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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 C50B2C04EB8 for ; Fri, 30 Nov 2018 22:34:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8515620863 for ; Fri, 30 Nov 2018 22:34:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8515620863 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=deltatee.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 S1726631AbeLAJpE (ORCPT ); Sat, 1 Dec 2018 04:45:04 -0500 Received: from ale.deltatee.com ([207.54.116.67]:45050 "EHLO ale.deltatee.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725790AbeLAJpE (ORCPT ); Sat, 1 Dec 2018 04:45:04 -0500 Received: from guinness.priv.deltatee.com ([172.16.1.162]) by ale.deltatee.com with esmtp (Exim 4.89) (envelope-from ) id 1gSrMO-0005ko-LN; Fri, 30 Nov 2018 15:34:09 -0700 To: Dan Williams Cc: Andrew Morton , stable , =?UTF-8?B?SsOpcsO0bWUgR2xpc3Nl?= , Christoph Hellwig , Linus Torvalds , Linux MM , Linux Kernel Mailing List , Maling list - DRI developers , Bjorn Helgaas , Stephen Bates References: <154275556908.76910.8966087090637564219.stgit@dwillia2-desk3.amr.corp.intel.com> <154275558526.76910.7535251937849268605.stgit@dwillia2-desk3.amr.corp.intel.com> <6875ca04-a36a-89ae-825b-f629ab011d47@deltatee.com> <14d6413c-b002-c152-5016-7ed659c08c24@deltatee.com> <43778343-6d43-eb43-0de0-3db6828902d0@deltatee.com> From: Logan Gunthorpe Message-ID: Date: Fri, 30 Nov 2018 15:34:07 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-CA Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 172.16.1.162 X-SA-Exim-Rcpt-To: sbates@raithlin.com, bhelgaas@google.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, torvalds@linux-foundation.org, hch@lst.de, jglisse@redhat.com, stable@vger.kernel.org, akpm@linux-foundation.org, dan.j.williams@intel.com X-SA-Exim-Mail-From: logang@deltatee.com Subject: Re: [PATCH v8 3/7] mm, devm_memremap_pages: Fix shutdown handling X-SA-Exim-Version: 4.2.1 (built Tue, 02 Aug 2016 21:08:31 +0000) X-SA-Exim-Scanned: Yes (on ale.deltatee.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018-11-30 3:28 p.m., Dan Williams wrote: > On Fri, Nov 30, 2018 at 2:19 PM Logan Gunthorpe wrote: >> >> Hey, >> >> On 2018-11-29 11:51 a.m., Dan Williams wrote: >>> Got it, let me see how bad moving arch_remove_memory() turns out, >>> sounds like a decent approach to coordinate multiple users of a single >>> ref. >> >> I've put together a patch set[1] that fixes all the users of >> devm_memremap_pages() without moving arch_remove_memory(). It's pretty >> clean except for the p2pdma case which is fairly tricky but I don't >> think there's an easy way around that. > > The solution I'm trying is to introduce a devm_memremap_pages_remove() > that each user can call after they have called percpu_ref_exit(), it's > just crashing for me currently... Ok, that's probably less of a clean up for other users, but sounds like it would be less tricky for p2pdma. I'd have to create a list of all pgmaps, but that's not so hard and doesn't create any nasty races to consider like my current solution. >> If you come up with a better solution that's great, otherwise let me >> know and I'll do some clean up and more testing and send this set to the >> lists. Though, we might need to wait for your patch to land before we >> can properly send the fix to it (the first patch in my series)... > > I'd say go ahead and send it. We can fix p2pdma as a follow-on. Send > it to Andrew as a patch relative to the current -next tree. Ok, though, how do I reference the current patch in Andrew's tree? Or does it matter? Logan