- 19 5月, 2014 3 次提交
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由 Peter Zijlstra 提交于
Alexander noticed that we use RCU iteration on rb->event_list but do not use list_{add,del}_rcu() to add,remove entries to that list, nor do we observe proper grace periods when re-using the entries. Merge ring_buffer_detach() into ring_buffer_attach() such that attaching to the NULL buffer is detaching. Furthermore, ensure that between any 'detach' and 'attach' of the same event we observe the required grace period, but only when strictly required. In effect this means that only ioctl(.request = PERF_EVENT_IOC_SET_OUTPUT) will wait for a grace period, while the normal initial attach and final detach will not be delayed. This patch should, I think, do the right thing under all circumstances, the 'normal' cases all should never see the extra grace period, but the two cases: 1) PERF_EVENT_IOC_SET_OUTPUT on an event which already has a ring_buffer set, will now observe the required grace period between removing itself from the old and attaching itself to the new buffer. This case is 'simple' in that both buffers are present in perf_event_set_output() one could think an unconditional synchronize_rcu() would be sufficient; however... 2) an event that has a buffer attached, the buffer is destroyed (munmap) and then the event is attached to a new/different buffer using PERF_EVENT_IOC_SET_OUTPUT. This case is more complex because the buffer destruction does: ring_buffer_attach(.rb = NULL) followed by the ioctl() doing: ring_buffer_attach(.rb = foo); and we still need to observe the grace period between these two calls due to us reusing the event->rb_entry list_head. In order to make 2 happen we use Paul's latest cond_synchronize_rcu() call. Cc: Paul Mackerras <paulus@samba.org> Cc: Stephane Eranian <eranian@google.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Galbraith <efault@gmx.de> Reported-by: NAlexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20140507123526.GD13658@twins.programming.kicks-ass.netSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Jiri Olsa 提交于
The perf cpu offline callback takes down all cpu context events and releases swhash->swevent_hlist. This could race with task context software event being just scheduled on this cpu via perf_swevent_add while cpu hotplug code already cleaned up event's data. The race happens in the gap between the cpu notifier code and the cpu being actually taken down. Note that only cpu ctx events are terminated in the perf cpu hotplug code. It's easily reproduced with: $ perf record -e faults perf bench sched pipe while putting one of the cpus offline: # echo 0 > /sys/devices/system/cpu/cpu1/online Console emits following warning: WARNING: CPU: 1 PID: 2845 at kernel/events/core.c:5672 perf_swevent_add+0x18d/0x1a0() Modules linked in: CPU: 1 PID: 2845 Comm: sched-pipe Tainted: G W 3.14.0+ #256 Hardware name: Intel Corporation Montevina platform/To be filled by O.E.M., BIOS AMVACRB1.86C.0066.B00.0805070703 05/07/2008 0000000000000009 ffff880077233ab8 ffffffff81665a23 0000000000200005 0000000000000000 ffff880077233af8 ffffffff8104732c 0000000000000046 ffff88007467c800 0000000000000002 ffff88007a9cf2a0 0000000000000001 Call Trace: [<ffffffff81665a23>] dump_stack+0x4f/0x7c [<ffffffff8104732c>] warn_slowpath_common+0x8c/0xc0 [<ffffffff8104737a>] warn_slowpath_null+0x1a/0x20 [<ffffffff8110fb3d>] perf_swevent_add+0x18d/0x1a0 [<ffffffff811162ae>] event_sched_in.isra.75+0x9e/0x1f0 [<ffffffff8111646a>] group_sched_in+0x6a/0x1f0 [<ffffffff81083dd5>] ? sched_clock_local+0x25/0xa0 [<ffffffff811167e6>] ctx_sched_in+0x1f6/0x450 [<ffffffff8111757b>] perf_event_sched_in+0x6b/0xa0 [<ffffffff81117a4b>] perf_event_context_sched_in+0x7b/0xc0 [<ffffffff81117ece>] __perf_event_task_sched_in+0x43e/0x460 [<ffffffff81096f1e>] ? put_lock_stats.isra.18+0xe/0x30 [<ffffffff8107b3c8>] finish_task_switch+0xb8/0x100 [<ffffffff8166a7de>] __schedule+0x30e/0xad0 [<ffffffff81172dd2>] ? pipe_read+0x3e2/0x560 [<ffffffff8166b45e>] ? preempt_schedule_irq+0x3e/0x70 [<ffffffff8166b45e>] ? preempt_schedule_irq+0x3e/0x70 [<ffffffff8166b464>] preempt_schedule_irq+0x44/0x70 [<ffffffff816707f0>] retint_kernel+0x20/0x30 [<ffffffff8109e60a>] ? lockdep_sys_exit+0x1a/0x90 [<ffffffff812a4234>] lockdep_sys_exit_thunk+0x35/0x67 [<ffffffff81679321>] ? sysret_check+0x5/0x56 Fixing this by tracking the cpu hotplug state and displaying the WARN only if current cpu is initialized properly. Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: stable@vger.kernel.org Reported-by: NFengguang Wu <fengguang.wu@intel.com> Signed-off-by: NJiri Olsa <jolsa@redhat.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1396861448-10097-1-git-send-email-jolsa@redhat.comSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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由 Peter Zijlstra 提交于
Vince reported that using a large sample_period (one with bit 63 set) results in wreckage since while the sample_period is fundamentally unsigned (negative periods don't make sense) the way we implement things very much rely on signed logic. So limit sample_period to 63 bits to avoid tripping over this. Reported-by: NVince Weaver <vincent.weaver@maine.edu> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/n/tip-p25fhunibl4y3qi0zuqmyf4b@git.kernel.orgSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 07 5月, 2014 2 次提交
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由 Peter Zijlstra 提交于
perf_pin_task_context() can return NULL but perf_event_init_context() assumes it will not, correct this. Reported-by: NVince Weaver <vincent.weaver@maine.edu> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Link: http://lkml.kernel.org/r/20140505171428.GU26782@laptop.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Peter Zijlstra 提交于
When removing a (sibling) event we do: raw_spin_lock_irq(&ctx->lock); perf_group_detach(event); raw_spin_unlock_irq(&ctx->lock); <hole> perf_remove_from_context(event); raw_spin_lock_irq(&ctx->lock); ... raw_spin_unlock_irq(&ctx->lock); Now, assuming the event is a sibling, it will be 'unreachable' for things like ctx_sched_out() because that iterates the groups->siblings, and we just unhooked the sibling. So, if during <hole> we get ctx_sched_out(), it will miss the event and not call event_sched_out() on it, leaving it programmed on the PMU. The subsequent perf_remove_from_context() call will find the ctx is inactive and only call list_del_event() to remove the event from all other lists. Hereafter we can proceed to free the event; while still programmed! Close this hole by moving perf_group_detach() inside the same ctx->lock region(s) perf_remove_from_context() has. The condition on inherited events only in __perf_event_exit_task() is likely complete crap because non-inherited events are part of groups too and we're tearing down just the same. But leave that for another patch. Most-likely-Fixes: e03a9a55 ("perf: Change close() semantics for group events") Reported-by: NVince Weaver <vincent.weaver@maine.edu> Tested-by: NVince Weaver <vincent.weaver@maine.edu> Much-staring-at-traces-by: NVince Weaver <vincent.weaver@maine.edu> Much-staring-at-traces-by: NThomas Gleixner <tglx@linutronix.de> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20140505093124.GN17778@laptop.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 27 2月, 2014 4 次提交
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由 Peter Zijlstra 提交于
Use the ctx pmu instead of the event pmu. When a group leader is a software event but the group contains hardware events, the entire group is on the hardware PMU. Using the hardware PMU for the transaction makes most sense since that's the most expensive one to programm (and software PMUs generally don't have TXN support anyway). Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-sctoo9t2f3nn2c9g568928q3@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Mark Rutland 提交于
Currently perf_branch_stack_sched_in iterates over the set of pmus, checks that each pmu has a flush_branch_stack callback, then overwrites the pmu before calling the callback. This is either redundant or broken. In systems with a single hw pmu, pmu == cpuctx->ctx.pmu, and thus the assignment is redundant. In systems with multiple hw pmus (i.e. multiple pmus with task_ctx_nr == perf_hw_context) the pmus share the same perf_cpu_context. Thus the assignment can cause one of the pmus to flush its branch stack repeatedly rather than causing each of the pmus to flush their branch stacks. Worse still, if only some pmus have the callback the assignment can result in a branch to NULL. This patch removes the redundant assignment. Signed-off-by: NMark Rutland <mark.rutland@arm.com> Acked-by: NWill Deacon <will.deacon@arm.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/1392054264-23570-3-git-send-email-mark.rutland@arm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Mark Rutland 提交于
For some reason find_pmu_context() is defined as returning void * rather than a __percpu struct perf_cpu_context *. As all the requisite types are defined in advance there's no reason to keep it that way. This patch modifies the prototype of pmu_find_context to return a __percpu struct perf_cpu_context *. Signed-off-by: NMark Rutland <mark.rutland@arm.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Reviewed-by: NDave Martin <Dave.Martin@arm.com> Acked-by: NWill Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/1392054264-23570-2-git-send-email-mark.rutland@arm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Peter Zijlstra 提交于
Drew Richardson reported that he could make the kernel go *boom* when hotplugging while having perf events active. It turned out that when you have a group event, the code in __perf_event_exit_context() fails to remove the group siblings from the context. We then proceed with destroying and freeing the event, and when you re-plug the CPU and try and add another event to that CPU, things go *boom* because you've still got dead entries there. Reported-by: NDrew Richardson <drew.richardson@arm.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Will Deacon <will.deacon@arm.com> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/n/tip-k6v5wundvusvcseqj1si0oz0@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 22 2月, 2014 1 次提交
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由 Peter Zijlstra 提交于
On Mon, Feb 10, 2014 at 08:45:16AM -0800, Dave Hansen wrote: > The reason I coded this up was that NMIs were firing off so fast that > nothing else was getting a chance to run. With this patch, at least the > printk() would come out and I'd have some idea what was going on. It will start spewing to early_printk() (which is a lot nicer to use from NMI context too) when it fails to queue the IRQ-work because its already enqueued. It does have the false-positive for when two CPUs trigger the warn concurrently, but that should be rare and some extra clutter on the early printk shouldn't be a problem. Cc: hpa@zytor.com Cc: tglx@linutronix.de Cc: dzickus@redhat.com Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: mingo@kernel.org Fixes: 6a02ad66 ("perf/x86: Push the duration-logging printk() to IRQ context") Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20140211150116.GO27965@twins.programming.kicks-ass.netSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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- 13 2月, 2014 1 次提交
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由 Tejun Heo 提交于
If !NULL, @skip_css makes cgroup_taskset_for_each() skip the matching css. The intention of the interface is to make it easy to skip css's (cgroup_subsys_states) which already match the migration target; however, this is entirely unnecessary as migration taskset doesn't include tasks which are already in the target cgroup. Drop @skip_css from cgroup_taskset_for_each(). Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NLi Zefan <lizefan@huawei.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Cc: Daniel Borkmann <dborkman@redhat.com>
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- 12 2月, 2014 1 次提交
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由 Tejun Heo 提交于
css_from_dir() returns the matching css (cgroup_subsys_state) given a dentry and subsystem. The function doesn't pin the css before returning and requires the caller to be holding RCU read lock or cgroup_mutex and handling pinning on the caller side. Given that users of the function are likely to want to pin the returned css (both existing users do) and that getting and putting css's are very cheap, there's no reason for the interface to be tricky like this. Rename css_from_dir() to css_tryget_from_dir() and make it try to pin the found css and return it only if pinning succeeded. The callers are updated so that they no longer do RCU locking and pinning around the function and just use the returned css. This will also ease converting cgroup to kernfs. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NMichal Hocko <mhocko@suse.cz> Acked-by: NLi Zefan <lizefan@huawei.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
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- 09 2月, 2014 1 次提交
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由 Peter Zijlstra 提交于
Calling printk() from NMI context is bad (TM), so move it to IRQ context. This also avoids the problem where the printk() time is measured by the generic NMI duration goo and triggers a second warning. Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Don Zickus <dzickus@redhat.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Link: http://lkml.kernel.org/n/tip-75dv35xf6dhhmeb7nq6fua31@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 08 2月, 2014 1 次提交
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由 Tejun Heo 提交于
cgroup_subsys is a bit messier than it needs to be. * The name of a subsys can be different from its internal identifier defined in cgroup_subsys.h. Most subsystems use the matching name but three - cpu, memory and perf_event - use different ones. * cgroup_subsys_id enums are postfixed with _subsys_id and each cgroup_subsys is postfixed with _subsys. cgroup.h is widely included throughout various subsystems, it doesn't and shouldn't have claim on such generic names which don't have any qualifier indicating that they belong to cgroup. * cgroup_subsys->subsys_id should always equal the matching cgroup_subsys_id enum; however, we require each controller to initialize it and then BUG if they don't match, which is a bit silly. This patch cleans up cgroup_subsys names and initialization by doing the followings. * cgroup_subsys_id enums are now postfixed with _cgrp_id, and each cgroup_subsys with _cgrp_subsys. * With the above, renaming subsys identifiers to match the userland visible names doesn't cause any naming conflicts. All non-matching identifiers are renamed to match the official names. cpu_cgroup -> cpu mem_cgroup -> memory perf -> perf_event * controllers no longer need to initialize ->subsys_id and ->name. They're generated in cgroup core and set automatically during boot. * Redundant cgroup_subsys declarations removed. * While updating BUG_ON()s in cgroup_init_early(), convert them to WARN()s. BUGging that early during boot is stupid - the kernel can't print anything, even through serial console and the trap handler doesn't even link stack frame properly for back-tracing. This patch doesn't introduce any behavior changes. v2: Rebased on top of fe1217c4 ("net: net_cls: move cgroupfs classid handling into core"). Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NNeil Horman <nhorman@tuxdriver.com> Acked-by: N"David S. Miller" <davem@davemloft.net> Acked-by: N"Rafael J. Wysocki" <rjw@rjwysocki.net> Acked-by: NMichal Hocko <mhocko@suse.cz> Acked-by: NPeter Zijlstra <peterz@infradead.org> Acked-by: NAristeu Rozanski <aris@redhat.com> Acked-by: NIngo Molnar <mingo@redhat.com> Acked-by: NLi Zefan <lizefan@huawei.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Balbir Singh <bsingharora@gmail.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Serge E. Hallyn <serue@us.ibm.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Thomas Graf <tgraf@suug.ch>
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- 12 1月, 2014 2 次提交
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由 Yann Droneaud 提交于
Unlike recent modern userspace API such as: epoll_create1 (EPOLL_CLOEXEC), eventfd (EFD_CLOEXEC), fanotify_init (FAN_CLOEXEC), inotify_init1 (IN_CLOEXEC), signalfd (SFD_CLOEXEC), timerfd_create (TFD_CLOEXEC), or the venerable general purpose open (O_CLOEXEC), perf_event_open() syscall lack a flag to atomically set FD_CLOEXEC (eg. close-on-exec) flag on file descriptor it returns to userspace. The present patch adds a PERF_FLAG_FD_CLOEXEC flag to allow perf_event_open() syscall to atomically set close-on-exec. Having this flag will enable userspace to remove the file descriptor from the list of file descriptors being inherited across exec, without the need to call fcntl(fd, F_SETFD, FD_CLOEXEC) and the associated race condition between the current thread and another thread calling fork(2) then execve(2). Links: - Secure File Descriptor Handling (Ulrich Drepper, 2008) http://udrepper.livejournal.com/20407.html - Excuse me son, but your code is leaking !!! (Dan Walsh, March 2012) http://danwalsh.livejournal.com/53603.html - Notes in DMA buffer sharing: leak and security hole http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/dma-buf-sharing.txt?id=v3.13-rc3#n428Signed-off-by: NYann Droneaud <ydroneaud@opteya.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/8c03f54e1598b1727c19706f3af03f98685d9fe6.1388952061.git.ydroneaud@opteya.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Stephane Eranian 提交于
This patch fixes a problem with the initialization of the struct perf_event active_entry field. It is defined inside an anonymous union and was initialized in perf_event_alloc() using INIT_LIST_HEAD(). However at that time, we do not know whether the event is going to use active_entry or hlist_entry (SW). Or at last, we don't want to make that determination there. The problem is that hlist and list_head are not initialized the same way. One is okay with NULL (from kzmalloc), the other needs to pointers to point to self. This patch resolves this problem by dropping the union. This will avoid problems later on, if someone starts using active_entry or hlist_entry without verifying that they actually overlap. This also solves the initialization problem. Signed-off-by: NStephane Eranian <eranian@google.com> Cc: ak@linux.intel.com Cc: acme@redhat.com Cc: jolsa@redhat.com Cc: zheng.z.yan@intel.com Cc: bp@alien8.de Cc: vincent.weaver@maine.edu Cc: maria.n.dimakopoulou@gmail.com Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1389176153-3128-2-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 17 12月, 2013 2 次提交
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由 Peter Zijlstra 提交于
Vince Weaver reports that, on all architectures apart from ARM, PERF_EVENT_IOC_PERIOD doesn't actually update the period until the next event fires. This is counter-intuitive behaviour and is better dealt with in the core code. This patch ensures that the period is forcefully reset when dealing with such a request in the core code. A subsequent patch removes the equivalent hack from the ARM back-end. Reported-by: NVince Weaver <vincent.weaver@maine.edu> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Signed-off-by: NWill Deacon <will.deacon@arm.com> Link: http://lkml.kernel.org/r/1385560479-11014-1-git-send-email-will.deacon@arm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Alexander Shishkin 提交于
Currently, only one PMU in a context gets disabled during unthrottling and event_sched_{out,in}(), however, events in one context may belong to different pmus, which results in PMUs being reprogrammed while they are still enabled. This means that mixed PMU use [which is rare in itself] resulted in potentially completely unreliable results: corrupted events, bogus results, etc. This patch temporarily disables PMUs that correspond to each event in the context while these events are being modified. Signed-off-by: NAlexander Shishkin <alexander.shishkin@linux.intel.com> Reviewed-by: NAndi Kleen <ak@linux.intel.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Stephane Eranian <eranian@google.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Link: http://lkml.kernel.org/r/1387196256-8030-1-git-send-email-alexander.shishkin@linux.intel.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 27 11月, 2013 1 次提交
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由 Stephane Eranian 提交于
This patch adds a new field to the struct perf_event. It is intended to be used to chain events which are active (enabled). It helps in the hardware layer for PMUs which do not have actual counter restrictions, i.e., free running read-only counters. Active events are chained as opposed to being tracked via the counter they use. To save space we use a union with hlist_entry as both are mutually exclusive (suggested by Jiri Olsa). Signed-off-by: NStephane Eranian <eranian@google.com> Reviewed-by: NAndi Kleen <ak@linux.intel.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: acme@redhat.com Cc: jolsa@redhat.com Cc: zheng.z.yan@intel.com Cc: bp@alien8.de Cc: maria.n.dimakopoulou@gmail.com Link: http://lkml.kernel.org/r/1384275531-10892-2-git-send-email-eranian@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 19 11月, 2013 1 次提交
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由 Peter Zijlstra 提交于
Currently we only allocate a single cpu hashtable for per-cpu swevents; do away with this optimization for it is fragile in the face of things like perf_pmu_migrate_context(). The easiest thing is to make sure all CPUs are consistent wrt state. Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20130913111447.GN31370@twins.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 13 11月, 2013 1 次提交
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由 Oleg Nesterov 提交于
Add two trivial helpers list_next_entry() and list_prev_entry(), they can have a lot of users including list.h itself. In fact the 1st one is already defined in events/core.c and bnx2x_sp.c, so the patch simply moves the definition to list.h. Signed-off-by: NOleg Nesterov <oleg@redhat.com> Cc: Eilon Greenstein <eilong@broadcom.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 06 11月, 2013 1 次提交
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由 Oleg Nesterov 提交于
While this is really minor, but strncpy() does the unnecessary zero-padding till the end of tmp[16] and it is called every time we are going to use the string literal. Turn these strncpy()'s into the single strlcpy() under the new label, saves 72 bytes. Signed-off-by: NOleg Nesterov <oleg@redhat.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131017182417.GA17753@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 29 10月, 2013 5 次提交
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由 Peter Zijlstra 提交于
Currently we only optimize the context switch between two contexts that have the same parent; this forgoes the optimization between parent and child context, even though these contexts could be equivalent too. Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Shishkin, Alexander <alexander.shishkin@intel.com> Link: http://lkml.kernel.org/r/20131007164257.GH3081@twins.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Peter Zijlstra 提交于
Oleg complained about the excessive 0-ing in perf_event_mmap_event(), so try and be smarter about it while keeping it fairly fool proof and avoid leaking random bits out to userspace. Suggested-by: NOleg Nesterov <oleg@redhat.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-8jirlm99m6if2z13wd6rbyu6@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Oleg Nesterov 提交于
perf_event_mmap_event() does kzalloc(PATH_MAX + sizeof(u64)) to ensure we can align the size later. However this means that we actually allocate PAGE_SIZE * 2 buffer, seems too much. Change this code to allocate PATH_MAX==PAGE_SIZE bytes, but tell d_path() to not use the last sizeof(u64) bytes. Note: it is not clear why do we need __GFP_ZERO, see the next patch. Signed-off-by: NOleg Nesterov <oleg@redhat.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131016201004.GC23214@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Oleg Nesterov 提交于
1. perf_event_mmap(vma) is never called with a gate_vma-like arg, remove the "if (!vma->vm_mm)" code. 2. arch_vma_name() can use the chached value of mmap_event->vma. 3. Change the code to not call arch_vma_name() twice. 4. Purely cosmetic, but since we use "goto got_name" all the time remove "else" from "[stack]" branch just for symmetry. Signed-off-by: NOleg Nesterov <oleg@redhat.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131016200945.GB23214@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Peter Zijlstra 提交于
There's nothing atomic about atomic_set vs atomic_read; so remove the atomic_t usage. Also, make running_sample_length static as it really is (and should be) local to this translation unit. Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: eranian@google.com Cc: Don Zickus <dzickus@redhat.com> Cc: jmario@redhat.com Cc: acme@infradead.org Cc: dave.hansen@linux.intel.com Link: http://lkml.kernel.org/n/tip-vw9lg588x1ic248whybjon0c@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 18 10月, 2013 1 次提交
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由 Stephane Eranian 提交于
For now, we disable the extended MMAP record support (MMAP2). We have identified cases where it would not report the correct mapping information, clone(VM_CLONE) but with separate pids. We will revisit the support once we find a solution for this case. The patch changes the kernel to return EINVAL if attr->mmap2 is set. The patch also modifies the perf tool to use regular PERF_RECORD_MMAP for synthetic events and it also prevents the tool from requesting attr->mmap2 mode because the kernel would reject it. The support will be revisited once the kenrel interface is updated. In V2, we reduce the patch to the strict minimum. In V3, we avoid calling perf_event_open() with mmap2 set because we know it will fail and require fallback retry. Signed-off-by: NStephane Eranian <eranian@google.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20131017173215.GA8820@quadSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
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- 04 10月, 2013 3 次提交
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由 Andi Kleen 提交于
Add a generic qualifier for transaction events, as a new sample type that returns a flag word. This is particularly useful for qualifying aborts: to distinguish aborts which happen due to asynchronous events (like conflicts caused by another CPU) versus instructions that lead to an abort. The tuning strategies are very different for those cases, so it's important to distinguish them easily and early. Since it's inconvenient and inflexible to filter for this in the kernel we report all the events out and allow some post processing in user space. The flags are based on the Intel TSX events, but should be fairly generic and mostly applicable to other HTM architectures too. In addition to various flag words there's also reserved space to report an program supplied abort code. For TSX this is used to distinguish specific classes of aborts, like a lock busy abort when doing lock elision. Flags: Elision and generic transactions (ELISION vs TRANSACTION) (HLE vs RTM on TSX; IBM etc. would likely only use TRANSACTION) Aborts caused by current thread vs aborts caused by others (SYNC vs ASYNC) Retryable transaction (RETRY) Conflicts with other threads (CONFLICT) Transaction write capacity overflow (CAPACITY WRITE) Transaction read capacity overflow (CAPACITY READ) Transactions implicitely aborted can also return an abort code. This can be used to signal specific events to the profiler. A common case is abort on lock busy in a RTM eliding library (code 0xff) To handle this case we include the TSX abort code Common example aborts in TSX would be: - Data conflict with another thread on memory read. Flags: TRANSACTION|ASYNC|CONFLICT - executing a WRMSR in a transaction. Flags: TRANSACTION|SYNC - HLE transaction in user space is too large Flags: ELISION|SYNC|CAPACITY-WRITE The only flag that is somewhat TSX specific is ELISION. This adds the perf core glue needed for reporting the new flag word out. v2: Add MEM/MISC v3: Move transaction to the end v4: Separate capacity-read/write and remove misc v5: Remove _SAMPLE. Move abort flags to 32bit. Rename transaction to txn Signed-off-by: NAndi Kleen <ak@linux.intel.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1379688044-14173-2-git-send-email-andi@firstfloor.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Knut Petersen 提交于
/proc/sys/kernel/perf_event_max_sample_rate will accept negative values as well as 0. Negative values are unreasonable, and 0 causes a divide by zero exception in perf_proc_update_handler. This patch enforces a lower limit of 1. Signed-off-by: NKnut Petersen <Knut_Petersen@t-online.de> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/5242DB0C.4070005@t-online.deSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Peter Zijlstra 提交于
While auditing the list_entry usage due to a trinity bug I found that perf_pmu_migrate_context violates the rules for perf_event::event_entry. The problem is that perf_event::event_entry is a RCU list element, and hence we must wait for a full RCU grace period before re-using the element after deletion. Therefore the usage in perf_pmu_migrate_context() which re-uses the entry immediately is broken. For now introduce another list_head into perf_event for this specific usage. This doesn't actually fix the trinity report because that never goes through this code. Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/n/tip-mkj72lxagw1z8fvjm648iznw@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 27 9月, 2013 1 次提交
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由 Greg Kroah-Hartman 提交于
The dev_attrs field of struct bus_type is going away soon, dev_groups should be used instead. This converts the pmu bus code to use the correct field. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net> Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
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- 20 9月, 2013 1 次提交
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由 Peter Zijlstra 提交于
Solve the problems around the broken definition of perf_event_mmap_page:: cap_usr_time and cap_usr_rdpmc fields which used to overlap, partially fixed by: 860f085b ("perf: Fix broken union in 'struct perf_event_mmap_page'") The problem with the fix (merged in v3.12-rc1 and not yet released officially), noticed by Vince Weaver is that the new behavior is not detectable by new user-space, and that due to the reuse of the field names it's easy to mis-compile a binary if old headers are used on a new kernel or new headers are used on an old kernel. To solve all that make this change explicit, detectable and self-contained, by iterating the ABI the following way: - Always clear bit 0, and rename it to usrpage->cap_bit0, to at least not confuse old user-space binaries. RDPMC will be marked as unavailable to old binaries but that's within the ABI, this is a capability bit. - Rename bit 1 to ->cap_bit0_is_deprecated and always set it to 1, so new libraries can reliably detect that bit 0 is deprecated and perma-zero without having to check the kernel version. - Use bits 2, 3, 4 for the newly defined, correct functionality: cap_user_rdpmc : 1, /* The RDPMC instruction can be used to read counts */ cap_user_time : 1, /* The time_* fields are used */ cap_user_time_zero : 1, /* The time_zero field is used */ - Rename all the bitfield names in perf_event.h to be different from the old names, to make sure it's not possible to mis-compile it accidentally with old assumptions. The 'size' field can then be used in the future to add new fields and it will act as a natural ABI version indicator as well. Also adjust tools/perf/ userspace for the new definitions, noticed by Adrian Hunter. Reported-by: NVince Weaver <vincent.weaver@maine.edu> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Also-Fixed-by: NAdrian Hunter <adrian.hunter@intel.com> Link: http://lkml.kernel.org/n/tip-zr03yxjrpXesOzzupszqglbv@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 11 9月, 2013 1 次提交
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由 Arnaldo Carvalho de Melo 提交于
The ino_generation field was added in the PERF_RECORD_MMAP2 record in the 13d7a241 cset but no space for it was allocated, corrupting the PERF_FORMAT_{TIME,CPU,TID,etc} area (sample_type/sample_id_all), fix it. Detected with one of the regression tests done by 'perf test': [root@sandy ~]# perf test -v 7 7: Validate PERF_RECORD_* events & perf_sample fields : --- start --- 61315294449606 0 PERF_RECORD_SAMPLE 61315294453161 0 PERF_RECORD_SAMPLE 61315294454441 0 PERF_RECORD_SAMPLE 61315294455709 0 PERF_RECORD_SAMPLE 61315295600899 0 PERF_RECORD_COMM: sleep:6500 27917287430500 342521613 PERF_RECORD_MMAP2 6500/6500: [0x400000(0x7000) @ 0 00:1d 311442 9016]: /usr/bin/sleep MMAP2 going backwards in time, prev=61315295600899, curr=27917287430500 MMAP2 with unexpected cpu, expected 0, got 342521613 MMAP2 with unexpected pid, expected 6500, got 1701606191 MMAP2 with unexpected tid, expected 6500, got 28773 27917287430500 342561333 PERF_RECORD_MMAP2 6500/6500: [0x3b7e000000(0x223000) @ 0 00:1d 309186 9016]: /usr/lib64/ld-2.16.so MMAP2 with unexpected cpu, expected 0, got 342561333 MMAP2 with unexpected pid, expected 6500, got 1932408369 MMAP2 with unexpected tid, expected 6500, got 111 27917287430500 342600095 PERF_RECORD_MMAP2 6500/6500: [0x7fffbd7dc000(0x1000) @ 0x7fffbd7dc000 00:00 0 0]: [vdso] MMAP2 with unexpected cpu, expected 0, got 342600095 MMAP2 with unexpected pid, expected 6500, got 1935963739 MMAP2 with unexpected tid, expected 6500, got 23919 27917287430500 342882834 PERF_RECORD_MMAP2 6500/6500: [0x3b7e400000(0x3b8000) @ 0 00:1d 309187 9016]: /usr/lib64/libc-2.16.so MMAP2 with unexpected cpu, expected 0, got 342882834 MMAP2 with unexpected pid, expected 6500, got 909192754 MMAP2 with unexpected tid, expected 6500, got 7303982 61316297195411 0 PERF_RECORD_EXIT(6500:6500):(6500:6500) ---- end ---- Validate PERF_RECORD_* events & perf_sample fields: FAILED! [root@sandy ~]# After this patch: [root@sandy ~]# perf test 7 7: Validate PERF_RECORD_* events & perf_sample fields : Ok [root@sandy ~]# Acked-by: NPeter Zijlstra <peterz@infradead.org> Acked-by: NStephane Eranian <eranian@google.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-heeuv986b8ha7whqg4o3he7c@git.kernel.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
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- 02 9月, 2013 2 次提交
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由 Stephane Eranian 提交于
Adds a new PERF_RECORD_MMAP2 record type which is essence an expanded version of PERF_RECORD_MMAP. Used to request mmap records with more information about the mapping, including device major, minor and the inode number and generation for mappings associated with files or shared memory segments. Works for code and data (with attr->mmap_data set). Existing PERF_RECORD_MMAP record is unmodified by this patch. Signed-off-by: NStephane Eranian <eranian@google.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Link: http://lkml.kernel.org/r/1377079825-19057-2-git-send-email-eranian@google.com [ Added Al to the Cc:. Are the ino, maj/min exports of vma->vm_file OK? ] Signed-off-by: NIngo Molnar <mingo@kernel.org>
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由 Jiri Olsa 提交于
The current throttling code triggers WARN below via following workload (only hit on AMD machine with 48 CPUs): # while [ 1 ]; do perf record perf bench sched messaging; done WARNING: at arch/x86/kernel/cpu/perf_event.c:1054 x86_pmu_start+0xc6/0x100() SNIP Call Trace: <IRQ> [<ffffffff815f62d6>] dump_stack+0x19/0x1b [<ffffffff8105f531>] warn_slowpath_common+0x61/0x80 [<ffffffff8105f60a>] warn_slowpath_null+0x1a/0x20 [<ffffffff810213a6>] x86_pmu_start+0xc6/0x100 [<ffffffff81129dd2>] perf_adjust_freq_unthr_context.part.75+0x182/0x1a0 [<ffffffff8112a058>] perf_event_task_tick+0xc8/0xf0 [<ffffffff81093221>] scheduler_tick+0xd1/0x140 [<ffffffff81070176>] update_process_times+0x66/0x80 [<ffffffff810b9565>] tick_sched_handle.isra.15+0x25/0x60 [<ffffffff810b95e1>] tick_sched_timer+0x41/0x60 [<ffffffff81087c24>] __run_hrtimer+0x74/0x1d0 [<ffffffff810b95a0>] ? tick_sched_handle.isra.15+0x60/0x60 [<ffffffff81088407>] hrtimer_interrupt+0xf7/0x240 [<ffffffff81606829>] smp_apic_timer_interrupt+0x69/0x9c [<ffffffff8160569d>] apic_timer_interrupt+0x6d/0x80 <EOI> [<ffffffff81129f74>] ? __perf_event_task_sched_in+0x184/0x1a0 [<ffffffff814dd937>] ? kfree_skbmem+0x37/0x90 [<ffffffff815f2c47>] ? __slab_free+0x1ac/0x30f [<ffffffff8118143d>] ? kfree+0xfd/0x130 [<ffffffff81181622>] kmem_cache_free+0x1b2/0x1d0 [<ffffffff814dd937>] kfree_skbmem+0x37/0x90 [<ffffffff814e03c4>] consume_skb+0x34/0x80 [<ffffffff8158b057>] unix_stream_recvmsg+0x4e7/0x820 [<ffffffff814d5546>] sock_aio_read.part.7+0x116/0x130 [<ffffffff8112c10c>] ? __perf_sw_event+0x19c/0x1e0 [<ffffffff814d5581>] sock_aio_read+0x21/0x30 [<ffffffff8119a5d0>] do_sync_read+0x80/0xb0 [<ffffffff8119ac85>] vfs_read+0x145/0x170 [<ffffffff8119b699>] SyS_read+0x49/0xa0 [<ffffffff810df516>] ? __audit_syscall_exit+0x1f6/0x2a0 [<ffffffff81604a19>] system_call_fastpath+0x16/0x1b ---[ end trace 622b7e226c4a766a ]--- The reason is a race in perf_event_task_tick() throttling code. The race flow (simplified code): - perf_throttled_count is per cpu variable and is CPU throttling flag, here starting with 0 - perf_throttled_seq is sequence/domain for allowed count of interrupts within the tick, gets increased each tick on single CPU (CPU bounded event): ... workload perf_event_task_tick: | | T0 inc(perf_throttled_seq) | T1 needs_unthr = xchg(perf_throttled_count, 0) == 0 tick gets interrupted: ... event gets throttled under new seq ... T2 last NMI comes, event is throttled - inc(perf_throttled_count) back to tick: | perf_adjust_freq_unthr_context: | | T3 unthrottling is skiped for event (needs_unthr == 0) | T4 event is stop and started via freq adjustment | tick ends ... workload ... no sample is hit for event ... perf_event_task_tick: | | T5 needs_unthr = xchg(perf_throttled_count, 0) != 0 (from T2) | T6 unthrottling is done on event (interrupts == MAX_INTERRUPTS) | event is already started (from T4) -> WARN Fixing this by not checking needs_unthr again and thus check all events for unthrottling. Signed-off-by: NJiri Olsa <jolsa@redhat.com> Reported-by: NJan Stancek <jstancek@redhat.com> Suggested-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Stephane Eranian <eranian@google.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1377355554-8934-1-git-send-email-jolsa@redhat.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 30 8月, 2013 1 次提交
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由 Adrian Hunter 提交于
The event stream is not always parsable because the format of a sample is dependent on the sample_type of the selected event. When there is more than one selected event and the sample_types are not the same then parsing becomes problematic. A sample can be matched to its selected event using the ID that is allocated when the event is opened. Unfortunately, to get the ID from the sample means first parsing it. This patch adds a new sample format bit PERF_SAMPLE_IDENTIFER that puts the ID at a fixed position so that the ID can be retrieved without parsing the sample. For sample events, that is the first position immediately after the header. For non-sample events, that is the last position. In this respect parsing samples requires that the sample_type and ID values are recorded. For example, perf tools records struct perf_event_attr and the IDs within the perf.data file. Those must be read first before it is possible to parse samples found later in the perf.data file. Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com> Tested-by: NStephane Eranian <eranian@google.com> Acked-by: NPeter Zijlstra <peterz@infradead.org> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Namhyung Kim <namhyung@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/1377591794-30553-6-git-send-email-adrian.hunter@intel.comSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>
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- 27 8月, 2013 1 次提交
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由 Tejun Heo 提交于
cgroup_css_from_dir() will grow another user. In preparation, make the following changes. * All css functions are prefixed with just "css_", rename it to css_from_dir(). * Take dentry * instead of file * as dentry is what ultimately identifies a cgroup and file may not always be available. Note that the function now checkes whether @dentry->d_inode is NULL as the caller now may specify a negative dentry. * Make it take cgroup_subsys * instead of integer subsys_id. This simplifies the function and allows specifying no subsystem for cgroup->dummy_css. * Make return section a bit less verbose. This patch doesn't introduce any behavior changes. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NLi Zefan <lizefan@huawei.com> Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@redhat.com>
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- 16 8月, 2013 2 次提交
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由 Peter Zijlstra 提交于
We should not be calling calc_timer_values() for events that do not actually have an mmap()'ed userpage. Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20130802191630.GT27162@twins.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Frederic Weisbecker 提交于
Freq events may not always be affine to a particular CPU. As such, account_event_cpu() may crash if we account per cpu a freq event that has event->cpu == -1. To solve this, lets account freq events globally. In practice this doesn't change much the picture because perf tools create per-task perf events with one event per CPU by default. Profiling a single CPU is usually a corner case so there is no much point in optimizing things that way. Reported-by: NJiri Olsa <jolsa@redhat.com> Suggested-by: NPeter Zijlstra <peterz@infradead.org> Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Tested-by: NJiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Stephane Eranian <eranian@google.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1375460996-16329-3-git-send-email-fweisbec@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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