Commit 137d09f0 authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: introduce zombie list for fast shrinking extent trees 



This patch removes refcount, and instead, adds zombie_list to shrink directly
without radix tree traverse.

Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent c00ba554

fs/f2fs/extent_cache.c

+21 −28
Original line number Diff line number Diff line
@@ -68,13 +68,13 @@ static struct extent_tree *__grab_extent_tree(struct inode *inode) 
		et->root = RB_ROOT;

		et->cached_en = NULL;

		rwlock_init(&et->lock);

		atomic_set(&et->refcount, 0);

		INIT_LIST_HEAD(&et->list);

		et->count = 0;

		atomic_inc(&sbi->total_ext_tree);

	} else {

		atomic_dec(&sbi->total_zombie_tree);

		list_del_init(&et->list);

	}

	atomic_inc(&et->refcount);

	up_write(&sbi->extent_tree_lock);



	/* never died until evict_inode */
@@ -551,9 +551,9 @@ static unsigned int f2fs_update_extent_tree_range(struct inode *inode, 
unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink)

{

	struct extent_tree *treevec[EXT_TREE_VEC_SIZE];

	struct extent_tree *et, *next;

	struct extent_node *en, *tmp;

	unsigned long ino = F2FS_ROOT_INO(sbi);

	struct radix_tree_root *root = &sbi->extent_tree_root;

	unsigned int found;

	unsigned int node_cnt = 0, tree_cnt = 0;

	int remained;
@@ -569,20 +569,13 @@ unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink) 
		goto out;



	/* 1. remove unreferenced extent tree */

	while ((found = radix_tree_gang_lookup(root,

				(void **)treevec, ino, EXT_TREE_VEC_SIZE))) {

		unsigned i;



		ino = treevec[found - 1]->ino + 1;

		for (i = 0; i < found; i++) {

			struct extent_tree *et = treevec[i];



			if (!atomic_read(&et->refcount)) {

	list_for_each_entry_safe(et, next, &sbi->zombie_list, list) {

		write_lock(&et->lock);

		node_cnt += __free_extent_tree(sbi, et, true);

		write_unlock(&et->lock);



				radix_tree_delete(root, et->ino);

		list_del_init(&et->list);

		radix_tree_delete(&sbi->extent_tree_root, et->ino);

		kmem_cache_free(extent_tree_slab, et);

		atomic_dec(&sbi->total_ext_tree);

		atomic_dec(&sbi->total_zombie_tree);
@@ -591,8 +584,6 @@ unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink) 
		if (node_cnt + tree_cnt >= nr_shrink)

			goto unlock_out;

	}

		}

	}

	up_write(&sbi->extent_tree_lock);



free_node:
@@ -619,7 +610,7 @@ unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink) 
	 */

	ino = F2FS_ROOT_INO(sbi);



	while ((found = radix_tree_gang_lookup(root,

	while ((found = radix_tree_gang_lookup(&sbi->extent_tree_root,

				(void **)treevec, ino, EXT_TREE_VEC_SIZE))) {

		unsigned i;
@@ -670,8 +661,10 @@ void f2fs_destroy_extent_tree(struct inode *inode) 
		return;



	if (inode->i_nlink && !is_bad_inode(inode) && et->count) {

		atomic_dec(&et->refcount);

		down_write(&sbi->extent_tree_lock);

		list_add_tail(&et->list, &sbi->zombie_list);

		atomic_inc(&sbi->total_zombie_tree);

		up_write(&sbi->extent_tree_lock);

		return;

	}
@@ -680,8 +673,7 @@ void f2fs_destroy_extent_tree(struct inode *inode) 


	/* delete extent tree entry in radix tree */

	down_write(&sbi->extent_tree_lock);

	atomic_dec(&et->refcount);

	f2fs_bug_on(sbi, atomic_read(&et->refcount) || et->count);

	f2fs_bug_on(sbi, et->count);

	radix_tree_delete(&sbi->extent_tree_root, inode->i_ino);

	kmem_cache_free(extent_tree_slab, et);

	atomic_dec(&sbi->total_ext_tree);
@@ -737,6 +729,7 @@ void init_extent_cache_info(struct f2fs_sb_info *sbi) 
	INIT_LIST_HEAD(&sbi->extent_list);

	spin_lock_init(&sbi->extent_lock);

	atomic_set(&sbi->total_ext_tree, 0);

	INIT_LIST_HEAD(&sbi->zombie_list);

	atomic_set(&sbi->total_zombie_tree, 0);

	atomic_set(&sbi->total_ext_node, 0);

}

fs/f2fs/f2fs.h

+2 −1
Original line number Diff line number Diff line
@@ -359,8 +359,8 @@ struct extent_tree { 
	struct rb_root root;		/* root of extent info rb-tree */

	struct extent_node *cached_en;	/* recently accessed extent node */

	struct extent_info largest;	/* largested extent info */

	struct list_head list;		/* to be used by sbi->zombie_list */

	rwlock_t lock;			/* protect extent info rb-tree */

	atomic_t refcount;		/* reference count of rb-tree */

	unsigned int count;		/* # of extent node in rb-tree*/

};
@@ -764,6 +764,7 @@ struct f2fs_sb_info { 
	struct list_head extent_list;		/* lru list for shrinker */

	spinlock_t extent_lock;			/* locking extent lru list */

	atomic_t total_ext_tree;		/* extent tree count */

	struct list_head zombie_list;		/* extent zombie tree list */

	atomic_t total_zombie_tree;		/* extent zombie tree count */

	atomic_t total_ext_node;		/* extent info count */