The patch titled
Subject: filemap: remove use of wait bookmarks
has been added to the -mm mm-unstable branch. Its filename is
filemap-remove-use-of-wait-bookmarks.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/filemap-remove-use-of-wait-bookmarks.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: "Matthew Wilcox (Oracle)" <willy@xxxxxxxxxxxxx>
Subject: filemap: remove use of wait bookmarks
Date: Tue, 10 Oct 2023 04:58:28 +0100
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.
Link: https://lkml.kernel.org/r/20231010035829.544242-1-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Bin Lai <sclaibin@xxxxxxxxx>
Cc: Benjamin Segall <bsegall@xxxxxxxxxx>
Cc: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
Cc: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Juri Lelli <juri.lelli@xxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Cc: Valentin Schneider <vschneid@xxxxxxxxxx>
Cc: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/filemap.c | 21 +--------------------
1 file changed, 1 insertion(+), 20 deletions(-)
--- a/mm/filemap.c~filemap-remove-use-of-wait-bookmarks
+++ a/mm/filemap.c
@@ -1133,32 +1133,13 @@ static void folio_wake_bit(struct folio
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's possible to miss clearing waiters here, when we woke our page
_
Patches currently in -mm which might be from willy@xxxxxxxxxxxxx are
mm-make-lock_folio_maybe_drop_mmap-vma-lock-aware.patch
mm-call-wp_page_copy-under-the-vma-lock.patch
mm-handle-shared-faults-under-the-vma-lock.patch
mm-handle-cow-faults-under-the-vma-lock.patch
mm-handle-read-faults-under-the-vma-lock.patch
mm-handle-write-faults-to-ro-pages-under-the-vma-lock.patch
iomap-hold-state_lock-over-call-to-ifs_set_range_uptodate.patch
iomap-protect-read_bytes_pending-with-the-state_lock.patch
mm-add-folio_end_read.patch
ext4-use-folio_end_read.patch
buffer-use-folio_end_read.patch
iomap-use-folio_end_read.patch
bitops-add-xor_unlock_is_negative_byte.patch
alpha-implement-xor_unlock_is_negative_byte.patch
m68k-implement-xor_unlock_is_negative_byte.patch
mips-implement-xor_unlock_is_negative_byte.patch
powerpc-implement-arch_xor_unlock_is_negative_byte-on-32-bit.patch
riscv-implement-xor_unlock_is_negative_byte.patch
s390-implement-arch_xor_unlock_is_negative_byte.patch
mm-delete-checks-for-xor_unlock_is_negative_byte.patch
mm-add-folio_xor_flags_has_waiters.patch
mm-make-__end_folio_writeback-return-void.patch
mm-use-folio_xor_flags_has_waiters-in-folio_end_writeback.patch
filemap-remove-use-of-wait-bookmarks.patch
sched-remove-wait-bookmarks.patch
