perf evlist: Clarify a bit the use of perf_mmap->refcnt
authorArnaldo Carvalho de Melo <acme@redhat.com>
Thu, 23 Feb 2017 16:24:34 +0000 (13:24 -0300)
committerArnaldo Carvalho de Melo <acme@redhat.com>
Fri, 3 Mar 2017 22:07:16 +0000 (19:07 -0300)
commit4738ca30b4a7a113084d7863846175094f95c62f
tree838fdd3b49d186f5fda9b23ab567e003c0634567
parent364fed351369e0193244fa2c78df855724cdddb9
perf evlist: Clarify a bit the use of perf_mmap->refcnt

This is an odd refcount use case, so add some more comments to help
understand that when it hits zero it really means that the mmap()ed area
(on a perf_event_open() returned fd) has been munmap()ed.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Elena Reshetova <elena.reshetova@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/20170223162344.GD3595@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
tools/perf/util/evlist.c