sched: Avoid throttle_cfs_rq() racing with period_timer stoppingBen Segall2013-10-292-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | throttle_cfs_rq() doesn't check to make sure that period_timer is running, and while update_curr/assign_cfs_runtime does, a concurrently running period_timer on another cpu could cancel itself between this cpu's update_curr and throttle_cfs_rq(). If there are no other cfs_rqs running in the tg to restart the timer, this causes the cfs_rq to be stranded forever. Fix this by calling __start_cfs_bandwidth() in throttle if the timer is inactive. (Also add some sched_debug lines for cfs_bandwidth.) Tested: make a run/sleep task in a cgroup, loop switching the cgroup between 1ms/100ms quota and unlimited, checking for timer_active=0 and throttled=1 as a failure. With the throttle_cfs_rq() change commented out this fails, with the full patch it passes. 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/20131016181632.22647.84174.stgit@sword-of-the-dawn.mtv.corp.google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | | sched: Guarantee new group-entities always have weightPaul Turner2013-10-291-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, group entity load-weights are initialized to zero. This admits some races with respect to the first time they are re-weighted in earlty use. ( Let g[x] denote the se for "g" on cpu "x". ) Suppose that we have root->a and that a enters a throttled state, immediately followed by a[0]->t1 (the only task running on cpu[0]) blocking: put_prev_task(group_cfs_rq(a[0]), t1) put_prev_entity(..., t1) check_cfs_rq_runtime(group_cfs_rq(a[0])) throttle_cfs_rq(group_cfs_rq(a[0])) Then, before unthrottling occurs, let a[0]->b[0]->t2 wake for the first time: enqueue_task_fair(rq[0], t2) enqueue_entity(group_cfs_rq(b[0]), t2) enqueue_entity_load_avg(group_cfs_rq(b[0]), t2) account_entity_enqueue(group_cfs_ra(b[0]), t2) update_cfs_shares(group_cfs_rq(b[0])) < skipped because b is part of a throttled hierarchy > enqueue_entity(group_cfs_rq(a[0]), b[0]) ... We now have b[0] enqueued, yet group_cfs_rq(a[0])->load.weight == 0 which violates invariants in several code-paths. Eliminate the possibility of this by initializing group entity weight. Signed-off-by: Paul Turner <pjt@google.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131016181627.22647.47543.stgit@sword-of-the-dawn.mtv.corp.google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | | sched: Fix hrtimer_cancel()/rq->lock deadlockBen Segall2013-10-291-4/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __start_cfs_bandwidth calls hrtimer_cancel while holding rq->lock, waiting for the hrtimer to finish. However, if sched_cfs_period_timer runs for another loop iteration, the hrtimer can attempt to take rq->lock, resulting in deadlock. Fix this by ensuring that cfs_b->timer_active is cleared only if the _latest_ call to do_sched_cfs_period_timer is returning as idle. Then __start_cfs_bandwidth can just call hrtimer_try_to_cancel and wait for that to succeed or timer_active == 1. 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/20131016181622.22647.16643.stgit@sword-of-the-dawn.mtv.corp.google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | | sched: Fix cfs_bandwidth misuse of hrtimer_expires_remainingBen Segall2013-10-291-3/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | | | | | sched: Fix race on toggling cfs_bandwidth_usedBen Segall2013-10-293-9/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | | | | | sched: Remove extra put_online_cpus() inside sched_setaffinity()Michael wang2013-10-281-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | | | | | sched/rt: Fix task_tick_rt() commentLi Bin2013-10-261-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | | | | | sched/wait: Fix build breakageThierry Reding2013-10-231-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The wait_event_interruptible_lock_irq() macro is missing a semi-colon which causes a build failure in the i915 DRM driver. Signed-off-by: Thierry Reding <treding@nvidia.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1382528455-29911-1-git-send-email-treding@nvidia.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | | sched/wait: Introduce prepare_to_wait_event()Oleg Nesterov2013-10-162-10/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | | | | | sched/wait: Add ___wait_cond_timeout() to wait_event*_timeout() tooOleg Nesterov2013-10-161-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 4c663cfc ("wait: fix false timeouts when using wait_event_timeout()") introduced the additional condition checks after a timeout but only in the "slow" __wait*() paths. wait_event_timeout(wq, CONDITION, 0) still returns 0 if CONDITION is already true and we do not call __wait*(). Now that we have ___wait_cond_timeout() we can use it instead to ensure that __ret will be properly updated. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131007183106.GA10973@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | | sched: Remove get_online_cpus() usagePeter Zijlstra2013-10-163-15/+48
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | | | | | sched: Fix race in migrate_swap_stop()Peter Zijlstra2013-10-163-9/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | | | | | sched/rt: Add missing rmb()Peter Zijlstra2013-10-161-1/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | | | | | sched/fair: Fix trivial typos in commentsKamalesh Babulal2013-10-141-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - '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>
| * | | | | | | sched: Remove bogus parameter in structured commentRamkumar Ramachandra2013-10-121-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | | | | | x86: Apply the asm_volatile_goto() compiler quirkIngo Molnar2013-10-111-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Apply the asm_volatile_goto() compiler quirk to the new rmwcc.h file as well, introduced in: c2daa3bed53a sched, x86: Provide a per-cpu preempt_count implementation Reported-and-tested-by: Fengguang Wu <fengguang.wu@intel.com> Reported-by: Oleg Nesterov <oleg@redhat.com> Reported-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Suggested-by: Jakub Jelinek <jakub@redhat.com> Reviewed-by: Richard Henderson <rth@twiddle.net> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | | Merge branch 'core/urgent' into sched/coreIngo Molnar2013-10-1172-202/+456
| |\ \ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Merge in asm goto fix, to be able to apply the asm/rmwcc.h fix. Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | | | sched/numa: Reflow task_numa_group() to avoid a compiler warningPeter Zijlstra2013-10-091-7/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
| * | | | | | | | sched/numa: Retry task_numa_migrate() periodicallyRik van Riel2013-10-091-9/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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>
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