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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 33683C433F5 for ; Wed, 23 Mar 2022 17:04:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245674AbiCWRFv (ORCPT ); Wed, 23 Mar 2022 13:05:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48384 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245665AbiCWRFl (ORCPT ); Wed, 23 Mar 2022 13:05:41 -0400 Received: from mail-qt1-x82c.google.com (mail-qt1-x82c.google.com [IPv6:2607:f8b0:4864:20::82c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CB7D2517E3 for ; Wed, 23 Mar 2022 10:04:06 -0700 (PDT) Received: by mail-qt1-x82c.google.com with SMTP id v2so1699000qtc.5 for ; Wed, 23 Mar 2022 10:04:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=Xnq4bRc3cz88ytLQgShmjJNQac+AYZh8iK8Px2OMFPU=; b=kNJF0xfmaBtRkYelsVEtH2PuynVN0qClkTty/AJqdCdvjWNfq2Xk2V4TNeY1tHRasf CTPK60t1bo6F9GX0IylFdyy0xJliGLDWAs7nUST7tNctmZzYcpVjzH/fak4ZXsxXO+S8 5jeejGeZpe5zVlWxy0jTumjLbwoLSDWAS28Mb2tPR983RMexa9B8B94uGt5Se317TlzA fU3WtHm9SV29L423AHw8spl6E8QxF+tMOI9rNhgvsxAgFQqdYolSOo6RHmtyy7VdSVHq kc2rJfdw5nu5tN4AsX1zAwXNsLQb3MEqwVrJye4pnhAnMx4BfdV47f/DQXRcjpQRr47j 0b3Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=Xnq4bRc3cz88ytLQgShmjJNQac+AYZh8iK8Px2OMFPU=; b=5dngY9jIDzioSBBqY6fZ56Q4U1BoNZHu+GLCgTflgP2PdIuCSpgKY3sQRRJhhH34+I g9rge9lO6VsIztFUnbDFdGJi2+40/oo6zoTM2lZAiyjsgVbCTRk940sEU8RqMbW8SkYe VbibaiJT2mOqSNG7pa1YQecU9MsmVTRhHnHfm6u3LhNyq8mUWohVzeaRWShVGAO/xEKy q66A+24mhrb8oIgVGoXQwanAZBborRZ5ZWtKK8OZMUp64jWt1WsdreC74VLv7C94FM8g 4HVQEjnjOuZfh9pe09F7rGmyGISsEqjRdwdukBTffSTnjpvJknMft2Xw77YE2ABpGgwh YmVQ== X-Gm-Message-State: AOAM532awb7hZEZwapXDoMzBs/PzNedeNtCScSV7N7TlgTaiAxY/RQ9P KgdkmN9u85gPPJrUdZCWWxCmSRI0kx6frA== X-Google-Smtp-Source: ABdhPJyYEQE0CYp6+og8QZG/WuYeFw545rz58LgI1p5Yq3Rl0fLB9/5tGE3gp9FdXtFsBCDq8JuXBA== X-Received: by 2002:a05:622a:28f:b0:2e1:cebc:8c44 with SMTP id z15-20020a05622a028f00b002e1cebc8c44mr679876qtw.648.1648055045822; Wed, 23 Mar 2022 10:04:05 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-142-162-113-129.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.162.113.129]) by smtp.gmail.com with ESMTPSA id e7-20020ac85987000000b002e1b7fa2201sm390829qte.56.2022.03.23.10.04.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Mar 2022 10:04:05 -0700 (PDT) Received: from jgg by mlx with local (Exim 4.94) (envelope-from ) id 1nX4Oy-004y0H-9Z; Wed, 23 Mar 2022 14:04:04 -0300 Date: Wed, 23 Mar 2022 14:04:04 -0300 From: Jason Gunthorpe To: Michal Hocko Cc: Juergen Gross , linux-mm@kvack.org, lkml , Andrew Morton , "xen-devel@lists.xenproject.org" , Jerome Glisse Subject: Re: blocking vs. non-blocking mmu notifiers Message-ID: <20220323170404.GK64706@ziepe.ca> References: <8e8ec786-74db-157b-a290-b1537941e91d@suse.com> <20220323163146.GI64706@ziepe.ca> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Mar 23, 2022 at 05:49:43PM +0100, Michal Hocko wrote: > > The bug here is that prior to commit a81461b0546c ("xen/gntdev: update > > to new mmu_notifier semantic") wired the mn_invl_range_start() which > > takes a mutex to invalidate_page, which is defined to run in an atomic > > context. > > Yeah, we have already identified that but quickly realized that the > whole mmu notifier overhaul which this fix depends on would be no no for > backporting to our older code base. So we are trying to find our way > around that. IMHO you don't need everything, just commit 369ea8242c0f ("mm/rmap: update to new mmu_notifier semantic v2") which adds the missing start/end outside the lock for the page callbacks. Then you can take safely a8146 into gntdev. Jason