From: Matthew Wilcox <willy@infradead.org>
To: Doug Anderson <dianders@chromium.org>
Cc: Mel Gorman <mgorman@techsingularity.net>,
Hillf Danton <hdanton@sina.com>,
Andrew Morton <akpm@linux-foundation.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Christian Brauner <brauner@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Yu Zhao <yuzhao@google.com>
Subject: Re: [PATCH v2 1/4] mm/filemap: Add folio_lock_timeout()
Date: Thu, 27 Apr 2023 03:16:23 +0100 [thread overview]
Message-ID: <ZEna98ttFA9FF14I@casper.infradead.org> (raw)
In-Reply-To: <CAD=FV=Xkg6XgSL0VVVUMm+8xQ65oDgKoTgG0qHY7ALBE3xhCmg@mail.gmail.com>
On Wed, Apr 26, 2023 at 02:39:56PM -0700, Doug Anderson wrote:
> Sure, I'm happy to do it like you say. Do you have any suggestions for
> the similar lock_buffer() case, or are you OK w/ the timeout there?
I'd do that similarly, ie:
+++ b/mm/migrate.c
@@ -691,38 +691,30 @@ EXPORT_SYMBOL(migrate_folio);
static bool buffer_migrate_lock_buffers(struct buffer_head *head,
enum migrate_mode mode)
{
- struct buffer_head *bh = head;
+ struct buffer_head *failed_bh, *bh = head;
- /* Simple case, sync compaction */
- if (mode != MIGRATE_ASYNC) {
- do {
- lock_buffer(bh);
- bh = bh->b_this_page;
-
- } while (bh != head);
-
- return true;
- }
-
- /* async case, we cannot block on lock_buffer so use trylock_buffer */
do {
if (!trylock_buffer(bh)) {
- /*
- * We failed to lock the buffer and cannot stall in
- * async migration. Release the taken locks
- */
- struct buffer_head *failed_bh = bh;
- bh = head;
- while (bh != failed_bh) {
- unlock_buffer(bh);
- bh = bh->b_this_page;
- }
- return false;
+ if (mode == MIGRATE_ASYNC)
+ goto unlock;
+ if (mode == MIGRATE_SYNC_LIGHT && !buffer_uptodate(bh))
+ goto unlock;
+ lock_buffer(bh);
}
bh = bh->b_this_page;
} while (bh != head);
return true;
+
+unlock:
+ /* Failed to lock the buffer and cannot stall */
+ failed_bh = bh;
+ bh = head;
+ while (bh != failed_bh) {
+ unlock_buffer(bh);
+ bh = bh->b_this_page;
+ }
+ return false;
}
static int __buffer_migrate_folio(struct address_space *mapping,
next prev parent reply other threads:[~2023-04-27 2:16 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-21 22:12 [PATCH v2 0/4] migrate: Avoid unbounded blocks in MIGRATE_SYNC_LIGHT Douglas Anderson
2023-04-21 22:12 ` [PATCH v2 1/4] mm/filemap: Add folio_lock_timeout() Douglas Anderson
2023-04-22 5:18 ` Hillf Danton
[not found] ` <20230423081203.1812-1-hdanton@sina.com>
2023-04-23 8:35 ` Gao Xiang
2023-04-23 9:49 ` Hillf Danton
2023-04-23 10:45 ` Gao Xiang
2023-04-24 16:56 ` Doug Anderson
2023-04-25 1:09 ` Hillf Danton
2023-04-25 14:19 ` Doug Anderson
2023-04-26 4:42 ` Hillf Danton
2023-04-26 4:55 ` Doug Anderson
2023-04-26 10:09 ` Mel Gorman
2023-04-26 15:14 ` Matthew Wilcox
2023-04-26 20:46 ` Doug Anderson
2023-04-26 21:26 ` Matthew Wilcox
2023-04-26 21:39 ` Doug Anderson
2023-04-27 2:16 ` Matthew Wilcox [this message]
2023-04-27 9:48 ` Mel Gorman
2023-04-28 8:17 ` Hillf Danton
2023-04-26 15:24 ` Linus Torvalds
2023-04-23 7:50 ` Huang, Ying
2023-04-24 8:22 ` Mel Gorman
2023-04-24 16:22 ` Doug Anderson
2023-04-25 8:00 ` Mel Gorman
2023-04-21 22:12 ` [PATCH v2 2/4] buffer: Add lock_buffer_timeout() Douglas Anderson
2023-04-23 8:47 ` Huang, Ying
2023-04-21 22:12 ` [PATCH v2 3/4] migrate_pages: Don't wait forever locking pages in MIGRATE_SYNC_LIGHT Douglas Anderson
2023-04-23 7:59 ` Huang, Ying
2023-04-24 9:38 ` Mel Gorman
2023-04-21 22:12 ` [PATCH v2 4/4] migrate_pages: Don't wait forever locking buffers " Douglas Anderson
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