From 27d8d5fe0ef9daeaafbdd32b14b32a2211930062 Mon Sep 17 00:00:00 2001 From: David Chinner Date: Thu, 30 Oct 2008 17:38:39 +1100 Subject: [XFS] Use a cursor for AIL traversal. To replace the current generation number ensuring sanity of the AIL traversal, replace it with an external cursor that is linked to the AIL. Basically, we store the next item in the cursor whenever we want to drop the AIL lock to do something to the current item. When we regain the lock. the current item may already be free, so we can't reference it, but the next item in the traversal is already held in the cursor. When we move or delete an object, we search all the active cursors and if there is an item match we clear the cursor(s) that point to the object. This forces the traversal to restart transparently. We don't invalidate the cursor on insert because the cursor still points to a valid item. If the intem is inserted between the current item and the cursor it does not matter; the traversal is considered to be past the insertion point so it will be picked up in the next traversal. Hence traversal restarts pretty much disappear altogether with this method of traversal, which should substantially reduce the overhead of pushing on a busy AIL. Version 2 o add restart logic o comment cursor interface o minor cleanups SGI-PV: 988143 SGI-Modid: xfs-linux-melb:xfs-kern:32347a Signed-off-by: David Chinner Signed-off-by: Lachlan McIlroy Signed-off-by: Christoph Hellwig --- fs/xfs/xfs_log.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/xfs/xfs_log.c') diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 0b02c6443551..4184085d44af 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -900,7 +900,7 @@ xfs_log_move_tail(xfs_mount_t *mp, int xfs_log_need_covered(xfs_mount_t *mp) { - int needed = 0, gen; + int needed = 0; xlog_t *log = mp->m_log; if (!xfs_fs_writable(mp)) @@ -909,7 +909,7 @@ xfs_log_need_covered(xfs_mount_t *mp) spin_lock(&log->l_icloglock); if (((log->l_covered_state == XLOG_STATE_COVER_NEED) || (log->l_covered_state == XLOG_STATE_COVER_NEED2)) - && !xfs_trans_first_ail(mp, &gen) + && !xfs_trans_first_ail(mp, NULL) && xlog_iclogs_empty(log)) { if (log->l_covered_state == XLOG_STATE_COVER_NEED) log->l_covered_state = XLOG_STATE_COVER_DONE; -- cgit v1.2.2 From 5b00f14fbd60d42441f78c0e414a539cbfba5cb9 Mon Sep 17 00:00:00 2001 From: David Chinner Date: Thu, 30 Oct 2008 17:39:00 +1100 Subject: [XFS] move the AIl traversal over to a consistent interface With the new cursor interface, it makes sense to make all the traversing code use the cursor interface and make the old one go away. This means more of the AIL interfacing is done by passing struct xfs_ail pointers around the place instead of struct xfs_mount pointers. We can replace the use of xfs_trans_first_ail() in xfs_log_need_covered() as it is only checking if the AIL is empty. We can do that with a call to xfs_trans_ail_tail() instead, where a zero LSN returned indicates and empty AIL... SGI-PV: 988143 SGI-Modid: xfs-linux-melb:xfs-kern:32348a Signed-off-by: David Chinner Signed-off-by: Lachlan McIlroy Signed-off-by: Christoph Hellwig --- fs/xfs/xfs_log.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'fs/xfs/xfs_log.c') diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 4184085d44af..31fbb2eea092 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -909,7 +909,7 @@ xfs_log_need_covered(xfs_mount_t *mp) spin_lock(&log->l_icloglock); if (((log->l_covered_state == XLOG_STATE_COVER_NEED) || (log->l_covered_state == XLOG_STATE_COVER_NEED2)) - && !xfs_trans_first_ail(mp, NULL) + && !xfs_trans_ail_tail(mp->m_ail) && xlog_iclogs_empty(log)) { if (log->l_covered_state == XLOG_STATE_COVER_NEED) log->l_covered_state = XLOG_STATE_COVER_DONE; @@ -946,7 +946,7 @@ xlog_assign_tail_lsn(xfs_mount_t *mp) xfs_lsn_t tail_lsn; xlog_t *log = mp->m_log; - tail_lsn = xfs_trans_tail_ail(mp); + tail_lsn = xfs_trans_ail_tail(mp->m_ail); spin_lock(&log->l_grant_lock); if (tail_lsn != 0) { log->l_tail_lsn = tail_lsn; -- cgit v1.2.2 From c7e8f268278a292d3823b4352182fa7755a71410 Mon Sep 17 00:00:00 2001 From: David Chinner Date: Thu, 30 Oct 2008 17:39:23 +1100 Subject: [XFS] Move the AIL lock into the struct xfs_ail Bring the ail lock inside the struct xfs_ail. This means the AIL can be entirely manipulated via the struct xfs_ail rather than needing both the struct xfs_mount and the struct xfs_ail. SGI-PV: 988143 SGI-Modid: xfs-linux-melb:xfs-kern:32350a Signed-off-by: David Chinner Signed-off-by: Lachlan McIlroy Signed-off-by: Christoph Hellwig --- fs/xfs/xfs_log.c | 1 - 1 file changed, 1 deletion(-) (limited to 'fs/xfs/xfs_log.c') diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 31fbb2eea092..a2f7422a749f 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -567,7 +567,6 @@ xfs_log_mount( /* * Initialize the AIL now we have a log. */ - spin_lock_init(&mp->m_ail_lock); error = xfs_trans_ail_init(mp); if (error) { cmn_err(CE_WARN, "XFS: AIL initialisation failed: error %d", error); -- cgit v1.2.2 From a9c21c1b9deaced836034e77fe25fe0b55c21f02 Mon Sep 17 00:00:00 2001 From: David Chinner Date: Thu, 30 Oct 2008 17:39:35 +1100 Subject: [XFS] Given the log a pointer to the AIL When we need to go from the log to the AIL, we have to go via the xfs_mount. Add a xfs_ail pointer to the log so we can go directly to the AIL associated with the log. SGI-PV: 988143 SGI-Modid: xfs-linux-melb:xfs-kern:32351a Signed-off-by: David Chinner Signed-off-by: Lachlan McIlroy Signed-off-by: Christoph Hellwig --- fs/xfs/xfs_log.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'fs/xfs/xfs_log.c') diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index a2f7422a749f..405a41ab6855 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -572,6 +572,7 @@ xfs_log_mount( cmn_err(CE_WARN, "XFS: AIL initialisation failed: error %d", error); goto error; } + mp->m_log->l_ailp = mp->m_ail; /* * skip log recovery on a norecovery mount. pretend it all @@ -908,7 +909,7 @@ xfs_log_need_covered(xfs_mount_t *mp) spin_lock(&log->l_icloglock); if (((log->l_covered_state == XLOG_STATE_COVER_NEED) || (log->l_covered_state == XLOG_STATE_COVER_NEED2)) - && !xfs_trans_ail_tail(mp->m_ail) + && !xfs_trans_ail_tail(log->l_ailp) && xlog_iclogs_empty(log)) { if (log->l_covered_state == XLOG_STATE_COVER_NEED) log->l_covered_state = XLOG_STATE_COVER_DONE; -- cgit v1.2.2 From 783a2f656f9674c31d4019708a94af93fa1d1c22 Mon Sep 17 00:00:00 2001 From: David Chinner Date: Thu, 30 Oct 2008 17:39:58 +1100 Subject: [XFS] Finish removing the mount pointer from the AIL API Change all the remaining AIL API functions that are passed struct xfs_mount pointers to pass pointers directly to the struct xfs_ail being used. With this conversion, all external access to the AIL is via the struct xfs_ail. Hence the operation and referencing of the AIL is almost entirely independent of the xfs_mount that is using it - it is now much more tightly tied to the log and the items it is tracking in the log than it is tied to the xfs_mount. SGI-PV: 988143 SGI-Modid: xfs-linux-melb:xfs-kern:32353a Signed-off-by: David Chinner Signed-off-by: Lachlan McIlroy Signed-off-by: Christoph Hellwig --- fs/xfs/xfs_log.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/xfs/xfs_log.c') diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 405a41ab6855..51840170b16c 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -1413,7 +1413,7 @@ xlog_grant_push_ail(xfs_mount_t *mp, */ if (threshold_lsn && !XLOG_FORCED_SHUTDOWN(log)) - xfs_trans_push_ail(mp, threshold_lsn); + xfs_trans_ail_push(log->l_ailp, threshold_lsn); } /* xlog_grant_push_ail */ -- cgit v1.2.2