From d6a079e82efd5fcbb1c7295f22e123c2cc748018 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Fri, 11 Mar 2011 11:52:25 +0000 Subject: GFS2: introduce AIL lock The log lock is currently used to protect the AIL lists and the movements of buffers into and out of them. The lists are self contained and no log specific items outside the lists are accessed when starting or emptying the AIL lists. Hence the operation of the AIL does not require the protection of the log lock so split them out into a new AIL specific lock to reduce the amount of traffic on the log lock. This will also reduce the amount of serialisation that occurs when the gfs2_logd pushes on the AIL to move it forward. This reduces the impact of log pushing on sequential write throughput. Signed-off-by: Dave Chinner Signed-off-by: Steven Whitehouse --- fs/gfs2/log.c | 30 ++++++++++++++++-------------- 1 file changed, 16 insertions(+), 14 deletions(-) (limited to 'fs/gfs2/log.c') diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c index eb01f3575e10..4e3c044934e6 100644 --- a/fs/gfs2/log.c +++ b/fs/gfs2/log.c @@ -88,8 +88,8 @@ void gfs2_remove_from_ail(struct gfs2_bufdata *bd) */ static void gfs2_ail1_start_one(struct gfs2_sbd *sdp, struct gfs2_ail *ai) -__releases(&sdp->sd_log_lock) -__acquires(&sdp->sd_log_lock) +__releases(&sdp->sd_ail_lock) +__acquires(&sdp->sd_ail_lock) { struct gfs2_bufdata *bd, *s; struct buffer_head *bh; @@ -117,7 +117,7 @@ __acquires(&sdp->sd_log_lock) list_move(&bd->bd_ail_st_list, &ai->ai_ail1_list); get_bh(bh); - gfs2_log_unlock(sdp); + spin_unlock(&sdp->sd_ail_lock); lock_buffer(bh); if (test_clear_buffer_dirty(bh)) { bh->b_end_io = end_buffer_write_sync; @@ -126,7 +126,7 @@ __acquires(&sdp->sd_log_lock) unlock_buffer(bh); brelse(bh); } - gfs2_log_lock(sdp); + spin_lock(&sdp->sd_ail_lock); retry = 1; break; @@ -175,10 +175,10 @@ static void gfs2_ail1_start(struct gfs2_sbd *sdp) struct gfs2_ail *ai; int done = 0; - gfs2_log_lock(sdp); + spin_lock(&sdp->sd_ail_lock); head = &sdp->sd_ail1_list; if (list_empty(head)) { - gfs2_log_unlock(sdp); + spin_unlock(&sdp->sd_ail_lock); return; } sync_gen = sdp->sd_ail_sync_gen++; @@ -189,13 +189,13 @@ static void gfs2_ail1_start(struct gfs2_sbd *sdp) if (ai->ai_sync_gen >= sync_gen) continue; ai->ai_sync_gen = sync_gen; - gfs2_ail1_start_one(sdp, ai); /* This may drop log lock */ + gfs2_ail1_start_one(sdp, ai); /* This may drop ail lock */ done = 0; break; } } - gfs2_log_unlock(sdp); + spin_unlock(&sdp->sd_ail_lock); } static int gfs2_ail1_empty(struct gfs2_sbd *sdp, int flags) @@ -203,7 +203,7 @@ static int gfs2_ail1_empty(struct gfs2_sbd *sdp, int flags) struct gfs2_ail *ai, *s; int ret; - gfs2_log_lock(sdp); + spin_lock(&sdp->sd_ail_lock); list_for_each_entry_safe_reverse(ai, s, &sdp->sd_ail1_list, ai_list) { if (gfs2_ail1_empty_one(sdp, ai, flags)) @@ -214,7 +214,7 @@ static int gfs2_ail1_empty(struct gfs2_sbd *sdp, int flags) ret = list_empty(&sdp->sd_ail1_list); - gfs2_log_unlock(sdp); + spin_unlock(&sdp->sd_ail_lock); return ret; } @@ -247,7 +247,7 @@ static void ail2_empty(struct gfs2_sbd *sdp, unsigned int new_tail) int wrap = (new_tail < old_tail); int a, b, rm; - gfs2_log_lock(sdp); + spin_lock(&sdp->sd_ail_lock); list_for_each_entry_safe(ai, safe, &sdp->sd_ail2_list, ai_list) { a = (old_tail <= ai->ai_first); @@ -263,7 +263,7 @@ static void ail2_empty(struct gfs2_sbd *sdp, unsigned int new_tail) kfree(ai); } - gfs2_log_unlock(sdp); + spin_unlock(&sdp->sd_ail_lock); } /** @@ -421,7 +421,7 @@ static unsigned int current_tail(struct gfs2_sbd *sdp) struct gfs2_ail *ai; unsigned int tail; - gfs2_log_lock(sdp); + spin_lock(&sdp->sd_ail_lock); if (list_empty(&sdp->sd_ail1_list)) { tail = sdp->sd_log_head; @@ -430,7 +430,7 @@ static unsigned int current_tail(struct gfs2_sbd *sdp) tail = ai->ai_first; } - gfs2_log_unlock(sdp); + spin_unlock(&sdp->sd_ail_lock); return tail; } @@ -743,10 +743,12 @@ void gfs2_log_flush(struct gfs2_sbd *sdp, struct gfs2_glock *gl) sdp->sd_log_commited_databuf = 0; sdp->sd_log_commited_revoke = 0; + spin_lock(&sdp->sd_ail_lock); if (!list_empty(&ai->ai_ail1_list)) { list_add(&ai->ai_list, &sdp->sd_ail1_list); ai = NULL; } + spin_unlock(&sdp->sd_ail_lock); gfs2_log_unlock(sdp); trace_gfs2_log_flush(sdp, 0); up_write(&sdp->sd_log_flush_lock); -- cgit v1.2.3-58-ga151