xfs: convert inode shrinker to per-filesystem contexts
Now the shrinker passes us a context, wire up a shrinker context per
filesystem. This allows us to remove the global mount list and the
locking problems that introduced. It also means that a shrinker call
does not need to traverse clean filesystems before finding a
filesystem with reclaimable inodes. This significantly reduces
scanning overhead when lots of filesystems are present.
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c
index be37582..f433819 100644
--- a/fs/xfs/linux-2.6/xfs_sync.c
+++ b/fs/xfs/linux-2.6/xfs_sync.c
@@ -828,14 +828,7 @@
/*
* Shrinker infrastructure.
- *
- * This is all far more complex than it needs to be. It adds a global list of
- * mounts because the shrinkers can only call a global context. We need to make
- * the shrinkers pass a context to avoid the need for global state.
*/
-static LIST_HEAD(xfs_mount_list);
-static struct rw_semaphore xfs_mount_list_lock;
-
static int
xfs_reclaim_inode_shrink(
struct shrinker *shrink,
@@ -847,65 +840,38 @@
xfs_agnumber_t ag;
int reclaimable = 0;
+ mp = container_of(shrink, struct xfs_mount, m_inode_shrink);
if (nr_to_scan) {
if (!(gfp_mask & __GFP_FS))
return -1;
- down_read(&xfs_mount_list_lock);
- list_for_each_entry(mp, &xfs_mount_list, m_mplist) {
- xfs_inode_ag_iterator(mp, xfs_reclaim_inode, 0,
+ xfs_inode_ag_iterator(mp, xfs_reclaim_inode, 0,
XFS_ICI_RECLAIM_TAG, 1, &nr_to_scan);
- if (nr_to_scan <= 0)
- break;
- }
- up_read(&xfs_mount_list_lock);
- }
+ /* if we don't exhaust the scan, don't bother coming back */
+ if (nr_to_scan > 0)
+ return -1;
+ }
- down_read(&xfs_mount_list_lock);
- list_for_each_entry(mp, &xfs_mount_list, m_mplist) {
- for (ag = 0; ag < mp->m_sb.sb_agcount; ag++) {
- pag = xfs_perag_get(mp, ag);
- reclaimable += pag->pag_ici_reclaimable;
- xfs_perag_put(pag);
- }
+ for (ag = 0; ag < mp->m_sb.sb_agcount; ag++) {
+ pag = xfs_perag_get(mp, ag);
+ reclaimable += pag->pag_ici_reclaimable;
+ xfs_perag_put(pag);
}
- up_read(&xfs_mount_list_lock);
return reclaimable;
}
-static struct shrinker xfs_inode_shrinker = {
- .shrink = xfs_reclaim_inode_shrink,
- .seeks = DEFAULT_SEEKS,
-};
-
-void __init
-xfs_inode_shrinker_init(void)
-{
- init_rwsem(&xfs_mount_list_lock);
- register_shrinker(&xfs_inode_shrinker);
-}
-
-void
-xfs_inode_shrinker_destroy(void)
-{
- ASSERT(list_empty(&xfs_mount_list));
- unregister_shrinker(&xfs_inode_shrinker);
-}
-
void
xfs_inode_shrinker_register(
struct xfs_mount *mp)
{
- down_write(&xfs_mount_list_lock);
- list_add_tail(&mp->m_mplist, &xfs_mount_list);
- up_write(&xfs_mount_list_lock);
+ 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)
{
- down_write(&xfs_mount_list_lock);
- list_del(&mp->m_mplist);
- up_write(&xfs_mount_list_lock);
+ unregister_shrinker(&mp->m_inode_shrink);
}