linux-kernel - [PATCHv4 2/3] ext4: use non-movable memory for the ext4 superblock

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Message-Id: <1409815781-28011-3-git-send-email-gioh.kim@lge.com>
Date:	Thu,  4 Sep 2014 16:29:40 +0900
From:	Gioh Kim <gioh.kim@....com>
To:	gioh.kim@....com, akpm@...ux-foundation.org, jack@...e.cz,
	tytso@....edu, linux-fsdevel@...r.kernel.org,
	linux-ext4@...r.kernel.org, linux-kernel@...r.kernel.org,
	viro@...iv.linux.org.uk, paulmck@...ux.vnet.ibm.com,
	peterz@...radead.org, adilger.kernel@...ger.ca
Cc:	minchan@...nel.org, js1304@...il.com, gunho.lee@....com
Subject: [PATCHv4 2/3] ext4: use non-movable memory for the ext4 superblock

A buffer-cache for superblock is disturbing page migration,
because the buffer-cache is not released until unmount.
The buffer-cache must be allocated from non-movable area.

Signed-off-by: Gioh Kim <gioh.kim@....com>
Reviewed-by: Jan Kara <jack@...e.cz>
---
 fs/ext4/super.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 32b43ad..e4b62b3 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -3435,7 +3435,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		logical_sb_block = sb_block;
 	}
 
-	if (!(bh = sb_bread(sb, logical_sb_block))) {
+	if (!(bh = sb_bread_unmovable(sb, logical_sb_block))) {
 		ext4_msg(sb, KERN_ERR, "unable to read superblock");
 		goto out_fail;
 	}
@@ -3645,7 +3645,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 		brelse(bh);
 		logical_sb_block = sb_block * EXT4_MIN_BLOCK_SIZE;
 		offset = do_div(logical_sb_block, blocksize);
-		bh = sb_bread(sb, logical_sb_block);
+		bh = sb_bread_unmovable(sb, logical_sb_block);
 		if (!bh) {
 			ext4_msg(sb, KERN_ERR,
 			       "Can't read superblock on 2nd try");
@@ -3867,7 +3867,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
 
 	for (i = 0; i < db_count; i++) {
 		block = descriptor_loc(sb, logical_sb_block, i);
-		sbi->s_group_desc[i] = sb_bread(sb, block);
+		sbi->s_group_desc[i] = sb_bread_unmovable(sb, block);
 		if (!sbi->s_group_desc[i]) {
 			ext4_msg(sb, KERN_ERR,
 			       "can't read group descriptor %d", i);
-- 
1.7.9.5

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