From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267243AbUHTPdU (ORCPT ); Fri, 20 Aug 2004 11:33:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266739AbUHTPdU (ORCPT ); Fri, 20 Aug 2004 11:33:20 -0400 Received: from mail1.kontent.de ([81.88.34.36]:59855 "EHLO Mail1.KONTENT.De") by vger.kernel.org with ESMTP id S267243AbUHTPcs (ORCPT ); Fri, 20 Aug 2004 11:32:48 -0400 From: Oliver Neukum To: "Stephen C. Tweedie" Subject: Re: PF_MEMALLOC in 2.6 Date: Fri, 20 Aug 2004 17:34:10 +0200 User-Agent: KMail/1.6.2 Cc: Hugh Dickins , Pete Zaitcev , Arjan van de Ven , Alan Cox , Greg KH , linux-kernel , Rik van Riel References: <1092997872.1996.51.camel@sisko.scot.redhat.com> In-Reply-To: <1092997872.1996.51.camel@sisko.scot.redhat.com> MIME-Version: 1.0 Content-Disposition: inline Content-Type: text/plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Message-Id: <200408201734.10317.oliver@neukum.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Am Freitag, 20. August 2004 12:31 schrieb Stephen C. Tweedie: > Hi, > > On Thu, 2004-08-19 at 13:41, Hugh Dickins wrote: > > > Or would it solve the problem at hand, if it made itself PF_MEMALLOC > > just while servicing a request from a PF_MEMALLOC? > > It's not the PF_* state of the caller who submitted the IO that matters, > though --- it's the state of all threads _waiting_ on the IO, which may > be different, and which can change even after the IO has begun. > > Eg. kswapd does a writepage, the writepage needs to allocate disk space, > and in doing so tries to access a metadata block which is already > undergoing IO from a different thread altogether. Then how do the current SCSI drivers work? Regards Oliver