- 03 10月, 2014 1 次提交
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由 Peter Zijlstra 提交于
Oleg noticed that a cleanup by Sylvain actually uncovered a bug; by calling perf_event_free_task() when failing sched_fork() we will not yet have done the memset() on ->perf_event_ctxp[] and will therefore try and 'free' the inherited contexts, which are still in use by the parent process. This is bad.. Suggested-by: NOleg Nesterov <oleg@redhat.com> Reported-by: NOleg Nesterov <oleg@redhat.com> Reported-by: NSylvain 'ythier' Hitier <sylvain.hitier@gmail.com> Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 09 9月, 2014 1 次提交
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由 Cong Wang 提交于
We saw a kernel soft lockup in perf_remove_from_context(), it looks like the `perf` process, when exiting, could not go out of the retry loop. Meanwhile, the target process was forking a child. So either the target process should execute the smp function call to deactive the event (if it was running) or it should do a context switch which deactives the event. It seems we optimize out a context switch in perf_event_context_sched_out(), and what's more important, we still test an obsolete task pointer when retrying, so no one actually would deactive that event in this situation. Fix it directly by reloading the task pointer in perf_remove_from_context(). This should cure the above soft lockup. Signed-off-by: NCong Wang <cwang@twopensource.com> Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/1409696840-843-1-git-send-email-xiyou.wangcong@gmail.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 20 8月, 2014 1 次提交
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由 Pawel Moll 提交于
When running a 32-bit userspace on a 64-bit kernel (eg. i386 application on x86_64 kernel or 32-bit arm userspace on arm64 kernel) some of the perf ioctls must be treated with special care, as they have a pointer size encoded in the command. For example, PERF_EVENT_IOC_ID in 32-bit world will be encoded as 0x80042407, but 64-bit kernel will expect 0x80082407. In result the ioctl will fail returning -ENOTTY. This patch solves the problem by adding code fixing up the size as compat_ioctl file operation. Reported-by: NDrew Richardson <drew.richardson@arm.com> Signed-off-by: NPawel Moll <pawel.moll@arm.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Jiri Olsa <jolsa@redhat.com> Link: http://lkml.kernel.org/r/1402671812-9078-1-git-send-email-pawel.moll@arm.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 16 7月, 2014 3 次提交
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由 Jiri Olsa 提交于
The following patch added another way to get mmap name: 78d683e8 ("mm, fs: Add vm_ops->name as an alternative to arch_vma_name") The vdso vma mapping already switch to this and we no longer get vdso name via arch_vma_name function. Adding this way to the perf mmap event name retrieval code. Caught this via perf test: $ sudo ./perf test -v 7 7: Validate PERF_RECORD_* events & perf_sample fields : --- start --- SNIP PERF_RECORD_MMAP for [vdso] missing! test child finished with 255 ---- end ---- Validate PERF_RECORD_* events & perf_sample fields: FAILED! Signed-off-by: NJiri Olsa <jolsa@kernel.org> Acked-by: NAndy Lutomirski <luto@amacapital.net> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1405353439-14211-1-git-send-email-jolsa@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Peter Zijlstra 提交于
Sasha Levin reported: > While fuzzing with trinity inside a KVM tools guest running the latest -next > kernel I've stumbled on the following spew: > > ====================================================== > [ INFO: possible circular locking dependency detected ] > 3.15.0-next-20140613-sasha-00026-g6dd125d-dirty #654 Not tainted > ------------------------------------------------------- > trinity-c578/9725 is trying to acquire lock: > (&(&pool->lock)->rlock){-.-...}, at: __queue_work (kernel/workqueue.c:1346) > > but task is already holding lock: > (&ctx->lock){-.....}, at: perf_event_exit_task (kernel/events/core.c:7471 kernel/events/core.c:7533) > > which lock already depends on the new lock. > 1 lock held by trinity-c578/9725: > #0: (&ctx->lock){-.....}, at: perf_event_exit_task (kernel/events/core.c:7471 kernel/events/core.c:7533) > > Call Trace: > dump_stack (lib/dump_stack.c:52) > print_circular_bug (kernel/locking/lockdep.c:1216) > __lock_acquire (kernel/locking/lockdep.c:1840 kernel/locking/lockdep.c:1945 kernel/locking/lockdep.c:2131 kernel/locking/lockdep.c:3182) > lock_acquire (./arch/x86/include/asm/current.h:14 kernel/locking/lockdep.c:3602) > _raw_spin_lock (include/linux/spinlock_api_smp.h:143 kernel/locking/spinlock.c:151) > __queue_work (kernel/workqueue.c:1346) > queue_work_on (kernel/workqueue.c:1424) > free_object (lib/debugobjects.c:209) > __debug_check_no_obj_freed (lib/debugobjects.c:715) > debug_check_no_obj_freed (lib/debugobjects.c:727) > kmem_cache_free (mm/slub.c:2683 mm/slub.c:2711) > free_task (kernel/fork.c:221) > __put_task_struct (kernel/fork.c:250) > put_ctx (include/linux/sched.h:1855 kernel/events/core.c:898) > perf_event_exit_task (kernel/events/core.c:907 kernel/events/core.c:7478 kernel/events/core.c:7533) > do_exit (kernel/exit.c:766) > do_group_exit (kernel/exit.c:884) > get_signal_to_deliver (kernel/signal.c:2347) > do_signal (arch/x86/kernel/signal.c:698) > do_notify_resume (arch/x86/kernel/signal.c:751) > int_signal (arch/x86/kernel/entry_64.S:600) Urgh.. so the only way I can make that happen is through: perf_event_exit_task_context() raw_spin_lock(&child_ctx->lock); unclone_ctx(child_ctx) put_ctx(ctx->parent_ctx); raw_spin_unlock_irqrestore(&child_ctx->lock); And we can avoid this by doing the change below. I can't immediately see how this changed recently, but given that you say it's easy to reproduce, lets fix this. Reported-by: NSasha Levin <sasha.levin@oracle.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Tejun Heo <tj@kernel.org> Cc: Dave Jones <davej@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140623141242.GB19860@laptop.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Peter Zijlstra 提交于
Vince reported that commit 15a2d4de ("perf: Always destroy groups on exit") causes a regression with grouped events. In particular his read_group_attached.c test fails. https://github.com/deater/perf_event_tests/blob/master/tests/bugs/read_group_attached.c Because of the context switch optimization in perf_event_context_sched_out() the 'original' event may end up in the child process and when that exits the change in the patch in question destroys the actual grouping. Therefore revert that change and only destroy inherited groups. Reported-by: NVince Weaver <vincent.weaver@maine.edu> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/n/tip-zedy3uktcp753q8fw8dagx7a@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 05 7月, 2014 1 次提交
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由 Jiri Olsa 提交于
Leftover from '8dc85d54 perf: Multiple task contexts'. Signed-off-by: NJiri Olsa <jolsa@kernel.org> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Link: http://lkml.kernel.org/r/1403598026-2310-1-git-send-email-jolsa@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 02 7月, 2014 1 次提交
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由 Jiri Olsa 提交于
The context check in perf_event_context_sched_out allows non-cloned context to be part of the optimized schedule out switch. This could move non-cloned context into another workload child. Once this child exits, the context is closed and leaves all original (parent) events in closed state. Any other new cloned event will have closed state and not measure anything. And probably causing other odd bugs. Signed-off-by: NJiri Olsa <jolsa@kernel.org> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: <stable@vger.kernel.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1403598026-2310-2-git-send-email-jolsa@kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 09 6月, 2014 2 次提交
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由 Don Zickus 提交于
This reverts commit 3090ffb5. Re-enable the mmap2 interface as we will have a user soon. Since things have changed since perf disabled mmap2, small tweaks to the revert had to be done: o commit 9d4ecc88 forced (n!=8) to become (n<7) o a new libunwind test needed updating to use mmap2 interface Signed-off-by: NDon Zickus <dzickus@redhat.com> Link: http://lkml.kernel.org/r/1401461382-209586-1-git-send-email-dzickus@redhat.comSigned-off-by: NJiri Olsa <jolsa@kernel.org>
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由 Peter Zijlstra 提交于
The mmap2 interface was missing the protection and flags bits needed to accurately determine if a mmap memory area was shared or private and if it was readable or not. Signed-off-by: NPeter Zijlstra <peterz@infradead.org> [tweaked patch to compile and wrote changelog] Signed-off-by: NDon Zickus <dzickus@redhat.com> Link: http://lkml.kernel.org/r/1400526833-141779-2-git-send-email-dzickus@redhat.comSigned-off-by: NJiri Olsa <jolsa@kernel.org>
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- 06 6月, 2014 2 次提交
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由 Adrian Hunter 提交于
perf tools like 'perf report' can aggregate samples by comm strings, which generally works. However, there are other potential use-cases. For example, to pair up 'calls' with 'returns' accurately (from branch events like Intel BTS) it is necessary to identify whether the process has exec'd. Although a comm event is generated when an 'exec' happens it is also generated whenever the comm string is changed on a whim (e.g. by prctl PR_SET_NAME). This patch adds a flag to the comm event to differentiate one case from the other. In order to determine whether the kernel supports the new flag, a selection bit named 'exec' is added to struct perf_event_attr. The bit does nothing but will cause perf_event_open() to fail if the bit is set on kernels that do not have it defined. Signed-off-by: NAdrian Hunter <adrian.hunter@intel.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/537D9EBE.7030806@intel.com Cc: Paul Mackerras <paulus@samba.org> Cc: Dave Jones <davej@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: David Ahern <dsahern@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: NIngo Molnar <mingo@kernel.org>
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由 Peter Zijlstra 提交于
perf_event_comm() assumes that set_task_comm() is only called on exec(), and in particular that its only called on current. Neither are true, as Dave reported a WARN triggered by set_task_comm() being called on !current. Separate the exec() hook from the comm hook. Reported-by: NDave Jones <davej@redhat.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-fsdevel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/r/20140521153219.GH5226@laptop.programming.kicks-ass.net [ Build fix. ] Signed-off-by: NIngo Molnar <mingo@kernel.org>
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- 05 6月, 2014 2 次提交
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由 Vince Weaver 提交于
Add common code to generate -ENOTSUPP at event creation time if an architecture attempts to create a sampled event and PERF_PMU_NO_INTERRUPT is set. This adds a new pmu->capabilities flag. Initially we only support PERF_PMU_NO_INTERRUPT (to indicate a PMU has no support for generating hardware interrupts) but there are other capabilities that can be added later. Signed-off-by: NVince Weaver <vincent.weaver@maine.edu> Acked-by: NWill Deacon <will.deacon@arm.com> [peterz: rename to PERF_PMU_CAP_* and moved the pmu::capabilities word into a hole] Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1405161708060.11099@vincent-weaver-1.umelst.maine.eduSigned-off-by: NIngo Molnar <mingo@kernel.org> Signed-off-by: NIngo Molnar <mingo@kernel.org>
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由 Peter Zijlstra 提交于
While that mutex should guard the elements, it doesn't guard against the use-after-free that's from list_for_each_entry_rcu(). __perf_event_exit_task() can actually free the event. And because list addition/deletion is guarded by both ctx->mutex and ctx->lock, holding ctx->mutex is sufficient for reading the list, so we don't actually need the rcu list iteration. Fixes: 3a497f48 ("perf: Simplify perf_event_exit_task_context()") Reported-by: NSasha Levin <sasha.levin@oracle.com> Tested-by: NSasha Levin <sasha.levin@oracle.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Dave Jones <davej@redhat.com> Cc: acme@ghostprotocols.net Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/20140529170024.GA2315@laptop.programming.kicks-ass.netSigned-off-by: NIngo Molnar <mingo@kernel.org>
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- 19 5月, 2014 4 次提交
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由 Borislav Petkov 提交于
... in 3a497f48 ("perf: Simplify perf_event_exit_task_context()") Signed-off-by: NBorislav Petkov <bp@suse.de> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1399720259-28275-1-git-send-email-bp@alien8.deSigned-off-by: NThomas Gleixner <tglx@linutronix.de>
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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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- 14 5月, 2014 1 次提交
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由 Tejun Heo 提交于
Unlike the more usual refcnting, what css_tryget() provides is the distinction between online and offline csses instead of protection against upping a refcnt which already reached zero. cgroup is planning to provide actual tryget which fails if the refcnt already reached zero. Let's rename the existing trygets so that they clearly indicate that they're onliness. I thought about keeping the existing names as-are and introducing new names for the planned actual tryget; however, given that each controller participates in the synchronization of the online state, it seems worthwhile to make it explicit that these functions are about on/offline state. Rename css_tryget() to css_tryget_online() and css_tryget_from_dir() to css_tryget_online_from_dir(). This is pure rename. v2: cgroup_freezer grew new usages of css_tryget(). Update accordingly. Signed-off-by: NTejun Heo <tj@kernel.org> Acked-by: NJohannes Weiner <hannes@cmpxchg.org> Acked-by: NMichal Hocko <mhocko@suse.cz> Acked-by: NLi Zefan <lizefan@huawei.com> Cc: Vivek Goyal <vgoyal@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> 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@kernel.org>
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- 07 5月, 2014 7 次提交
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由 Peter Zijlstra 提交于
Instead of jumping through hoops to make sure to find (and exit) each event, do it the simple straight fwd way. Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-tij931199thfkys8vbnokdpf@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Peter Zijlstra 提交于
Primarily make perf_event_release_kernel() into put_event(), this will allow kernel space to create per-task inherited events, and is safer in general. Also, document the free_event() assumptions. Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-rk9pvr6e1d0559lxstltbztc@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Peter Zijlstra 提交于
Document and validate the locking assumption of event_sched_in(). Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-sybq1publ9xt5no77cwvi0eo@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Peter Zijlstra 提交于
Commit 38b435b1 ("perf: Fix tear-down of inherited group events") states that we need to destroy groups for inherited events, but it doesn't make any sense to not also destroy groups for normal events. And while it usually makes no difference (the normal events won't leak, and its very likely all the group events will die in quick succession) it does make the code more consistent and closes a potential hole for trouble. Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-426egt8zmsm12d2q8k2xz4tt@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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由 Peter Zijlstra 提交于
Make sure all events in a group have the same inherit state. It was possible for group leaders to have inherit set while sibling events would not have inherit set. In this case we'd still inherit the siblings, leading to some non-fatal weirdness. Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-r32tt8yldvic3jlcghd3g35u@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@kernel.org>
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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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- 18 4月, 2014 1 次提交
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由 Yan, Zheng 提交于
This patch adds support for building PMU driver as module. It exports the functions perf_pmu_{register,unregister}() and adds reference tracking for the PMU driver module. When the PMU driver is built as a module, each active event of the PMU holds a reference to the driver module. Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com> Signed-off-by: NPeter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1395133004-23205-1-git-send-email-zheng.z.yan@intel.com Cc: eranian@google.com Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: linux-kernel@vger.kernel.org Signed-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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