From 26b06a6958df0f12f1a654db8598433eb89cc024 Mon Sep 17 00:00:00 2001 From: Steven Whitehouse Date: Sat, 21 May 2011 19:21:07 +0100 Subject: [PATCH] GFS2: Wait properly when flushing the ail list The ail flush code has always relied upon log flushing to prevent it from spinning needlessly. This fixes it to wait on the last I/O request submitted (we don't need to wait for all of it) instead of either spinning with io_schedule or sleeping. As a result cpu usage of gfs2_logd is much reduced with certain workloads. Reported-by: Abhijith Das Tested-by: Abhijith Das Signed-off-by: Steven Whitehouse --- fs/gfs2/log.c | 29 ++++++++++++++++++++++++++--- 1 file changed, 26 insertions(+), 3 deletions(-) diff --git a/fs/gfs2/log.c b/fs/gfs2/log.c index cec26c00b50d..903115f2bb34 100644 --- a/fs/gfs2/log.c +++ b/fs/gfs2/log.c @@ -228,6 +228,27 @@ static int gfs2_ail1_empty(struct gfs2_sbd *sdp) return ret; } +static void gfs2_ail1_wait(struct gfs2_sbd *sdp) +{ + struct gfs2_ail *ai; + struct gfs2_bufdata *bd; + struct buffer_head *bh; + + spin_lock(&sdp->sd_ail_lock); + list_for_each_entry_reverse(ai, &sdp->sd_ail1_list, ai_list) { + list_for_each_entry(bd, &ai->ai_ail1_list, bd_ail_st_list) { + bh = bd->bd_bh; + if (!buffer_locked(bh)) + continue; + get_bh(bh); + spin_unlock(&sdp->sd_ail_lock); + wait_on_buffer(bh); + brelse(bh); + return; + } + } + spin_unlock(&sdp->sd_ail_lock); +} /** * gfs2_ail2_empty_one - Check whether or not a trans in the AIL has been synced @@ -878,9 +899,9 @@ void gfs2_meta_syncfs(struct gfs2_sbd *sdp) gfs2_log_flush(sdp, NULL); for (;;) { gfs2_ail1_start(sdp); + gfs2_ail1_wait(sdp); if (gfs2_ail1_empty(sdp)) break; - msleep(10); } } @@ -920,12 +941,14 @@ int gfs2_logd(void *data) if (gfs2_ail_flush_reqd(sdp)) { gfs2_ail1_start(sdp); - io_schedule(); + gfs2_ail1_wait(sdp); gfs2_ail1_empty(sdp); gfs2_log_flush(sdp, NULL); } - wake_up(&sdp->sd_log_waitq); + if (!gfs2_ail_flush_reqd(sdp)) + wake_up(&sdp->sd_log_waitq); + t = gfs2_tune_get(sdp, gt_logd_secs) * HZ; if (freezing(current)) refrigerator(); -- 2.20.1