linux-kernel - RE: [PATCH] bdi: use deferable timer for sync

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

Date:	Fri, 8 Oct 2010 18:04:44 +0800
From:	"Wu, Xia" <xia.wu@...el.com>
To:	Christoph Hellwig <hch@....de>,
	Yong Wang <yong.y.wang@...ux.intel.com>
CC:	Jens Axboe <jaxboe@...ionio.com>,
	Artem Bityutskiy <Artem.Bityutskiy@...ia.com>,
	"Wu, Fengguang" <fengguang.wu@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-mm@...ck.org" <linux-mm@...ck.org>
Subject: RE: [PATCH] bdi: use deferable timer for sync_supers task


On Fri, Oct 08, 2010 at 04:35:14PM +0800, Yong Wang wrote:
> > sync_supers task currently wakes up periodically for superblock
> > writeback. This hurts power on battery driven devices. This patch
> > turns this housekeeping timer into a deferable timer so that it
> > does not fire when system is really idle.

> How long can the timer be defereed?  We can't simply stop writing
> out data for a long time.  I think the current timer value should be
> the upper bound, but allowing to fire earlier to run during the
> same wakeup cycle as others is fine.

If the system is in sleep state, this timer can be deferred to the next wake-up interrupt.
If the system is busy, this timer will fire at the scheduled time.


--
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/