Commit af4dcb6d authored by Amir Goldstein's avatar Amir Goldstein Committed by Miklos Szeredi
Browse files

ovl: use plain list filler in indexdir and workdir cleanup 



Those two cleanup routines are using the helper ovl_dir_read() with the
merge dir filler, which populates an rb tree, that is never used.

The index dir entry names all have a long (42 bytes) constant prefix, so it
is not surprising that perf top has demostrated high CPU usage by rb tree
population during cleanup of a large index dir:

      - 9.53% ovl_fill_merge
         - 78.41% ovl_cache_entry_find_link.constprop.27
            + 72.11% strncmp

Use the plain list filler that does not populate the unneeded rb tree.

Signed-off-by: default avatarAmir Goldstein <amir73il@gmail.com>
Signed-off-by: default avatarMiklos Szeredi <mszeredi@redhat.com>
parent 8ea28765

fs/overlayfs/readdir.c

+2 −10
Original line number Diff line number Diff line
@@ -1071,14 +1071,10 @@ static int ovl_workdir_cleanup_recurse(struct ovl_fs *ofs, const struct path *pa 
	int err;

	struct inode *dir = path->dentry->d_inode;

	LIST_HEAD(list);

	struct rb_root root = RB_ROOT;

	struct ovl_cache_entry *p;

	struct ovl_readdir_data rdd = {

		.ctx.actor = ovl_fill_merge,

		.dentry = NULL,

		.ctx.actor = ovl_fill_plain,

		.list = &list,

		.root = &root,

		.is_lowest = false,

	};

	bool incompat = false;
@@ -1159,14 +1155,10 @@ int ovl_indexdir_cleanup(struct ovl_fs *ofs) 
	struct inode *dir = indexdir->d_inode;

	struct path path = { .mnt = ovl_upper_mnt(ofs), .dentry = indexdir };

	LIST_HEAD(list);

	struct rb_root root = RB_ROOT;

	struct ovl_cache_entry *p;

	struct ovl_readdir_data rdd = {

		.ctx.actor = ovl_fill_merge,

		.dentry = NULL,

		.ctx.actor = ovl_fill_plain,

		.list = &list,

		.root = &root,

		.is_lowest = false,

	};



	err = ovl_dir_read(&path, &rdd);