From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it1-f198.google.com (mail-it1-f198.google.com [209.85.166.198]) by kanga.kvack.org (Postfix) with ESMTP id D3BE16B5A79 for ; Fri, 30 Nov 2018 17:34:14 -0500 (EST) Received: by mail-it1-f198.google.com with SMTP id k133so656025ite.4 for ; Fri, 30 Nov 2018 14:34:14 -0800 (PST) Received: from ale.deltatee.com (ale.deltatee.com. [207.54.116.67]) by mx.google.com with ESMTPS id d67si317879itc.14.2018.11.30.14.34.13 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 30 Nov 2018 14:34:13 -0800 (PST) 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 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-CA Content-Transfer-Encoding: 7bit Subject: Re: [PATCH v8 3/7] mm, devm_memremap_pages: Fix shutdown handling Sender: owner-linux-mm@kvack.org List-ID: 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 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