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 <dchinner@redhat.com>
Reviewed-by: Alex Elder <aelder@sgi.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/fs/xfs/xfs_trans_priv.h b/fs/xfs/xfs_trans_priv.h
index 6ebd322bd37..6b164e9e9a1 100644
--- a/fs/xfs/xfs_trans_priv.h
+++ b/fs/xfs/xfs_trans_priv.h
@@ -104,12 +104,13 @@ xfs_trans_ail_delete(
 	xfs_trans_ail_delete_bulk(ailp, &lip, 1);
 }
 
-void			xfs_trans_ail_push(struct xfs_ail *, xfs_lsn_t);
+void			xfs_ail_push(struct xfs_ail *, xfs_lsn_t);
+void			xfs_ail_push_all(struct xfs_ail *);
+xfs_lsn_t		xfs_ail_min_lsn(struct xfs_ail *ailp);
+
 void			xfs_trans_unlocked_item(struct xfs_ail *,
 					xfs_log_item_t *);
 
-xfs_lsn_t		xfs_trans_ail_tail(struct xfs_ail *ailp);
-
 struct xfs_log_item	*xfs_trans_ail_cursor_first(struct xfs_ail *ailp,
 					struct xfs_ail_cursor *cur,
 					xfs_lsn_t lsn);