xfs: make use of new shrinker callout for the inode cache

Convert the inode reclaim shrinker to use the new per-sb shrinker
operations. This allows much bigger reclaim batches to be used, and
allows the XFS inode cache to be shrunk in proportion with the VFS
dentry and inode caches. This avoids the problem of the VFS caches
being shrunk significantly before the XFS inode cache is shrunk
resulting in imbalances in the caches during reclaim.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 27 insertions, 44 deletions

diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c
index 8ecad5ff9f9..9bd7e895a4e 100644
--- a/fs/xfs/linux-2.6/xfs_sync.c
+++ b/fs/xfs/linux-2.6/xfs_sync.c
@@ -179,6 +179,8 @@ restart:
 		if (error == EFSCORRUPTED)
 			break;
 
+		cond_resched();
+
 	} while (nr_found && !done);
 
 	if (skipped) {
@@ -986,6 +988,8 @@ restart:
 
 			*nr_to_scan -= XFS_LOOKUP_BATCH;
 
+			cond_resched();
+
 		} while (nr_found && !done && *nr_to_scan > 0);
 
 		if (trylock && !done)
@@ -1003,7 +1007,7 @@ restart:
 	 * ensure that when we get more reclaimers than AGs we block rather
 	 * than spin trying to execute reclaim.
 	 */
-	if (trylock && skipped && *nr_to_scan > 0) {
+	if (skipped && (flags & SYNC_WAIT) && *nr_to_scan > 0) {
 		trylock = 0;
 		goto restart;
 	}
@@ -1021,44 +1025,38 @@ xfs_reclaim_inodes(
 }
 
 /*
- * Inode cache shrinker.
+ * Scan a certain number of inodes for reclaim.
  *
  * When called we make sure that there is a background (fast) inode reclaim in
- * progress, while we will throttle the speed of reclaim via doiing synchronous
+ * progress, while we will throttle the speed of reclaim via doing synchronous
  * reclaim of inodes. That means if we come across dirty inodes, we wait for
  * them to be cleaned, which we hope will not be very long due to the
  * background walker having already kicked the IO off on those dirty inodes.
  */
-static int
-xfs_reclaim_inode_shrink(
-	struct shrinker	*shrink,
-	struct shrink_control *sc)
+void
+xfs_reclaim_inodes_nr(
+	struct xfs_mount	*mp,
+	int			nr_to_scan)
 {
-	struct xfs_mount *mp;
-	struct xfs_perag *pag;
-	xfs_agnumber_t	ag;
-	int		reclaimable;
-	int nr_to_scan = sc->nr_to_scan;
-	gfp_t gfp_mask = sc->gfp_mask;
-
-	mp = container_of(shrink, struct xfs_mount, m_inode_shrink);
-	if (nr_to_scan) {
-		/* kick background reclaimer and push the AIL */
-		xfs_syncd_queue_reclaim(mp);
-		xfs_ail_push_all(mp->m_ail);
+	/* kick background reclaimer and push the AIL */
+	xfs_syncd_queue_reclaim(mp);
+	xfs_ail_push_all(mp->m_ail);
 
-		if (!(gfp_mask & __GFP_FS))
-			return -1;
+	xfs_reclaim_inodes_ag(mp, SYNC_TRYLOCK | SYNC_WAIT, &nr_to_scan);
+}
 
-		xfs_reclaim_inodes_ag(mp, SYNC_TRYLOCK | SYNC_WAIT,
-					&nr_to_scan);
-		/* terminate if we don't exhaust the scan */
-		if (nr_to_scan > 0)
-			return -1;
-       }
+/*
+ * Return the number of reclaimable inodes in the filesystem for
+ * the shrinker to determine how much to reclaim.
+ */
+int
+xfs_reclaim_inodes_count(
+	struct xfs_mount	*mp)
+{
+	struct xfs_perag	*pag;
+	xfs_agnumber_t		ag = 0;
+	int			reclaimable = 0;
 
-	reclaimable = 0;
-	ag = 0;
 	while ((pag = xfs_perag_get_tag(mp, ag, XFS_ICI_RECLAIM_TAG))) {
 		ag = pag->pag_agno + 1;
 		reclaimable += pag->pag_ici_reclaimable;
@@ -1067,18 +1065,3 @@ xfs_reclaim_inode_shrink(
 	return reclaimable;
 }
 
-void
-xfs_inode_shrinker_register(
-	struct xfs_mount	*mp)
-{
-	mp->m_inode_shrink.shrink = xfs_reclaim_inode_shrink;
-	mp->m_inode_shrink.seeks = DEFAULT_SEEKS;
-	register_shrinker(&mp->m_inode_shrink);
-}
-
-void
-xfs_inode_shrinker_unregister(
-	struct xfs_mount	*mp)
-{
-	unregister_shrinker(&mp->m_inode_shrink);
-}