diff options
| author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2010-05-20 16:21:55 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2010-05-21 11:37:58 +0200 |
| commit | adb8e118f288dc4c569ac9a89010b81a4745fbf0 (patch) | |
| tree | 40f2bbbe7c59fb4b4a44120fa9cc79822b68e545 /kernel/perf_event.c | |
| parent | 0e2e63dd608bf5844ffae7bf7d860de18a62724c (diff) | |
perf: Fix wakeup storm for RO mmap()s
RO mmap()s don't update the tail pointer, so
comparing against it for determining the written data
size doesn't really do any good.
Keep track of when we last did a wakeup, and compare
against that.
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
LKML-Reference: <20100521090710.684479310@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/perf_event.c')
| -rw-r--r-- | kernel/perf_event.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 7a932526946..1531e0b409a 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -3056,8 +3056,8 @@ int perf_output_begin(struct perf_output_handle *handle, handle->offset = offset; handle->head = head; - if (head - tail > data->watermark) - local_inc(&data->wakeup); + if (head - local_read(&data->wakeup) > data->watermark) + local_add(data->watermark, &data->wakeup); if (have_lost) { lost_event.header.type = PERF_RECORD_LOST; |