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14 Aug 2022 19:51:43 -0700 X-IronPort-AV: E=Sophos;i="5.93,237,1654585200"; d="scan'208";a="635326866" Received: from yhuang6-desk2.sh.intel.com (HELO yhuang6-desk2.ccr.corp.intel.com) ([10.238.208.55]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Aug 2022 19:51:41 -0700 From: "Huang, Ying" To: "Wang, Haiyue" Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "akpm@linux-foundation.org" , "david@redhat.com" , "linmiaohe@huawei.com" , "songmuchun@bytedance.com" , "naoya.horiguchi@linux.dev" , "alex.sierra@amd.com" Subject: Re: [PATCH v3 1/2] mm: migration: fix the FOLL_GET failure on following huge page References: <20220812084921.409142-1-haiyue.wang@intel.com> <20220815010349.432313-1-haiyue.wang@intel.com> <20220815010349.432313-2-haiyue.wang@intel.com> <878rnqe074.fsf@yhuang6-desk2.ccr.corp.intel.com> Date: Mon, 15 Aug 2022 10:51:37 +0800 In-Reply-To: (Haiyue Wang's message of "Mon, 15 Aug 2022 10:15:41 +0800") Message-ID: <87o7wmcj7q.fsf@yhuang6-desk2.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; 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b=N4XRgnpgcfAeyOsuSq6pGNaGRViGwHSJMCZK6WvyBYixv/jZ/99stOunb25xeqMJK4sRTE RT+qTCCfX5d716cXPiKZN/U7WQn1N25OWG3jZleGuxP7gezfEX4+yh5YDMzBeFKdlxm2kS AhQgrm2GDA64JJpXSh11ryHPbacTtDo= X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: 55331201AA X-Rspam-User: X-Stat-Signature: qnxaqwi4izn9y7gszdx994gk1fipcihf Authentication-Results: imf03.hostedemail.com; dkim=none ("invalid DKIM record") header.d=intel.com header.s=Intel header.b=HlzDOkER; dmarc=pass (policy=none) header.from=intel.com; spf=pass (imf03.hostedemail.com: domain of ying.huang@intel.com designates 192.55.52.93 as permitted sender) smtp.mailfrom=ying.huang@intel.com X-HE-Tag: 1660531905-367560 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: "Wang, Haiyue" writes: >> -----Original Message----- >> From: Wang, Haiyue >> Sent: Monday, August 15, 2022 10:11 >> To: Huang, Ying >> Cc: linux-mm@kvack.org; linux-kernel@vger.kernel.org; akpm@linux-foundation.org; david@redhat.com; >> linmiaohe@huawei.com; songmuchun@bytedance.com; naoya.horiguchi@linux.dev; alex.sierra@amd.com >> Subject: RE: [PATCH v3 1/2] mm: migration: fix the FOLL_GET failure on following huge page >> >> > -----Original Message----- >> > From: Huang, Ying >> > Sent: Monday, August 15, 2022 09:59 >> > To: Wang, Haiyue >> > Cc: linux-mm@kvack.org; linux-kernel@vger.kernel.org; akpm@linux-foundation.org; david@redhat.com; >> > linmiaohe@huawei.com; songmuchun@bytedance.com; naoya.horiguchi@linux.dev; alex.sierra@amd.com >> > Subject: Re: [PATCH v3 1/2] mm: migration: fix the FOLL_GET failure on following huge page >> > >> > Haiyue Wang writes: >> > > > >> > >> > > This is an temporary solution to mitigate the racing fix. >> > >> > Why is it "racing fix"? This isn't a race condition fix. >> >> The 'Fixes' commit is about race condition fix. >> >> How about " his is an temporary solution to mitigate the side effect >> Of the race condition fix" > > Try to add more words to make things clean: > > "This is an temporary solution to mitigate the side effect of the race > condition fix by calling follow_page() with FOLL_GET set." Looks good to me. Thanks! Best Regards, Huang, Ying >> >> > >> > Best Regards, >> > Huang, Ying >> > >> > > After supporting follow huge page by FOLL_GET is done, this fix can be >> > > reverted safely. >> > > >> > > Fixes: 4cd614841c06 ("mm: migration: fix possible do_pages_stat_array racing with memory offline") >> > > Signed-off-by: Haiyue Wang >> > >> > [snip]