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Commit 79344efb authored by Jaegeuk Kim's avatar Jaegeuk Kim
Browse files

f2fs: read node blocks ahead when truncating blocks 



This patch enables reading node blocks in advance when truncating large
data blocks.

 > time rm $MNT/testfile (500GB) after drop_cachees
Before : 9.422 s
After  : 4.821 s

Reported-by: default avatarStephen Bates <stephen.bates@microsemi.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent e12dd7bd

fs/f2fs/file.c

+1 −1
Original line number Diff line number Diff line
@@ -584,7 +584,7 @@ int truncate_blocks(struct inode *inode, u64 from, bool lock) 
	}



	set_new_dnode(&dn, inode, ipage, NULL, 0);

	err = get_dnode_of_data(&dn, free_from, LOOKUP_NODE);

	err = get_dnode_of_data(&dn, free_from, LOOKUP_NODE_RA);

	if (err) {

		if (err == -ENOENT)

			goto free_next;

fs/f2fs/node.c

+28 −24
Original line number Diff line number Diff line
@@ -407,6 +407,29 @@ void get_node_info(struct f2fs_sb_info *sbi, nid_t nid, struct node_info *ni) 
	up_write(&nm_i->nat_tree_lock);

}



/*

 * readahead MAX_RA_NODE number of node pages.

 */

static void ra_node_pages(struct page *parent, int start, int n)

{

	struct f2fs_sb_info *sbi = F2FS_P_SB(parent);

	struct blk_plug plug;

	int i, end;

	nid_t nid;



	blk_start_plug(&plug);



	/* Then, try readahead for siblings of the desired node */

	end = start + n;

	end = min(end, NIDS_PER_BLOCK);

	for (i = start; i < end; i++) {

		nid = get_nid(parent, i, false);

		ra_node_page(sbi, nid);

	}



	blk_finish_plug(&plug);

}



pgoff_t get_next_page_offset(struct dnode_of_data *dn, pgoff_t pgofs)

{

	const long direct_index = ADDRS_PER_INODE(dn->inode);
@@ -707,6 +730,8 @@ static int truncate_nodes(struct dnode_of_data *dn, unsigned int nofs, 
		return PTR_ERR(page);

	}



	ra_node_pages(page, ofs, NIDS_PER_BLOCK);



	rn = F2FS_NODE(page);

	if (depth < 3) {

		for (i = ofs; i < NIDS_PER_BLOCK; i++, freed++) {
@@ -784,6 +809,8 @@ static int truncate_partial_nodes(struct dnode_of_data *dn, 
		nid[i + 1] = get_nid(pages[i], offset[i + 1], false);

	}



	ra_node_pages(pages[idx], offset[idx + 1], NIDS_PER_BLOCK);



	/* free direct nodes linked to a partial indirect node */

	for (i = offset[idx + 1]; i < NIDS_PER_BLOCK; i++) {

		child_nid = get_nid(pages[idx], i, false);
@@ -1095,29 +1122,6 @@ void ra_node_page(struct f2fs_sb_info *sbi, nid_t nid) 
	f2fs_put_page(apage, err ? 1 : 0);

}



/*

 * readahead MAX_RA_NODE number of node pages.

 */

static void ra_node_pages(struct page *parent, int start)

{

	struct f2fs_sb_info *sbi = F2FS_P_SB(parent);

	struct blk_plug plug;

	int i, end;

	nid_t nid;



	blk_start_plug(&plug);



	/* Then, try readahead for siblings of the desired node */

	end = start + MAX_RA_NODE;

	end = min(end, NIDS_PER_BLOCK);

	for (i = start; i < end; i++) {

		nid = get_nid(parent, i, false);

		ra_node_page(sbi, nid);

	}



	blk_finish_plug(&plug);

}



static struct page *__get_node_page(struct f2fs_sb_info *sbi, pgoff_t nid,

					struct page *parent, int start)

{
@@ -1141,7 +1145,7 @@ static struct page *__get_node_page(struct f2fs_sb_info *sbi, pgoff_t nid, 
	}



	if (parent)

		ra_node_pages(parent, start + 1);

		ra_node_pages(parent, start + 1, MAX_RA_NODE);



	lock_page(page);