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Commit 7023a1ad authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: shrink unreferenced extent_caches first 



If an extent_tree entry has a zero reference count, we can drop it from the
cache in higher priority rather than currently referencing entries.

Reviewed-by: default avatarChao Yu <chao2.yu@samsung.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent bb96a8d5

fs/f2fs/data.c

+41 −10
Original line number Diff line number Diff line
@@ -662,21 +662,15 @@ unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink) 
	struct radix_tree_root *root = &sbi->extent_tree_root;

	unsigned int found;

	unsigned int node_cnt = 0, tree_cnt = 0;

	int remained;



	if (!test_opt(sbi, EXTENT_CACHE))

		return 0;



	spin_lock(&sbi->extent_lock);

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

		if (!nr_shrink--)

			break;

		list_del_init(&en->list);

	}

	spin_unlock(&sbi->extent_lock);



	if (!down_write_trylock(&sbi->extent_tree_lock))

		goto out;



	/* 1. remove unreferenced extent tree */

	while ((found = radix_tree_gang_lookup(root,

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

		unsigned i;
@@ -685,17 +679,54 @@ unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *sbi, int nr_shrink) 
		for (i = 0; i < found; i++) {

			struct extent_tree *et = treevec[i];



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

				write_lock(&et->lock);

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

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

				write_unlock(&et->lock);

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



				radix_tree_delete(root, et->ino);

				kmem_cache_free(extent_tree_slab, et);

				sbi->total_ext_tree--;

				tree_cnt++;



				if (node_cnt + tree_cnt >= nr_shrink)

					goto unlock_out;

			}

		}

	}

	up_write(&sbi->extent_tree_lock);



	/* 2. remove LRU extent entries */

	if (!down_write_trylock(&sbi->extent_tree_lock))

		goto out;



	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--)

			break;

		list_del_init(&en->list);

	}

	spin_unlock(&sbi->extent_lock);



	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];



			write_lock(&et->lock);

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

			write_unlock(&et->lock);



			if (node_cnt + tree_cnt >= nr_shrink)

				break;

		}

	}

unlock_out:

	up_write(&sbi->extent_tree_lock);

out:

	trace_f2fs_shrink_extent_tree(sbi, node_cnt, tree_cnt);