Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752869AbaKCBVN (ORCPT ); Sun, 2 Nov 2014 20:21:13 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:51272 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751250AbaKCBVM (ORCPT ); Sun, 2 Nov 2014 20:21:12 -0500 Message-ID: <5456D867.5020303@fb.com> Date: Sun, 2 Nov 2014 18:20:39 -0700 From: Jens Axboe User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.2.0 MIME-Version: 1.0 To: Richard Weinberger , Ezequiel Garcia , , CC: , , , Subject: Re: [PATCH] UBI: Block: Add blk-mq support References: <1414933255-3795-1-git-send-email-richard@nod.at> <5456A787.5060104@free-electrons.com> <5456AE72.1010409@nod.at> <5456AFEA.6000507@free-electrons.com> <5456B4F8.1000608@nod.at> In-Reply-To: <5456B4F8.1000608@nod.at> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [192.168.57.29] X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:5.12.52,1.0.28,0.0.0000 definitions=2014-11-03_01:2014-10-31,2014-11-02,1970-01-01 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 kscore.is_bulkscore=0 kscore.compositescore=0 circleOfTrustscore=0 compositescore=0.12498974524102 urlsuspect_oldscore=0.12498974524102 suspectscore=0 recipient_domain_to_sender_totalscore=0 phishscore=0 bulkscore=0 kscore.is_spamscore=0 recipient_to_sender_totalscore=0 recipient_domain_to_sender_domain_totalscore=2524143 rbsscore=0.12498974524102 spamscore=0 recipient_to_sender_domain_totalscore=4 urlsuspectscore=0.9 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=7.0.1-1402240000 definitions=main-1411030012 X-FB-Internal: deliver Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2014-11-02 15:49, Richard Weinberger wrote: > AFAICT blk-mq allocates one struct ubiblock_pdu per device. > As all IO is done via scattergather the memory footprint should be good. > But I'm sure Christoph can tell you the glory details. That is true, the request list and pdu is allocated upfront. If that is a problem, the pdu need not be allocated upfront but could be done at IO time instead. With that comes a bit more complicated retry handling, for memory shortage situations. -- Jens Axboe -- 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/