Commit 536ac8ae authored Feb 12, 2009 by Chris Mason

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>

parent b288052e

fs/btrfs/extent-tree.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -2872,6 +2872,7 @@ static noinline int find_free_extent(struct btrfs_trans_handle *trans,

		if (data & BTRFS_BLOCK_GROUP_METADATA) {
		last_ptr = &root->fs_info->last_alloc;
		if (!btrfs_test_opt(root, SSD))
		empty_cluster = 64 * 1024;
		}

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