[PATCH 5/8] ring-buffer: Make benchmark handle missed events
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From: Steven Rostedt on 27 Apr 2010 21:40 From: Steven Rostedt <srostedt(a)redhat.com> 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(a)elte.hu> Signed-off-by: Steven Rostedt <rostedt(a)goodmis.org> --- kernel/trace/ring_buffer_benchmark.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/kernel/trace/ring_buffer_benchmark.c b/kernel/trace/ring_buffer_benchmark.c index dc56556..302f8a6 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))) { -- 1.7.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |