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ring-buffer: Make benchmark handle missed events

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With the addition of the "missed events" flags that is stored in the
commit field of the ring buffer page, the ring_buffer_benchmark
was not updated to handle this. If events are missed, then the
missed events flag is set in the ring buffer page, the benchmark
will count that flag as part of the size of the page and will hit the BUG()
when it tries to read beyond the page.

The solution is simply to have the ring buffer benchmark mask off
the extra bits.

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Steven Rostedt 2010-04-27 13:26:58 -04:00 committed by Steven Rostedt
parent 72c9ddfd4c
commit a838b2e634
1 changed files with 2 additions and 1 deletions
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3
kernel/trace/ring_buffer_benchmark.c
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@ -113,7 +113,8 @@ static enum event_status read_page(int cpu)
ret = ring_buffer_read_page(buffer, &bpage, PAGE_SIZE, cpu, 1);
if (ret >= 0) {
rpage = bpage;
commit = local_read(&rpage->commit);
/* The commit may have missed event flags set, clear them */
commit = local_read(&rpage->commit) & 0xfffff;
for (i = 0; i < commit && !kill_test; i += inc) {
if (i >= (PAGE_SIZE - offsetof(struct rb_page, data))) {