kernel-ark/kernel/events
Jiri Olsa fadfe7be6e perf: Add queued work to remove orphaned child events
In cases when the  owner task exits before the workload and the
workload made some forks, all the events stay in until the last
workload process exits. Thats' because each child event holds
parent reference.

We want to release all children events once the parent is gone,
because at that time there's no process to read them anyway, so
they're just eating resources.

This removal  races with process exit, which removes all events
and fork, which clone events.  To be clear of those two, adding
work queue to remove orphaned child for context in case such
event is detected.

Using delayed work queue (with delay == 1), because we queue this
work under perf scheduler callbacks. Normal work queue tries to wake
up the queue process, which deadlocks on rq->lock in this place.

Also preventing clones from abandoned parent event.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/1406896382-18404-4-git-send-email-jolsa@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-08-13 07:51:04 +02:00
..
callchain.c perf: Roll back callchain buffer refcount under the callchain mutex 2013-08-16 17:55:50 +02:00
core.c perf: Add queued work to remove orphaned child events 2014-08-13 07:51:04 +02:00
hw_breakpoint.c hw_breakpoint: Introduce "struct bp_cpuinfo" 2013-06-20 17:58:57 +02:00
internal.h perf: Fix arch_perf_out_copy_user default 2013-11-06 12:34:25 +01:00
Makefile uprobes: Move to kernel/events/ 2012-02-22 11:08:00 +01:00
ring_buffer.c perf: Optimize ring-buffer write by depending on control dependencies 2013-12-11 15:53:22 +01:00
uprobes.c uprobes: Change unregister/apply to WARN() if uprobe/consumer is gone 2014-06-30 13:22:15 -04:00