diff mbox series

[v3,3/6] btrfs: delayed refs pre-flushing should only run the heads we have

Message ID a32cf92bd7cfc7bc4b2baaa1e251860626c39231.1608137316.git.josef@toxicpanda.com (mailing list archive)
State New, archived
Headers show
Series A variety of lock contention fixes | expand

Commit Message

Josef Bacik Dec. 16, 2020, 4:49 p.m. UTC 
Previously our delayed ref running used the total number of items as the
items to run.  However we changed that to number of heads to run with
the delayed_refs_rsv, as generally we want to run all of the operations
for one bytenr.

But with btrfs_run_delayed_refs(trans, 0) we set our count to 2x the
number of items that we have.  This is generally fine, but if we have
some operation generation loads of delayed refs while we're doing this
pre-flushing in the transaction commit, we'll just spin forever doing
delayed refs.

Fix this to simply pick the number of delayed refs we currently have,
that way we do not end up doing a lot of extra work that's being
generated in other threads.

Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/extent-tree.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index d79b8369e6aa..b6d774803a2c 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2160,7 +2160,7 @@  int btrfs_run_delayed_refs(struct btrfs_trans_handle *trans,
 
 	delayed_refs = &trans->transaction->delayed_refs;
 	if (count == 0)
-		count = atomic_read(&delayed_refs->num_entries) * 2;
+		count = delayed_refs->num_heads_ready;
 
 again:
 #ifdef SCRAMBLE_DELAYED_REFS