From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EF438C46475 for ; Mon, 5 Nov 2018 12:02:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C150620825 for ; Mon, 5 Nov 2018 12:02:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C150620825 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729611AbeKEVVf (ORCPT ); Mon, 5 Nov 2018 16:21:35 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44008 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727048AbeKEVVe (ORCPT ); Mon, 5 Nov 2018 16:21:34 -0500 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D7E00308A972; Mon, 5 Nov 2018 12:02:10 +0000 (UTC) Received: from ming.t460p (ovpn-8-33.pek2.redhat.com [10.72.8.33]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 569F865F49; Mon, 5 Nov 2018 12:01:59 +0000 (UTC) Date: Mon, 5 Nov 2018 20:01:54 +0800 From: Ming Lei To: Johannes Thumshirn Cc: Jens Axboe , Linux Block Layer Mailinglist , Hannes Reinecke , Linux Kernel Mailinglist , Jan Kara , Sagi Grimberg Subject: Re: [PATCH] block: respect virtual boundary mask in bvecs Message-ID: <20181105120153.GD12367@ming.t460p> References: <20181105102301.9752-1-jthumshirn@suse.de> <20181105105548.GC12367@ming.t460p> <7c649b43-f952-cf94-93d6-44fb153acced@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <7c649b43-f952-cf94-93d6-44fb153acced@suse.de> User-Agent: Mutt/1.9.1 (2017-09-22) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.41]); Mon, 05 Nov 2018 12:02:11 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 05, 2018 at 12:50:50PM +0100, Johannes Thumshirn wrote: > On 05/11/2018 11:55, Ming Lei wrote: > > On Mon, Nov 05, 2018 at 11:23:01AM +0100, Johannes Thumshirn wrote: > >> With drivers like iSer we are seeing a lot of bio splitting and smaller I/Os > >> being submitted to the driver. > >> > >> The root cause of this issue that the virtual boundary mask code does not take > >> into consideration that some of the memory segments in the SG list may have > >> come from a huge memory page that is being managed in the SG list as 4K > > > > I guess you mean something like 64K PAGE_SIZE, instead of huge page. > > No I mean like a 2M page from an upper layer. If you mean the real huge page, this patch shouldn't have made a difference because bio_vec->bv_offset is in [0, PAGE_SIZE), and iSer sets virt boundary as 4K - 1. However, things will change after multipage bvec is introduced. Thanks, Ming