summaryrefslogtreecommitdiff
path: root/kernel/sched/deadline.c
AgeCommit message (Collapse)AuthorFilesLines
2016-08-10sched/deadline: Fix lock pinning warning during CPU hotplugWanpeng Li1-1/+4
The following warning can be triggered by hot-unplugging the CPU on which an active SCHED_DEADLINE task is running on: WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:3531 lock_release+0x690/0x6a0 releasing a pinned lock Call Trace: dump_stack+0x99/0xd0 __warn+0xd1/0xf0 ? dl_task_timer+0x1a1/0x2b0 warn_slowpath_fmt+0x4f/0x60 ? sched_clock+0x13/0x20 lock_release+0x690/0x6a0 ? enqueue_pushable_dl_task+0x9b/0xa0 ? enqueue_task_dl+0x1ca/0x480 _raw_spin_unlock+0x1f/0x40 dl_task_timer+0x1a1/0x2b0 ? push_dl_task.part.31+0x190/0x190 WARNING: CPU: 0 PID: 0 at kernel/locking/lockdep.c:3649 lock_unpin_lock+0x181/0x1a0 unpinning an unpinned lock Call Trace: dump_stack+0x99/0xd0 __warn+0xd1/0xf0 warn_slowpath_fmt+0x4f/0x60 lock_unpin_lock+0x181/0x1a0 dl_task_timer+0x127/0x2b0 ? push_dl_task.part.31+0x190/0x190 As per the comment before this code, its safe to drop the RQ lock here, and since we (potentially) change rq, unpin and repin to avoid the splat. Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> [ Rewrote changelog. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luca Abeni <luca.abeni@unitn.it> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1470274940-17976-1-git-send-email-wanpeng.li@hotmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-12sched/core: Provide a tsk_nr_cpus_allowed() helperThomas Gleixner1-14/+14
tsk_nr_cpus_allowed() is an accessor for task->nr_cpus_allowed which allows us to change the representation of ->nr_cpus_allowed if required. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/1462969411-17735-2-git-send-email-bigeasy@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-12sched/core: Use tsk_cpus_allowed() instead of accessing ->cpus_allowedThomas Gleixner1-1/+1
Use the future-safe accessor for struct task_struct's. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/1462969411-17735-1-git-send-email-bigeasy@linutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-12Merge branch 'sched/urgent' into sched/core to pick up fixesIngo Molnar1-0/+1
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-10sched/rt, sched/dl: Don't push if task's scheduling class was changedXunlei Pang1-0/+1
We got this warning: WARNING: CPU: 1 PID: 2468 at kernel/sched/core.c:1161 set_task_cpu+0x1af/0x1c0 [...] Call Trace: dump_stack+0x63/0x87 __warn+0xd1/0xf0 warn_slowpath_null+0x1d/0x20 set_task_cpu+0x1af/0x1c0 push_dl_task.part.34+0xea/0x180 push_dl_tasks+0x17/0x30 __balance_callback+0x45/0x5c __sched_setscheduler+0x906/0xb90 SyS_sched_setattr+0x150/0x190 do_syscall_64+0x62/0x110 entry_SYSCALL64_slow_path+0x25/0x25 This corresponds to: WARN_ON_ONCE(p->state == TASK_RUNNING && p->sched_class == &fair_sched_class && (p->on_rq && !task_on_rq_migrating(p))) It happens because in find_lock_later_rq(), the task whose scheduling class was changed to fair class is still pushed away as if it were a deadline task ... So, check in find_lock_later_rq() after double_lock_balance(), if the scheduling class of the deadline task was changed, break and retry. Apply the same logic to RT tasks. Signed-off-by: Xunlei Pang <xlpang@redhat.com> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Juri Lelli <juri.lelli@arm.com> Link: http://lkml.kernel.org/r/1462767091-1215-1-git-send-email-xlpang@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-05locking/lockdep, sched/core: Implement a better lock pinning schemePeter Zijlstra1-5/+6
The problem with the existing lock pinning is that each pin is of value 1; this mean you can simply unpin if you know its pinned, without having any extra information. This scheme generates a random (16 bit) cookie for each pin and requires this same cookie to unpin. This means you have to keep the cookie in context. No objsize difference for !LOCKDEP kernels. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> 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>
2016-05-05sched/core: Introduce 'struct rq_flags'Peter Zijlstra1-3/+3
In order to be able to pass around more than just the IRQ flags in the future, add a rq_flags structure. No difference in code generation for the x86_64-defconfig build I tested. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-04-28sched/cpufreq: Optimize cpufreq update kicker to avoid update multiple timesWanpeng Li1-4/+4
Sometimes delta_exec is 0 due to update_curr() is called multiple times, this is captured by: u64 delta_exec = rq_clock_task(rq) - curr->se.exec_start; This patch optimizes the cpufreq update kicker by bailing out when nothing changed, it will benefit the upcoming schedutil, since otherwise it will (over)react to the special util/max combination. Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> 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/1461316044-9520-1-git-send-email-wanpeng.li@hotmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-03-16Merge tag 'pm+acpi-4.6-rc1-1' of ↵Linus Torvalds1-0/+4
git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm Pull power management and ACPI updates from Rafael Wysocki: "This time the majority of changes go into cpufreq and they are significant. First off, the way CPU frequency updates are triggered is different now. Instead of having to set up and manage a deferrable timer for each CPU in the system to evaluate and possibly change its frequency periodically, cpufreq governors set up callbacks to be invoked by the scheduler on a regular basis (basically on utilization updates). The "old" governors, "ondemand" and "conservative", still do all of their work in process context (although that is triggered by the scheduler now), but intel_pstate does it all in the callback invoked by the scheduler with no need for any additional asynchronous processing. Of course, this eliminates the overhead related to the management of all those timers, but also it allows the cpufreq governor code to be simplified quite a bit. On top of that, the common code and data structures used by the "ondemand" and "conservative" governors are cleaned up and made more straightforward and some long-standing and quite annoying problems are addressed. In particular, the handling of governor sysfs attributes is modified and the related locking becomes more fine grained which allows some concurrency problems to be avoided (particularly deadlocks with the core cpufreq code). In principle, the new mechanism for triggering frequency updates allows utilization information to be passed from the scheduler to cpufreq. Although the current code doesn't make use of it, in the works is a new cpufreq governor that will make decisions based on the scheduler's utilization data. That should allow the scheduler and cpufreq to work more closely together in the long run. In addition to the core and governor changes, cpufreq drivers are updated too. Fixes and optimizations go into intel_pstate, the cpufreq-dt driver is updated on top of some modification in the Operating Performance Points (OPP) framework and there are fixes and other updates in the powernv cpufreq driver. Apart from the cpufreq updates there is some new ACPICA material, including a fix for a problem introduced by previous ACPICA updates, and some less significant changes in the ACPI code, like CPPC code optimizations, ACPI processor driver cleanups and support for loading ACPI tables from initrd. Also updated are the generic power domains framework, the Intel RAPL power capping driver and the turbostat utility and we have a bunch of traditional assorted fixes and cleanups. Specifics: - Redesign of cpufreq governors and the intel_pstate driver to make them use callbacks invoked by the scheduler to trigger CPU frequency evaluation instead of using per-CPU deferrable timers for that purpose (Rafael Wysocki). - Reorganization and cleanup of cpufreq governor code to make it more straightforward and fix some concurrency problems in it (Rafael Wysocki, Viresh Kumar). - Cleanup and improvements of locking in the cpufreq core (Viresh Kumar). - Assorted cleanups in the cpufreq core (Rafael Wysocki, Viresh Kumar, Eric Biggers). - intel_pstate driver updates including fixes, optimizations and a modification to make it enable enable hardware-coordinated P-state selection (HWP) by default if supported by the processor (Philippe Longepe, Srinivas Pandruvada, Rafael Wysocki, Viresh Kumar, Felipe Franciosi). - Operating Performance Points (OPP) framework updates to improve its handling of voltage regulators and device clocks and updates of the cpufreq-dt driver on top of that (Viresh Kumar, Jon Hunter). - Updates of the powernv cpufreq driver to fix initialization and cleanup problems in it and correct its worker thread handling with respect to CPU offline, new powernv_throttle tracepoint (Shilpasri Bhat). - ACPI cpufreq driver optimization and cleanup (Rafael Wysocki). - ACPICA updates including one fix for a regression introduced by previos changes in the ACPICA code (Bob Moore, Lv Zheng, David Box, Colin Ian King). - Support for installing ACPI tables from initrd (Lv Zheng). - Optimizations of the ACPI CPPC code (Prashanth Prakash, Ashwin Chaugule). - Support for _HID(ACPI0010) devices (ACPI processor containers) and ACPI processor driver cleanups (Sudeep Holla). - Support for ACPI-based enumeration of the AMBA bus (Graeme Gregory, Aleksey Makarov). - Modification of the ACPI PCI IRQ management code to make it treat 255 in the Interrupt Line register as "not connected" on x86 (as per the specification) and avoid attempts to use that value as a valid interrupt vector (Chen Fan). - ACPI APEI fixes related to resource leaks (Josh Hunt). - Removal of modularity from a few ACPI drivers (BGRT, GHES, intel_pmic_crc) that cannot be built as modules in practice (Paul Gortmaker). - PNP framework update to make it treat ACPI_RESOURCE_TYPE_SERIAL_BUS as a valid resource type (Harb Abdulhamid). - New device ID (future AMD I2C controller) in the ACPI driver for AMD SoCs (APD) and in the designware I2C driver (Xiangliang Yu). - Assorted ACPI cleanups (Colin Ian King, Kaiyen Chang, Oleg Drokin). - cpuidle menu governor optimization to avoid a square root computation in it (Rasmus Villemoes). - Fix for potential use-after-free in the generic device properties framework (Heikki Krogerus). - Updates of the generic power domains (genpd) framework including support for multiple power states of a domain, fixes and debugfs output improvements (Axel Haslam, Jon Hunter, Laurent Pinchart, Geert Uytterhoeven). - Intel RAPL power capping driver updates to reduce IPI overhead in it (Jacob Pan). - System suspend/hibernation code cleanups (Eric Biggers, Saurabh Sengar). - Year 2038 fix for the process freezer (Abhilash Jindal). - turbostat utility updates including new features (decoding of more registers and CPUID fields, sub-second intervals support, GFX MHz and RC6 printout, --out command line option), fixes (syscall jitter detection and workaround, reductioin of the number of syscalls made, fixes related to Xeon x200 processors, compiler warning fixes) and cleanups (Len Brown, Hubert Chrzaniuk, Chen Yu)" * tag 'pm+acpi-4.6-rc1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (182 commits) tools/power turbostat: bugfix: TDP MSRs print bits fixing tools/power turbostat: correct output for MSR_NHM_SNB_PKG_CST_CFG_CTL dump tools/power turbostat: call __cpuid() instead of __get_cpuid() tools/power turbostat: indicate SMX and SGX support tools/power turbostat: detect and work around syscall jitter tools/power turbostat: show GFX%rc6 tools/power turbostat: show GFXMHz tools/power turbostat: show IRQs per CPU tools/power turbostat: make fewer systems calls tools/power turbostat: fix compiler warnings tools/power turbostat: add --out option for saving output in a file tools/power turbostat: re-name "%Busy" field to "Busy%" tools/power turbostat: Intel Xeon x200: fix turbo-ratio decoding tools/power turbostat: Intel Xeon x200: fix erroneous bclk value tools/power turbostat: allow sub-sec intervals ACPI / APEI: ERST: Fixed leaked resources in erst_init ACPI / APEI: Fix leaked resources intel_pstate: Do not skip samples partially intel_pstate: Remove freq calculation from intel_pstate_calc_busy() intel_pstate: Move intel_pstate_calc_busy() into get_target_pstate_use_performance() ...
2016-03-14Merge branch 'pm-cpufreq'Rafael J. Wysocki1-0/+4
* pm-cpufreq: (94 commits) intel_pstate: Do not skip samples partially intel_pstate: Remove freq calculation from intel_pstate_calc_busy() intel_pstate: Move intel_pstate_calc_busy() into get_target_pstate_use_performance() intel_pstate: Optimize calculation for max/min_perf_adj intel_pstate: Remove extra conversions in pid calculation cpufreq: Move scheduler-related code to the sched directory Revert "cpufreq: postfix policy directory with the first CPU in related_cpus" cpufreq: Reduce cpufreq_update_util() overhead a bit cpufreq: Select IRQ_WORK if CPU_FREQ_GOV_COMMON is set cpufreq: Remove 'policy->governor_enabled' cpufreq: Rename __cpufreq_governor() to cpufreq_governor() cpufreq: Relocate handle_update() to kill its declaration cpufreq: governor: Drop unnecessary checks from show() and store() cpufreq: governor: Fix race in dbs_update_util_handler() cpufreq: governor: Make gov_set_update_util() static cpufreq: governor: Narrow down the dbs_data_mutex coverage cpufreq: governor: Make dbs_data_mutex static cpufreq: governor: Relocate definitions of tuners structures cpufreq: governor: Move per-CPU data to the common code cpufreq: governor: Make governor private data per-policy ...
2016-03-09cpufreq: Add mechanism for registering utilization update callbacksRafael J. Wysocki1-0/+4
Introduce a mechanism by which parts of the cpufreq subsystem ("setpolicy" drivers or the core) can register callbacks to be executed from cpufreq_update_util() which is invoked by the scheduler's update_load_avg() on CPU utilization changes. This allows the "setpolicy" drivers to dispense with their timers and do all of the computations they need and frequency/voltage adjustments in the update_load_avg() code path, among other things. The update_load_avg() changes were suggested by Peter Zijlstra. Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Ingo Molnar <mingo@kernel.org>
2016-03-08sched/deadline: Remove dl_new from struct sched_dl_entityLuca Abeni1-22/+13
The dl_new field of struct sched_dl_entity is currently used to identify new deadline tasks, so that their deadline and runtime can be properly initialised. However, these tasks can be easily identified by checking if their deadline is smaller than the current time when they switch to SCHED_DEADLINE. So, dl_new can be removed by introducing this check in switched_to_dl(); this allows to simplify the SCHED_DEADLINE code. Signed-off-by: Luca Abeni <luca.abeni@unitn.it> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> 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/1457350024-7825-2-git-send-email-luca.abeni@unitn.it Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-29sched/deadline: Remove superfluous call to switched_to_dl()Peter Zijlstra1-2/+1
if (A || B) { } else if (A && !B) { } If A we'll take the first branch, if !A we will not satisfy the second. Therefore the second branch will never be taken. Reported-by: luca abeni <luca.abeni@unitn.it> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Juri Lelli <juri.lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20160225140149.GK6357@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-29sched/deadline: Always calculate end of period on sched_yield()Peter Zijlstra1-9/+13
Steven noticed that occasionally a sched_yield() call would not result in a wait for the next period edge as expected. It turns out that when we call update_curr_dl() and end up with delta_exec <= 0, we will bail early and fail to throttle. Further inspection of the yield code revealed that yield_task_dl() clearing dl.runtime is wrong too, it will not account the last bit of runtime which could result in dl.runtime < 0, which in turn means that replenish would gift us with too much runtime. Fix both issues by not relying on the dl.runtime value for yield. Reported-by: Steven Rostedt <rostedt@goodmis.org> Tested-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Clark Williams <williams@redhat.com> Cc: Daniel Bristot de Oliveira <bristot@redhat.com> Cc: John Kacur <jkacur@redhat.com> Cc: Juri Lelli <juri.lelli@gmail.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/20160223122822.GP6357@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-02-17sched/deadline: Fix trivial typo in printk() messageSteven Rostedt1-1/+1
It's "too much" not "to much". Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Acked-by: Juri Lelli <juri.lelli@arm.com> Cc: Jiri Kosina <trivial@kernel.org> Cc: Juri Lelli <juri.lelli@gmail.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/20160210120422.4ca77e68@gandalf.local.home Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-01-06sched/deadline: Fix the earliest_dl.next logicWanpeng Li1-52/+7
earliest_dl.next should cache deadline of the earliest ready task that is also enqueued in the pushable rbtree, as pull algorithm uses this information to find candidates for migration: if the earliest_dl.next deadline of source rq is earlier than the earliest_dl.curr deadline of destination rq, the task from the source rq can be pulled. However, current implementation only guarantees that earliest_dl.next is the deadline of the next ready task instead of the next pushable task; which will result in potentially holding both rqs' lock and find nothing to migrate because of affinity constraints. In addition, current logic doesn't update the next candidate for pushing in pick_next_task_dl(), even if the running task is never eligible. This patch fixes both problems by updating earliest_dl.next when pushable dl task is enqueued/dequeued, similar to what we already do for RT. Tested-by: Luca Abeni <luca.abeni@unitn.it> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Juri Lelli <juri.lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1449135730-27202-1-git-send-email-wanpeng.li@hotmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-10-23sched/core: Add missing lockdep_unpin() annotationsPeter Zijlstra1-1/+8
Luca and Wanpeng reported two missing annotations that led to false lockdep complaints. Add the missing annotations. Reported-by: Luca Abeni <luca.abeni@unitn.it> Reported-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: cbce1a686700 ("sched,lockdep: Employ lock pinning") Link: http://lkml.kernel.org/r/20151023095008.GY17308@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-10-20sched/deadline: Fix migration of SCHED_DEADLINE tasksLuca Abeni1-3/+5
Commit: 9d5142624256 ("sched/deadline: Reduce rq lock contention by eliminating locking of non-feasible target") broke select_task_rq_dl() and find_lock_later_rq(), because it introduced a comparison between the local task's deadline and dl.earliest_dl.curr of the remote queue. However, if the remote runqueue does not contain any SCHED_DEADLINE task its earliest_dl.curr is 0 (always smaller than the deadline of the local task) and the remote runqueue is not selected for pushing. As a result, if an application creates multiple SCHED_DEADLINE threads, they will never be pushed to runqueues that do not already contain SCHED_DEADLINE tasks. This patch fixes the issue by checking if dl.dl_nr_running == 0. Signed-off-by: Luca Abeni <luca.abeni@unitn.it> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Wanpeng Li <wanpeng.li@linux.intel.com> Fixes: 9d5142624256 ("sched/deadline: Reduce rq lock contention by eliminating locking of non-feasible target") Link: http://lkml.kernel.org/r/1444982781-15608-1-git-send-email-luca.abeni@unitn.it Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-08-12sched/deadline: Fix comment in enqueue_task_dl()Andrea Parri1-1/+1
The "dl_boosted" flag is set by comparing *absolute* deadlines (c.f., rt_mutex_setprio()). Signed-off-by: Andrea Parri <parri.andrea@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1438782979-9057-2-git-send-email-parri.andrea@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-08-12sched/deadline: Fix comment in push_dl_tasks()Andrea Parri1-1/+1
The comment is "misleading"; fix it by adapting a comment from push_rt_tasks(). Signed-off-by: Andrea Parri <parri.andrea@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1438782979-9057-1-git-send-email-parri.andrea@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-08-12sched: Change the sched_class::set_cpus_allowed() calling contextPeter Zijlstra1-37/+2
Change the calling context of sched_class::set_cpus_allowed() such that we can assume the task is inactive. This allows us to easily make changes that affect accounting done by enqueue/dequeue. This does in fact completely remove set_cpus_allowed_rt() and greatly reduces set_cpus_allowed_dl(). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dedekind1@gmail.com Cc: juri.lelli@arm.com Cc: mgorman@suse.de Cc: riel@redhat.com Cc: rostedt@goodmis.org Link: http://lkml.kernel.org/r/20150515154833.667516139@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-08-12sched: Make sched_class::set_cpus_allowed() unconditionalPeter Zijlstra1-8/+12
Give every class a set_cpus_allowed() method, this enables some small optimization in the RT,DL implementation by avoiding a double cpumask_weight() call. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dedekind1@gmail.com Cc: juri.lelli@arm.com Cc: mgorman@suse.de Cc: riel@redhat.com Cc: rostedt@goodmis.org Link: http://lkml.kernel.org/r/20150515154833.614517487@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-08-03sched/deadline: Remove a redundant condition from task_woken_dl()Xunlei Pang1-1/+0
'p' has been already queued at this point, so "!task_running(rq, p)" and "p->nr_cpus_allowed > 1" imply that "has_pushable_dl_tasks(rq)" is true, so it can be removed. Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Juri Lelli <juri.lelli@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1435995563-3723-2-git-send-email-xlpang@126.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-06-24Merge branch 'sched-hrtimers-for-linus' of ↵Linus Torvalds1-103/+135
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
2015-06-22Merge branch 'timers-core-for-linus' of ↵Linus Torvalds1-10/+2
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 ...
2015-06-19sched/deadline: Remove needless parameter in dl_runtime_exceeded()Zhiqiang Zhang1-2/+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>
2015-06-19sched/deadline: Reduce rq lock contention by eliminating locking of ↵Wanpeng Li1-1/+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>
2015-06-19sched/deadline: Make init_sched_dl_class() __initWanpeng Li1-1/+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>
2015-06-19sched/deadline: Optimize pull_dl_task()Wanpeng Li1-1/+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>
2015-06-19sched,lockdep: Employ lock pinningPeter Zijlstra1-0/+8
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>
2015-06-19sched,dl: Fix sched class hopping CBS holePeter Zijlstra1-66/+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>
2015-06-19sched, dl: Convert switched_{from, to}_dl() / prio_changed_dl() to balance ↵Peter Zijlstra1-21/+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>
2015-06-19sched,dl: Remove return value from pull_dl_task()Peter Zijlstra1-10/+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>
2015-06-19sched: Replace post_schedule with a balance callback listPeter Zijlstra1-10/+11
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>
2015-06-19Merge branch 'timers/core' into sched/hrtimersThomas Gleixner1-10/+2
Merge sched/core and timers/core so we can apply the sched balancing patch queue, which depends on both.
2015-05-08sched, timer: Convert usages of ACCESS_ONCE() in the scheduler to ↵Jason Low1-1/+1
READ_ONCE()/WRITE_ONCE() ACCESS_ONCE doesn't work reliably on non-scalar types. This patch removes the rest of the existing usages of ACCESS_ONCE() in the scheduler, and use the new READ_ONCE() and WRITE_ONCE() APIs as appropriate. Signed-off-by: Jason Low <jason.low2@hp.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Waiman Long <Waiman.Long@hp.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Aswin Chandramouleeswaran <aswin@hp.com> Cc: Borislav Petkov <bp@alien8.de> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Preeti U Murthy <preeti@linux.vnet.ibm.com> Cc: Scott J Norton <scott.norton@hp.com> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/1430251224-5764-2-git-send-email-jason.low2@hp.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-22sched: deadline: Use hrtimer_start()Thomas Gleixner1-10/+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>
2015-04-02sched/deadline: Support DL task migration during CPU hotplugWanpeng Li1-0/+57
I observed that DL tasks can't be migrated to other CPUs during CPU hotplug, in addition, task may/may not be running again if CPU is added back. The root cause which I found is that DL tasks will be throtted and removed from the DL rq after comsuming all their budget, which leads to the situation that stop task can't pick them up from the DL rq and migrate them to other CPUs during hotplug. The method to reproduce: schedtool -E -t 50000:100000 -e ./test Actually './test' is just a simple for loop. Then observe which CPU the test task is on and offline it: echo 0 > /sys/devices/system/cpu/cpuN/online This patch adds the DL task migration during CPU hotplug by finding a most suitable later deadline rq after DL timer fires if current rq is offline. If it fails to find a suitable later deadline rq then it falls back to any eligible online CPU in so that the deadline task will come back to us, and the push/pull mechanism should then move it around properly. Suggested-and-Acked-by: Juri Lelli <juri.lelli@arm.com> Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: http://lkml.kernel.org/r/1427411315-4298-1-git-send-email-wanpeng.li@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-02sched/deadline: Always enqueue on previous rq when dl_task_timer() firesJuri Lelli1-2/+2
dl_task_timer() may fire on a different rq from where a task was removed after throttling. Since the call path is: dl_task_timer() -> enqueue_task_dl() -> enqueue_dl_entity() -> replenish_dl_entity() and replenish_dl_entity() uses dl_se's rq, we can't use current's rq in dl_task_timer(), but we need to lock the task's previous one. Tested-by: Wanpeng Li <wanpeng.li@linux.intel.com> Signed-off-by: Juri Lelli <juri.lelli@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Kirill Tkhai <ktkhai@parallels.com> Cc: Juri Lelli <juri.lelli@gmail.com> Fixes: 3960c8c0c789 ("sched: Make dl_task_time() use task_rq_lock()") Link: http://lkml.kernel.org/r/1427792017-7356-1-git-send-email-juri.lelli@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-04-02sched/core: Remove unused argument from init_[rt|dl]_rq()Abel Vesa1-1/+1
Obviously, 'rq' is not used in these two functions, therefore, there is no reason for it to be passed as an argument. Signed-off-by: Abel Vesa <abelvesa@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: http://lkml.kernel.org/r/1425383427-26244-1-git-send-email-abelvesa@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-27sched/deadline: Avoid a superfluous checkWanpeng Li1-8/+0
Since commit 40767b0dc768 ("sched/deadline: Fix deadline parameter modification handling") we clear the thottled state when switching from a dl task, therefore we should never find it set in switching to a dl task. Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> [ Improved the changelog. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Juri Lelli <juri.lelli@arm.com> Link: http://lkml.kernel.org/r/1426590931-4639-1-git-send-email-wanpeng.li@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-03-10sched/deadline: Add rq->clock update skip for dl task yieldWanpeng Li1-0/+6
This patch adds rq->clock update skip for SCHED_DEADLINE task yield, to tell update_rq_clock() that we've just updated the clock, so that we don't do a microscopic update in schedule() and double the fastpath cost. Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1425961200-3809-1-git-send-email-wanpeng.li@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-02-18sched/dl: Do update_rq_clock() in yield_task_dl()Kirill Tkhai1-0/+1
update_curr_dl() needs actual rq clock. Signed-off-by: Kirill Tkhai <ktkhai@parallels.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1423040972.18770.10.camel@tkhai Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-02-18sched/dl: Prevent enqueue of a sleeping task in dl_task_timer()Kirill Tkhai1-0/+20
A deadline task may be throttled and dequeued at the same time. This happens, when it becomes throttled in schedule(), which is called to go to sleep: current->state = TASK_INTERRUPTIBLE; schedule() deactivate_task() dequeue_task_dl() update_curr_dl() start_dl_timer() __dequeue_task_dl() prev->on_rq = 0; Later the timer fires, but the task is still dequeued: dl_task_timer() enqueue_task_dl() /* queues on dl_rq; on_rq remains 0 */ Someone wakes it up: try_to_wake_up() enqueue_dl_entity() BUG_ON(on_dl_rq()) Patch fixes this problem, it prevents queueing !on_rq tasks on dl_rq. Reported-by: Fengguang Wu <fengguang.wu@intel.com> Signed-off-by: Kirill Tkhai <ktkhai@parallels.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> [ Wrote comment. ] Cc: Juri Lelli <juri.lelli@arm.com> Fixes: 1019a359d3dc ("sched/deadline: Fix stale yield state") Link: http://lkml.kernel.org/r/1374601424090314@web4j.yandex.ru Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-02-18sched: Make dl_task_time() use task_rq_lock()Peter Zijlstra1-9/+3
Kirill reported that a dl task can be throttled and dequeued at the same time. This happens, when it becomes throttled in schedule(), which is called to go to sleep: current->state = TASK_INTERRUPTIBLE; schedule() deactivate_task() dequeue_task_dl() update_curr_dl() start_dl_timer() __dequeue_task_dl() prev->on_rq = 0; This invalidates the assumption from commit 0f397f2c90ce ("sched/dl: Fix race in dl_task_timer()"): "The only reason we don't strictly need ->pi_lock now is because we're guaranteed to have p->state == TASK_RUNNING here and are thus free of ttwu races". And therefore we have to use the full task_rq_lock() here. This further amends the fact that we forgot to update the rq lock loop for TASK_ON_RQ_MIGRATE, from commit cca26e8009d1 ("sched: Teach scheduler to understand TASK_ON_RQ_MIGRATING state"). Reported-by: Kirill Tkhai <ktkhai@parallels.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@arm.com> Link: http://lkml.kernel.org/r/20150217123139.GN5029@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-02-04sched/deadline: Fix stale yield statePeter Zijlstra1-19/+19
When we fail to start the deadline timer in update_curr_dl(), we forget to clear ->dl_yielded, resulting in wrecked time keeping. Since the natural place to clear both ->dl_yielded and ->dl_throttled is in replenish_dl_entity(); both are after all waiting for that event; make it so. Luckily since 67dfa1b756f2 ("sched/deadline: Implement cancel_dl_timer() to use in switched_from_dl()") the task_on_rq_queued() condition in dl_task_timer() must be true, and can therefore call enqueue_task_dl() unconditionally. Reported-by: Wanpeng Li <wanpeng.li@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Kirill Tkhai <ktkhai@parallels.com> Cc: Juri Lelli <juri.lelli@arm.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1416962647-76792-4-git-send-email-wanpeng.li@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-02-04sched/deadline: Fix hrtick for a non-leftmost taskWanpeng Li1-1/+7
After update_curr_dl() the current task might not be the leftmost task anymore. In that case do not start a new hrtick for it. In this case NEED_RESCHED will be set and the next schedule will start the hrtick for the new task if and when appropriate. Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com> Acked-by: Juri Lelli <juri.lelli@arm.com> [ Rewrote the changelog and comment. ] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Kirill Tkhai <ktkhai@parallels.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1416962647-76792-2-git-send-email-wanpeng.li@linux.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-02-04Merge branch 'sched/urgent' into sched/core, to merge fixes before applying ↵Ingo Molnar1-1/+2
new patches Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-02-04sched/deadline: Fix deadline parameter modification handlingPeter Zijlstra1-1/+2
Commit 67dfa1b756f2 ("sched/deadline: Implement cancel_dl_timer() to use in switched_from_dl()") removed the hrtimer_try_cancel() function call out from init_dl_task_timer(), which gets called from __setparam_dl(). The result is that we can now re-init the timer while its active -- this is bad and corrupts timer state. Furthermore; changing the parameters of an active deadline task is tricky in that you want to maintain guarantees, while immediately effective change would allow one to circumvent the CBS guarantees -- this too is bad, as one (bad) task should not be able to affect the others. Rework things to avoid both problems. We only need to initialize the timer once, so move that to __sched_fork() for new tasks. Then make sure __setparam_dl() doesn't affect the current running state but only updates the parameters used to calculate the next scheduling period -- this guarantees the CBS functions as expected (albeit slightly pessimistic). This however means we need to make sure __dl_clear_params() needs to reset the active state otherwise new (and tasks flipping between classes) will not properly (re)compute their first instance. Todo: close class flipping CBS hole. Todo: implement delayed BW release. Reported-by: Luca Abeni <luca.abeni@unitn.it> Acked-by: Juri Lelli <juri.lelli@arm.com> Tested-by: Luca Abeni <luca.abeni@unitn.it> Fixes: 67dfa1b756f2 ("sched/deadline: Implement cancel_dl_timer() to use in switched_from_dl()") Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <stable@vger.kernel.org> Cc: Kirill Tkhai <tkhai@yandex.ru> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20150128140803.GF23038@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-01-30sched/deadline: Modify cpudl::free_cpus to reflect rd->onlineXunlei Pang1-3/+2
Currently, cpudl::free_cpus contains all CPUs during init, see cpudl_init(). When calling cpudl_find(), we have to add rd->span to avoid selecting the cpu outside the current root domain, because cpus_allowed cannot be depended on when performing clustered scheduling using the cpuset, see find_later_rq(). This patch adds cpudl_set_freecpu() and cpudl_clear_freecpu() for changing cpudl::free_cpus when doing rq_online_dl()/rq_offline_dl(), so we can avoid the rd->span operation when calling cpudl_find() in find_later_rq(). Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Juri Lelli <juri.lelli@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1421642980-10045-1-git-send-email-pang.xunlei@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-02 21:18:21 +0000