[PATCH 2/2] xfs: process free extents to busy list in FIFO order

Darrick J. Wong
2023-10-09T18:26:02Z

From: Darrick J. Wong <djwong@kernel.org>

When we're adding extents to the busy discard list, add them to the tail
of the list so that we get FIFO order. For FITRIM commands, this means
that we send discard bios sorted in order from longest to shortest, like
we did before commit 89cfa899608fc.

For transactions that are freeing extents, this puts them in the
transaction's busy list in FIFO order as well, which shouldn't make any
noticeable difference.

Fixes: 89cfa899608fc ("xfs: reduce AGF hold times during fstrim operations")
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
fs/xfs/xfs_extent_busy.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_extent_busy.c b/fs/xfs/xfs_extent_busy.c
index 746814815b1da..9ecfdcdc752f7 100644
--- a/fs/xfs/xfs_extent_busy.c
+++ b/fs/xfs/xfs_extent_busy.c
@@ -62,7 +62,8 @@ xfs_extent_busy_insert_list(
rb_link_node(&new->rb_node, parent, rbp);
rb_insert_color(&new->rb_node, &pag->pagb_tree);

- list_add(&new->list, busy_list);
+ /* always process discard lists in fifo order */
+ list_add_tail(&new->list, busy_list);
spin_unlock(&pag->pagb_lock);
}