diff options
| author | Roman Gushchin <guro@fb.com> | 2020-02-28 16:14:11 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-04-23 10:36:15 +0200 |
| commit | 41d097c83343326c5c72c9801a5222b2a575a27a (patch) | |
| tree | ceb3ebd34460605d14283bd0eaba4d7a51846854 /fs | |
| parent | 6ccc74c083c0d472ac64f3733f5b7bf3f99f261e (diff) | |
ext4: use non-movable memory for superblock readahead
commit d87f639258a6a5980183f11876c884931ad93da2 upstream.
Since commit a8ac900b8163 ("ext4: use non-movable memory for the
superblock") buffers for ext4 superblock were allocated using
the sb_bread_unmovable() helper which allocated buffer heads
out of non-movable memory blocks. It was necessarily to not block
page migrations and do not cause cma allocation failures.
However commit 85c8f176a611 ("ext4: preload block group descriptors")
broke this by introducing pre-reading of the ext4 superblock.
The problem is that __breadahead() is using __getblk() underneath,
which allocates buffer heads out of movable memory.
It resulted in page migration failures I've seen on a machine
with an ext4 partition and a preallocated cma area.
Fix this by introducing sb_breadahead_unmovable() and
__breadahead_gfp() helpers which use non-movable memory for buffer
head allocations and use them for the ext4 superblock readahead.
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Fixes: 85c8f176a611 ("ext4: preload block group descriptors")
Signed-off-by: Roman Gushchin <guro@fb.com>
Link: https://lore.kernel.org/r/20200229001411.128010-1-guro@fb.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/buffer.c | 11 | ||||
| -rw-r--r-- | fs/ext4/inode.c | 2 | ||||
| -rw-r--r-- | fs/ext4/super.c | 2 |
3 files changed, 13 insertions, 2 deletions
diff --git a/fs/buffer.c b/fs/buffer.c index 91ceca52d14f..79c9562434a8 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1337,6 +1337,17 @@ void __breadahead(struct block_device *bdev, sector_t block, unsigned size) } EXPORT_SYMBOL(__breadahead); +void __breadahead_gfp(struct block_device *bdev, sector_t block, unsigned size, + gfp_t gfp) +{ + struct buffer_head *bh = __getblk_gfp(bdev, block, size, gfp); + if (likely(bh)) { + ll_rw_block(REQ_OP_READ, REQ_RAHEAD, 1, &bh); + brelse(bh); + } +} +EXPORT_SYMBOL(__breadahead_gfp); + /** * __bread_gfp() - reads a specified block and returns the bh * @bdev: the block_device to read from diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index d2edd6e9072f..b9473fcc110f 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4680,7 +4680,7 @@ make_io: if (end > table) end = table; while (b <= end) - sb_breadahead(sb, b++); + sb_breadahead_unmovable(sb, b++); } /* diff --git a/fs/ext4/super.c b/fs/ext4/super.c index a1eca6d30643..8f7a46d3abff 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -4283,7 +4283,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) /* Pre-read the descriptors into the buffer cache */ for (i = 0; i < db_count; i++) { block = descriptor_loc(sb, logical_sb_block, i); - sb_breadahead(sb, block); + sb_breadahead_unmovable(sb, block); } for (i = 0; i < db_count; i++) { |