diff options
Diffstat (limited to 'fs/inode.c')
-rw-r--r-- | fs/inode.c | 117 |
1 files changed, 9 insertions, 108 deletions
diff --git a/fs/inode.c b/fs/inode.c index 0450e25aeda..1fdbb64a952 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -73,7 +73,7 @@ __cacheline_aligned_in_smp DEFINE_SPINLOCK(inode_wb_list_lock); * * We don't actually need it to protect anything in the umount path, * but only need to cycle through it to make sure any inode that - * prune_icache took off the LRU list has been fully torn down by the + * prune_icache_sb took off the LRU list has been fully torn down by the * time we are past evict_inodes. */ static DECLARE_RWSEM(iprune_sem); @@ -544,7 +544,7 @@ void evict_inodes(struct super_block *sb) dispose_list(&dispose); /* - * Cycle through iprune_sem to make sure any inode that prune_icache + * Cycle through iprune_sem to make sure any inode that prune_icache_sb * moved off the list before we took the lock has been fully torn * down. */ @@ -612,9 +612,10 @@ static int can_unuse(struct inode *inode) } /* - * Scan `goal' inodes on the unused list for freeable ones. They are moved to a - * temporary list and then are freed outside sb->s_inode_lru_lock by - * dispose_list(). + * Walk the superblock inode LRU for freeable inodes and attempt to free them. + * This is called from the superblock shrinker function with a number of inodes + * to trim from the LRU. Inodes to be freed are moved to a temporary list and + * then are freed outside inode_lock by dispose_list(). * * Any inodes which are pinned purely because of attached pagecache have their * pagecache removed. If the inode has metadata buffers attached to @@ -628,14 +629,15 @@ static int can_unuse(struct inode *inode) * LRU does not have strict ordering. Hence we don't want to reclaim inodes * with this flag set because they are the inodes that are out of order. */ -static void shrink_icache_sb(struct super_block *sb, int *nr_to_scan) +void prune_icache_sb(struct super_block *sb, int nr_to_scan) { LIST_HEAD(freeable); int nr_scanned; unsigned long reap = 0; + down_read(&iprune_sem); spin_lock(&sb->s_inode_lru_lock); - for (nr_scanned = *nr_to_scan; nr_scanned >= 0; nr_scanned--) { + for (nr_scanned = nr_to_scan; nr_scanned >= 0; nr_scanned--) { struct inode *inode; if (list_empty(&sb->s_inode_lru)) @@ -707,111 +709,11 @@ static void shrink_icache_sb(struct super_block *sb, int *nr_to_scan) else __count_vm_events(PGINODESTEAL, reap); spin_unlock(&sb->s_inode_lru_lock); - *nr_to_scan = nr_scanned; dispose_list(&freeable); -} - -static void prune_icache(int count) -{ - struct super_block *sb, *p = NULL; - int w_count; - int unused = inodes_stat.nr_unused; - int prune_ratio; - int pruned; - - if (unused == 0 || count == 0) - return; - down_read(&iprune_sem); - if (count >= unused) - prune_ratio = 1; - else - prune_ratio = unused / count; - spin_lock(&sb_lock); - list_for_each_entry(sb, &super_blocks, s_list) { - if (list_empty(&sb->s_instances)) - continue; - if (sb->s_nr_inodes_unused == 0) - continue; - sb->s_count++; - /* Now, we reclaim unused dentrins with fairness. - * We reclaim them same percentage from each superblock. - * We calculate number of dentries to scan on this sb - * as follows, but the implementation is arranged to avoid - * overflows: - * number of dentries to scan on this sb = - * count * (number of dentries on this sb / - * number of dentries in the machine) - */ - spin_unlock(&sb_lock); - if (prune_ratio != 1) - w_count = (sb->s_nr_inodes_unused / prune_ratio) + 1; - else - w_count = sb->s_nr_inodes_unused; - pruned = w_count; - /* - * We need to be sure this filesystem isn't being unmounted, - * otherwise we could race with generic_shutdown_super(), and - * end up holding a reference to an inode while the filesystem - * is unmounted. So we try to get s_umount, and make sure - * s_root isn't NULL. - */ - if (down_read_trylock(&sb->s_umount)) { - if ((sb->s_root != NULL) && - (!list_empty(&sb->s_dentry_lru))) { - shrink_icache_sb(sb, &w_count); - pruned -= w_count; - } - up_read(&sb->s_umount); - } - spin_lock(&sb_lock); - if (p) - __put_super(p); - count -= pruned; - p = sb; - /* more work left to do? */ - if (count <= 0) - break; - } - if (p) - __put_super(p); - spin_unlock(&sb_lock); up_read(&iprune_sem); } -/* - * shrink_icache_memory() will attempt to reclaim some unused inodes. Here, - * "unused" means that no dentries are referring to the inodes: the files are - * not open and the dcache references to those inodes have already been - * reclaimed. - * - * This function is passed the number of inodes to scan, and it returns the - * total number of remaining possibly-reclaimable inodes. - */ -static int shrink_icache_memory(struct shrinker *shrink, - struct shrink_control *sc) -{ - int nr = sc->nr_to_scan; - gfp_t gfp_mask = sc->gfp_mask; - - if (nr) { - /* - * Nasty deadlock avoidance. We may hold various FS locks, - * and we don't want to recurse into the FS that called us - * in clear_inode() and friends.. - */ - if (!(gfp_mask & __GFP_FS)) - return -1; - prune_icache(nr); - } - return (get_nr_inodes_unused() / 100) * sysctl_vfs_cache_pressure; -} - -static struct shrinker icache_shrinker = { - .shrink = shrink_icache_memory, - .seeks = DEFAULT_SEEKS, -}; - static void __wait_on_freeing_inode(struct inode *inode); /* * Called with the inode lock held. @@ -1691,7 +1593,6 @@ void __init inode_init(void) (SLAB_RECLAIM_ACCOUNT|SLAB_PANIC| SLAB_MEM_SPREAD), init_once); - register_shrinker(&icache_shrinker); /* Hash may have been set up in inode_init_early */ if (!hashdist) |