Commit-ID: 8e7abf1c62941ebb7a1416cbc62392c8a0902625 Gitweb: http://git.kernel.org/tip/8e7abf1c62941ebb7a1416cbc62392c8a0902625 Author: Steven Rostedt <srostedt@xxxxxxxxxx> AuthorDate: Wed, 6 May 2009 10:26:45 -0400 Committer: Steven Rostedt <rostedt@xxxxxxxxxxx> CommitDate: Wed, 6 May 2009 12:49:19 -0400 ring-buffer: remove unneeded conditional in rb_reserve_next The code in __rb_reserve_next checks on page overflow if it is the original commiter and then resets the page back to the original setting. Although this is fine, and the code is correct, it is a bit fragil. Some experimental work I did breaks it easily. The better and more robust solution is to have all commiters that overflow the page, simply subtract what they added. [ Impact: more robust ring buffer account management ] Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx> --- kernel/trace/ring_buffer.c | 8 +++----- 1 files changed, 3 insertions(+), 5 deletions(-) diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 424129e..03ed52b 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -1290,9 +1290,8 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, rb_event_set_padding(event); } - if (tail <= BUF_PAGE_SIZE) - /* Set the write back to the previous setting */ - local_set(&tail_page->write, tail); + /* Set the write back to the previous setting */ + local_sub(length, &tail_page->write); /* * If this was a commit entry that failed, @@ -1311,8 +1310,7 @@ __rb_reserve_next(struct ring_buffer_per_cpu *cpu_buffer, out_reset: /* reset write */ - if (tail <= BUF_PAGE_SIZE) - local_set(&tail_page->write, tail); + local_sub(length, &tail_page->write); if (likely(lock_taken)) __raw_spin_unlock(&cpu_buffer->lock); -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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