Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422998AbWLVOBz (ORCPT ); Fri, 22 Dec 2006 09:01:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1422999AbWLVOBz (ORCPT ); Fri, 22 Dec 2006 09:01:55 -0500 Received: from pentafluge.infradead.org ([213.146.154.40]:34018 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1422998AbWLVOBy (ORCPT ); Fri, 22 Dec 2006 09:01:54 -0500 Date: Fri, 22 Dec 2006 14:01:39 +0000 From: Christoph Hellwig To: Kiyoshi Ueda Cc: jens.axboe@oracle.com, agk@redhat.com, mchristi@redhat.com, linux-kernel@vger.kernel.org, dm-devel@redhat.com, j-nomura@ce.jp.nec.com Subject: Re: [RFC PATCH 1/8] rqbased-dm: allow blk_get_request() to be called from interrupt context Message-ID: <20061222140139.GA26033@infradead.org> Mail-Followup-To: Christoph Hellwig , Kiyoshi Ueda , jens.axboe@oracle.com, agk@redhat.com, mchristi@redhat.com, linux-kernel@vger.kernel.org, dm-devel@redhat.com, j-nomura@ce.jp.nec.com References: <20061219.171119.18572687.k-ueda@ct.jp.nec.com> <20061220134848.GF10535@kernel.dk> <20061220.125002.71083198.k-ueda@ct.jp.nec.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20061220.125002.71083198.k-ueda@ct.jp.nec.com> User-Agent: Mutt/1.4.2.2i X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 865 Lines: 17 On Wed, Dec 20, 2006 at 12:50:02PM -0500, Kiyoshi Ueda wrote: > Because I'd like to use blk_get_request() in q->request_fn() > which can be called from interrupt context like below: > scsi_io_completion -> scsi_end_request -> scsi_next_command > -> scsi_run_queue -> blk_run_queue -> q->request_fn > Or request should not be allocated in q->request_fn() anyway? > Do you have any other ideas? The right long-term fix is to make sure request_fn is only ever called from process context. This means moving retry handling to a thread instead of a softirq, but this will need careful performance testing and tweaking. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/