linux-kernel - [PATCH] block core: use round_jiffies on timer to reduce wakeups

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-next>] [day] [month] [year] [list]

Message-ID: <4AFA03BB.90405@oracle.com>
Date:	Tue, 10 Nov 2009 16:22:19 -0800
From:	Randy Dunlap <randy.dunlap@...cle.com>
To:	lkml <linux-kernel@...r.kernel.org>,
	Jens Axboe <jens.axboe@...cle.com>
Subject: [PATCH] block core: use round_jiffies on timer to reduce wakeups

From: Randy Dunlap <randy.dunlap@...cle.com>

Use round_jiffies() variant to schedule the timer along with
other timer wakeups on the same CPU.

Source file also needs to include jiffies.h since it uses
functions or macros from it.

Signed-off-by: Randy Dunlap <randy.dunlap@...cle.com>
---
 block/blk-core.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

--- lnx-2632-rc6.orig/block/blk-core.c
+++ lnx-2632-rc6/block/blk-core.c
@@ -17,6 +17,7 @@
 #include <linux/bio.h>
 #include <linux/blkdev.h>
 #include <linux/highmem.h>
+#include <linux/jiffies.h>
 #include <linux/mm.h>
 #include <linux/kernel_stat.h>
 #include <linux/string.h>
@@ -212,7 +213,8 @@ void blk_plug_device(struct request_queu
 		return;
 
 	if (!queue_flag_test_and_set(QUEUE_FLAG_PLUGGED, q)) {
-		mod_timer(&q->unplug_timer, jiffies + q->unplug_delay);
+		mod_timer(&q->unplug_timer,
+			round_jiffies_up(jiffies + q->unplug_delay));
 		trace_block_plug(q);
 	}
 }
--
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/