SSDs perform badly with sub-4k writes (because they perfrorm read-modify-write internally), so make sure that we write at least 4k when committing.
Signed-off-by: Mikulas Patocka <[email protected]> Fixes: 991bd8d7bc78 ("dm writecache: commit just one block, not a full page") Index: linux/drivers/md/dm-writecache.c =================================================================== --- linux.orig/drivers/md/dm-writecache.c +++ linux/drivers/md/dm-writecache.c @@ -533,7 +533,11 @@ static void ssd_commit_superblock(struct region.bdev = wc->ssd_dev->bdev; region.sector = 0; - region.count = wc->block_size >> SECTOR_SHIFT; + region.count = max(4096U, wc->block_size) >> SECTOR_SHIFT; + + if (unlikely(region.sector + region.count > wc->metadata_sectors)) + region.count = wc->metadata_sectors - region.sector; + region.sector += wc->start_sector; req.bi_op = REQ_OP_WRITE; -- dm-devel mailing list [email protected] https://listman.redhat.com/mailman/listinfo/dm-devel
