linux/kernel/events/core.c, branch v3.6

perf/hwpb: Invoke __perf_event_disable() if interrupts are already disabled

2012-09-04T15:29:53Z

While debugging a warning message on PowerPC while using hardware breakpoints, it was discovered that when perf_event_disable is invoked through hw_breakpoint_handler function with interrupts disabled, a subsequent IPI in the code path would trigger a WARN_ON_ONCE message in smp_call_function_single function. This patch calls __perf_event_disable() when interrupts are already disabled, instead of perf_event_disable(). Reported-by: Edjunior Barbosa Machado Signed-off-by: K.Prasad [naveen.n.rao@linux.vnet.ibm.com: v3: Check to make sure we target current task] Signed-off-by: Naveen N. Rao Acked-by: Frederic Weisbecker Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20120802081635.5811.17737.stgit@localhost.localdomain [ Fixed build error on MIPS. ] Signed-off-by: Ingo Molnar

perf_event: Switch to internal refcount, fix race with close()

2012-09-04T15:29:22Z

Don't mess with file refcounts (or keep a reference to file, for that matter) in perf_event. Use explicit refcount of its own instead. Deal with the race between the final reference to event going away and new children getting created for it by use of atomic_long_inc_not_zero() in inherit_event(); just have the latter free what it had allocated and return NULL, that works out just fine (children of siblings of something doomed are created as singletons, same as if the child of leader had been created and immediately killed). Signed-off-by: Al Viro Cc: stable@kernel.org Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20120820135925.GG23464@ZenIV.linux.org.uk Signed-off-by: Ingo Molnar

perf/trace: Add ability to set a target task for events

2012-07-31T15:02:05Z

A few events are interesting not only for a current task. For example, sched_stat_* events are interesting for a task which wakes up. For this reason, it will be good if such events will be delivered to a target task too. Now a target task can be set by using __perf_task(). The original idea and a draft patch belongs to Peter Zijlstra. I need these events for profiling sleep times. sched_switch is used for getting callchains and sched_stat_* is used for getting time periods. These events are combined in user space, then it can be analyzed by perf tools. Inspired-by: Peter Zijlstra Cc: Steven Rostedt Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: Steven Rostedt Cc: Arun Sharma Signed-off-by: Andrew Vagin Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1342016098-213063-1-git-send-email-avagin@openvz.org Signed-off-by: Ingo Molnar

perf: Introduce perf_pmu_migrate_context()

2012-06-18T10:13:21Z

Originally from Peter Zijlstra. The helper migrates perf events from one cpu to another cpu. Signed-off-by: Zheng Yan Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1339741902-8449-5-git-send-email-zheng.z.yan@intel.com Signed-off-by: Ingo Molnar

perf: Allow the PMU driver to choose the CPU on which to install events

2012-06-18T10:13:21Z

Allow the pmu->event_init callback to change event->cpu, so the PMU driver can choose the CPU on which to install events. Signed-off-by: Zheng Yan Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1339741902-8449-4-git-send-email-zheng.z.yan@intel.com Signed-off-by: Ingo Molnar

perf: Avoid race between cpu hotplug and installing event

2012-06-18T10:13:20Z

perf_event_open() requires the cpu on which to install event is online, but the cpu can go offline after perf_event_open checks that. Add a get_online_cpus()/put_online_cpus() pair to avoid the race. Signed-off-by: Zheng Yan Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1339741902-8449-3-git-send-email-zheng.z.yan@intel.com Signed-off-by: Ingo Molnar

perf: Use css_tryget() to avoid propping up css refcount

2012-06-18T09:45:57Z

An rmdir pushes css's ref count to zero. However, if the associated directory is open at the time, the dentry ref count is non-zero. If the fd for this directory is then passed into perf_event_open, it does a css_get(). This bounces the ref count back up from zero. This is a problem by itself. But what makes it turn into a crash is the fact that we end up doing an extra dput, since we perform a dput when css_put sees the ref count go down to zero. css_tryget() does not fall into that trap. So, we use that instead. Reproduction test-case for the bug: #include #include #include #include #include #include #include #include #include #define PERF_FLAG_PID_CGROUP (1U << 2) int perf_event_open(struct perf_event_attr *hw_event_uptr, pid_t pid, int cpu, int group_fd, unsigned long flags) { return syscall(__NR_perf_event_open,hw_event_uptr, pid, cpu, group_fd, flags); } /* * Directly poke at the perf_event bug, since it's proving hard to repro * depending on where in the kernel tree. what moved? */ int main(int argc, char **argv) { int fd; struct perf_event_attr attr; memset(&attr, 0, sizeof(attr)); attr.exclude_kernel = 1; attr.size = sizeof(attr); mkdir("/dev/cgroup/perf_event/blah", 0777); fd = open("/dev/cgroup/perf_event/blah", O_RDONLY); perror("open"); rmdir("/dev/cgroup/perf_event/blah"); sleep(2); perf_event_open(&attr, fd, 0, -1, PERF_FLAG_PID_CGROUP); perror("perf_event_open"); close(fd); return 0; } Signed-off-by: Salman Qazi Signed-off-by: Peter Zijlstra Acked-by: Tejun Heo Link: http://lkml.kernel.org/r/20120614223108.1025.2503.stgit@dungbeetle.mtv.corp.google.com Signed-off-by: Ingo Molnar

perf: Remove duplicate invocation on perf_event_for_each

2012-05-31T17:01:00Z

The @func callback was invoked twice for group leader when perf_event_for_each() called. It seems the commit 75f937f24bd9 ("perf_counter: Fix ctx->mutex vs counter ->mutex inversion") made the mistake during the change. Signed-off-by: Namhyung Kim Acked-by: Peter Zijlstra Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1338443506-25009-1-git-send-email-namhyung.kim@lge.com Signed-off-by: Arnaldo Carvalho de Melo

Revert "sched, perf: Use a single callback into the scheduler"

2012-05-23T15:40:51Z

This reverts commit cb04ff9ac424 ("sched, perf: Use a single callback into the scheduler"). Before this change was introduced, the process switch worked like this (wrt. to perf event schedule): schedule (prev, next) - schedule out all perf events for prev - switch to next - schedule in all perf events for current (next) After the commit, the process switch looks like: schedule (prev, next) - schedule out all perf events for prev - schedule in all perf events for (next) - switch to next The problem is, that after we schedule perf events in, the pmu is enabled and we can receive events even before we make the switch to next - so "current" still being prev process (event SAMPLE data are filled based on the value of the "current" process). Thats exactly what we see for test__PERF_RECORD test. We receive SAMPLES with PID of the process that our tracee is scheduled from. Discussed with Peter Zijlstra: > Bah!, yeah I guess reverting is the right thing for now. Sad > though. > > So by having the two hooks we have a black-spot between them > where we receive no events at all, this black-spot covers the > hand-over of current and we thus don't receive the 'wrong' > events. > > I rather liked we could do away with both that black-spot and > clean up the code a little, but apparently people rely on it. Signed-off-by: Jiri Olsa Acked-by: Peter Zijlstra Cc: acme@redhat.com Cc: paulus@samba.org Cc: cjashfor@linux.vnet.ibm.com Cc: fweisbec@gmail.com Cc: eranian@google.com Link: http://lkml.kernel.org/r/20120523111302.GC1638@m.brq.redhat.com Signed-off-by: Ingo Molnar

Merge remote-tracking branch 'tip/perf/urgent' into perf/core

2012-05-18T16:13:33Z

Merge reason: We are going to queue up a dependent patch: "perf tools: Move parse event automated tests to separated object" That depends on: commit e7c72d8 perf tools: Add 'G' and 'H' modifiers to event parsing Conflicts: tools/perf/builtin-stat.c Conflicted with the recent 'perf_target' patches when checking the result of perf_evsel open routines to see if a retry is needed to cope with older kernels where the exclude guest/host perf_event_attr bits were not used. Signed-off-by: Arnaldo Carvalho de Melo