From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nigel Cunningham Subject: Re: question on freeze and aio Date: Sat, 10 Feb 2007 09:08:46 +1100 Message-ID: <1171058926.1484.74.camel@nigel.suspend2.net> References: Reply-To: nigel@nigel.suspend2.net Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: 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: Alan Stern Cc: linux-pm@lists.osdl.org List-Id: linux-pm@vger.kernel.org Hi. On Fri, 2007-02-09 at 17:03 -0500, Alan Stern wrote: > On Sat, 10 Feb 2007, Nigel Cunningham wrote: > = > > Hi. > > = > > On Fri, 2007-02-09 at 17:04 +0100, Oliver Neukum 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 think > > 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 aio = > 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... Hmm. That applies to Raid, too? I've had some reports of raid i/o being caught in the BUG_ON() I have to catch I/O that shouldn't be happening, but haven't gotten around to looking at them yet. Regards, Nigel