From fd074841cfe01b006465fb9388091012585e8dfb Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Fri, 8 Apr 2011 12:45:07 +1000 Subject: xfs: push the AIL from memory reclaim and periodic sync When we are short on memory, we want to expedite the cleaning of dirty objects. Hence when we run short on memory, we need to kick the AIL flushing into action to clean as many dirty objects as quickly as possible. To implement this, sample the lsn of the log item at the head of the AIL and use that as the push target for the AIL flush. Further, we keep items in the AIL that are dirty that are not tracked any other way, so we can get objects sitting in the AIL that don't get written back until the AIL is pushed. Hence to get the filesystem to the idle state, we might need to push the AIL to flush out any remaining dirty objects sitting in the AIL. This requires the same push mechanism as the reclaim push. This patch also renames xfs_trans_ail_tail() to xfs_ail_min_lsn() to match the new xfs_ail_max_lsn() function introduced in this patch. Similarly for xfs_trans_ail_push -> xfs_ail_push. Signed-off-by: Dave Chinner Reviewed-by: Alex Elder --- fs/xfs/xfs_log.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'fs/xfs/xfs_log.c') diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 25efa9b8a602..24643169e632 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -761,7 +761,7 @@ xfs_log_need_covered(xfs_mount_t *mp) break; case XLOG_STATE_COVER_NEED: case XLOG_STATE_COVER_NEED2: - if (!xfs_trans_ail_tail(log->l_ailp) && + if (!xfs_ail_min_lsn(log->l_ailp) && xlog_iclogs_empty(log)) { if (log->l_covered_state == XLOG_STATE_COVER_NEED) log->l_covered_state = XLOG_STATE_COVER_DONE; @@ -801,7 +801,7 @@ xlog_assign_tail_lsn( xfs_lsn_t tail_lsn; struct log *log = mp->m_log; - tail_lsn = xfs_trans_ail_tail(mp->m_ail); + tail_lsn = xfs_ail_min_lsn(mp->m_ail); if (!tail_lsn) tail_lsn = atomic64_read(&log->l_last_sync_lsn); @@ -1239,7 +1239,7 @@ xlog_grant_push_ail( * the filesystem is shutting down. */ if (!XLOG_FORCED_SHUTDOWN(log)) - xfs_trans_ail_push(log->l_ailp, threshold_lsn); + xfs_ail_push(log->l_ailp, threshold_lsn); } /* -- cgit v1.2.3 From da8a1a4a4dfc1ead12c343b992fc8300a22d33d0 Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Fri, 8 Apr 2011 12:45:07 +1000 Subject: xfs: convert log tail checking to a warning On the Power platform, the log tail debug checks fire excessively causing the system to panic early in testing. The debug checks are known to be racy, though on x86_64 there is no evidence that they trigger at all. We want to keep the checks active on debug systems to alert us to problems with log space accounting, but we need to reduce the impact of a racy check on testing on the Power platform. As a result, convert the ASSERT conditions to warnings, and allow them to fire only once per filesystem mount. This will prevent false positives from interfering with testing, whilst still providing us with the indication that they may be a problem with log space accounting should that occur. Signed-off-by: Dave Chinner Reviewed-by: Christoph Hellwig Reviewed-by: Alex Elder --- fs/xfs/xfs_log.c | 32 ++++++++++++++++++++++++-------- 1 file changed, 24 insertions(+), 8 deletions(-) (limited to 'fs/xfs/xfs_log.c') diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 24643169e632..b612ce4520ae 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -3407,6 +3407,17 @@ xlog_verify_dest_ptr( xfs_emerg(log->l_mp, "%s: invalid ptr", __func__); } +/* + * Check to make sure the grant write head didn't just over lap the tail. If + * the cycles are the same, we can't be overlapping. Otherwise, make sure that + * the cycles differ by exactly one and check the byte count. + * + * This check is run unlocked, so can give false positives. Rather than assert + * on failures, use a warn-once flag and a panic tag to allow the admin to + * determine if they want to panic the machine when such an error occurs. For + * debug kernels this will have the same effect as using an assert but, unlinke + * an assert, it can be turned off at runtime. + */ STATIC void xlog_verify_grant_tail( struct log *log) @@ -3414,17 +3425,22 @@ xlog_verify_grant_tail( int tail_cycle, tail_blocks; int cycle, space; - /* - * Check to make sure the grant write head didn't just over lap the - * tail. If the cycles are the same, we can't be overlapping. - * Otherwise, make sure that the cycles differ by exactly one and - * check the byte count. - */ xlog_crack_grant_head(&log->l_grant_write_head, &cycle, &space); xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_blocks); if (tail_cycle != cycle) { - ASSERT(cycle - 1 == tail_cycle); - ASSERT(space <= BBTOB(tail_blocks)); + if (cycle - 1 != tail_cycle && + !(log->l_flags & XLOG_TAIL_WARN)) { + xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES, + "%s: cycle - 1 != tail_cycle", __func__); + log->l_flags |= XLOG_TAIL_WARN; + } + + if (space > BBTOB(tail_blocks) && + !(log->l_flags & XLOG_TAIL_WARN)) { + xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES, + "%s: space > BBTOB(tail_blocks)", __func__); + log->l_flags |= XLOG_TAIL_WARN; + } } } -- cgit v1.2.3