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authorSteven Rostedt <srostedt@redhat.com>2010-04-27 21:26:58 +0400
committerSteven Rostedt <rostedt@goodmis.org>2010-04-27 21:26:58 +0400
commita838b2e634405fb89ddbf4fa9412acb33911911f (patch)
tree987cb7b9bb5f7558b72760ba18a0979ac19212fd /kernel/trace
parent72c9ddfd4c5bf54ef03cfdf57026416cb678eeba (diff)
downloadlinux-a838b2e634405fb89ddbf4fa9412acb33911911f.tar.xz
ring-buffer: Make benchmark handle missed events
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>
Diffstat (limited to 'kernel/trace')
-rw-r--r--kernel/trace/ring_buffer_benchmark.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c
index dc56556b55a2..302f8a614635 100644
--- a/kernel/trace/ring_buffer_benchmark.c
+++ b/kernel/trace/ring_buffer_benchmark.c
@@ -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))) {