From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cuda.sgi.com (cuda3.sgi.com [192.48.176.15]) by oss.sgi.com (8.14.3/8.14.3/SuSE Linux 0.8) with ESMTP id n2FBfJNc007742 for ; Sun, 15 Mar 2009 06:41:39 -0500 Received: from mail.internode.on.net (localhost [127.0.0.1]) by cuda.sgi.com (Spam Firewall) with ESMTP id B30371C43931 for ; Sun, 15 Mar 2009 04:40:56 -0700 (PDT) Received: from mail.internode.on.net (bld-mail11.adl2.internode.on.net [203.16.214.75]) by cuda.sgi.com with ESMTP id OnG0a6GuzlawkmNS for ; Sun, 15 Mar 2009 04:40:56 -0700 (PDT) Received: from destruction.internal (unverified [203.206.165.193]) by mail.internode.on.net (SurgeMail 3.8f2) with ESMTP id 46133687-1927428 for ; Sun, 15 Mar 2009 22:10:54 +1030 (CDT) Received: from dave by destruction.internal with local (Exim 4.69) (envelope-from ) id 1Liohw-0006l3-0l for xfs@oss.sgi.com; Sun, 15 Mar 2009 22:40:44 +1100 From: Dave Chinner Subject: [PATCH 2/2] XFS: Inform the xfsaild of the push target before sleeping Date: Sun, 15 Mar 2009 22:40:43 +1100 Message-Id: <1237117243-25940-3-git-send-email-david@fromorbit.com> In-Reply-To: <1237117243-25940-1-git-send-email-david@fromorbit.com> References: <1237117243-25940-1-git-send-email-david@fromorbit.com> List-Id: XFS Filesystem from SGI List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: xfs-bounces@oss.sgi.com Errors-To: xfs-bounces@oss.sgi.com To: xfs@oss.sgi.com When trying to reserve log space, we find the amount of space we need, then go to sleep waiting for space. When we are woken, we try to push the tail of the log forward to make sure we have space available. Unfortunately, this means that if there is not space available, and everyone who needs space goes to sleep there is no-one left to push the tail of the log to make space available. Once we have a thread waiting for space to become available, the others queue up behind it in a FIFO, and none of them push the tail of the log. This can result in everyone going to sleep in xlog_grant_log_space() if the first sleeper races with the last I/O that moves the tail of the log forward. With no further I/O tomove the tail of the log, there is nothing to wake the sleepers and hence all transactions just stop. Fix this by making sure the xfsaild will create enough space for the transaction that is about to sleep by moving the push target far enough forwards to ensure that that the curent proceeees will have enough space available when it is woken. That is, we push the AIL before we go to sleep. Because we've inserted the log ticket into the queue before we've pushed and gone to sleep, subsequent transactions will wait behind this one. Hence we are guaranteed to have space available when we are woken. Signed-off-by: Dave Chinner --- fs/xfs/xfs_log.c | 37 +++++++++++++++++++------------------ 1 files changed, 19 insertions(+), 18 deletions(-) diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 60e6e63..278960c 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -2573,18 +2573,19 @@ redo: xlog_ins_ticketq(&log->l_reserve_headq, tic); xlog_trace_loggrant(log, tic, "xlog_grant_log_space: sleep 2"); + spin_unlock(&log->l_grant_lock); + xlog_grant_push_ail(log->l_mp, need_bytes); + spin_lock(&log->l_grant_lock); + XFS_STATS_INC(xs_sleep_logspace); sv_wait(&tic->t_wait, PINOD|PLTWAIT, &log->l_grant_lock, s); - if (XLOG_FORCED_SHUTDOWN(log)) { - spin_lock(&log->l_grant_lock); + spin_lock(&log->l_grant_lock); + if (XLOG_FORCED_SHUTDOWN(log)) goto error_return; - } xlog_trace_loggrant(log, tic, "xlog_grant_log_space: wake 2"); - xlog_grant_push_ail(log->l_mp, need_bytes); - spin_lock(&log->l_grant_lock); goto redo; } else if (tic->t_flags & XLOG_TIC_IN_Q) xlog_del_ticketq(&log->l_reserve_headq, tic); @@ -2663,7 +2664,7 @@ xlog_regrant_write_log_space(xlog_t *log, * for more free space, otherwise try to get some space for * this transaction. */ - + need_bytes = tic->t_unit_res; if ((ntic = log->l_write_headq)) { free_bytes = xlog_space_left(log, log->l_grant_write_cycle, log->l_grant_write_bytes); @@ -2683,26 +2684,25 @@ xlog_regrant_write_log_space(xlog_t *log, xlog_trace_loggrant(log, tic, "xlog_regrant_write_log_space: sleep 1"); + spin_unlock(&log->l_grant_lock); + xlog_grant_push_ail(log->l_mp, need_bytes); + spin_lock(&log->l_grant_lock); + XFS_STATS_INC(xs_sleep_logspace); sv_wait(&tic->t_wait, PINOD|PLTWAIT, &log->l_grant_lock, s); /* If we're shutting down, this tic is already * off the queue */ - if (XLOG_FORCED_SHUTDOWN(log)) { - spin_lock(&log->l_grant_lock); + spin_lock(&log->l_grant_lock); + if (XLOG_FORCED_SHUTDOWN(log)) goto error_return; - } xlog_trace_loggrant(log, tic, "xlog_regrant_write_log_space: wake 1"); - xlog_grant_push_ail(log->l_mp, tic->t_unit_res); - spin_lock(&log->l_grant_lock); } } - need_bytes = tic->t_unit_res; - redo: if (XLOG_FORCED_SHUTDOWN(log)) goto error_return; @@ -2712,19 +2712,20 @@ redo: if (free_bytes < need_bytes) { if ((tic->t_flags & XLOG_TIC_IN_Q) == 0) xlog_ins_ticketq(&log->l_write_headq, tic); + spin_unlock(&log->l_grant_lock); + xlog_grant_push_ail(log->l_mp, need_bytes); + spin_lock(&log->l_grant_lock); + XFS_STATS_INC(xs_sleep_logspace); sv_wait(&tic->t_wait, PINOD|PLTWAIT, &log->l_grant_lock, s); /* If we're shutting down, this tic is already off the queue */ - if (XLOG_FORCED_SHUTDOWN(log)) { - spin_lock(&log->l_grant_lock); + spin_lock(&log->l_grant_lock); + if (XLOG_FORCED_SHUTDOWN(log)) goto error_return; - } xlog_trace_loggrant(log, tic, "xlog_regrant_write_log_space: wake 2"); - xlog_grant_push_ail(log->l_mp, need_bytes); - spin_lock(&log->l_grant_lock); goto redo; } else if (tic->t_flags & XLOG_TIC_IN_Q) xlog_del_ticketq(&log->l_write_headq, tic); -- 1.6.2 _______________________________________________ xfs mailing list xfs@oss.sgi.com http://oss.sgi.com/mailman/listinfo/xfs