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2015-09-18cgroup: generalize obtaining the handles of and notifying cgroup filesTejun Heo
cgroup core handles creations and removals of cgroup interface files as described by cftypes. There are cases where the handle for a given file instance is necessary, for example, to generate a file modified event. Currently, this is handled by explicitly matching the callback method pointer and storing the file handle manually in cgroup_add_file(). While this simple approach works for cgroup core files, it can't for controller interface files. This patch generalizes cgroup interface file handle handling. struct cgroup_file is defined and each cftype can optionally tell cgroup core to store the file handle by setting ->file_offset. A file handle remains accessible as long as the containing css is accessible. Both "cgroup.procs" and "cgroup.events" are converted to use the new generic mechanism instead of hooking directly into cgroup_add_file(). Also, cgroup_file_notify() which takes a struct cgroup_file and generates a file modified event on it is added and replaces explicit kernfs_notify() invocations. This generalizes cgroup file handle handling and allows controllers to generate file modified notifications. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org>
2015-09-18cgroup: restructure file creation / removal handlingTejun Heo
The file creation / removal path has always been a bit icky and the planned notification update requires css during file creation. Restructure as follows. * cgroup_addrm_files() now takes both @css and @cgrp and is only called directly by other file handling functions. * cgroup_populate/clear_dir() are replaced with css_populate/clear_dir() taking @css and @cgrp_override. @cgrp_override is used only when files needs to be created on / removed from a cgroup which isn't attached to @css which happens during subsystem rebinds. Subsystem loops are moved to the callers. * cgroup_add_file() now takes both @css and @cgrp. @css isn't used yet but will be used by the planned notification update. This patch doens't cause any behavior changes. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org>
2015-09-18cgroup: cosmetic updates to rebind_subsystems()Tejun Heo
* Use local variables @scgrp and @dcgrp for @src_root->cgrp and @dst_root->cgrp respectively. * Use initializers to set @src_root and @css in the inner bind loop. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org>
2015-09-18cgroup: make cgroup_addrm_files() clean up after itself on failuresTejun Heo
After a file creation failure, cgroup_addrm_files() it didn't remove the files which had already been created. When cgroup_populate_dir() is the caller, this is fine as the caller performs cleanup; however, for other callers, this may leave unactivated dangling files behind. As kernfs directory removals are recursive, this doesn't lead to permanent memory leak but it can, for example, fail future attempts to create those files again. There's no point in keeping around this sort of subtlety and it gets in the way of planned updates to file handling. This patch makes cgroup_addrm_files() clean up after itself on failures. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org>
2015-09-18cgroup: relocate cgroup_populate_dir()Tejun Heo
Move it upwards so that it's right below cgroup_clear_dir() and the forward declaration is unnecessary. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org>
2015-09-18cgroup: replace cftype->mode with CFTYPE_WORLD_WRITABLETejun Heo
cftype->mode allows controllers to give arbitrary permissions to interface knobs. Except for "cgroup.event_control", the existing uses are spurious. * Some explicitly specify S_IRUGO | S_IWUSR even though that's the default. * "cpuset.memory_pressure" specifies S_IRUGO while also setting a write callback which returns -EACCES. All it needs to do is simply not setting a write callback. "cgroup.event_control" uses cftype->mode to make the file world-writable. It's a misdesigned interface and we don't want controllers to be tweaking interface file permissions in general. This patch removes cftype->mode and all its spurious uses and implements CFTYPE_WORLD_WRITABLE for "cgroup.event_control" which is marked as compatibility-only. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org>
2015-09-18cgroup: replace "cgroup.populated" with "cgroup.events"Tejun Heo
memcg already uses "memory.events" for event reporting and other controllers may need event reporting too. Let's standardize on "$SUBSYS.events" interface file for reporting events which don't happen too frequently and thus can share event notification. "cgroup.populated" is replaced with "populated" field in "cgroup.events" and documentation is updated accordingly. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Li Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org>
2015-09-18Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvmLinus Torvalds
Pull KVM fixes from Paolo Bonzini: "Mostly stable material, a lot of ARM fixes" * tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (22 commits) sched: access local runqueue directly in single_task_running arm/arm64: KVM: Remove 'config KVM_ARM_MAX_VCPUS' arm64: KVM: Remove all traces of the ThumbEE registers arm: KVM: Disable virtual timer even if the guest is not using it arm64: KVM: Disable virtual timer even if the guest is not using it arm/arm64: KVM: vgic: Check for !irqchip_in_kernel() when mapping resources KVM: s390: Replace incorrect atomic_or with atomic_andnot arm: KVM: Fix incorrect device to IPA mapping arm64: KVM: Fix user access for debug registers KVM: vmx: fix VPID is 0000H in non-root operation KVM: add halt_attempted_poll to VCPU stats kvm: fix zero length mmio searching kvm: fix double free for fast mmio eventfd kvm: factor out core eventfd assign/deassign logic kvm: don't try to register to KVM_FAST_MMIO_BUS for non mmio eventfd KVM: make the declaration of functions within 80 characters KVM: arm64: add workaround for Cortex-A57 erratum #852523 KVM: fix polling for guest halt continued even if disable it arm/arm64: KVM: Fix PSCI affinity info return value for non valid cores arm64: KVM: set {v,}TCR_EL2 RES1 bits ...
2015-09-18cgroup: replace cgroup_on_dfl() tests in controllers with cgroup_subsys_on_dfl()Tejun Heo
cgroup_on_dfl() tests whether the cgroup's root is the default hierarchy; however, an individual controller is only interested in whether the controller is attached to the default hierarchy and never tests a cgroup which doesn't belong to the hierarchy that the controller is attached to. This patch replaces cgroup_on_dfl() tests in controllers with faster static_key based cgroup_subsys_on_dfl(). This leaves cgroup core as the only user of cgroup_on_dfl() and the function is moved from the header file to cgroup.c. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Zefan Li <lizefan@huawei.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org>
2015-09-18cgroup: replace cgroup_subsys->disabled tests with cgroup_subsys_enabled()Tejun Heo
Replace cgroup_subsys->disabled tests in controllers with cgroup_subsys_enabled(). cgroup_subsys_enabled() requires literal subsys name as its parameter and thus can't be used for cgroup core which iterates through controllers. For cgroup core, introduce and use cgroup_ssid_enabled() which uses slower static_key_enabled() test and can be indexed by subsys ID. This leaves cgroup_subsys->disabled unused. Removed. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Zefan Li <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org>
2015-09-18cgroup: implement static_key based cgroup_subsys_enabled() and ↵Tejun Heo
cgroup_subsys_on_dfl() Whether a subsys is enabled and attached to the default hierarchy seldom changes and may be tested in the hot paths. This patch implements static_key based cgroup_subsys_enabled() and cgroup_subsys_on_dfl() tests. The following patches will update the users and remove duplicate mechanisms. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Zefan Li <lizefan@huawei.com>
2015-09-18Merge branch 'irq-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull irq updates from Thomas Gleixner: "This is a rather large update post rc1 due to the final steps of cleanups and API changes which had to wait for the preparatory patches to hit your tree. - Regression fixes for ARM GIC irqchips - Regression fixes and lockdep anotations for renesas irq chips - The leftovers of the cleanup and preparatory patches which have been ignored by maintainers - Final conversions of the newly merged users of obsolete APIs - Final removal of obsolete APIs - Final removal of ARM artifacts which had been introduced during the conversion of ARM to the generic interrupt code. - Final split of the irq_data into chip specific and common data to reflect the needs of hierarchical irq domains. - Treewide removal of the first argument of interrupt flow handlers, i.e. the irq number, which is not used by the majority of handlers and simple to retrieve from the other argument the irq descriptor. - A few comment updates and build warning fixes" * 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (40 commits) arm64: Remove ununsed set_irq_flags ARM: Remove ununsed set_irq_flags sh: Kill off set_irq_flags usage irqchip: Kill off set_irq_flags usage gpu/drm: Kill off set_irq_flags usage genirq: Remove irq argument from irq flow handlers genirq: Move field 'msi_desc' from irq_data into irq_common_data genirq: Move field 'affinity' from irq_data into irq_common_data genirq: Move field 'handler_data' from irq_data into irq_common_data genirq: Move field 'node' from irq_data into irq_common_data irqchip/gic-v3: Use IRQD_FORWARDED_TO_VCPU flag irqchip/gic: Use IRQD_FORWARDED_TO_VCPU flag genirq: Provide IRQD_FORWARDED_TO_VCPU status flag genirq: Simplify irq_data_to_desc() genirq: Remove __irq_set_handler_locked() pinctrl/pistachio: Use irq_set_handler_locked gpio: vf610: Use irq_set_handler_locked powerpc/mpc8xx: Use irq_set_handler_locked() powerpc/ipic: Use irq_set_handler_locked() powerpc/cpm2: Use irq_set_handler_locked() ...
2015-09-18sched: access local runqueue directly in single_task_runningDominik Dingel
Commit 2ee507c47293 ("sched: Add function single_task_running to let a task check if it is the only task running on a cpu") referenced the current runqueue with the smp_processor_id. When CONFIG_DEBUG_PREEMPT is enabled, that is only allowed if preemption is disabled or the currrent task is bound to the local cpu (e.g. kernel worker). With commit f78195129963 ("kvm: add halt_poll_ns module parameter") KVM calls single_task_running. If CONFIG_DEBUG_PREEMPT is enabled that generates a lot of kernel messages. To avoid adding preemption in that cases, as it would limit the usefulness, we change single_task_running to access directly the cpu local runqueue. Cc: Tim Chen <tim.c.chen@linux.intel.com> Suggested-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: <stable@vger.kernel.org> Fixes: 2ee507c472939db4b146d545352b8a7c79ef47f8 Signed-off-by: Dominik Dingel <dingel@linux.vnet.ibm.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2015-09-18locking/pvqspinlock: Kick the PV CPU unconditionally when _Q_SLOW_VALWaiman Long
If _Q_SLOW_VAL has been set, the vCPU state must have been vcpu_hashed. The extra check at the end of __pv_queued_spin_unlock() is unnecessary and can be removed. Signed-off-by: Waiman Long <Waiman.Long@hpe.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Douglas Hatch <doug.hatch@hp.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Scott J Norton <scott.norton@hp.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1441996658-62854-3-git-send-email-Waiman.Long@hpe.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-18locking/osq: Relax atomic semanticsDavidlohr Bueso
... by using acquire/release for ops around the lock->tail. As such, weakly ordered archs can benefit from more relaxed use of barriers when issuing atomics. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <Waiman.Long@hpe.com> Link: http://lkml.kernel.org/r/1442216244-4409-3-git-send-email-dave@stgolabs.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-18locking/qrwlock: Rename ->lock to ->wait_lockDavidlohr Bueso
... trivial, but reads a little nicer when we name our actual primitive 'lock'. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Waiman Long <Waiman.Long@hpe.com> Link: http://lkml.kernel.org/r/1442216244-4409-1-git-send-email-dave@stgolabs.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-18Merge branch 'perf/urgent' into perf/core, to pick up fixes before applying ↵Ingo Molnar
new changes Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-18sched/fair: Remove unnecessary parameter for group_classify()Leo Yan
The group_classify() function does not use the "env" parameter, so remove it. Also unify code to always use group_classify() to calculate group's load type. Signed-off-by: Leo Yan <leo.yan@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1442314605-14838-1-git-send-email-leo.yan@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-18sched/fair: Polish comments for LOAD_AVG_MAXLeo Yan
Macro LOAD_AVG_MAX is defined far away from the precompuated tables for decay calculation in code; So explicitly comments for this. Also fix one typo: s/LOAD_MAX_AVG/LOAD_AVG_MAX. Signed-off-by: Leo Yan <leo.yan@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1442314657-14949-1-git-send-email-leo.yan@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-18sched/numa: Limit the amount of virtual memory scanned in task_numa_work()Rik van Riel
Currently task_numa_work() scans up to numa_balancing_scan_size_mb worth of memory per invocation, but only counts memory areas that have at least one PTE that is still present and not marked for numa hint faulting. It will skip over arbitarily large amounts of memory that are either unused, full of swap ptes, or full of PTEs that were already marked for NUMA hint faults but have not been faulted on yet. This can cause excessive amounts of CPU use, due to there being essentially no upper limit on the scan rate of very large processes that are not yet in a phase where they are actively accessing old memory pages (eg. they are still initializing their data). Avoid that problem by placing an upper limit on the amount of virtual memory that task_numa_work() scans in each invocation. This can be a higher limit than "pages", to ensure the task still skips over unused areas fairly quickly. While we are here, also fix the "nr_pte_updates" logic, so it only counts page ranges with ptes in them. Reported-by: Andrea Arcangeli <aarcange@redhat.com> Reported-by: Jan Stancek <jstancek@redhat.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20150911090027.4a7987bd@annuminas.surriel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-18sched/core: Make policy-testing consistentHenrik Austad
Most of the policy-tests are done via the <class>_policy() helpers with the notable exception of idle. A new wrapper for valid_policy() has also been added to improve readability in set_load_weight(). This commit does not change the logical behavior of the scheduler core. Signed-off-by: Henrik Austad <henrik@austad.us> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/1441810841-4756-1-git-send-email-henrik@austad.us Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-18Merge branch 'linus' into sched/core, to pick up fixes before applying new ↵Ingo Molnar
changes Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-18perf: Fix races in computing the header sizesPeter Zijlstra
There are two races with the current code: - Another event can join the group and compute a larger header_size concurrently, if the smaller store wins we'll have an incorrect header_size set. - We compute the header_size after the event becomes active, therefore its possible to use the size before its computed. Remedy the first by moving the computation inside the ctx::mutex lock, and the second by placing it _before_ perf_install_in_context(). Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-18perf: Fix u16 overflowsPeter Zijlstra
Vince reported that its possible to overflow the various size fields and get weird stuff if you stick too many events in a group. Put a lid on this by requiring the fixed record size not exceed 16k. This is still a fair amount of events (silly amount really) and leaves plenty room for callchains and stack dwarves while also avoiding overflowing the u16 variables. Reported-by: Vince Weaver <vincent.weaver@maine.edu> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-18perf: Restructure perf syscall point of no returnPeter Zijlstra
The exclusive_event_installable() stuff only works because its exclusive with the grouping bits. Rework the code such that there is a sane place to error out before we go do things we cannot undo. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-18sched: Fix crash trying to dequeue/enqueue the idle threadPeter Zijlstra
Sasha reports that his virtual machine tries to schedule the idle thread since commit 6c37067e2786 ("sched: Change the sched_class::set_cpus_allowed() calling context"). Hit trace shows this happening from idle_thread_get()->init_idle(), which is the _second_ init_idle() invocation on that task_struct, the first being done through idle_init()->fork_idle(). (this code is insane...) Because we call init_idle() twice in a row, its ->sched_class == &idle_sched_class and ->on_rq = TASK_ON_RQ_QUEUED. This means do_set_cpus_allowed() think we're queued and will call dequeue_task(), which is implemented with BUG() for the idle class, seeing how dequeueing the idle task is a daft thing. Aside of the whole insanity of calling init_idle() _twice_, change the code to call set_cpus_allowed_common() instead as this is 'obviously' before the idle task gets ran etc.. Reported-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Fixes: 6c37067e2786 ("sched: Change the sched_class::set_cpus_allowed() calling context") Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-17Merge branch 'timers-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull timer fixes from Ingo Molnar: "A fix for an abs()/abs64() bug that caused too slow NTP convergence on 32-bit kernels, plus a removal of an obsolete clockevents driver facility after all users got converted during the merge window" * 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: clockevents: Remove unused set_mode() callback time: Fix timekeeping_freqadjust()'s incorrect use of abs() instead of abs64()
2015-09-17Merge branch 'sched-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull scheduler fixes from Ingo Molnar: "A migrate_tasks() locking fix, and a late-coming nohz change plus a nohz debug check" * 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: sched: 'Annotate' migrate_tasks() nohz: Assert existing housekeepers when nohz full enabled nohz: Affine unpinned timers to housekeepers
2015-09-17Merge branch 'locking-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking fixes from Ingo Molnar: "Spinlock performance regression fix, plus documentation fixes" * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: locking/static_keys: Fix up the static keys documentation locking/qspinlock/x86: Only emit the test-and-set fallback when building guest support locking/qspinlock/x86: Fix performance regression under unaccelerated VMs locking/static_keys: Fix a silly typo
2015-09-16cgroup: simplify threadgroup lockingTejun Heo
Note: This commit was originally committed as b5ba75b5fc0e but got reverted by f9f9e7b77614 due to the performance regression from the percpu_rwsem write down/up operations added to cgroup task migration path. percpu_rwsem changes which alleviate the performance issue are pending for v4.4-rc1 merge window. Re-apply. Now that threadgroup locking is made global, code paths around it can be simplified. * lock-verify-unlock-retry dancing removed from __cgroup_procs_write(). * Race protection against de_thread() removed from cgroup_update_dfl_csses(). Signed-off-by: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/g/55F8097A.7000206@de.ibm.com
2015-09-16sched, cgroup: replace signal_struct->group_rwsem with a global percpu_rwsemTejun Heo
Note: This commit was originally committed as d59cfc09c32a but got reverted by 0c986253b939 due to the performance regression from the percpu_rwsem write down/up operations added to cgroup task migration path. percpu_rwsem changes which alleviate the performance issue are pending for v4.4-rc1 merge window. Re-apply. The cgroup side of threadgroup locking uses signal_struct->group_rwsem to synchronize against threadgroup changes. This per-process rwsem adds small overhead to thread creation, exit and exec paths, forces cgroup code paths to do lock-verify-unlock-retry dance in a couple places and makes it impossible to atomically perform operations across multiple processes. This patch replaces signal_struct->group_rwsem with a global percpu_rwsem cgroup_threadgroup_rwsem which is cheaper on the reader side and contained in cgroups proper. This patch converts one-to-one. This does make writer side heavier and lower the granularity; however, cgroup process migration is a fairly cold path, we do want to optimize thread operations over it and cgroup migration operations don't take enough time for the lower granularity to matter. Signed-off-by: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/g/55F8097A.7000206@de.ibm.com Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org>
2015-09-16Revert "sched, cgroup: replace signal_struct->group_rwsem with a global ↵Tejun Heo
percpu_rwsem" This reverts commit d59cfc09c32a2ae31f1c3bc2983a0cd79afb3f14. d59cfc09c32a ("sched, cgroup: replace signal_struct->group_rwsem with a global percpu_rwsem") and b5ba75b5fc0e ("cgroup: simplify threadgroup locking") changed how cgroup synchronizes against task fork and exits so that it uses global percpu_rwsem instead of per-process rwsem; unfortunately, the write [un]lock paths of percpu_rwsem always involve synchronize_rcu_expedited() which turned out to be too expensive. Improvements for percpu_rwsem are scheduled to be merged in the coming v4.4-rc1 merge window which alleviates this issue. For now, revert the two commits to restore per-process rwsem. They will be re-applied for the v4.4-rc1 merge window. Signed-off-by: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/g/55F8097A.7000206@de.ibm.com Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: stable@vger.kernel.org # v4.2+
2015-09-16Revert "cgroup: simplify threadgroup locking"Tejun Heo
This reverts commit b5ba75b5fc0e8404e2c50cb68f39bb6a53fc916f. d59cfc09c32a ("sched, cgroup: replace signal_struct->group_rwsem with a global percpu_rwsem") and b5ba75b5fc0e ("cgroup: simplify threadgroup locking") changed how cgroup synchronizes against task fork and exits so that it uses global percpu_rwsem instead of per-process rwsem; unfortunately, the write [un]lock paths of percpu_rwsem always involve synchronize_rcu_expedited() which turned out to be too expensive. Improvements for percpu_rwsem are scheduled to be merged in the coming v4.4-rc1 merge window which alleviates this issue. For now, revert the two commits to restore per-process rwsem. They will be re-applied for the v4.4-rc1 merge window. Signed-off-by: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/g/55F8097A.7000206@de.ibm.com Reported-by: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: stable@vger.kernel.org # v4.2+
2015-09-16genirq: Remove irq argument from irq flow handlersThomas Gleixner
Most interrupt flow handlers do not use the irq argument. Those few which use it can retrieve the irq number from the irq descriptor. Remove the argument. Search and replace was done with coccinelle and some extra helper scripts around it. Thanks to Julia for her help! Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Julia Lawall <Julia.Lawall@lip6.fr> Cc: Jiang Liu <jiang.liu@linux.intel.com>
2015-09-16genirq: Move field 'msi_desc' from irq_data into irq_common_dataJiang Liu
MSI descriptors are per-irq instead of per irqchip, so move it into struct irq_common_data. Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Jason Cooper <jason@lakedaemon.net> Cc: Kevin Cernekee <cernekee@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Marc Zyngier <marc.zyngier@arm.com> Link: http://lkml.kernel.org/r/1433145945-789-35-git-send-email-jiang.liu@linux.intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-09-16genirq: Move field 'affinity' from irq_data into irq_common_dataJiang Liu
Irq affinity mask is per-irq instead of per irqchip, so move it into struct irq_common_data. Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Jason Cooper <jason@lakedaemon.net> Cc: Kevin Cernekee <cernekee@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Link: http://lkml.kernel.org/r/1433303281-27688-1-git-send-email-jiang.liu@linux.intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-09-16genirq: Move field 'handler_data' from irq_data into irq_common_dataJiang Liu
Handler data (handler_data) is per-irq instead of per irqchip, so move it into struct irq_common_data. Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Jason Cooper <jason@lakedaemon.net> Cc: Kevin Cernekee <cernekee@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Marc Zyngier <marc.zyngier@arm.com> Link: http://lkml.kernel.org/r/1433145945-789-13-git-send-email-jiang.liu@linux.intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-09-16genirq: Move field 'node' from irq_data into irq_common_dataJiang Liu
NUMA node information is per-irq instead of per-irqchip, so move it into struct irq_common_data. Also use CONFIG_NUMA to guard irq_common_data.node. Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Tony Luck <tony.luck@intel.com> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Jason Cooper <jason@lakedaemon.net> Cc: Kevin Cernekee <cernekee@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Link: http://lkml.kernel.org/r/1433145945-789-8-git-send-email-jiang.liu@linux.intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2015-09-16PM / sleep: Report interrupt that caused system wakeupAlexandra Yates
Add a sysfs attribute, /sys/power/pm_wakeup_irq, reporting the IRQ number of the first wakeup interrupt (that is, the first interrupt from an IRQ line armed for system wakeup) seen by the kernel during the most recent system suspend/resume cycle. This feature will be useful for system wakeup diagnostics of spurious wakeup interrupts. Signed-off-by: Alexandra Yates <alexandra.yates@linux.intel.com> [ rjw: Fixed up pm_wakeup_irq definition ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-09-14clockevents: Remove unused set_mode() callbackViresh Kumar
All users are migrated to the per-state callbacks, get rid of the unused interface and the core support code. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linaro-kernel@lists.linaro.org Cc: John Stultz <john.stultz@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/fd60de14cf6d125489c031207567bb255ad946f6.1441943991.git.viresh.kumar@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13perf/core: Define PERF_PMU_TXN_READ interfaceSukadev Bhattiprolu
Define a new PERF_PMU_TXN_READ interface to read a group of counters at once. pmu->start_txn() // Initialize before first event for each event in group pmu->read(event); // Queue each event to be read rc = pmu->commit_txn() // Read/update all queued counters Note that we use this interface with all PMUs. PMUs that implement this interface use the ->read() operation to _queue_ the counters to be read and use ->commit_txn() to actually read all the queued counters at once. PMUs that don't implement PERF_PMU_TXN_READ ignore ->start_txn() and ->commit_txn() and continue to read counters one at a time. Thanks to input from Peter Zijlstra. Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Link: http://lkml.kernel.org/r/1441336073-22750-9-git-send-email-sukadev@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13perf/core: Add return value for perf_event_read()Sukadev Bhattiprolu
When we implement the ability to read several counters at once (using the PERF_PMU_TXN_READ transaction interface), perf_event_read() can fail when the 'group' parameter is true (eg: trying to read too many events at once). For now, have perf_event_read() return an integer. Ignore the return value when the 'group' parameter is false. Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Link: http://lkml.kernel.org/r/1441336073-22750-8-git-send-email-sukadev@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13perf/core: Invert perf_read_group() loopsPeter Zijlstra
In order to enable the use of perf_event_read(.group = true), we need to invert the sibling-child loop nesting of perf_read_group(). Currently we iterate the child list for each sibling, this precludes using group reads. Flip things around so we iterate each group for each child. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> [ Made the patch compile and things. ] Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Link: http://lkml.kernel.org/r/1441336073-22750-7-git-send-email-sukadev@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13perf/core: Add group reads to perf_event_read()Peter Zijlstra
Enable perf_event_read() to update entire groups at once, this will be useful for read transactions. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Link: http://lkml.kernel.org/r/20150723080435.GE25159@twins.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13perf/core: Rename perf_event_read_{one,group}, perf_read_hwPeter Zijlstra (Intel)
In order to free up the perf_event_read_group() name: s/perf_event_read_\(one\|group\)/perf_read_\1/g s/perf_read_hw/__perf_read/g Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Link: http://lkml.kernel.org/r/1441336073-22750-5-git-send-email-sukadev@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13perf/core: Split perf_event_read() and perf_event_count()Sukadev Bhattiprolu
perf_event_read() does two things: - call the PMU to read/update the counter value, and - compute the total count of the event and its children Not all callers need both. perf_event_reset() for instance needs the first piece but doesn't need the second. Similarly, when we implement the ability to read a group of events using the transaction interface, we would need the two pieces done independently. Break up perf_event_read() and have it just read/update the counter and have the callers compute the total count if necessary. Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Link: http://lkml.kernel.org/r/1441336073-22750-4-git-send-email-sukadev@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13perf/core: Add a 'flags' parameter to the PMU transactional interfacesSukadev Bhattiprolu
Currently, the PMU interface allows reading only one counter at a time. But some PMUs like the 24x7 counters in Power, support reading several counters at once. To leveage this functionality, extend the transaction interface to support a "transaction type". The first type, PERF_PMU_TXN_ADD, refers to the existing transactions, i.e. used to _schedule_ all the events on the PMU as a group. A second transaction type, PERF_PMU_TXN_READ, will be used in a follow-on patch, by the 24x7 counters to read several counters at once. Extend the transaction interfaces to the PMU to accept a 'txn_flags' parameter and use this parameter to ignore any transactions that are not of type PERF_PMU_TXN_ADD. Thanks to Peter Zijlstra for his input. Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> [peterz: s390 compile fix] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Michael Ellerman <mpe@ellerman.id.au> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Link: http://lkml.kernel.org/r/1441336073-22750-3-git-send-email-sukadev@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13perf/core: Delete PF_EXITING checks from perf_cgroup_exit() callbackKirill Tkhai
cgroup_exit() is not called from copy_process() after commit: e8604cb43690 ("cgroup: fix spurious lockdep warning in cgroup_exit()") from do_exit(). So this check is useless and the comment is obsolete. Signed-off-by: Kirill Tkhai <ktkhai@odin.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Link: http://lkml.kernel.org/r/55E444C8.3020402@odin.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13time: Fix timekeeping_freqadjust()'s incorrect use of abs() instead of abs64()John Stultz
The internal clocksteering done for fine-grained error correction uses a logarithmic approximation, so any time adjtimex() adjusts the clock steering, timekeeping_freqadjust() quickly approximates the correct clock frequency over a series of ticks. Unfortunately, the logic in timekeeping_freqadjust(), introduced in commit: dc491596f639 ("timekeeping: Rework frequency adjustments to work better w/ nohz") used the abs() function with a s64 error value to calculate the size of the approximated adjustment to be made. Per include/linux/kernel.h: "abs() should not be used for 64-bit types (s64, u64, long long) - use abs64()". Thus on 32-bit platforms, this resulted in the clocksteering to take a quite dampended random walk trying to converge on the proper frequency, which caused the adjustments to be made much slower then intended (most easily observed when large adjustments are made). This patch fixes the issue by using abs64() instead. Reported-by: Nuno Gonçalves <nunojpg@gmail.com> Tested-by: Nuno Goncalves <nunojpg@gmail.com> Signed-off-by: John Stultz <john.stultz@linaro.org> Cc: <stable@vger.kernel.org> # v3.17+ Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Miroslav Lichvar <mlichvar@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Prarit Bhargava <prarit@redhat.com> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1441840051-20244-1-git-send-email-john.stultz@linaro.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-09-13sched/fair: Optimize per entity utilization trackingPeter Zijlstra
Currently the load_{sum,avg} and util_{sum,avg} tracking is asymmetric in that load tracking gets a 2^10 unit from the weight, but util gets no such factor. This results in more lost bits for util scaling and asymmetric scaling rules. Fix this by removing shifts, such that we gain the 2^10 factor from scaling. There is no risk of overflowing the u32 as the max value is now LOAD_AVG_MAX << 10, which is still well below UINT_MAX. This further entangles the assumption that both LOAD and CAPACITY shifts are the same (and 10) so put in an assertion for that. This fixes the math for the LOAD_RESOLUTION != 0 case. 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>