mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-23 20:53:53 +08:00
d8a8cfc769
While going through the event inheritance code Oleg got confused. Add some comments to better explain the silent dissapearance of orphaned events. So what happens is that at perf_event_release_kernel() time; when an event looses its connection to userspace (and ceases to exist from the user's perspective) we can still have an arbitrary amount of inherited copies of the event. We want to synchronously find and remove all these child events. Since that requires a bit of lock juggling, there is the possibility that concurrent clone()s will create new child events. Therefore we first mark the parent event as DEAD, which marks all the extant child events as orphaned. We then avoid copying orphaned events; in order to avoid getting more of them. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: fweisbec@gmail.com Link: http://lkml.kernel.org/r/20170316125823.289567442@infradead.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|---|---|---|
| .. | ||
| callchain.c | ||
| core.c | ||
| hw_breakpoint.c | ||
| internal.h | ||
| Makefile | ||
| ring_buffer.c | ||
| uprobes.c | ||