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Commit 479c6412 authored Jun 21, 2016 by Darrick J. Wong Committed by Dave Chinner Jun 21, 2016

xfs: enable buffer deadlock postmortem diagnosis via ftrace



Create a second buf_trylock tracepoint so that we can distinguish
between a successful and a failed trylock.  With this piece, we can
use a script to look at the ftrace output to detect buffer deadlocks.

[dchinner: update to if/else as per hch's suggestion]

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>

parent 3f94c441

fs/xfs/xfs_buf.c

+5 −3

Original line number	Diff line number	Diff line
		@@ -944,10 +944,12 @@ xfs_buf_trylock(
		int locked;

		locked = down_trylock(&bp->b_sema) == 0;
		if (locked)
		if (locked) {
		XB_SET_OWNER(bp);

		trace_xfs_buf_trylock(bp, _RET_IP_);
		} else {
		trace_xfs_buf_trylock_fail(bp, _RET_IP_);
		}
		return locked;
		}

fs/xfs/xfs_trace.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -354,6 +354,7 @@ DEFINE_BUF_EVENT(xfs_buf_submit_wait);
		DEFINE_BUF_EVENT(xfs_buf_bawrite);
		DEFINE_BUF_EVENT(xfs_buf_lock);
		DEFINE_BUF_EVENT(xfs_buf_lock_done);
		DEFINE_BUF_EVENT(xfs_buf_trylock_fail);
		DEFINE_BUF_EVENT(xfs_buf_trylock);
		DEFINE_BUF_EVENT(xfs_buf_unlock);
		DEFINE_BUF_EVENT(xfs_buf_iowait);