The original problem of the overly long list of waiters on a
locked page was solved properly by commit 9a1ea439b16b ("mm:
put_and_wait_on_page_locked() while page is migrated"). In
the meantime, using bookmarks for the writeback bit can cause
livelocks, so we need to stop using them.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
mm/filemap.c | 21 +--------------------
1 file changed, 1 insertion(+), 20 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index b2728eb52407..bb8ec585dea8 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1151,32 +1151,13 @@ static void folio_wake_bit(struct folio *folio, int bit_nr)
wait_queue_head_t *q = folio_waitqueue(folio);
struct wait_page_key key;
unsigned long flags;
- wait_queue_entry_t bookmark;
key.folio = folio;
key.bit_nr = bit_nr;
key.page_match = 0;
- bookmark.flags = 0;
- bookmark.private = NULL;
- bookmark.func = NULL;
- INIT_LIST_HEAD(&bookmark.entry);
-
spin_lock_irqsave(&q->lock, flags);
- __wake_up_locked_key_bookmark(q, TASK_NORMAL, &key, &bookmark);
-
- while (bookmark.flags & WQ_FLAG_BOOKMARK) {
- /*
- * Take a breather from holding the lock,
- * allow pages that finish wake up asynchronously
- * to acquire the lock and remove themselves
- * from wait queue
- */
- spin_unlock_irqrestore(&q->lock, flags);
- cpu_relax();
- spin_lock_irqsave(&q->lock, flags);
- __wake_up_locked_key_bookmark(q, TASK_NORMAL, &key, &bookmark);
- }
+ __wake_up_locked_key(q, TASK_NORMAL, &key);
/*
* It is possible for other pages to have collided on the waitqueue
--
2.34.1
--vQ4HEjhWuFe4e0zu
Content-Type: text/plain; charset=us-ascii
Content-Disposition: attachment;
filename="0002-sched-Remove-wait-bookmarks.patch"
