From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966061AbeEXJhL (ORCPT ); Thu, 24 May 2018 05:37:11 -0400 Received: from mail-pg0-f67.google.com ([74.125.83.67]:41585 "EHLO mail-pg0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965783AbeEXJhH (ORCPT ); Thu, 24 May 2018 05:37:07 -0400 X-Google-Smtp-Source: AB8JxZoSLQMtZHDpreqZJ3JpUSNbEezGxLcV2/vJ0iVSH/OTD3AZcdhQzjELdmSgSKe2RsYqBOsLkw== Subject: Re: [PATCH v2] mm/ksm: ignore STABLE_FLAG of rmap_item->address in rmap_walk_ksm 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 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> <198fe48c-0d26-7dd1-89dc-415bd3c7ab41@gmail.com> <575857e6-c8ec-efa0-6434-b78a513aeaba@arm.com> From: Jia He Message-ID: <2c220e3d-8ff1-f9a9-9038-fff38952b8b1@gmail.com> Date: Thu, 24 May 2018 17:36:57 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <575857e6-c8ec-efa0-6434-b78a513aeaba@arm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/24/2018 5:01 PM, Suzuki K Poulose Wrote: > On 24/05/18 09:50, Jia He wrote: >> 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,  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.  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.  Is that the only >>>>> misbehaviour which this bug causes?  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. > > Hi Jia, > > Thanks for the update. I think that should eventually hit mainline. When it does, > please could you send the patch to stable kernel versions too ? > > Usually having a "Cc: stable@kernel.vger.org" in the original patch (for > critical fixes) would have done the trick. But since we don't have it, > please send it following the stable kernel rules. > > Cheers > Suzuki > Ok,thanks for pointing -- Cheers, Jia From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f71.google.com (mail-pg0-f71.google.com [74.125.83.71]) by kanga.kvack.org (Postfix) with ESMTP id EB3926B0008 for ; Thu, 24 May 2018 05:37:08 -0400 (EDT) Received: by mail-pg0-f71.google.com with SMTP id q7-v6so445418pgt.11 for ; Thu, 24 May 2018 02:37:08 -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 e4-v6sor6191792pga.252.2018.05.24.02.37.07 for (Google Transport Security); Thu, 24 May 2018 02:37:07 -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> <198fe48c-0d26-7dd1-89dc-415bd3c7ab41@gmail.com> <575857e6-c8ec-efa0-6434-b78a513aeaba@arm.com> From: Jia He Message-ID: <2c220e3d-8ff1-f9a9-9038-fff38952b8b1@gmail.com> Date: Thu, 24 May 2018 17:36:57 +0800 MIME-Version: 1.0 In-Reply-To: <575857e6-c8ec-efa0-6434-b78a513aeaba@arm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit 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 On 5/24/2018 5:01 PM, Suzuki K Poulose Wrote: > On 24/05/18 09:50, Jia He wrote: >> 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. > > Hi Jia, > > Thanks for the update. I think that should eventually hit mainline. When it does, > please could you send the patch to stable kernel versions too ? > > Usually having a "Cc: stable@kernel.vger.org" in the original patch (for > critical fixes) would have done the trick. But since we don't have it, > please send it following the stable kernel rules. > > Cheers > Suzuki > Ok,thanks for pointing -- Cheers, Jia