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authorDavid Chinner <david@fromorbit.com>2008-10-30 17:38:39 +1100
committerLachlan McIlroy <lachlan@sgi.com>2008-10-30 17:38:39 +1100
commit27d8d5fe0ef9daeaafbdd32b14b32a2211930062 (patch)
treee170fd577c1f6e58bee1cabb5cad75ced643c3ac /fs/xfs/xfs_log.c
parent82fa9012458d867936d7bf130e6e14bdebc6873c (diff)
[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 <david@fromorbit.com> Signed-off-by: Lachlan McIlroy <lachlan@sgi.com> Signed-off-by: Christoph Hellwig <hch@infradead.org>
Diffstat (limited to 'fs/xfs/xfs_log.c')
-rw-r--r--fs/xfs/xfs_log.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index 0b02c644355..4184085d44a 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;