Btrfs: use larger metadata clusters in ssd mode

Larger metadata clusters can significantly improve writeback performance
on ssd drives with large erasure blocks.  The larger clusters make it
more likely a given IO will completely overwrite the ssd block, so it
doesn't have to do an internal rwm cycle.

On spinning media, lager metadata clusters end up spreading out the
metadata more over time, which makes fsck slower, so we don't want this
to be the default.

Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Chris Mason 2009-02-12 09:41:38 -05:00
parent b288052e17
commit 536ac8ae86

View File

@ -2872,7 +2872,8 @@ static noinline int find_free_extent(struct btrfs_trans_handle *trans,
if (data & BTRFS_BLOCK_GROUP_METADATA) {
last_ptr = &root->fs_info->last_alloc;
empty_cluster = 64 * 1024;
if (!btrfs_test_opt(root, SSD))
empty_cluster = 64 * 1024;
}
if ((data & BTRFS_BLOCK_GROUP_DATA) && btrfs_test_opt(root, SSD))