Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760441AbcDFChL (ORCPT ); Tue, 5 Apr 2016 22:37:11 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:49742 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753966AbcDFChJ (ORCPT ); Tue, 5 Apr 2016 22:37:09 -0400 MIME-Version: 1.0 In-Reply-To: <20160406023411.GA7793@kmo-pixel> References: <1459878246-9249-1-git-send-email-ming.lei@canonical.com> <20160406003025.GC31161@kmo-pixel> <20160406011028.GA32334@kmo-pixel> <20160406012839.GA32713@kmo-pixel> <20160406022249.GB7452@kmo-pixel> <20160406023411.GA7793@kmo-pixel> Date: Wed, 6 Apr 2016 10:37:05 +0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH] block: make sure big bio is splitted into at most 256 bvecs From: Ming Lei To: Kent Overstreet Cc: Jens Axboe , Linux Kernel Mailing List , linux-block@vger.kernel.org, Christoph Hellwig , Eric Wheeler , Sebastian Roesner , "4.2+" , Shaohua Li Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 873 Lines: 23 On Wed, Apr 6, 2016 at 10:34 AM, Kent Overstreet wrote: > On Wed, Apr 06, 2016 at 10:30:22AM +0800, Ming Lei wrote: >> Now limit.max_segments is for limiting segments from hw view, one this >> segment may include lots of pages/bvecs. >> >> The current bio_clone() issue is that we can't clone from one bio which >> includes more than 256 bvecs, maybe all these 256 bvecs belong to >> one same hw segment. > > So the distinction is purely a post multipage bvec thing? Even after multipage bvec is applied, the limit for max bvecs is still needed for some cases like bio bounce, in which bio_clone() need to clone single page bvec. Thanks, > -- > To unsubscribe from this list: send the line "unsubscribe linux-block" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html