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* sched: Fix a race between __kthread_bind() and sched_setaffinity()Peter Zijlstra2015-08-125-18/+52
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Because sched_setscheduler() checks p->flags & PF_NO_SETAFFINITY without locks, a caller might observe an old value and race with the set_cpus_allowed_ptr() call from __kthread_bind() and effectively undo it: __kthread_bind() do_set_cpus_allowed() <SYSCALL> sched_setaffinity() if (p->flags & PF_NO_SETAFFINITIY) set_cpus_allowed_ptr() p->flags |= PF_NO_SETAFFINITY Fix the bug by putting everything under the regular scheduler locks. This also closes a hole in the serialization of task_struct::{nr_,}cpus_allowed. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Tejun Heo <tj@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Oleg Nesterov <oleg@redhat.com> 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/20150515154833.545640346@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched: Ensure a task has a non-normalized vruntime when returning back to CFSByungchul Park2015-08-121-2/+17
| | | | | | | | | | | | | | | | | | | | | Current code ensures that a task has a normalized vruntime when switching away from the fair class, but it does not ensure the task has a non-normalized vruntime when switching back to the fair class. This is an example breaking this consistency: 1. a task is in fair class and !queued 2. changes its class to RT class (still !queued) 3. changes its class to fair class again (still !queued) Signed-off-by: Byungchul Park <byungchul.park@lge.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/1439197375-27927-1-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/numa: Fix NUMA_DIRECT topology identificationAravind Gopalakrishnan2015-08-121-1/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Systems which have all nodes at a distance of at most 1 hop should be identified as 'NUMA_DIRECT'. However, the scheduler incorrectly identifies it as 'NUMA_BACKPLANE'. This is because 'n' is assigned to sched_max_numa_distance but the code (mis)interprets it to mean 'number of hops'. Rik had actually used sched_domains_numa_levels for detecting a 'NUMA_DIRECT' topology: http://marc.info/?l=linux-kernel&m=141279712429834&w=2 But that was changed when he removed the hops table in the subsequent version: http://marc.info/?l=linux-kernel&m=141353106106771&w=2 Fixing the issue here. Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Rik van Riel <riel@redhat.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/1439256048-3748-1-git-send-email-Aravind.Gopalakrishnan@amd.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* tile: Reorganize _switch_to()Chris Metcalf2015-08-082-12/+6
| | | | | | | | | | | | | | | Move the simulator bits into finish_arch_post_lock_switch() and properly call __switch_to() from _switch_to(). Signed-off-by: Chris Metcalf <cmetcalf@ezchip.com> Cc: <efault@gmx.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1438783412-10990-1-git-send-email-cmetcalf@ezchip.com [ Made it a delta to: fe363adb9225 ("sched, tile: Remove finish_arch_switch"). ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched, sparc32: Update scheduler comments in copy_thread()Ingo Molnar2015-08-041-5/+5
| | | | | | | | | | | | | | There's no finish_arch_switch() anymore in the latest scheduler tree. Also update some other details. Cc: David S. Miller <davem@davemloft.net> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Cc: sparclinux@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched: Remove finish_arch_switch()Peter Zijlstra2015-08-042-4/+0
| | | | | | | | | | | | One less arch hook.. 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: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched, tile: Remove finish_arch_switchChris Metcalf2015-08-042-9/+18
| | | | | | | | | | | | | | Move the simulator bits into switch_to() and use finish_arch_post_lock_switch() for the homecache migration bits. Signed-off-by: Chris Metcalf <cmetcalf@ezchip.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> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched, sh: Fold finish_arch_switch() into switch_to()Peter Zijlstra2015-08-041-6/+2
| | | | | | | | | | | | | | | | | The code looks buggy; why would we be restoring the previous task's DSP state after we've switched to the next task? Fix that and put the restore in switch_to(), removing the need for finish_arch_switch(). 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: linux-kernel@vger.kernel.org Cc: michael@amarulasolutions.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched, score: Remove finish_arch_switch()Peter Zijlstra2015-08-041-2/+0
| | | | | | | | | | | | An empty implementation, make it go away. 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: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched, avr32: Remove finish_arch_switch()Peter Zijlstra2015-08-041-2/+5
| | | | | | | | | | | | | | Fold the tracing hook into switch_to() in order to remove finish_arch_switch(). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> 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: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched, MIPS: Get rid of finish_arch_switch()Ralf Baechle2015-08-041-25/+23
| | | | | | | | | | | | | | | MIPS was using finish_arch_switch() as a hook to restore and initialize CPU context for all threads, even newly created kernel and user threads. This is however entirely solvable within switch_to() so get rid of finish_arch_switch() which is in the way of scheduler cleanups. Signed-off-by: Ralf Baechle <ralf@linux-mips.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: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched, arm: Remove finish_arch_switch()Will Deacon2015-08-041-1/+4
| | | | | | | | | | | | | | | Fold finish_arch_switch() into switch_to(). Signed-off-by: Will Deacon <will.deacon@arm.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> Cc: linux-kernel@vger.kernel.org Cc: linux@arm.linux.org.uk [ Fixed up the SOB chain. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/fair: Clean up load average referencesYuyang Du2015-08-031-15/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For cfs_rq, we have load.weight, runnable_load_avg, and load_avg. Clean up how they are used: - First, as group sched_entity already largely uses load_avg, we now expand to use load_avg in all cases. - Second, for CPU-wide load balancing, we choose to use runnable_load_avg in all cases, which is the same as before this series. Signed-off-by: Yuyang Du <yuyang.du@intel.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> Cc: arjan@linux.intel.com Cc: bsegall@google.com Cc: dietmar.eggemann@arm.com Cc: fengguang.wu@intel.com Cc: len.brown@intel.com Cc: morten.rasmussen@arm.com Cc: pjt@google.com Cc: rafael.j.wysocki@intel.com Cc: umgwanakikbuti@gmail.com Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/1436918682-4971-8-git-send-email-yuyang.du@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/fair: Provide runnable_load_avg back to cfs_rqYuyang Du2015-08-033-10/+49
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The cfs_rq's load_avg is composed of runnable_load_avg and blocked_load_avg. Before this series, sometimes the runnable_load_avg is used, and sometimes the load_avg is used. Completely replacing all uses of runnable_load_avg with load_avg may be too big a leap, i.e., the blocked_load_avg is concerned to result in overrated load. Therefore, we get runnable_load_avg back. The new cfs_rq's runnable_load_avg is improved to be updated with all of the runnable sched_eneities at the same time, so the one sched_entity updated and the others stale problem is solved. Signed-off-by: Yuyang Du <yuyang.du@intel.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> Cc: arjan@linux.intel.com Cc: bsegall@google.com Cc: dietmar.eggemann@arm.com Cc: fengguang.wu@intel.com Cc: len.brown@intel.com Cc: morten.rasmussen@arm.com Cc: pjt@google.com Cc: rafael.j.wysocki@intel.com Cc: umgwanakikbuti@gmail.com Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/1436918682-4971-7-git-send-email-yuyang.du@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/fair: Remove task and group entity load when they are deadYuyang Du2015-08-031-1/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | When task exits or group is destroyed, the entity's load should be removed from its parent cfs_rq's load. Otherwise, it will take time for the parent cfs_rq to decay the dead entity's load to 0, which is not desired. Signed-off-by: Yuyang Du <yuyang.du@intel.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> Cc: arjan@linux.intel.com Cc: bsegall@google.com Cc: dietmar.eggemann@arm.com Cc: fengguang.wu@intel.com Cc: len.brown@intel.com Cc: morten.rasmussen@arm.com Cc: pjt@google.com Cc: rafael.j.wysocki@intel.com Cc: umgwanakikbuti@gmail.com Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/1436918682-4971-6-git-send-email-yuyang.du@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/fair: Init cfs_rq's sched_entity load averageYuyang Du2015-08-033-7/+8
| | | | | | | | | | | | | | | | | | | | | | | | | The runnable load and utilization averages of cfs_rq's sched_entity were not initiated. Like done to a task, give new cfs_rq' sched_entity start values to heavy its load in infant time. Signed-off-by: Yuyang Du <yuyang.du@intel.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> Cc: arjan@linux.intel.com Cc: bsegall@google.com Cc: dietmar.eggemann@arm.com Cc: fengguang.wu@intel.com Cc: len.brown@intel.com Cc: morten.rasmussen@arm.com Cc: pjt@google.com Cc: rafael.j.wysocki@intel.com Cc: umgwanakikbuti@gmail.com Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/1436918682-4971-5-git-send-email-yuyang.du@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/fair: Implement update_blocked_averages() for CONFIG_FAIR_GROUP_SCHED=nVincent Guittot2015-08-031-0/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The load and the utilization of idle CPUs must be updated periodically in order to decay the blocked part. If CONFIG_FAIR_GROUP_SCHED is not set, the load and util of idle cpus are not decayed and stay at the values set before becoming idle. Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Yuyang Du <yuyang.du@intel.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> Cc: arjan@linux.intel.com Cc: bsegall@google.com Cc: dietmar.eggemann@arm.com Cc: fengguang.wu@intel.com Cc: len.brown@intel.com Cc: morten.rasmussen@arm.com Cc: pjt@google.com Cc: rafael.j.wysocki@intel.com Cc: umgwanakikbuti@gmail.com Link: http://lkml.kernel.org/r/1436918682-4971-4-git-send-email-yuyang.du@intel.com [ Fixed up the SOB chain. ] Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/fair: Rewrite runnable load and utilization average trackingYuyang Du2015-08-035-494/+249
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The idea of runnable load average (let runnable time contribute to weight) was proposed by Paul Turner and Ben Segall, and it is still followed by this rewrite. This rewrite aims to solve the following issues: 1. cfs_rq's load average (namely runnable_load_avg and blocked_load_avg) is updated at the granularity of an entity at a time, which results in the cfs_rq's load average is stale or partially updated: at any time, only one entity is up to date, all other entities are effectively lagging behind. This is undesirable. To illustrate, if we have n runnable entities in the cfs_rq, as time elapses, they certainly become outdated: t0: cfs_rq { e1_old, e2_old, ..., en_old } and when we update: t1: update e1, then we have cfs_rq { e1_new, e2_old, ..., en_old } t2: update e2, then we have cfs_rq { e1_old, e2_new, ..., en_old } ... We solve this by combining all runnable entities' load averages together in cfs_rq's avg, and update the cfs_rq's avg as a whole. This is based on the fact that if we regard the update as a function, then: w * update(e) = update(w * e) and update(e1) + update(e2) = update(e1 + e2), then w1 * update(e1) + w2 * update(e2) = update(w1 * e1 + w2 * e2) therefore, by this rewrite, we have an entirely updated cfs_rq at the time we update it: t1: update cfs_rq { e1_new, e2_new, ..., en_new } t2: update cfs_rq { e1_new, e2_new, ..., en_new } ... 2. cfs_rq's load average is different between top rq->cfs_rq and other task_group's per CPU cfs_rqs in whether or not blocked_load_average contributes to the load. The basic idea behind runnable load average (the same for utilization) is that the blocked state is taken into account as opposed to only accounting for the currently runnable state. Therefore, the average should include both the runnable/running and blocked load averages. This rewrite does that. In addition, we also combine runnable/running and blocked averages of all entities into the cfs_rq's average, and update it together at once. This is based on the fact that: update(runnable) + update(blocked) = update(runnable + blocked) This significantly reduces the code as we don't need to separately maintain/update runnable/running load and blocked load. 3. How task_group entities' share is calculated is complex and imprecise. We reduce the complexity in this rewrite to allow a very simple rule: the task_group's load_avg is aggregated from its per CPU cfs_rqs's load_avgs. Then group entity's weight is simply proportional to its own cfs_rq's load_avg / task_group's load_avg. To illustrate, if a task_group has { cfs_rq1, cfs_rq2, ..., cfs_rqn }, then, task_group_avg = cfs_rq1_avg + cfs_rq2_avg + ... + cfs_rqn_avg, then cfs_rqx's entity's share = cfs_rqx_avg / task_group_avg * task_group's share To sum up, this rewrite in principle is equivalent to the current one, but fixes the issues described above. Turns out, it significantly reduces the code complexity and hence increases clarity and efficiency. In addition, the new averages are more smooth/continuous (no spurious spikes and valleys) and updated more consistently and quickly to reflect the load dynamics. As a result, we have less load tracking overhead, better performance, and especially better power efficiency due to more balanced load. Signed-off-by: Yuyang Du <yuyang.du@intel.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> Cc: arjan@linux.intel.com Cc: bsegall@google.com Cc: dietmar.eggemann@arm.com Cc: fengguang.wu@intel.com Cc: len.brown@intel.com Cc: morten.rasmussen@arm.com Cc: pjt@google.com Cc: rafael.j.wysocki@intel.com Cc: umgwanakikbuti@gmail.com Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/1436918682-4971-3-git-send-email-yuyang.du@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/fair: Remove rq's runnable avgYuyang Du2015-08-033-29/+5
| | | | | | | | | | | | | | | | | | | | | | | | | The current rq->avg is not used at all since its merge into the kernel, and the code is in the scheduler's hot path, so remove it. Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: Yuyang Du <yuyang.du@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@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: arjan@linux.intel.com Cc: bsegall@google.com Cc: fengguang.wu@intel.com Cc: len.brown@intel.com Cc: morten.rasmussen@arm.com Cc: pjt@google.com Cc: rafael.j.wysocki@intel.com Cc: umgwanakikbuti@gmail.com Cc: vincent.guittot@linaro.org Link: http://lkml.kernel.org/r/1436918682-4971-2-git-send-email-yuyang.du@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* stop_machine: Remove cpu_stop_work's from list in cpu_stop_park()Oleg Nesterov2015-08-031-2/+4
| | | | | | | | | | | | | | | | | | | | | | cpu_stop_park() does cpu_stop_signal_done() but leaves the work on stopper->works. The owner of this work can free/reuse this memory right after that and corrupt the list, so if this CPU becomes online again cpu_stopper_thread() will crash. Signed-off-by: Oleg Nesterov <oleg@redhat.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: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dave@stgolabs.net Cc: der.herr@hofr.at Cc: paulmck@linux.vnet.ibm.com Cc: riel@redhat.com Cc: viro@ZenIV.linux.org.uk Link: http://lkml.kernel.org/r/20150630012958.GA23944@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* stop_machine: Use 'cpu_stop_fn_t' where possibleOleg Nesterov2015-08-032-8/+8
| | | | | | | | | | | | | | | | | | | | Cosmetic, but 'cpu_stop_fn_t' actually makes the code more readable and it doesn't break cscope. And most of the declarations already use it. Signed-off-by: Oleg Nesterov <oleg@redhat.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: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dave@stgolabs.net Cc: der.herr@hofr.at Cc: paulmck@linux.vnet.ibm.com Cc: riel@redhat.com Cc: viro@ZenIV.linux.org.uk Link: http://lkml.kernel.org/r/20150630012955.GA23937@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* stop_machine: Unexport __stop_machine()Oleg Nesterov2015-08-033-22/+4
| | | | | | | | | | | | | | | | | | | | The only caller outside of stop_machine.c is _cpu_down(), it can use stop_machine(). get_online_cpus() is fine under cpu_hotplug_begin(). Signed-off-by: Oleg Nesterov <oleg@redhat.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: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dave@stgolabs.net Cc: der.herr@hofr.at Cc: paulmck@linux.vnet.ibm.com Cc: riel@redhat.com Cc: viro@ZenIV.linux.org.uk Link: http://lkml.kernel.org/r/20150630012951.GA23934@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* stop_machine: Don't do for_each_cpu() twice in queue_stop_cpus_work()Oleg Nesterov2015-08-031-10/+7
| | | | | | | | | | | | | | | | | | | queue_stop_cpus_work() can do everything in one for_each_cpu() loop. Signed-off-by: Oleg Nesterov <oleg@redhat.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: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dave@stgolabs.net Cc: der.herr@hofr.at Cc: paulmck@linux.vnet.ibm.com Cc: riel@redhat.com Cc: viro@ZenIV.linux.org.uk Link: http://lkml.kernel.org/r/20150630012948.GA23927@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* stop_machine: Move 'cpu_stopper_task' and 'stop_cpus_work' into 'struct ↵Oleg Nesterov2015-08-031-8/+9
| | | | | | | | | | | | | | | | | | | | | | cpu_stopper' Multpiple DEFINE_PER_CPU's do not make sense, move all the per-cpu variables into 'struct cpu_stopper'. Signed-off-by: Oleg Nesterov <oleg@redhat.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: Tejun Heo <tj@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: dave@stgolabs.net Cc: der.herr@hofr.at Cc: paulmck@linux.vnet.ibm.com Cc: riel@redhat.com Cc: viro@ZenIV.linux.org.uk Link: http://lkml.kernel.org/r/20150630012944.GA23924@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/preempt: Fix cond_resched_lock() and cond_resched_softirq()Konstantin Khlebnikov2015-08-035-18/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | These functions check should_resched() before unlocking spinlock/bh-enable: preempt_count always non-zero => should_resched() always returns false. cond_resched_lock() worked iff spin_needbreak is set. This patch adds argument "preempt_offset" to should_resched(). preempt_count offset constants for that: PREEMPT_DISABLE_OFFSET - offset after preempt_disable() PREEMPT_LOCK_OFFSET - offset after spin_lock() SOFTIRQ_DISABLE_OFFSET - offset after local_bh_distable() SOFTIRQ_LOCK_OFFSET - offset after spin_lock_bh() Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Graf <agraf@suse.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: bdb438065890 ("sched: Extract the basic add/sub preempt_count modifiers") Link: http://lkml.kernel.org/r/20150715095204.12246.98268.stgit@buzz Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/preempt, powerpc, kvm: Use need_resched() instead of should_resched()Konstantin Khlebnikov2015-08-031-1/+1
| | | | | | | | | | | | | | | | | | Function should_resched() is equal to (!preempt_count() && need_resched()). In preemptive kernel preempt_count here is non-zero because of vc->lock. Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Graf <agraf@suse.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150715095203.12246.72922.stgit@buzz Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/preempt, xen: Use need_resched() instead of should_resched()Konstantin Khlebnikov2015-08-031-1/+1
| | | | | | | | | | | | | | | | | | | This code is used only when CONFIG_PREEMPT=n and only in non-atomic context: xen_in_preemptible_hcall is set only in privcmd_ioctl_hypercall(). Thus preempt_count is zero and should_resched() is equal to need_resched(). Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Graf <agraf@suse.de> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150715095201.12246.49283.stgit@buzz Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/fair: Beef up wake_wide()Mike Galbraith2015-08-032-36/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | Josef Bacik reported that Facebook sees better performance with their 1:N load (1 dispatch/node, N workers/node) when carrying an old patch to try very hard to wake to an idle CPU. While looking at wake_wide(), I noticed that it doesn't pay attention to the wakeup of a many partner waker, returning 1 only when waking one of its many partners. Correct that, letting explicit domain flags override the heuristic. While at it, adjust task_struct bits, we don't need a 64-bit counter. Tested-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com> [ Tidy things up. ] 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: kernel-team<Kernel-team@fb.com> Cc: morten.rasmussen@arm.com Cc: riel@redhat.com Link: http://lkml.kernel.org/r/1436888390.7983.49.camel@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched: Introduce the 'trace_sched_waking' tracepointPeter Zijlstra2015-08-034-14/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Mathieu reported that since 317f394160e9 ("sched: Move the second half of ttwu() to the remote cpu") trace_sched_wakeup() can happen out of context of the waker. This is a problem when you want to analyse wakeup paths because it is now very hard to correlate the wakeup event to whoever issued the wakeup. OTOH trace_sched_wakeup() is issued at the point where we set p->state = TASK_RUNNING, which is right were we hand the task off to the scheduler, so this is an important point when looking at scheduling behaviour, up to here its been the wakeup path everything hereafter is due to scheduler policy. To bridge this gap, introduce a second tracepoint: trace_sched_waking. It is guaranteed to be called in the waker context. Reported-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Francis Giraldeau <francis.giraldeau@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150609091336.GQ3644@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/cputime: Guarantee stime + utime == rtimePeter Zijlstra2015-08-034-61/+97
| | | | | | | | | | | | | | | | | | | | | | | | | | | While the current code guarantees monotonicity for stime and utime independently of one another, it does not guarantee that the sum of both is equal to the total time we started out with. This confuses things (and peoples) who look at this sum, like top, and will report >100% usage followed by a matching period of 0%. Rework the code to provide both individual monotonicity and a coherent sum. Suggested-by: Fredrik Markstrom <fredrik.markstrom@gmail.com> Reported-by: Fredrik Markstrom <fredrik.markstrom@gmail.com> Tested-by: Fredrik Markstrom <fredrik.markstrom@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rik van Riel <riel@redhat.com> Cc: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: jason.low2@hp.com Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched, sysctl: Delete an unnecessary check before unregister_sysctl_table()Markus Elfring2015-08-031-2/+1
| | | | | | | | | | | | | | | | The unregister_sysctl_table() function tests whether its argument is NULL and then returns immediately. Thus the test around the call is not needed. This issue was detected by using the Coccinelle software. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> 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/5597877E.3060503@users.sourceforge.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/deadline: Remove a redundant condition from task_woken_dl()Xunlei Pang2015-08-031-1/+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>
* sched/rt: Remove a redundant condition from task_woken_rt()Xunlei Pang2015-08-031-1/+0
| | | | | | | | | | | | | | | | | 'p' has been already queued at this point, so "!task_running(rq, p)" and "p->nr_cpus_allowed > 1" imply that "has_pushable_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/1435995563-3723-1-git-send-email-xlpang@126.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/fair: Avoid pulling all tasks in idle balancingYuyang Du2015-08-031-0/+7
| | | | | | | | | | | | | | | | | | | | In idle balancing where a CPU going idle pulls tasks from another CPU, a livelock may happen if the CPU pulls all tasks from another, makes it idle, and this iterates. So just avoid this. Reported-by: Rabin Vincent <rabin.vincent@axis.com> Signed-off-by: Yuyang Du <yuyang.du@intel.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Ben Segall <bsegall@google.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Mike Galbraith <umgwanakikbuti@gmail.com> Cc: Morten Rasmussen <morten.rasmussen@arm.com> Cc: Paul Turner <pjt@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150705221151.GF5197@intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/idle: Move latency tracing stop/start calls deeper inside the idle loopLucas Stach2015-07-212-9/+9
| | | | | | | | | | | | | | | | | | | | | | | | Make sure to stop tracing only once we are past a point where all latency tracing events have been processed (irqs are not enabled again). This has the slight advantage of capturing more latency related events in the idle path, but most importantly it makes sure that latency tracing doesn't get re-enabled inadvertently when new events are coming in. This makes the irqsoff latency tracer useful again, as we stop capturing CPU sleep time as IRQ latency. Signed-off-by: Lucas Stach <l.stach@pengutronix.de> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: kernel@pengutronix.de Cc: patchwork-lst@pengutronix.de Link: http://lkml.kernel.org/r/1437410090-3747-1-git-send-email-l.stach@pengutronix.de Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/fair: Fix a comment reflecting function name changeByungchul Park2015-07-071-1/+1
| | | | | | | | | | | | | update_cfs_rq_load_contribution() was changed to __update_cfs_rq_tg_load_contrib() - sync up the commit in calc_tg_weight() too. Signed-off-by: Byungchul Park <byungchul.park@lge.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/1436187062-19658-1-git-send-email-byungchul.park@lge.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/fair: Clean up the __sched_period() codeBoqun Feng2015-07-071-9/+4
| | | | | | | | | | | | | | | | | | | Since commit: 4bf0b77158 ("sched: remove do_div() from __sched_slice()") ... the logic of __sched_period() can be implemented as a single if-else without any local variables, so this patch cleans it up with an if-else statement, which expresses the function's logic straightforwardly. Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> 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/1435847152-29543-1-git-send-email-boqun.feng@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/numa: Consider 'imbalance_pct' when comparing loads in numa_has_capacity()Srikar Dronamraju2015-07-071-2/+3
| | | | | | | | | | | | | | | | | This is consistent with all other load balancing instances where we absorb unfairness upto env->imbalance_pct. Absorbing unfairness upto env->imbalance_pct allows to pull and retain task to their preferred nodes. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Rik van Riel <riel@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1434455762-30857-3-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/numa: Prefer NUMA hotness over cache hotnessSrikar Dronamraju2015-07-072-77/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The current load balancer may not try to prevent a task from moving out of a preferred node to a less preferred node. The reason for this being: - Since sched features NUMA and NUMA_RESIST_LOWER are disabled by default, migrate_degrades_locality() always returns false. - Even if NUMA_RESIST_LOWER were to be enabled, if its cache hot, migrate_degrades_locality() never gets called. The above behaviour can mean that tasks can move out of their preferred node but they may be eventually be brought back to their preferred node by numa balancer (due to higher numa faults). To avoid the above, this commit merges migrate_degrades_locality() and migrate_improves_locality(). It also replaces 3 sched features NUMA, NUMA_FAVOUR_HIGHER and NUMA_RESIST_LOWER by a single sched feature NUMA. Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Rik van Riel <riel@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Mike Galbraith <efault@gmx.de> Link: http://lkml.kernel.org/r/1434455762-30857-2-git-send-email-srikar@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/numa: Check sched_feat(NUMA) in migrate_improves_locality()bsegall@google.com2015-07-071-2/+2
| | | | | | | | | | | | | | | migrate_improves_locality checked sched_feat(NUMA_FAVOUR_HIGHER) but not sched_feat(NUMA), so disabling just the NUMA feature would leave it working off of old data. Signed-off-by: Ben Segall <bsegall@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/xm26si9rtqbm.fsf@sword-of-the-dawn.mtv.corp.google.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* sched/fair: Test list head instead of list entry in throttle_cfs_rq()Cong Wang2015-07-061-1/+1
| | | | | | | | | | | | | | | | | | | | According to the comments, we need to test if this is the first throttled task, however, list_empty() tests on the entry cfs_rq->throttled_list, not the head, this is wrong. This is a bug because we don't re-init the list entry after removing it from the list, so list_empty() could return false even if the list is really empty. Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com> Signed-off-by: Cong Wang <cwang@twopensource.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Ben Segall <bsegall@google.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/1435174907-432-1-git-send-email-xiyou.wangcong@gmail.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
* Merge tag 'ext4_for_linus_stable' of ↵Linus Torvalds2015-07-055-21/+47
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4 Pull ext4 bugfixes from Ted Ts'o: "Bug fixes (all for stable kernels) for ext4: - address corner cases for indirect blocks->extent migration - fix reserved block accounting invalidate_page when page_size != block_size (i.e., ppc or 1k block size file systems) - fix deadlocks when a memcg is under heavy memory pressure - fix fencepost error in lazytime optimization" * tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: ext4: replace open coded nofail allocation in ext4_free_blocks() ext4: correctly migrate a file with a hole at the beginning ext4: be more strict when migrating to non-extent based file ext4: fix reservation release on invalidatepage for delalloc fs ext4: avoid deadlocks in the writeback path by using sb_getblk_gfp bufferhead: Add _gfp version for sb_getblk() ext4: fix fencepost error in lazytime optimization
| * ext4: replace open coded nofail allocation in ext4_free_blocks()Michal Hocko2015-07-051-11/+5
| | | | | | | | | | | | | | | | | | | | | | | | ext4_free_blocks is looping around the allocation request and mimics __GFP_NOFAIL behavior without any allocation fallback strategy. Let's remove the open coded loop and replace it with __GFP_NOFAIL. Without the flag the allocator has no way to find out never-fail requirement and cannot help in any way. Signed-off-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org
| * ext4: correctly migrate a file with a hole at the beginningEryu Guan2015-07-041-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently ext4_ind_migrate() doesn't correctly handle a file which contains a hole at the beginning of the file. This caused the migration to be done incorrectly, and then if there is a subsequent following delayed allocation write to the "hole", this would reclaim the same data blocks again and results in fs corruption. # assmuing 4k block size ext4, with delalloc enabled # skip the first block and write to the second block xfs_io -fc "pwrite 4k 4k" -c "fsync" /mnt/ext4/testfile # converting to indirect-mapped file, which would move the data blocks # to the beginning of the file, but extent status cache still marks # that region as a hole chattr -e /mnt/ext4/testfile # delayed allocation writes to the "hole", reclaim the same data block # again, results in i_blocks corruption xfs_io -c "pwrite 0 4k" /mnt/ext4/testfile umount /mnt/ext4 e2fsck -nf /dev/sda6 ... Inode 53, i_blocks is 16, should be 8. Fix? no ... Signed-off-by: Eryu Guan <guaneryu@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org
| * ext4: be more strict when migrating to non-extent based fileEryu Guan2015-07-031-1/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently the check in ext4_ind_migrate() is not enough before doing the real conversion: a) delayed allocated extents could bypass the check on eh->eh_entries and eh->eh_depth This can be demonstrated by this script xfs_io -fc "pwrite 0 4k" -c "pwrite 8k 4k" /mnt/ext4/testfile chattr -e /mnt/ext4/testfile where testfile has two extents but still be converted to non-extent based file format. b) only extent length is checked but not the offset, which would result in data lose (delalloc) or fs corruption (nodelalloc), because non-extent based file only supports at most (12 + 2^10 + 2^20 + 2^30) blocks This can be demostrated by xfs_io -fc "pwrite 5T 4k" /mnt/ext4/testfile chattr -e /mnt/ext4/testfile sync If delalloc is enabled, dmesg prints EXT4-fs warning (device dm-4): ext4_block_to_path:105: block 1342177280 > max in inode 53 EXT4-fs (dm-4): Delayed block allocation failed for inode 53 at logical offset 1342177280 with max blocks 1 with error 5 EXT4-fs (dm-4): This should not happen!! Data will be lost If delalloc is disabled, e2fsck -nf shows corruption Inode 53, i_size is 5497558142976, should be 4096. Fix? no Fix the two issues by a) forcing all delayed allocation blocks to be allocated before checking eh->eh_depth and eh->eh_entries b) limiting the last logical block of the extent is within direct map Signed-off-by: Eryu Guan <guaneryu@gmail.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org
| * ext4: fix reservation release on invalidatepage for delalloc fsLukas Czerner2015-07-031-3/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On delalloc enabled file system on invalidatepage operation in ext4_da_page_release_reservation() we want to clear the delayed buffer and remove the extent covering the delayed buffer from the extent status tree. However currently there is a bug where on the systems with page size > block size we will always remove extents from the start of the page regardless where the actual delayed buffers are positioned in the page. This leads to the errors like this: EXT4-fs warning (device loop0): ext4_da_release_space:1225: ext4_da_release_space: ino 13, to_free 1 with only 0 reserved data blocks This however can cause data loss on writeback time if the file system is in ENOSPC condition because we're releasing reservation for someones else delayed buffer. Fix this by only removing extents that corresponds to the part of the page we want to invalidate. This problem is reproducible by the following fio receipt (however I was only able to reproduce it with fio-2.1 or older. [global] bs=8k iodepth=1024 iodepth_batch=60 randrepeat=1 size=1m directory=/mnt/test numjobs=20 [job1] ioengine=sync bs=1k direct=1 rw=randread filename=file1:file2 [job2] ioengine=libaio rw=randwrite direct=1 filename=file1:file2 [job3] bs=1k ioengine=posixaio rw=randwrite direct=1 filename=file1:file2 [job5] bs=1k ioengine=sync rw=randread filename=file1:file2 [job7] ioengine=libaio rw=randwrite filename=file1:file2 [job8] ioengine=posixaio rw=randwrite filename=file1:file2 [job10] ioengine=mmap rw=randwrite bs=1k filename=file1:file2 [job11] ioengine=mmap rw=randwrite direct=1 filename=file1:file2 Signed-off-by: Lukas Czerner <lczerner@redhat.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Reviewed-by: Jan Kara <jack@suse.cz> Cc: stable@vger.kernel.org
| * ext4: avoid deadlocks in the writeback path by using sb_getblk_gfpNikolay Borisov2015-07-021-3/+3
| | | | | | | | | | | | | | | | | | Switch ext4 to using sb_getblk_gfp with GFP_NOFS added to fix possible deadlocks in the page writeback path. Signed-off-by: Nikolay Borisov <kernel@kyup.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org
| * bufferhead: Add _gfp version for sb_getblk()Nikolay Borisov2015-07-021-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | sb_getblk() is used during ext4 (and possibly other FSes) writeback paths. Sometimes such path require allocating memory and guaranteeing that such allocation won't block. Currently, however, there is no way to provide user flags for sb_getblk which could lead to deadlocks. This patch implements a sb_getblk_gfp with the only difference it can accept user-provided GFP flags. Signed-off-by: Nikolay Borisov <kernel@kyup.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org
| * ext4: fix fencepost error in lazytime optimizationTheodore Ts'o2015-07-011-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | Commit 8f4d8558391: "ext4: fix lazytime optimization" was not a complete fix. In the case where the inode number is a multiple of 16, and we could still end up updating an inode with dirty timestamps written to the wrong inode on disk. Oops. This can be easily reproduced by using generic/005 with a file system with metadata_csum and lazytime enabled. Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org
* | Linux 4.2-rc1v4.2-rc1Linus Torvalds2015-07-051-2/+2
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