Commit 201ef5e0 authored by Hou Pengyang's avatar Hou Pengyang Committed by Jaegeuk Kim
Browse files

f2fs: improve shrink performance of extent nodes 



On the worst case, we need to scan the whole radix tree and every rb-tree to
free the victimed extent_nodes when shrinking.

Pengyang initially introduced a victim_list to record the victimed extent_nodes,
and free these extent_nodes by just scanning a list.

Later, Chao Yu enhances the original patch to improve memory footprint by
removing victim list.

The policy of lru list shrinking becomes:
1) lock lru list's lock
2) trylock extent tree's lock
3) remove extent node from lru list
4) unlock lru list's lock
5) do shrink
6) repeat 1) to 5)

Signed-off-by: default avatarHou Pengyang <houpengyang@huawei.com>
Signed-off-by: default avatarChao Yu <chao2.yu@samsung.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 42926744

fs/f2fs/extent_cache.c

+28 −48
Original line number Diff line number Diff line
@@ -33,6 +33,7 @@ static struct extent_node *__attach_extent_node(struct f2fs_sb_info *sbi, 


	en->ei = *ei;

	INIT_LIST_HEAD(&en->list);

	en->et = et;



	rb_link_node(&en->rb_node, parent, p);

	rb_insert_color(&en->rb_node, &et->root);
@@ -63,7 +64,7 @@ static void __release_extent_node(struct f2fs_sb_info *sbi, 
			struct extent_tree *et, struct extent_node *en)

{

	spin_lock(&sbi->extent_lock);

	if (!list_empty(&en->list))

	f2fs_bug_on(sbi, list_empty(&en->list));

	list_del_init(&en->list);

	spin_unlock(&sbi->extent_lock);
@@ -147,7 +148,7 @@ static struct extent_node *__init_extent_tree(struct f2fs_sb_info *sbi, 
}



static unsigned int __free_extent_tree(struct f2fs_sb_info *sbi,

					struct extent_tree *et, bool free_all)

					struct extent_tree *et)

{

	struct rb_node *node, *next;

	struct extent_node *en;
@@ -157,11 +158,7 @@ static unsigned int __free_extent_tree(struct f2fs_sb_info *sbi, 
	while (node) {

		next = rb_next(node);

		en = rb_entry(node, struct extent_node, rb_node);



		if (free_all)

		__release_extent_node(sbi, et, en);

		else if (list_empty(&en->list))

			__detach_extent_node(sbi, et, en);

		node = next;

	}
@@ -532,7 +529,7 @@ static unsigned int f2fs_update_extent_tree_range(struct inode *inode, 
	}



	if (is_inode_flag_set(F2FS_I(inode), FI_NO_EXTENT))

		__free_extent_tree(sbi, et, true);

		__free_extent_tree(sbi, et);



	write_unlock(&et->lock);
@@ -541,14 +538,10 @@ 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);

	unsigned int found;

	struct extent_node *en;

	unsigned int node_cnt = 0, tree_cnt = 0;

	int remained;

	bool do_free = false;



	if (!test_opt(sbi, EXTENT_CACHE))

		return 0;
@@ -563,10 +556,10 @@ unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink) 
	list_for_each_entry_safe(et, next, &sbi->zombie_list, list) {

		if (atomic_read(&et->node_cnt)) {

			write_lock(&et->lock);

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

			node_cnt += __free_extent_tree(sbi, et);

			write_unlock(&et->lock);

		}



		f2fs_bug_on(sbi, atomic_read(&et->node_cnt));

		list_del_init(&et->list);

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

		kmem_cache_free(extent_tree_slab, et);
@@ -587,42 +580,29 @@ free_node: 
	remained = nr_shrink - (node_cnt + tree_cnt);



	spin_lock(&sbi->extent_lock);

	list_for_each_entry_safe(en, tmp, &sbi->extent_list, list) {

		if (!remained--)

	for (; remained > 0; remained--) {

		if (list_empty(&sbi->extent_list))

			break;

		list_del_init(&en->list);

		do_free = true;

		en = list_first_entry(&sbi->extent_list,

					struct extent_node, list);

		et = en->et;

		if (!write_trylock(&et->lock)) {

			/* refresh this extent node's position in extent list */

			list_move_tail(&en->list, &sbi->extent_list);

			continue;

		}

	spin_unlock(&sbi->extent_lock);



	if (do_free == false)

		goto unlock_out;



	/*

	 * reset ino for searching victims from beginning of global extent tree.

	 */

	ino = F2FS_ROOT_INO(sbi);



	while ((found = radix_tree_gang_lookup(&sbi->extent_tree_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];

		list_del_init(&en->list);

		spin_unlock(&sbi->extent_lock);



			if (!atomic_read(&et->node_cnt))

				continue;

		__detach_extent_node(sbi, et, en);



			if (write_trylock(&et->lock)) {

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

		write_unlock(&et->lock);

		node_cnt++;

		spin_lock(&sbi->extent_lock);

	}

	spin_unlock(&sbi->extent_lock);



			if (node_cnt + tree_cnt >= nr_shrink)

				goto unlock_out;

		}

	}

unlock_out:

	up_write(&sbi->extent_tree_lock);

out:
@@ -641,7 +621,7 @@ unsigned int f2fs_destroy_extent_node(struct inode *inode) 
		return 0;



	write_lock(&et->lock);

	node_cnt = __free_extent_tree(sbi, et, true);

	node_cnt = __free_extent_tree(sbi, et);

	write_unlock(&et->lock);



	return node_cnt;

fs/f2fs/f2fs.h

+1 −0
Original line number Diff line number Diff line
@@ -354,6 +354,7 @@ struct extent_node { 
	struct rb_node rb_node;		/* rb node located in rb-tree */

	struct list_head list;		/* node in global extent list of sbi */

	struct extent_info ei;		/* extent info */

	struct extent_tree *et;		/* extent tree pointer */

};



struct extent_tree {

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