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* Merge branch 'sched-hrtimers-for-linus' of ↵Linus Torvalds2015-06-245-402/+500
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Thomas Gleixner: "This series of scheduler updates depends on sched/core and timers/core branches, which are already in your tree: - Scheduler balancing overhaul to plug a hard to trigger race which causes an oops in the balancer (Peter Zijlstra) - Lockdep updates which are related to the balancing updates (Peter Zijlstra)" * 'sched-hrtimers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched,lockdep: Employ lock pinning lockdep: Implement lock pinning lockdep: Simplify lock_release() sched: Streamline the task migration locking a little sched: Move code around sched,dl: Fix sched class hopping CBS hole sched, dl: Convert switched_{from, to}_dl() / prio_changed_dl() to balance callbacks sched,dl: Remove return value from pull_dl_task() sched, rt: Convert switched_{from, to}_rt() / prio_changed_rt() to balance callbacks sched,rt: Remove return value from pull_rt_task() sched: Allow balance callbacks for check_class_changed() sched: Use replace normalize_task() with __sched_setscheduler() sched: Replace post_schedule with a balance callback list
| * sched,lockdep: Employ lock pinningPeter Zijlstra2015-06-195-8/+71
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Employ the new lockdep lock pinning annotation to ensure no 'accidental' lock-breaks happen with rq->lock. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: ktkhai@parallels.com Cc: rostedt@goodmis.org Cc: juri.lelli@gmail.com Cc: pang.xunlei@linaro.org Cc: oleg@redhat.com Cc: wanpeng.li@linux.intel.com Cc: umgwanakikbuti@gmail.com Link: http://lkml.kernel.org/r/20150611124744.003233193@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * sched: Streamline the task migration locking a littlePeter Zijlstra2015-06-191-42/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The whole migrate_task{,s}() locking seems a little shaky, there's a lot of dropping an require happening. Pull the locking up into the callers as far as possible to streamline the lot. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: ktkhai@parallels.com Cc: rostedt@goodmis.org Cc: juri.lelli@gmail.com Cc: pang.xunlei@linaro.org Cc: oleg@redhat.com Cc: wanpeng.li@linux.intel.com Cc: umgwanakikbuti@gmail.com Link: http://lkml.kernel.org/r/20150611124743.755256708@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * sched: Move code aroundPeter Zijlstra2015-06-191-186/+178
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In preparation to reworking set_cpus_allowed_ptr() move some code around. This also removes some superfluous #ifdefs and adds comments to some #endifs. text data bss dec hex filename 12211532 1738144 1081344 15031020 e55aec defconfig-build/vmlinux.pre 12211532 1738144 1081344 15031020 e55aec defconfig-build/vmlinux.post Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: ktkhai@parallels.com Cc: rostedt@goodmis.org Cc: juri.lelli@gmail.com Cc: pang.xunlei@linaro.org Cc: oleg@redhat.com Cc: wanpeng.li@linux.intel.com Cc: umgwanakikbuti@gmail.com Link: http://lkml.kernel.org/r/20150611124743.662086684@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * sched,dl: Fix sched class hopping CBS holePeter Zijlstra2015-06-191-66/+86
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We still have a few pending issues with the deadline code, one of which is that switching between scheduling classes can 'leak' CBS state. Close the hole by retaining the current CBS state when leaving SCHED_DEADLINE and unconditionally programming the deadline timer. The timer will then reset the CBS state if the task is still !SCHED_DEADLINE by the time it hits. If the task left SCHED_DEADLINE it will not call task_dead_dl() and we'll not cancel the hrtimer, leaving us a pending timer in free space. Avoid this by giving the timer a task reference, this avoids littering the task exit path for this rather uncommon case. In order to do this, I had to move dl_task_offline_migration() below the replenishment, such that the task_rq()->lock fully covers that. While doing this, I noticed that it (was) buggy in assuming a task is enqueued and or we need to enqueue the task now. Fixing this means select_task_rq_dl() might encounter an offline rq -- look into that. As a result this kills cancel_dl_timer() which included a rq->lock break. Fixes: 40767b0dc768 ("sched/deadline: Fix deadline parameter modification handling") Cc: Wanpeng Li <wanpeng.li@linux.intel.com> Cc: Luca Abeni <luca.abeni@unitn.it> Cc: Juri Lelli <juri.lelli@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: ktkhai@parallels.com Cc: rostedt@goodmis.org Cc: juri.lelli@gmail.com Cc: pang.xunlei@linaro.org Cc: oleg@redhat.com Cc: wanpeng.li@linux.intel.com Cc: Luca Abeni <luca.abeni@unitn.it> Cc: Juri Lelli <juri.lelli@arm.com> Cc: umgwanakikbuti@gmail.com Link: http://lkml.kernel.org/r/20150611124743.574192138@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * sched, dl: Convert switched_{from, to}_dl() / prio_changed_dl() to balance ↵Peter Zijlstra2015-06-191-21/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | callbacks Remove the direct {push,pull} balancing operations from switched_{from,to}_dl() / prio_changed_dl() and use the balance callback queue. Again, err on the side of too many reschedules; since too few is a hard bug while too many is just annoying. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: ktkhai@parallels.com Cc: rostedt@goodmis.org Cc: juri.lelli@gmail.com Cc: pang.xunlei@linaro.org Cc: oleg@redhat.com Cc: wanpeng.li@linux.intel.com Cc: umgwanakikbuti@gmail.com Link: http://lkml.kernel.org/r/20150611124742.968262663@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * sched,dl: Remove return value from pull_dl_task()Peter Zijlstra2015-06-191-10/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In order to be able to use pull_dl_task() from a callback, we need to do away with the return value. Since the return value indicates if we should reschedule, do this inside the function. Since not all callers currently do this, this can increase the number of reschedules due rt balancing. Too many reschedules is not a correctness issues, too few are. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: ktkhai@parallels.com Cc: rostedt@goodmis.org Cc: juri.lelli@gmail.com Cc: pang.xunlei@linaro.org Cc: oleg@redhat.com Cc: wanpeng.li@linux.intel.com Cc: umgwanakikbuti@gmail.com Link: http://lkml.kernel.org/r/20150611124742.859398977@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * sched, rt: Convert switched_{from, to}_rt() / prio_changed_rt() to balance ↵Peter Zijlstra2015-06-191-16/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | callbacks Remove the direct {push,pull} balancing operations from switched_{from,to}_rt() / prio_changed_rt() and use the balance callback queue. Again, err on the side of too many reschedules; since too few is a hard bug while too many is just annoying. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: ktkhai@parallels.com Cc: rostedt@goodmis.org Cc: juri.lelli@gmail.com Cc: pang.xunlei@linaro.org Cc: oleg@redhat.com Cc: wanpeng.li@linux.intel.com Cc: umgwanakikbuti@gmail.com Link: http://lkml.kernel.org/r/20150611124742.766832367@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * sched,rt: Remove return value from pull_rt_task()Peter Zijlstra2015-06-191-11/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In order to be able to use pull_rt_task() from a callback, we need to do away with the return value. Since the return value indicates if we should reschedule, do this inside the function. Since not all callers currently do this, this can increase the number of reschedules due rt balancing. Too many reschedules is not a correctness issues, too few are. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: ktkhai@parallels.com Cc: rostedt@goodmis.org Cc: juri.lelli@gmail.com Cc: pang.xunlei@linaro.org Cc: oleg@redhat.com Cc: wanpeng.li@linux.intel.com Cc: umgwanakikbuti@gmail.com Link: http://lkml.kernel.org/r/20150611124742.679002000@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * sched: Allow balance callbacks for check_class_changed()Peter Zijlstra2015-06-191-3/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In order to remove dropping rq->lock from the switched_{to,from}()/prio_changed() sched_class methods, run the balance callbacks after it. We need to remove dropping rq->lock because its buggy, suppose using sched_setattr()/sched_setscheduler() to change a running task from FIFO to OTHER. By the time we get to switched_from_rt() the task is already enqueued on the cfs runqueues. If switched_from_rt() does pull_rt_task() and drops rq->lock, load-balancing can come in and move our task @p to another rq. The subsequent switched_to_fair() still assumes @p is on @rq and bad things will happen. By using balance callbacks we delay the load-balancing operations {rt,dl}x{push,pull} until we've done all the important work and the task is fully set up. Furthermore, the balance callbacks do not know about @p, therefore they cannot get confused like this. Reported-by: Mike Galbraith <umgwanakikbuti@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: ktkhai@parallels.com Cc: rostedt@goodmis.org Cc: juri.lelli@gmail.com Cc: pang.xunlei@linaro.org Cc: oleg@redhat.com Cc: wanpeng.li@linux.intel.com Link: http://lkml.kernel.org/r/20150611124742.615343911@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * sched: Use replace normalize_task() with __sched_setscheduler()Peter Zijlstra2015-06-191-42/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reduce duplicate logic; normalize_task() is a simplified version of __sched_setscheduler(). Parametrize the difference and collapse. This reduces the amount of check_class_changed() sites. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: ktkhai@parallels.com Cc: rostedt@goodmis.org Cc: juri.lelli@gmail.com Cc: pang.xunlei@linaro.org Cc: oleg@redhat.com Cc: wanpeng.li@linux.intel.com Cc: umgwanakikbuti@gmail.com Link: http://lkml.kernel.org/r/20150611124742.532642391@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * sched: Replace post_schedule with a balance callback listPeter Zijlstra2015-06-194-38/+63
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Generalize the post_schedule() stuff into a balance callback list. This allows us to more easily use it outside of schedule() and cross sched_class. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: ktkhai@parallels.com Cc: rostedt@goodmis.org Cc: juri.lelli@gmail.com Cc: pang.xunlei@linaro.org Cc: oleg@redhat.com Cc: wanpeng.li@linux.intel.com Cc: umgwanakikbuti@gmail.com Link: http://lkml.kernel.org/r/20150611124742.424032725@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * Merge branch 'timers/core' into sched/hrtimersThomas Gleixner2015-06-196-102/+52
| |\ | | | | | | | | | | | | Merge sched/core and timers/core so we can apply the sched balancing patch queue, which depends on both.
* | \ Merge tag 'pm+acpi-4.2-rc1' of ↵Linus Torvalds2015-06-231-55/+59
|\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management and ACPI updates from Rafael Wysocki: "The rework of backlight interface selection API from Hans de Goede stands out from the number of commits and the number of affected places perspective. The cpufreq core fixes from Viresh Kumar are quite significant too as far as the number of commits goes and because they should reduce CPU online/offline overhead quite a bit in the majority of cases. From the new featues point of view, the ACPICA update (to upstream revision 20150515) adding support for new ACPI 6 material to ACPICA is the one that matters the most as some new significant features will be based on it going forward. Also included is an update of the ACPI device power management core to follow ACPI 6 (which in turn reflects the Windows' device PM implementation), a PM core extension to support wakeup interrupts in a more generic way and support for the ACPI _CCA device configuration object. The rest is mostly fixes and cleanups all over and some documentation updates, including new DT bindings for Operating Performance Points. There is one fix for a regression introduced in the 4.1 cycle, but it adds quite a number of lines of code, it wasn't really ready before Thursday and you were on vacation, so I refrained from pushing it on the last minute for 4.1. Specifics: - ACPICA update to upstream revision 20150515 including basic support for ACPI 6 features: new ACPI tables introduced by ACPI 6 (STAO, XENV, WPBT, NFIT, IORT), changes related to the other tables (DTRM, FADT, LPIT, MADT), new predefined names (_BTH, _CR3, _DSD, _LPI, _MTL, _PRR, _RDI, _RST, _TFP, _TSN), fixes and cleanups (Bob Moore, Lv Zheng). - ACPI device power management core code update to follow ACPI 6 which reflects the ACPI device power management implementation in Windows (Rafael J Wysocki). - rework of the backlight interface selection logic to reduce the number of kernel command line options and improve the handling of DMI quirks that may be involved in that and to make the code generally more straightforward (Hans de Goede). - fixes for the ACPI Embedded Controller (EC) driver related to the handling of EC transactions (Lv Zheng). - fix for a regression related to the ACPI resources management and resulting from a recent change of ACPI initialization code ordering (Rafael J Wysocki). - fix for a system initialization regression related to ACPI introduced during the 3.14 cycle and caused by running the code that switches the platform over to the ACPI mode too early in the initialization sequence (Rafael J Wysocki). - support for the ACPI _CCA device configuration object related to DMA cache coherence (Suravee Suthikulpanit). - ACPI/APEI fixes and cleanups (Jiri Kosina, Borislav Petkov). - ACPI battery driver cleanups (Luis Henriques, Mathias Krause). - ACPI processor driver cleanups (Hanjun Guo). - cleanups and documentation update related to the ACPI device properties interface based on _DSD (Rafael J Wysocki). - ACPI device power management fixes (Rafael J Wysocki). - assorted cleanups related to ACPI (Dominik Brodowski, Fabian Frederick, Lorenzo Pieralisi, Mathias Krause, Rafael J Wysocki). - fix for a long-standing issue causing General Protection Faults to be generated occasionally on return to user space after resume from ACPI-based suspend-to-RAM on 32-bit x86 (Ingo Molnar). - fix to make the suspend core code return -EBUSY consistently in all cases when system suspend is aborted due to wakeup detection (Ruchi Kandoi). - support for automated device wakeup IRQ handling allowing drivers to make their PM support more starightforward (Tony Lindgren). - new tracepoints for suspend-to-idle tracing and rework of the prepare/complete callbacks tracing in the PM core (Todd E Brandt, Rafael J Wysocki). - wakeup sources framework enhancements (Jin Qian). - new macro for noirq system PM callbacks (Grygorii Strashko). - assorted cleanups related to system suspend (Rafael J Wysocki). - cpuidle core cleanups to make the code more efficient (Rafael J Wysocki). - powernv/pseries cpuidle driver update (Shilpasri G Bhat). - cpufreq core fixes related to CPU online/offline that should reduce the overhead of these operations quite a bit, unless the CPU in question is physically going away (Viresh Kumar, Saravana Kannan). - serialization of cpufreq governor callbacks to avoid race conditions in some cases (Viresh Kumar). - intel_pstate driver fixes and cleanups (Doug Smythies, Prarit Bhargava, Joe Konno). - cpufreq driver (arm_big_little, cpufreq-dt, qoriq) updates (Sudeep Holla, Felipe Balbi, Tang Yuantian). - assorted cleanups in cpufreq drivers and core (Shailendra Verma, Fabian Frederick, Wang Long). - new Device Tree bindings for representing Operating Performance Points (Viresh Kumar). - updates for the common clock operations support code in the PM core (Rajendra Nayak, Geert Uytterhoeven). - PM domains core code update (Geert Uytterhoeven). - Intel Knights Landing support for the RAPL (Running Average Power Limit) power capping driver (Dasaratharaman Chandramouli). - fixes related to the floor frequency setting on Atom SoCs in the RAPL power capping driver (Ajay Thomas). - runtime PM framework documentation update (Ben Dooks). - cpupower tool fix (Herton R Krzesinski)" * tag 'pm+acpi-4.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (194 commits) cpuidle: powernv/pseries: Auto-promotion of snooze to deeper idle state x86: Load __USER_DS into DS/ES after resume PM / OPP: Add binding for 'opp-suspend' PM / OPP: Allow multiple OPP tables to be passed via DT PM / OPP: Add new bindings to address shortcomings of existing bindings ACPI: Constify ACPI device IDs in documentation ACPI / enumeration: Document the rules regarding the PRP0001 device ID ACPI / video: Make acpi_video_unregister_backlight() private acpi-video-detect: Remove old API toshiba-acpi: Port to new backlight interface selection API thinkpad-acpi: Port to new backlight interface selection API sony-laptop: Port to new backlight interface selection API samsung-laptop: Port to new backlight interface selection API msi-wmi: Port to new backlight interface selection API msi-laptop: Port to new backlight interface selection API intel-oaktrail: Port to new backlight interface selection API ideapad-laptop: Port to new backlight interface selection API fujitsu-laptop: Port to new backlight interface selection API eeepc-laptop: Port to new backlight interface selection API dell-wmi: Port to new backlight interface selection API ...
| * \ \ Merge branch 'pm-cpuidle'Rafael J. Wysocki2015-06-191-55/+59
| |\ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * pm-cpuidle: cpuidle: Do not use CPUIDLE_DRIVER_STATE_START in cpuidle.c cpuidle: Select a different state on tick_broadcast_enter() failures sched / idle: Call default_idle_call() from cpuidle_enter_state() sched / idle: Call idle_set_state() from cpuidle_enter_state() cpuidle: Fix the kerneldoc comment for cpuidle_enter_state() sched / idle: Eliminate the "reflect" check from cpuidle_idle_call() cpuidle: Check the sign of index in cpuidle_reflect() sched / idle: Move the default idle call code to a separate function
| | * | | sched / idle: Call default_idle_call() from cpuidle_enter_state()Rafael J. Wysocki2015-05-141-13/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The check of the cpuidle_enter() return value against -EBUSY made in call_cpuidle() will not be necessary any more if cpuidle_enter_state() calls default_idle_call() directly when it is about to return -EBUSY, so make that happen and eliminate the check. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Tested-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Tested-by: Sudeep Holla <sudeep.holla@arm.com> Acked-by: Kevin Hilman <khilman@linaro.org>
| | * | | sched / idle: Call idle_set_state() from cpuidle_enter_state()Rafael J. Wysocki2015-05-141-6/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Introduce a wrapper function around idle_set_state() called sched_idle_set_state() that will pass this_rq() to it as the first argument and make cpuidle_enter_state() call the new function before and after entering the target state. At the same time, remove direct invocations of idle_set_state() from call_cpuidle(). This will allow the invocation of default_idle_call() to be moved from call_cpuidle() to cpuidle_enter_state() safely and call_cpuidle() to be simplified a bit as a result. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Tested-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Tested-by: Sudeep Holla <sudeep.holla@arm.com> Acked-by: Kevin Hilman <khilman@linaro.org>
| | * | | sched / idle: Eliminate the "reflect" check from cpuidle_idle_call()Rafael J. Wysocki2015-05-041-44/+46
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since cpuidle_reflect() should only be called if the idle state to enter was selected by cpuidle_select(), there is the "reflect" variable in cpuidle_idle_call() whose value is used to determine whether or not that is the case. However, if the entire code run between the conditional setting "reflect" and the call to cpuidle_reflect() is moved to a separate function, it will be possible to call that new function in both branches of the conditional, in which case cpuidle_reflect() will only need to be called from one of them too and the "reflect" variable won't be necessary any more. This eliminates one check made by cpuidle_idle_call() on the majority of its invocations, so change the code as described. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
| | * | | sched / idle: Move the default idle call code to a separate functionRafael J. Wysocki2015-05-041-19/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move the code under the "use_default" label in cpuidle_idle_call() into a separate (new) function. This just allows the subsequent changes to be more stratightforward. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Reviewed-by: Daniel Lezcano <daniel.lezcano@linaro.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
* | | | | Merge branch 'timers-nohz-for-linus' of ↵Linus Torvalds2015-06-221-1/+3
|\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull NOHZ updates from Thomas Gleixner: "A few updates to the nohz infrastructure: - recursion protection for context tracking - make the TIF_NOHZ inheritance smarter - isolate cpus which belong to the NOHZ full set" * 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: nohz: Set isolcpus when nohz_full is set nohz: Add tick_nohz_full_add_cpus_to() API context_tracking: Inherit TIF_NOHZ through forks instead of context switches context_tracking: Protect against recursion
| * | | | | nohz: Set isolcpus when nohz_full is setChris Metcalf2015-05-071-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | nohz_full is only useful with isolcpus are also set, since otherwise the scheduler has to run periodically to try to determine whether to steal work from other cores. Accordingly, when booting with nohz_full=xxx on the command line, we should act as if isolcpus=xxx was also set, and set (or extend) the isolcpus set to include the nohz_full cpus. Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Mike Galbraith <umgwanakikbuti@gmail.com> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Jones <davej@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1430928266-24888-5-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | context_tracking: Inherit TIF_NOHZ through forks instead of context switchesFrederic Weisbecker2015-05-071-1/+0
| | |/ / / | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | TIF_NOHZ is used by context_tracking to force syscall slow-path on every task in order to track userspace roundtrips. As such, it must be set on all running tasks. It's currently explicitly inherited through context switches. There is no need to do it in this fast-path though. The flag could simply be set once for all on all tasks, whether they are running or not. Lets do this by setting the flag for the init task on early boot, and let it propagate through fork inheritance. While at it, mark context_tracking_cpu_set() as init code, we only need it at early boot time. Suggested-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Chris Metcalf <cmetcalf@ezchip.com> Cc: Dave Jones <davej@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Paul E . McKenney <paulmck@linux.vnet.ibm.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J . Wysocki <rafael.j.wysocki@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1430928266-24888-3-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* | | | | Merge branch 'timers-core-for-linus' of ↵Linus Torvalds2015-06-226-108/+55
|\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer updates from Thomas Gleixner: "A rather largish update for everything time and timer related: - Cache footprint optimizations for both hrtimers and timer wheel - Lower the NOHZ impact on systems which have NOHZ or timer migration disabled at runtime. - Optimize run time overhead of hrtimer interrupt by making the clock offset updates smarter - hrtimer cleanups and removal of restrictions to tackle some problems in sched/perf - Some more leap second tweaks - Another round of changes addressing the 2038 problem - First step to change the internals of clock event devices by introducing the necessary infrastructure - Allow constant folding for usecs/msecs_to_jiffies() - The usual pile of clockevent/clocksource driver updates The hrtimer changes contain updates to sched, perf and x86 as they depend on them plus changes all over the tree to cleanup API changes and redundant code, which got copied all over the place. The y2038 changes touch s390 to remove the last non 2038 safe code related to boot/persistant clock" * 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (114 commits) clocksource: Increase dependencies of timer-stm32 to limit build wreckage timer: Minimize nohz off overhead timer: Reduce timer migration overhead if disabled timer: Stats: Simplify the flags handling timer: Replace timer base by a cpu index timer: Use hlist for the timer wheel hash buckets timer: Remove FIFO "guarantee" timers: Sanitize catchup_timer_jiffies() usage hrtimer: Allow hrtimer::function() to free the timer seqcount: Introduce raw_write_seqcount_barrier() seqcount: Rename write_seqcount_barrier() hrtimer: Fix hrtimer_is_queued() hole hrtimer: Remove HRTIMER_STATE_MIGRATE selftest: Timers: Avoid signal deadlock in leap-a-day timekeeping: Copy the shadow-timekeeper over the real timekeeper last clockevents: Check state instead of mode in suspend/resume path selftests: timers: Add leap-second timer edge testing to leap-a-day.c ntp: Do leapsecond adjustment in adjtimex read path time: Prevent early expiry of hrtimers[CLOCK_REALTIME] at the leap second edge ntp: Introduce and use SECS_PER_DAY macro instead of 86400 ...
| * | | | | timer: Reduce timer migration overhead if disabledThomas Gleixner2015-06-191-6/+3
| | |_|_|/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Eric reported that the timer_migration sysctl is not really nice performance wise as it needs to check at every timer insertion whether the feature is enabled or not. Further the check does not live in the timer code, so we have an extra function call which checks an extra cache line to figure out that it is disabled. We can do better and store that information in the per cpu (hr)timer bases. I pondered to use a static key, but that's a nightmare to update from the nohz code and the timer base cache line is hot anyway when we select a timer base. The old logic enabled the timer migration unconditionally if CONFIG_NO_HZ was set even if nohz was disabled on the kernel command line. With this modification, we start off with migration disabled. The user visible sysctl is still set to enabled. If the kernel switches to NOHZ migration is enabled, if the user did not disable it via the sysctl prior to the switch. If nohz=off is on the kernel command line, migration stays disabled no matter what. Before: 47.76% hog [.] main 14.84% [kernel] [k] _raw_spin_lock_irqsave 9.55% [kernel] [k] _raw_spin_unlock_irqrestore 6.71% [kernel] [k] mod_timer 6.24% [kernel] [k] lock_timer_base.isra.38 3.76% [kernel] [k] detach_if_pending 3.71% [kernel] [k] del_timer 2.50% [kernel] [k] internal_add_timer 1.51% [kernel] [k] get_nohz_timer_target 1.28% [kernel] [k] __internal_add_timer 0.78% [kernel] [k] timerfn 0.48% [kernel] [k] wake_up_nohz_cpu After: 48.10% hog [.] main 15.25% [kernel] [k] _raw_spin_lock_irqsave 9.76% [kernel] [k] _raw_spin_unlock_irqrestore 6.50% [kernel] [k] mod_timer 6.44% [kernel] [k] lock_timer_base.isra.38 3.87% [kernel] [k] detach_if_pending 3.80% [kernel] [k] del_timer 2.67% [kernel] [k] internal_add_timer 1.33% [kernel] [k] __internal_add_timer 0.73% [kernel] [k] timerfn 0.54% [kernel] [k] wake_up_nohz_cpu Reported-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paul McKenney <paulmck@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: John Stultz <john.stultz@linaro.org> Cc: Joonwoo Park <joonwoop@codeaurora.org> Cc: Wenbo Wang <wenbo.wang@memblaze.com> Link: http://lkml.kernel.org/r/20150526224512.127050787@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | Merge branch 'linus' into timers/coreThomas Gleixner2015-05-192-57/+28
| |\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | Make sure the upstream fixes are applied before adding further modifications.
| * | | | | sched,perf: Fix periodic timersPeter Zijlstra2015-05-184-20/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the below two commits (see Fixes) we have periodic timers that can stop themselves when they're no longer required, but need to be (re)-started when their idle condition changes. Further complications is that we want the timer handler to always do the forward such that it will always correctly deal with the overruns, and we do not want to race such that the handler has already decided to stop, but the (external) restart sees the timer still active and we end up with a 'lost' timer. The problem with the current code is that the re-start can come before the callback does the forward, at which point the forward from the callback will WARN about forwarding an enqueued timer. Now, conceptually its easy to detect if you're before or after the fwd by comparing the expiration time against the current time. Of course, that's expensive (and racy) because we don't have the current time. Alternatively one could cache this state inside the timer, but then everybody pays the overhead of maintaining this extra state, and that is undesired. The only other option that I could see is the external timer_active variable, which I tried to kill before. I would love a nicer interface for this seemingly simple 'problem' but alas. Fixes: 272325c4821f ("perf: Fix mux_interval hrtimer wreckage") Fixes: 77a4d1a1b9a1 ("sched: Cleanup bandwidth timers") Cc: pjt@google.com Cc: tglx@linutronix.de Cc: klamm@yandex-team.ru Cc: mingo@kernel.org Cc: bsegall@google.com Cc: hpa@zytor.com Cc: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: http://lkml.kernel.org/r/20150514102311.GX21418@twins.programming.kicks-ass.net
| * | | | | sched: debug: Remove the cfs bandwidth timer_active printoutThomas Gleixner2015-04-231-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The struct member is gone. Reported-by: fengguang.wu@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org>
| * | | | | sched: Cleanup bandwidth timersPeter Zijlstra2015-04-224-61/+31
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Roman reported a 3 cpu lockup scenario involving __start_cfs_bandwidth(). The more I look at that code the more I'm convinced its crack, that entire __start_cfs_bandwidth() thing is brain melting, we don't need to cancel a timer before starting it, *hrtimer_start*() will happily remove the timer for you if its still enqueued. Removing that, removes a big part of the problem, no more ugly cancel loop to get stuck in. So now, if I understand things right, the entire reason you have this cfs_b->lock guarded ->timer_active nonsense is to make sure we don't accidentally lose the timer. It appears to me that it should be possible to guarantee that same by unconditionally (re)starting the timer when !queued. Because regardless what hrtimer::function will return, if we beat it to (re)enqueue the timer, it doesn't matter. Now, because hrtimers don't come with any serialization guarantees we must ensure both handler and (re)start loop serialize their access to the hrtimer to avoid both trying to forward the timer at the same time. Update the rt bandwidth timer to match. This effectively reverts: 09dc4ab03936 ("sched/fair: Fix tg_set_cfs_bandwidth() deadlock on rq->lock"). Reported-by: Roman Gushchin <klamm@yandex-team.ru> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Ben Segall <bsegall@google.com> Cc: Paul Turner <pjt@google.com> Link: http://lkml.kernel.org/r/20150415095011.804589208@infradead.org Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | | sched: deadline: Use hrtimer_start()Thomas Gleixner2015-04-221-10/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | hrtimer_start() does not longer defer already expired timers to the softirq. Get rid of the __hrtimer_start_range_ns() invocation. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/20150414203502.627353666@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
| * | | | | sched: core: Use hrtimer_start[_expires]()Thomas Gleixner2015-04-222-21/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | hrtimer_start() now enforces a timer interrupt when an already expired timer is enqueued. Get rid of the __hrtimer_start_range_ns() invocations and the loops around it. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Link: http://lkml.kernel.org/r/20150414203502.531131739@linutronix.de Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | | | | | Merge branch 'sched-core-for-linus' of ↵Linus Torvalds2015-06-2213-363/+487
|\ \ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler updates from Ingo Molnar: "The main changes are: - lockless wakeup support for futexes and IPC message queues (Davidlohr Bueso, Peter Zijlstra) - Replace spinlocks with atomics in thread_group_cputimer(), to improve scalability (Jason Low) - NUMA balancing improvements (Rik van Riel) - SCHED_DEADLINE improvements (Wanpeng Li) - clean up and reorganize preemption helpers (Frederic Weisbecker) - decouple page fault disabling machinery from the preemption counter, to improve debuggability and robustness (David Hildenbrand) - SCHED_DEADLINE documentation updates (Luca Abeni) - topology CPU masks cleanups (Bartosz Golaszewski) - /proc/sched_debug improvements (Srikar Dronamraju)" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (79 commits) sched/deadline: Remove needless parameter in dl_runtime_exceeded() sched: Remove superfluous resetting of the p->dl_throttled flag sched/deadline: Drop duplicate init_sched_dl_class() declaration sched/deadline: Reduce rq lock contention by eliminating locking of non-feasible target sched/deadline: Make init_sched_dl_class() __init sched/deadline: Optimize pull_dl_task() sched/preempt: Add static_key() to preempt_notifiers sched/preempt: Fix preempt notifiers documentation about hlist_del() within unsafe iteration sched/stop_machine: Fix deadlock between multiple stop_two_cpus() sched/debug: Add sum_sleep_runtime to /proc/<pid>/sched sched/debug: Replace vruntime with wait_sum in /proc/sched_debug sched/debug: Properly format runnable tasks in /proc/sched_debug sched/numa: Only consider less busy nodes as numa balancing destinations Revert 095bebf61a46 ("sched/numa: Do not move past the balance point if unbalanced") sched/fair: Prevent throttling in early pick_next_task_fair() preempt: Reorganize the notrace definitions a bit preempt: Use preempt_schedule_context() as the official tracing preemption point sched: Make preempt_schedule_context() function-tracing safe x86: Remove cpu_sibling_mask() and cpu_core_mask() x86: Replace cpu_**_mask() with topology_**_cpumask() ...
| * | | | | | sched/deadline: Remove needless parameter in dl_runtime_exceeded()Zhiqiang Zhang2015-06-191-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Sine commit 269ad8015a6b ("sched/deadline: Avoid double-accounting in case of missed deadlines), parameter 'rq' is no longer used, so remove it. Signed-off-by: Zhiqiang Zhang <zhangzhiqiang.zhang@huawei.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <juri.lelli@gmail.com> Cc: <luca.abeni@unitn.it> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1434338120-43773-1-git-send-email-zhangzhiqiang.zhang@huawei.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | sched: Remove superfluous resetting of the p->dl_throttled flagWanpeng Li2015-06-191-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Resetting the p->dl_throttled flag in rt_mutex_setprio() (for a task that is going to be boosted) is superfluous, as the natural place to do so is in replenish_dl_entity(). If the task was on the runqueue and it is boosted by a DL task, it will be enqueued back with ENQUEUE_REPLENISH flag set, which can guarantee that dl_throttled is reset in replenish_dl_entity(). This patch drops the resetting of throttled status in function rt_mutex_setprio(). Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1431496867-4194-6-git-send-email-wanpeng.li@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | sched/deadline: Drop duplicate init_sched_dl_class() declarationWanpeng Li2015-06-191-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are two init_sched_dl_class() declarations, this patch drops the duplicate. Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1431496867-4194-5-git-send-email-wanpeng.li@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | sched/deadline: Reduce rq lock contention by eliminating locking of ↵Wanpeng Li2015-06-191-1/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | non-feasible target This patch adds a check that prevents futile attempts to move DL tasks to a CPU with active tasks of equal or earlier deadline. The same behavior as commit 80e3d87b2c55 ("sched/rt: Reduce rq lock contention by eliminating locking of non-feasible target") for rt class. Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1431496867-4194-3-git-send-email-wanpeng.li@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | sched/deadline: Make init_sched_dl_class() __initWanpeng Li2015-06-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It's a bootstrap function, make init_sched_dl_class() __init. Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1431496867-4194-2-git-send-email-wanpeng.li@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | sched/deadline: Optimize pull_dl_task()Wanpeng Li2015-06-191-1/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | pull_dl_task() uses pick_next_earliest_dl_task() to select a migration candidate; this is sub-optimal since the next earliest task -- as per the regular runqueue -- might not be migratable at all. This could result in iterating the entire runqueue looking for a task. Instead iterate the pushable queue -- this queue only contains tasks that have at least 2 cpus set in their cpus_allowed mask. Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> [ Improved the changelog. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1431496867-4194-1-git-send-email-wanpeng.li@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | sched/preempt: Add static_key() to preempt_notifiersPeter Zijlstra2015-06-191-5/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Avoid touching the curr->preempt_notifier cacheline when not needed. Provides a small improvement on pipe-bench: taskset 01 perf stat --repeat 10 -- perf bench sched pipe before: Performance counter stats for 'perf bench sched pipe' (10 runs): 12385.016204 task-clock (msec) # 1.001 CPUs utilized ( +- 0.34% ) 2,000,023 context-switches # 0.161 M/sec ( +- 0.00% ) 0 cpu-migrations # 0.000 K/sec 175 page-faults # 0.014 K/sec ( +- 0.26% ) 41,376,162,250 cycles # 3.341 GHz ( +- 0.11% ) 17,389,139,321 stalled-cycles-frontend # 42.03% frontend cycles idle ( +- 0.25% ) <not supported> stalled-cycles-backend 68,788,588,003 instructions # 1.66 insns per cycle # 0.25 stalled cycles per insn ( +- 0.02% ) 13,449,387,620 branches # 1085.940 M/sec ( +- 0.02% ) 20,880,690 branch-misses # 0.16% of all branches ( +- 0.98% ) 12.372646094 seconds time elapsed ( +- 0.34% ) after: Performance counter stats for 'perf bench sched pipe' (10 runs): 12180.936528 task-clock (msec) # 1.001 CPUs utilized ( +- 0.33% ) 2,000,077 context-switches # 0.164 M/sec ( +- 0.00% ) 0 cpu-migrations # 0.000 K/sec 174 page-faults # 0.014 K/sec ( +- 0.27% ) 40,691,545,577 cycles # 3.341 GHz ( +- 0.06% ) 16,446,333,371 stalled-cycles-frontend # 40.42% frontend cycles idle ( +- 0.18% ) <not supported> stalled-cycles-backend 68,570,100,387 instructions # 1.69 insns per cycle # 0.24 stalled cycles per insn ( +- 0.01% ) 13,389,740,014 branches # 1099.237 M/sec ( +- 0.01% ) 20,175,440 branch-misses # 0.15% of all branches ( +- 0.52% ) 12.169253010 seconds time elapsed ( +- 0.33% ) Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | sched/preempt: Fix preempt notifiers documentation about hlist_del() within ↵Mathieu Desnoyers2015-06-191-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | unsafe iteration preempt_notifier_unregister() documents: "This is safe to call from within a preemption notifier." However, both fire_sched_in_preempt_notifiers() and fire_sched_out_preempt_notifiers() are using hlist_for_each_entry(), which is not safe against entry removal during iteration. Inspection of the KVM code does not reveal any use of preempt_notifier_unregister() within the preempt notifiers. Therefore, fix the comment. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1431881590-1456-1-git-send-email-mathieu.desnoyers@efficios.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | sched/debug: Add sum_sleep_runtime to /proc/<pid>/schedSrikar Dronamraju2015-06-191-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When CONFIG_SCHEDSTATS is enabled, /proc/<pid>/sched prints almost all sched statistics except sum_sleep_runtime. Since sum_sleep_runtime is a good info to collect, add this it to /proc/<pid>/sched. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1433751041-11724-4-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | sched/debug: Replace vruntime with wait_sum in /proc/sched_debugSrikar Dronamraju2015-06-191-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Within runnable tasks in /proc/sched_debug, vruntime is printed twice, once as tree-key and again as exec-runtime. Since exec-runtime isnt populated in !CONFIG_SCHEDSTATS, use this field to print wait_sum. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1433751041-11724-3-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | sched/debug: Properly format runnable tasks in /proc/sched_debugSrikar Dronamraju2015-06-191-2/+4
| | |_|_|_|/ | |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With !CONFIG_SCHEDSTATS, runnable tasks in /proc/sched_debug has too many columns than required. Fix this by printing appropriate columns. While at this, print sum_exec_runtime, since this information is available even in !CONFIG_SCHEDSTATS case. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Borislav Petkov <bp@alien8.de> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1433751041-11724-2-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | sched/numa: Only consider less busy nodes as numa balancing destinationsRik van Riel2015-06-071-2/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Changeset a43455a1d572 ("sched/numa: Ensure task_numa_migrate() checks the preferred node") fixes an issue where workloads would never converge on a fully loaded (or overloaded) system. However, it introduces a regression on less than fully loaded systems, where workloads converge on a few NUMA nodes, instead of properly staying spread out across the whole system. This leads to a reduction in available memory bandwidth, and usable CPU cache, with predictable performance problems. The root cause appears to be an interaction between the load balancer and NUMA balancing, where the short term load represented by the load balancer differs from the long term load the NUMA balancing code would like to base its decisions on. Simply reverting a43455a1d572 would re-introduce the non-convergence of workloads on fully loaded systems, so that is not a good option. As an aside, the check done before a43455a1d572 only applied to a task's preferred node, not to other candidate nodes in the system, so the converge-on-too-few-nodes problem still happens, just to a lesser degree. Instead, try to compensate for the impedance mismatch between the load balancer and NUMA balancing by only ever considering a lesser loaded node as a destination for NUMA balancing, regardless of whether the task is trying to move to the preferred node, or to another node. This patch also addresses the issue that a system with a single runnable thread would never migrate that thread to near its memory, introduced by 095bebf61a46 ("sched/numa: Do not move past the balance point if unbalanced"). A test where the main thread creates a large memory area, and spawns a worker thread to iterate over the memory (placed on another node by select_task_rq_fair), after which the main thread goes to sleep and waits for the worker thread to loop over all the memory now sees the worker thread migrated to where the memory is, instead of having all the memory migrated over like before. Jirka has run a number of performance tests on several systems: single instance SpecJBB 2005 performance is 7-15% higher on a 4 node system, with higher gains on systems with more cores per socket. Multi-instance SpecJBB 2005 (one per node), linpack, and stream see little or no changes with the revert of 095bebf61a46 and this patch. Reported-by: Artem Bityutski <dedekind1@gmail.com> Reported-by: Jirka Hladky <jhladky@redhat.com> Tested-by: Jirka Hladky <jhladky@redhat.com> Tested-by: Artem Bityutskiy <dedekind1@gmail.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150528095249.3083ade0@annuminas.surriel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | Revert 095bebf61a46 ("sched/numa: Do not move past the balance point if ↵Rik van Riel2015-06-071-26/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | unbalanced") Commit 095bebf61a46 ("sched/numa: Do not move past the balance point if unbalanced") broke convergence of workloads with just one runnable thread, by making it impossible for the one runnable thread on the system to move from one NUMA node to another. Instead, the thread would remain where it was, and pull all the memory across to its location, which is much slower than just migrating the thread to where the memory is. The next patch has a better fix for the issue that 095bebf61a46 tried to address. Reported-by: Jirka Hladky <jhladky@redhat.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dedekind1@gmail.com Cc: mgorman@suse.de Link: http://lkml.kernel.org/r/1432753468-7785-2-git-send-email-riel@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | sched/fair: Prevent throttling in early pick_next_task_fair()Ben Segall2015-06-071-11/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The optimized task selection logic optimistically selects a new task to run without first doing a full put_prev_task(). This is so that we can avoid a put/set on the common ancestors of the old and new task. Similarly, we should only call check_cfs_rq_runtime() to throttle eligible groups if they're part of the common ancestry, otherwise it is possible to end up with no eligible task in the simple task selection. Imagine: /root /prev /next /A /B If our optimistic selection ends up throttling /next, we goto simple and our put_prev_task() ends up throttling /prev, after which we're going to bug out in set_next_entity() because there aren't any tasks left. Avoid this scenario by only throttling common ancestors. Reported-by: Mohammed Naser <mnaser@vexxhost.com> Reported-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Ben Segall <bsegall@google.com> [ munged Changelog ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Roman Gushchin <klamm@yandex-team.ru> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: pjt@google.com Fixes: 678d5718d8d0 ("sched/fair: Optimize cgroup pick_next_task_fair()") Link: http://lkml.kernel.org/r/xm26wq1oswoq.fsf@sword-of-the-dawn.mtv.corp.google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | preempt: Use preempt_schedule_context() as the official tracing preemption pointFrederic Weisbecker2015-06-071-5/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | preempt_schedule_context() is a tracing safe preemption point but it's only used when CONFIG_CONTEXT_TRACKING=y. Other configs have tracing recursion issues since commit: b30f0e3ffedf ("sched/preempt: Optimize preemption operations on __schedule() callers") introduced function based preemp_count_*() ops. Lets make it available on all configs and give it a more appropriate name for its new position. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1433432349-1021-3-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | sched: Make preempt_schedule_context() function-tracing safeFrederic Weisbecker2015-06-071-2/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since function tracing disables preemption, it needs a safe preemption point to use when preemption is re-enabled without worrying about tracing recursion. Ie: to avoid tracing recursion, that preemption point can't be traced (use of notrace qualifier) and it can't call any traceable function before that preemption point disables preemption itself, which disarms the recursion. preempt_schedule() was fine until commit: b30f0e3ffedf ("sched/preempt: Optimize preemption operations on __schedule() callers") because PREEMPT_ACTIVE (which has the property to disable preemption and this disarm tracing preemption recursion) was set before calling any further function. But that commit introduced the use of preempt_count_add/sub() functions to set PREEMPT_ACTIVE and because these functions are called before preemption gets a chance to be disabled, we have a tracing recursion. preempt_schedule_context() is one of the possible preemption functions used by tracing. Its special purpose is to avoid tracing recursion against context tracking. Lets enhance this function to become more generally tracing safe by disabling preemption with raw accessors, such that no function is called before preemption gets disabled and disarm the tracing recursion. This function is going to become the specific tracing-safe preemption point in further commit. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1433432349-1021-2-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | Merge branch 'linus' into sched/core, to resolve conflictIngo Molnar2015-06-021-4/+1
| |\ \ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts: arch/sparc/include/asm/topology_64.h Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | sched/numa: Reduce conflict between fbq_classify_rq() and migrationRik van Riel2015-05-191-27/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It is possible for fbq_classify_rq() to indicate that a CPU has tasks that should be moved to another NUMA node, but for migrate_improves_locality and migrate_degrades_locality to not identify those tasks. This patch always gives preference to preferred node evaluations, and only checks the number of faults when evaluating moves between two non-preferred nodes on a larger NUMA system. On a two node system, the number of faults is never evaluated. Either a task is about to be pulled off its preferred node, or migrated onto it. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: mgorman@suse.de Link: http://lkml.kernel.org/r/20150514225936.35b91717@annuminas.surriel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
| * | | | | | sched/preempt: Optimize preemption operations on __schedule() callersFrederic Weisbecker2015-05-191-20/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __schedule() disables preemption and some of its callers (the preempt_schedule*() family) also set PREEMPT_ACTIVE. So we have two preempt_count() modifications that could be performed at once. Lets remove the preemption disablement from __schedule() and pull this responsibility to its callers in order to optimize preempt_count() operations in a single place. Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1431441711-29753-5-git-send-email-fweisbec@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
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