xfs: split the CIL lock

The xc_cil_lock is used for two purposes - to protect the CIL
itself, and to protect the push/commit state and lists. These are
two logically separate structures and operations, so can have their
own locks. This means that pushing on the CIL and the commit wait
ordering won't contend for a lock with other transactions that are
completing concurrently. As the CIL insertion is the hottest path
throught eh CIL, this is a big win.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h
index edd0964fb65c..136654b9400d 100644
--- a/fs/xfs/xfs_log_priv.h
+++ b/fs/xfs/xfs_log_priv.h
@@ -278,14 +278,17 @@ struct xfs_cil {
 	struct xlog		*xc_log;
 	struct list_head	xc_cil;
 	spinlock_t		xc_cil_lock;
+
+	struct rw_semaphore	xc_ctx_lock ____cacheline_aligned_in_smp;
 	struct xfs_cil_ctx	*xc_ctx;
-	struct rw_semaphore	xc_ctx_lock;
+
+	spinlock_t		xc_push_lock ____cacheline_aligned_in_smp;
+	xfs_lsn_t		xc_push_seq;
 	struct list_head	xc_committing;
 	wait_queue_head_t	xc_commit_wait;
 	xfs_lsn_t		xc_current_sequence;
 	struct work_struct	xc_push_work;
-	xfs_lsn_t		xc_push_seq;
-};
+} ____cacheline_aligned_in_smp;
 
 /*
  * The amount of log space we allow the CIL to aggregate is difficult to size.