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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no 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 014F1C31E40 for ; Fri, 9 Aug 2019 14:36:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D693920665 for ; Fri, 9 Aug 2019 14:36:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2407004AbfHIOg3 (ORCPT ); Fri, 9 Aug 2019 10:36:29 -0400 Received: from verein.lst.de ([213.95.11.211]:55735 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726157AbfHIOg2 (ORCPT ); Fri, 9 Aug 2019 10:36:28 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id E722868BFE; Fri, 9 Aug 2019 16:36:23 +0200 (CEST) Date: Fri, 9 Aug 2019 16:36:23 +0200 From: Christoph Hellwig To: Thomas Hellstrom Cc: Christoph Hellwig , Linus Torvalds , Andrew Morton , Jerome Glisse , Jason Gunthorpe , Steven Price , Linux-MM , Linux List Kernel Mailing Subject: Re: cleanup the walk_page_range interface Message-ID: <20190809143623.GA10269@lst.de> References: <20190808154240.9384-1-hch@lst.de> <20190808215632.GA12773@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 09, 2019 at 12:21:24AM +0200, Thomas Hellstrom wrote: > On 8/8/19 11:56 PM, Christoph Hellwig wrote: >> On Thu, Aug 08, 2019 at 10:50:37AM -0700, Linus Torvalds wrote: >>>> Note that both Thomas and Steven have series touching this area pending, >>>> and there are a couple consumer in flux too - the hmm tree already >>>> conflicts with this series, and I have potential dma changes on top of >>>> the consumers in Thomas and Steven's series, so we'll probably need a >>>> git tree similar to the hmm one to synchronize these updates. >>> I'd be willing to just merge this now, if that helps. The conversion >>> is mechanical, and my only slight worry would be that at least for my >>> original patch I didn't build-test the (few) non-x86 >>> architecture-specific cases. But I did end up looking at them fairly >>> closely (basically using some grep/sed scripts to see that the >>> conversions I did matched the same patterns). And your changes look >>> like obvious improvements too where any mistake would have been caught >>> by the compiler. >> I did cross compile the s390 and powerpc bits, but I do not have an >> openrisc compiler. >> >>> So I'm not all that worried from a functionality standpoint, and if >>> this will help the next merge window, I'll happily pull now. >> That would help with this series vs the others, but not with the other >> series vs each other. > > Although my series doesn't touch the pagewalk code, it rather borrowed some > concepts from it and used for the apply_to_page_range() interface. > > The reason being that the pagewalk code requires the mmap_sem to be held > (mainly for trans-huge pages and reading the vma->vm_flags if I understand > the code correctly). That is fine when you scan the vmas of a process, but > the helpers I wrote need to instead scan all vmas pointing into a struct > address_space, and taking the mmap_sem for each vma will create lock > inversion problems. True. So you'll just need to apply the same lessons there, and we should probably fine with this series going into 5.3-rc.