linux-kernel - [PATCH 002 of 2] md: Reduce CPU wastage on idle md array with a write-intent bitmap. fix

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Fri, 7 Mar 2008 16:00:53 +1100
From:	NeilBrown <neilb@...e.de>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	linux-raid@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 002 of 2] md: Reduce CPU wastage on idle md array with a write-intent bitmap. fix

Recent patch titled
  Reduce CPU wastage on idle md array with a write-intent bitmap.

would sometimes leave the array with dirty bitmap bits that stay
dirty.  A subsequent write would sort things out so it isn't a big
problem, but should be fixed nonetheless.

We need to make sure that when the bitmap becomes not "allclean", the
daemon_sleep really does get set to a sensible value.

Signed-off-by: Neil Brown <neilb@...e.de>

### Diffstat output
 ./drivers/md/bitmap.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff .prev/drivers/md/bitmap.c ./drivers/md/bitmap.c
--- .prev/drivers/md/bitmap.c	2008-03-07 15:51:23.000000000 +1100
+++ ./drivers/md/bitmap.c	2008-03-07 15:56:57.000000000 +1100
@@ -1045,7 +1045,8 @@ void bitmap_daemon_work(struct bitmap *b
 	if (bitmap == NULL)
 		return;
 	if (time_before(jiffies, bitmap->daemon_lastrun + bitmap->daemon_sleep*HZ))
-		return;
+		goto done;
+
 	bitmap->daemon_lastrun = jiffies;
 	if (bitmap->allclean) {
 		bitmap->mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
@@ -1142,6 +1143,7 @@ void bitmap_daemon_work(struct bitmap *b
 		}
 	}

+ done:
 	if (bitmap->allclean == 0)
 		bitmap->mddev->thread->timeout = bitmap->daemon_sleep * HZ;
 }
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/