From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f70.google.com (mail-pg0-f70.google.com [74.125.83.70]) by kanga.kvack.org (Postfix) with ESMTP id 92FDC6B0007 for ; Thu, 24 May 2018 04:50:26 -0400 (EDT) Received: by mail-pg0-f70.google.com with SMTP id t2-v6so408575pgo.0 for ; Thu, 24 May 2018 01:50:26 -0700 (PDT) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id h6-v6sor5493998pgc.313.2018.05.24.01.50.25 for (Google Transport Security); Thu, 24 May 2018 01:50:25 -0700 (PDT) Subject: Re: [PATCH v2] mm/ksm: ignore STABLE_FLAG of rmap_item->address in rmap_walk_ksm References: <20180503124415.3f9d38aa@p-imbrenda.boeblingen.de.ibm.com> <1525403506-6750-1-git-send-email-hejianet@gmail.com> <20180509163101.02f23de1842a822c61fc68ff@linux-foundation.org> <2cd6b39b-1496-bbd5-9e31-5e3dcb31feda@arm.com> <6c417ab1-a808-72ea-9618-3d76ec203684@arm.com> From: Jia He Message-ID: <198fe48c-0d26-7dd1-89dc-415bd3c7ab41@gmail.com> Date: Thu, 24 May 2018 16:50:16 +0800 MIME-Version: 1.0 In-Reply-To: <6c417ab1-a808-72ea-9618-3d76ec203684@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Suzuki K Poulose , Andrew Morton Cc: Andrea Arcangeli , Minchan Kim , Claudio Imbrenda , Arvind Yadav , Mike Rapoport , linux-mm@kvack.org, linux-kernel@vger.kernel.org, jia.he@hxt-semitech.com, Hugh Dickins Hi Suzuki On 5/24/2018 4:44 PM, Suzuki K Poulose Wrote: > On 14/05/18 10:45, Suzuki K Poulose wrote: >> On 10/05/18 00:31, Andrew Morton wrote: >>> On Fri,A 4 May 2018 11:11:46 +0800 Jia He wrote: >>> >>>> In our armv8a server(QDF2400), I noticed lots of WARN_ON caused by PAGE_SIZE >>>> unaligned for rmap_item->address under memory pressure tests(start 20 guests >>>> and run memhog in the host). >>>> >>>> ... >>>> >>>> In rmap_walk_ksm, the rmap_item->address might still have the STABLE_FLAG, >>>> then the start and end in handle_hva_to_gpa might not be PAGE_SIZE aligned. >>>> Thus it will cause exceptions in handle_hva_to_gpa on arm64. >>>> >>>> This patch fixes it by ignoring(not removing) the low bits of address when >>>> doing rmap_walk_ksm. >>>> >>>> Signed-off-by: jia.he@hxt-semitech.com >>> >>> I assumed you wanted this patch to be committed as >>> From:jia.he@hxt-semitech.com rather than From:hejianet@gmail.com, so I >>> made that change.A Please let me know if this was inappropriate. >>> >>> You can do this yourself by adding an explicit From: line to the very >>> start of the patch's email text. >>> >>> Also, a storm of WARN_ONs is pretty poor behaviour.A Is that the only >>> misbehaviour which this bug causes?A Do you think the fix should be >>> backported into earlier kernels? >>> > > > Jia, Andrew, > > What is the status of this patch ? > > Suzuki I thought the patch is merged into mmotm tree. http://www.ozlabs.org/~akpm/mmotm/series But I don't know what is the next step. Cheers, Jia