xfs: add trace points for log forces (14c26c6a) · Commits · 戴 / test

To enable easy tracing of the location of log forces and the frequency of them via perf, add a pair of trace points to the log force functions. This will help debug where excessive log forces are being issued from by simple perf commands like: # ~/perf/perf top -e xfs:xfs_log_force -G -U Which gives this sort of output: Events: 141 xfs:xfs_log_force - 100.00% [kernel] [k] xfs_log_force - xfs_log_force 87.04% xfsaild kthread kernel_thread_helper - 12.87% xfs_buf_lock _xfs_buf_find xfs_buf_get xfs_trans_get_buf xfs_da_do_buf xfs_da_get_buf xfs_dir2_data_init xfs_dir2_leaf_addname xfs_dir_createname xfs_create xfs_vn_mknod xfs_vn_create vfs_create do_last.isra.41 path_openat do_filp_open do_sys_open sys_open system_call_fastpath Signed-off-by:

Dave Chinner <dchinner@redhat.com> Reviewed-by:

Mark Tinguely <tinguely@sgi.com> Signed-off-by:

Ben Myers <bpm@sig.com>

fs/xfs/xfs_log.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -2941,6 +2941,7 @@ xfs_log_force(
		{
		int error;

		trace_xfs_log_force(mp, 0);
		error = _xfs_log_force(mp, flags, NULL);
		if (error)
		xfs_warn(mp, "%s: error %d returned.", __func__, error);
		@@ -3089,6 +3090,7 @@ xfs_log_force_lsn(
		{
		int error;

		trace_xfs_log_force(mp, lsn);
		error = _xfs_log_force_lsn(mp, lsn, flags, NULL);
		if (error)
		xfs_warn(mp, "%s: error %d returned.", __func__, error);

fs/xfs/xfs_trace.h

+16 −0

Original line number	Diff line number	Diff line
		@@ -874,6 +874,22 @@ DECLARE_EVENT_CLASS(xfs_log_item_class,
		__print_flags(__entry->flags, "\|", XFS_LI_FLAGS))
		)

		TRACE_EVENT(xfs_log_force,
		TP_PROTO(struct xfs_mount *mp, xfs_lsn_t lsn),
		TP_ARGS(mp, lsn),
		TP_STRUCT__entry(
		__field(dev_t, dev)
		__field(xfs_lsn_t, lsn)
		),
		TP_fast_assign(
		__entry->dev = mp->m_super->s_dev;
		__entry->lsn = lsn;
		),
		TP_printk("dev %d:%d lsn 0x%llx",
		MAJOR(__entry->dev), MINOR(__entry->dev),
		__entry->lsn)
		)

		#define DEFINE_LOG_ITEM_EVENT(name) \
		DEFINE_EVENT(xfs_log_item_class, name, \
		TP_PROTO(struct xfs_log_item *lip), \

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