diff options
| author | Roman Gushchin <guro@fb.com> | 2020-02-29 03:14:11 +0300 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2020-04-16 06:58:48 +0300 |
| commit | d87f639258a6a5980183f11876c884931ad93da2 (patch) | |
| tree | f840887fbe136455b2eb47710c222018352f566c /fs/buffer.c | |
| parent | c2a559bc0e7ed5a715ad6b947025b33cb7c05ea7 (diff) | |
| download | linux-d87f639258a6a5980183f11876c884931ad93da2.tar.xz | |
ext4: use non-movable memory for superblock readahead
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>
Diffstat (limited to 'fs/buffer.c')
| -rw-r--r-- | fs/buffer.c | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/fs/buffer.c b/fs/buffer.c index f73276d746bb..599a0bf7257b 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -1371,6 +1371,17 @@ 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 |