From 70e60ce71516c3a9e882edb70a09f696a05961db Mon Sep 17 00:00:00 2001 From: Dave Chinner Date: Tue, 20 Jul 2010 08:07:02 +1000 Subject: [PATCH] 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 Reviewed-by: Christoph Hellwig --- fs/xfs/linux-2.6/xfs_super.c | 2 -- fs/xfs/linux-2.6/xfs_sync.c | 62 ++++++++---------------------------- fs/xfs/linux-2.6/xfs_sync.h | 2 -- fs/xfs/xfs_mount.h | 2 +- 4 files changed, 15 insertions(+), 53 deletions(-) diff --git a/fs/xfs/linux-2.6/xfs_super.c b/fs/xfs/linux-2.6/xfs_super.c index f2d1718c9165..80938c736c27 100644 --- a/fs/xfs/linux-2.6/xfs_super.c +++ b/fs/xfs/linux-2.6/xfs_super.c @@ -1883,7 +1883,6 @@ init_xfs_fs(void) goto out_cleanup_procfs; vfs_initquota(); - xfs_inode_shrinker_init(); error = register_filesystem(&xfs_fs_type); if (error) @@ -1911,7 +1910,6 @@ exit_xfs_fs(void) { vfs_exitquota(); unregister_filesystem(&xfs_fs_type); - xfs_inode_shrinker_destroy(); xfs_sysctl_unregister(); xfs_cleanup_procfs(); xfs_buf_terminate(); diff --git a/fs/xfs/linux-2.6/xfs_sync.c b/fs/xfs/linux-2.6/xfs_sync.c index be375827af98..f433819611cb 100644 --- a/fs/xfs/linux-2.6/xfs_sync.c +++ b/fs/xfs/linux-2.6/xfs_sync.c @@ -828,14 +828,7 @@ xfs_reclaim_inodes( /* * 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_reclaim_inode_shrink( 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); } diff --git a/fs/xfs/linux-2.6/xfs_sync.h b/fs/xfs/linux-2.6/xfs_sync.h index cdcbaaca9880..e28139aaa4aa 100644 --- a/fs/xfs/linux-2.6/xfs_sync.h +++ b/fs/xfs/linux-2.6/xfs_sync.h @@ -55,8 +55,6 @@ int xfs_inode_ag_iterator(struct xfs_mount *mp, int (*execute)(struct xfs_inode *ip, struct xfs_perag *pag, int flags), int flags, int tag, int write_lock, int *nr_to_scan); -void xfs_inode_shrinker_init(void); -void xfs_inode_shrinker_destroy(void); void xfs_inode_shrinker_register(struct xfs_mount *mp); void xfs_inode_shrinker_unregister(struct xfs_mount *mp); diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h index 1d2c7eed4eda..5761087ee8ea 100644 --- a/fs/xfs/xfs_mount.h +++ b/fs/xfs/xfs_mount.h @@ -259,7 +259,7 @@ typedef struct xfs_mount { wait_queue_head_t m_wait_single_sync_task; __int64_t m_update_flags; /* sb flags we need to update on the next remount,rw */ - struct list_head m_mplist; /* inode shrinker mount list */ + struct shrinker m_inode_shrink; /* inode reclaim shrinker */ } xfs_mount_t; /*