From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751498Ab0DFIaK (ORCPT ); Tue, 6 Apr 2010 04:30:10 -0400 Received: from mailhub.sw.ru ([195.214.232.25]:31794 "EHLO relay.sw.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751036Ab0DFIaF (ORCPT ); Tue, 6 Apr 2010 04:30:05 -0400 From: Dmitry Monakhov To: Christoph Hellwig Cc: linux-kernel@vger.kernel.org, jens.axboe@oracle.com, mkp@mkp.net Subject: Re: [PATCH 4/5] blkdev: add discard payload flag References: <1269451988-5270-1-git-send-email-dmonakhov@openvz.org> <1269451988-5270-2-git-send-email-dmonakhov@openvz.org> <1269451988-5270-3-git-send-email-dmonakhov@openvz.org> <1269451988-5270-4-git-send-email-dmonakhov@openvz.org> <1269451988-5270-5-git-send-email-dmonakhov@openvz.org> <20100405200003.GB17589@infradead.org> Date: Tue, 06 Apr 2010 12:29:37 +0400 In-Reply-To: <20100405200003.GB17589@infradead.org> (Christoph Hellwig's message of "Mon, 5 Apr 2010 16:00:03 -0400") Message-ID: <87sk79vv9q.fsf@openvz.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1.50 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Christoph Hellwig writes: > On Wed, Mar 24, 2010 at 08:33:07PM +0300, Dmitry Monakhov wrote: >> Not all implementations require discard bio to be filled with one-sector >> sized payload. Let's allocate payload only when necessary. > > Neither this nor the next one are really needed as I have some patches > pending to move the payload allocation into the low level drivers. Ok good to know. As soon as i understand on low level you know how many memory you actually need to store a request range. BTW Do you know any drivers which max_discard_sectors contains some restricted value? Because my 5'th patch was aimed to optimize the case where discard request must being spitted to several bio-s.