From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: question on freeze and aio Date: Tue, 13 Feb 2007 16:53:15 +0100 Message-ID: <200702131653.15744.rjw@sisk.pl> References: <200702092309.11530.rjw@sisk.pl> <20070213101859.GD12996@elf.ucw.cz> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20070213101859.GD12996@elf.ucw.cz> Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.osdl.org Errors-To: linux-pm-bounces@lists.osdl.org To: Pavel Machek Cc: linux-pm@lists.osdl.org List-Id: linux-pm@vger.kernel.org On Tuesday, 13 February 2007 11:18, Pavel Machek wrote: > Hi! > = > > > > > can there be running aio requests if all tasks are frozen? > > > > = > > > > Since tasks are frozen, no new aio requests would be submitted. We = do a > > > > sync to ssek to complete existing requests; I haven't looked to see > > > > whether that would need extending to flush aio as well, but don't t= hink > > > > that would be the case. Given everyone else's silence, so far, you = might > > > > be better to ask the author(s) of the aio code. > > > = > > > I believe Nigel is basically correct. However sync will only flush a= io = > > > for block devices. Other types of aio will remain active. > > > = > > > aio callbacks are interrupt-driven and execute in a workqueue (see > > > fs/aio.c), and as far as I can tell that workqueue doesn't freeze. = > > > Unless some general facility freezes all workqueues... > > = > > No, workqueues are not frozen unless they are explicitly declared as > > freezeable. Which currently is only done by XFS, AFAIKS. > = > Ok, then we have a bug in swsusp. Can someone locate _which_ workqueue > is used for aio... and make it freezeable? Hm, so AIO is not needed for saving the image regardless of the system configuration? Rafael