- 07 6月, 2011 1 次提交
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由 Peter Zijlstra 提交于
A lost Quilt refresh of 2c29ef0f (perf: Simplify and fix __perf_install_in_context()) is causing grief and lockups, reported by Jiri Olsa. When installing an event in a task context, there's a number of issues: - there might not be an existing task context, in which case we should install the now current context; - there might already be a context, not the current one, in which case we should de-schedule the old and install the new; these cases were dealt with in the lost refresh, however there is one further case that was found in testing: - there might already be a context, the current one, in which case we should still de-schedule, and should take care to re-install it (note that task_ctx_sched_out() clears cpuctx->task_ctx). Reported-by: NJiri Olsa <jolsa@redhat.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1307399008.2497.971.camel@laptopSigned-off-by: NIngo Molnar <mingo@elte.hu>
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- 31 5月, 2011 1 次提交
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由 Peter Zijlstra 提交于
Ben changed the cgroup API in commit f780bdb7 (cgroups: add per-thread subsystem callbacks) in an incompatible way, but forgot to convert the perf cgroup bits. Avoid compile warnings and runtime splats and convert perf too ;-) Acked-by: NBen Blum <bblum@andrew.cmu.edu> Cc: Stephane Eranian <eranian@google.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/1306767651.1200.2990.camel@twinsSigned-off-by: NIngo Molnar <mingo@elte.hu>
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- 29 5月, 2011 9 次提交
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由 Peter Zijlstra 提交于
Since perf_install_in_context() will now install a context when we add the first event, we can de-schedule the context when the last event is removed. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110409192142.090431763@chello.nlSigned-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
In order to always call list_del_event() on the correct cpu if the event is part of an active context and avoid having to do two IPIs, change the close() semantics slightly. The current perf_event_disable() call would disable a whole group if the event that's being closed is the group leader, whereas the new code keeps the group siblings enabled. People should not rely on this behaviour and I don't think they do, but in case we find they do, the fix is easy and we have to take the double IPI cost. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Cc: Vince Weaver <vweaver1@eecs.utk.edu> Link: http://lkml.kernel.org/r/20110409192142.038377551@chello.nlSigned-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
This was scattered out - refactor it into a single function. No change in functionality. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110409192141.979862055@chello.nlSigned-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
Instead of tracking if a context is active or not, track which events of the context are active. By making it a bitmask of EVENT_PINNED|EVENT_FLEXIBLE we can simplify some of the scheduling routines since it can avoid adding events that are already active. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110409192141.930282378@chello.nlSigned-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
Currently __perf_install_in_context() will try and schedule in the event irrespective of our event scheduling rules, that is, we try to schedule CPU-pinned, TASK-pinned, CPU-flexible, TASK-flexible, but when creating a new event we simply try and schedule it on top of whatever is already on the PMU, this can lead to errors for pinned events. Therefore, simplify things and simply schedule everything out, add the event to the corresponding context and schedule everything back in. This also nicely handles the case where with __ARCH_WANT_INTERRUPTS_ON_CTXSW the IPI can come right in the middle of schedule, before we managed to call perf_event_task_sched_in(). Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110409192141.870894224@chello.nlSigned-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
Make task_ctx_sched_*() imply EVENT_ALL, since anything less will not actually have scheduled the task in/out at all. Since there's no site that schedules all of a task in (due to the interleave with flexible cpuctx) we can remove this function. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110409192141.817893268@chello.nlSigned-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
Currently we only hold one ctx->lock at a time, which results in us flipping back and forth between cpuctx->ctx.lock and task_ctx->lock. Avoid this and gain large atomic regions by holding both locks. We nest the task lock inside the cpu lock, since with task scheduling we might have to change task ctx while holding the cpu ctx lock. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110409192141.769881865@chello.nlSigned-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
Small cleanup to how we refcount in find_get_context(), this also allows us to use put_ctx() to free things instead of using kfree(). Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110409192141.719340481@chello.nlSigned-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
Oleg noted that ctx_sched_out() disables the PMU even though it might not actually do something, avoid needless PMU-disabling. Reported-by: NOleg Nesterov <oleg@redhat.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110409192141.665385503@chello.nlSigned-off-by: NIngo Molnar <mingo@elte.hu>
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- 28 5月, 2011 1 次提交
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由 Peter Zijlstra 提交于
Vince noticed that unless we mmap() a buffer, SIGIO gets lost. So explicitly push the wakeup (including signals) when requested. Reported-by: NVince Weaver <vweaver1@eecs.utk.edu> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Cc: <stable@kernel.org> Link: http://lkml.kernel.org/n/tip-2euus3f3x3dyvdk52cjxw8zu@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@elte.hu>
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- 04 5月, 2011 1 次提交
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由 Ingo Molnar 提交于
Fix a few inconsistent style bits that were added over the past few months. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-yv4hwf9yhnzoada8pcpb3a97@git.kernel.orgSigned-off-by: NIngo Molnar <mingo@elte.hu>
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- 03 5月, 2011 1 次提交
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由 Borislav Petkov 提交于
mv kernel/perf_event.c -> kernel/events/core.c. From there, all further sensible splitting can happen. The idea is that due to perf_event.c becoming pretty sizable and with the advent of the marriage with ftrace, splitting functionality into its logical parts should help speeding up the unification and to manage the complexity of the subsystem. Signed-off-by: NBorislav Petkov <borislav.petkov@amd.com>
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- 11 4月, 2011 1 次提交
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由 Stephane Eranian 提交于
There is a bug in perf_event_enable_on_exec() when cgroup events are active on a CPU: the cgroup events may be scheduled twice causing event state corruptions which eventually may lead to kernel panics. The reason is that the function needs to first schedule out the cgroup events, just like for the per-thread events. The cgroup event are scheduled back in automatically from the perf_event_context_sched_in() function. The patch also adds a WARN_ON_ONCE() is perf_cgroup_switch() to catch any bogus state. Signed-off-by: NStephane Eranian <eranian@google.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/r/20110406005454.GA1062@quadSigned-off-by: NIngo Molnar <mingo@elte.hu>
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- 05 4月, 2011 1 次提交
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由 Jason Baron 提交于
Introduce: static __always_inline bool static_branch(struct jump_label_key *key); instead of the old JUMP_LABEL(key, label) macro. In this way, jump labels become really easy to use: Define: struct jump_label_key jump_key; Can be used as: if (static_branch(&jump_key)) do unlikely code enable/disale via: jump_label_inc(&jump_key); jump_label_dec(&jump_key); that's it! For the jump labels disabled case, the static_branch() becomes an atomic_read(), and jump_label_inc()/dec() are simply atomic_inc(), atomic_dec() operations. We show testing results for this change below. Thanks to H. Peter Anvin for suggesting the 'static_branch()' construct. Since we now require a 'struct jump_label_key *key', we can store a pointer into the jump table addresses. In this way, we can enable/disable jump labels, in basically constant time. This change allows us to completely remove the previous hashtable scheme. Thanks to Peter Zijlstra for this re-write. Testing: I ran a series of 'tbench 20' runs 5 times (with reboots) for 3 configurations, where tracepoints were disabled. jump label configured in avg: 815.6 jump label *not* configured in (using atomic reads) avg: 800.1 jump label *not* configured in (regular reads) avg: 803.4 Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20110316212947.GA8792@redhat.com> Signed-off-by: NJason Baron <jbaron@redhat.com> Suggested-by: NH. Peter Anvin <hpa@linux.intel.com> Tested-by: NDavid Daney <ddaney@caviumnetworks.com> Acked-by: NRalf Baechle <ralf@linux-mips.org> Acked-by: NDavid S. Miller <davem@davemloft.net> Acked-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>
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- 31 3月, 2011 2 次提交
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由 Peter Zijlstra 提交于
sys_perf_event_open() had an imbalance in the number of task refs it took causing memory leakage Cc: Jiri Olsa <jolsa@redhat.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: stable@kernel.org # .37+ Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Frederic Weisbecker 提交于
Ensure we allow 512 kiB + 1 page for user control without assuming a 4096 bytes page size. Reported-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Stephane Eranian <eranian@google.com> Cc: <stable@kernel.org> LKML-Reference: <1301535209-9679-1-git-send-email-fweisbec@gmail.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 24 3月, 2011 1 次提交
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由 Frederic Weisbecker 提交于
The maximum kilobytes of locked memory that an unprivileged user can reserve is of 512 kB = 128 pages by default, scaled to the number of onlined CPUs, which fits well with the tools that use 128 data pages by default. However tools actually use 129 pages, because they need one more for the user control page. Thus the default mlock threshold is not sufficient for the default tools needs and we always end up to evaluate the constant mlock rlimit policy, which doesn't have this scaling with the number of online CPUs. Hence, on systems that have more than 16 CPUs, we overlap the rlimit threshold and fail to mmap: $ perf record ls Error: failed to mmap with 1 (Operation not permitted) Just increase the max unprivileged mlock threshold by one page so that it supports well perf tools even after 16 CPUs. Reported-by: NHan Pingtian <phan@redhat.com> Reported-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Reported-by: NArnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Acked-by: NArnaldo Carvalho de Melo <acme@redhat.com> Cc: Stephane Eranian <eranian@google.com> Cc: Stable <stable@kernel.org> LKML-Reference: <1300904979-5508-1-git-send-email-fweisbec@gmail.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 23 3月, 2011 1 次提交
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由 Stephane Eranian 提交于
This patch solves a stale pointer problem in update_cgrp_time_from_cpuctx(). The cpuctx->cgrp was not cleared on all possible event exit paths, including: close() perf_release() perf_release_kernel() list_del_event() This patch fixes list_del_event() to clear cpuctx->cgrp when there are no cgroup events left in the context. [ This second version makes the code compile when CONFIG_CGROUP_PERF is not enabled. We unconditionally define perf_cpu_context->cgrp. ] Signed-off-by: NStephane Eranian <eranian@google.com> Cc: peterz@infradead.org Cc: perfmon2-devel@lists.sf.net Cc: paulus@samba.org Cc: davem@davemloft.net LKML-Reference: <20110323150306.GA1580@quad> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 16 3月, 2011 3 次提交
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由 Peter Zijlstra 提交于
When destroying inherited events, we need to destroy groups too, otherwise the event iteration in perf_event_exit_task_context() will miss group siblings and we leak events with all the consequences. Reported-and-tested-by: NVince Weaver <vweaver1@eecs.utk.edu> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Cc: <stable@kernel.org> # .35+ LKML-Reference: <1300196470.2203.61.camel@twins> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Frederic Weisbecker 提交于
We toggle the state from start and stop callbacks but actually don't check it when the event triggers. Do it so that these callbacks actually work. Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Stephane Eranian <eranian@google.com> Cc: <stable@kernel.org> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1299529629-18280-2-git-send-email-fweisbec@gmail.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Frederic Weisbecker 提交于
Fix the mistakenly inverted check of events state. Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Stephane Eranian <eranian@google.com> Cc: <stable@kernel.org> LKML-Reference: <1299529629-18280-1-git-send-email-fweisbec@gmail.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 04 3月, 2011 5 次提交
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由 Peter Zijlstra 提交于
Li Zefan reported that the jump label code sleeps and we're calling it under a spinlock, *fail* ;-) Reported-by: NLi Zefan <lizf@cn.fujitsu.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Li Zefan 提交于
- Use kzalloc() to replace kmalloc() + memset(). - Remove redundant initialization, since alloc_percpu() returns zero-filled percpu memory. Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com> Acked-by: NStephane Eranian <eranian@google.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <4D6F347E.2010806@cn.fujitsu.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Li Zefan 提交于
In the failure path, we call perf_detach_cgroup(), but we didn't call perf_get_cgroup() prio to it. Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com> Acked-by: NStephane Eranian <eranian@google.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <4D6F346E.9070606@cn.fujitsu.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Li Zefan 提交于
In perf_cgroup_connect(), fput_light() is missing in a failure path. Signed-off-by: NLi Zefan <lizf@cn.fujitsu.com> Acked-by: NStephane Eranian <eranian@google.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <4D6F3461.6060406@cn.fujitsu.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Lin Ming 提交于
Currently, the event is not initialized if pmu is found in idr. This never causes bug just because now no pmu is associated with the idr id. Signed-off-by: NLin Ming <ming.m.lin@intel.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1298812411.2699.9.camel@localhost> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 23 2月, 2011 2 次提交
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由 Peter Zijlstra 提交于
There is no point in us having different code paths for nmi and !nmi here, so remove the !nmi one. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Cc: Stephane Eranian <eranian@google.com> LKML-Reference: <new-submission> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Stephane Eranian 提交于
This patches ensures that we do not end up calling perf_cgroup_from_task() when there is no cgroup event. This avoids potential RCU and locking issues. The change in perf_cgroup_set_timestamp() ensures we check against ctx->nr_cgroups. It also avoids calling perf_clock() tiwce in a row. It also ensures we do need to grab ctx->lock before calling the function. We drop update_cgrp_time() from task_clock_event_read() because it is not needed. This also avoids having to deal with perf_cgroup_from_task(). Thanks to Peter Zijlstra for his help on this. Signed-off-by: NStephane Eranian <eranian@gmail.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <4d5e76b8.815bdf0a.7ac3.774f@mx.google.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 16 2月, 2011 4 次提交
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由 Peter Zijlstra 提交于
There is no need to re-initialize the hrtimer every time we start it, so don't do that (shaves a few cycles). Also, since we know hrtimers run at a fixed rate (nanoseconds) we can pre-compute the desired frequency at which they tick. This avoids us having to go through the whole adaptive frequency feedback logic (shaves another few cycles). Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1297448589.5226.47.camel@laptop> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
By pre-computing the maximum number of samples per tick we can avoid a multiplication and a conditional since MAX_INTERRUPTS > max_samples_per_tick. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Stephane Eranian 提交于
This kernel patch adds the ability to filter monitoring based on container groups (cgroups). This is for use in per-cpu mode only. The cgroup to monitor is passed as a file descriptor in the pid argument to the syscall. The file descriptor must be opened to the cgroup name in the cgroup filesystem. For instance, if the cgroup name is foo and cgroupfs is mounted in /cgroup, then the file descriptor is opened to /cgroup/foo. Cgroup mode is activated by passing PERF_FLAG_PID_CGROUP in the flags argument to the syscall. For instance to measure in cgroup foo on CPU1 assuming cgroupfs is mounted under /cgroup: struct perf_event_attr attr; int cgroup_fd, fd; cgroup_fd = open("/cgroup/foo", O_RDONLY); fd = perf_event_open(&attr, cgroup_fd, 1, -1, PERF_FLAG_PID_CGROUP); close(cgroup_fd); Signed-off-by: NStephane Eranian <eranian@google.com> [ added perf_cgroup_{exit,attach} ] Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <4d590250.114ddf0a.689e.4482@mx.google.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
It was possible to call pmu::start() on an already running event. In particular this lead so some wreckage as the hrtimer events would re-initialize active timers. This was due to throttled events being activated again by scheduling. Scheduling in a context would add and force start events, resulting in running events with a possible throttle status. The next tick to hit that task will then try to unthrottle the event and call ->start() on an already running event. Reported-by: NJeff Moyer <jmoyer@redhat.com> Cc: <stable@kernel.org> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 03 2月, 2011 2 次提交
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由 Peter Zijlstra 提交于
It is quite possible for the event to have been disabled between perf_event_read() sending the IPI and the CPU servicing the IPI and calling __perf_event_read(), hence revalidate the state. Reported-by: NStephane Eranian <eranian@google.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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由 Peter Zijlstra 提交于
Oleg reported that on architectures with __ARCH_WANT_INTERRUPTS_ON_CTXSW the IPI from task_oncpu_function_call() can land before perf_event_task_sched_in() and cause interesting situations for eg. perf_install_in_context(). This patch reworks the task_oncpu_function_call() interface to give a more usable primitive as well as rework all its users to hopefully be more obvious as well as remove the races. While looking at the code I also found a number of races against perf_event_task_sched_out() which can flip contexts between tasks so plug those too. Reported-and-reviewed-by: NOleg Nesterov <oleg@redhat.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 28 1月, 2011 1 次提交
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由 Eric Dumazet 提交于
Commit 927c7a9e ("perf: Fix race in callchains") introduced a mismatch in the sizing of struct callchain_cpus_entries. nr_cpu_ids must be used instead of num_possible_cpus(), or we might get out of bound memory accesses on some machines. Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: David Miller <davem@davemloft.net> Cc: Stephane Eranian <eranian@google.com> CC: stable@kernel.org LKML-Reference: <1295980851.3588.351.camel@edumazet-laptop> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 22 1月, 2011 1 次提交
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由 Oleg Nesterov 提交于
In theory, almost every user of task->child->perf_event_ctxp[] is wrong. find_get_context() can install the new context at any moment, we need read_barrier_depends(). dbe08d82 "perf: Fix find_get_context() vs perf_event_exit_task() race" added rcu_dereference() into perf_event_exit_task_context() to make the precedent, but this makes __rcu_dereference_check() unhappy. Use rcu_dereference_raw() to shut up the warning. Reported-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NOleg Nesterov <oleg@redhat.com> Cc: acme@redhat.com Cc: paulus@samba.org Cc: stern@rowland.harvard.edu Cc: a.p.zijlstra@chello.nl Cc: fweisbec@gmail.com Cc: roland@redhat.com Cc: prasad@linux.vnet.ibm.com Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> LKML-Reference: <20110121174547.GA8796@redhat.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 21 1月, 2011 1 次提交
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由 Peter Zijlstra 提交于
Lockdep spotted: loop_1b_instruc/1899 is trying to acquire lock: (event_mutex){+.+.+.}, at: [<ffffffff810e1908>] perf_trace_init+0x3b/0x2f7 but task is already holding lock: (&ctx->mutex){+.+.+.}, at: [<ffffffff810eb45b>] perf_event_init_context+0xc0/0x218 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (&ctx->mutex){+.+.+.}: -> #2 (cpu_hotplug.lock){+.+.+.}: -> #1 (module_mutex){+.+...}: -> #0 (event_mutex){+.+.+.}: But because the deadlock would be cpuhotplug (cpu-event) vs fork (task-event) it cannot, in fact, happen. We can annotate this by giving the perf_event_context used for the cpuctx a different lock class from those used by tasks. Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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- 20 1月, 2011 1 次提交
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由 Oleg Nesterov 提交于
perf_event_init_task() should clear child->perf_event_ctxp[] before anything else. Otherwise, if perf_event_init_context(perf_hw_context) fails, perf_event_free_task() can free perf_event_ctxp[perf_sw_context] copied from parent->perf_event_ctxp[] by dup_task_struct(). Also move the initialization of perf_event_mutex and perf_event_list from perf_event_init_context() to perf_event_init_context(). Signed-off-by: NOleg Nesterov <oleg@redhat.com> Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> Cc: Alan Stern <stern@rowland.harvard.edu> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Prasad <prasad@linux.vnet.ibm.com> Cc: Roland McGrath <roland@redhat.com> LKML-Reference: <20110119182228.GC12183@redhat.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
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