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[115.124.30.57]) by mx.google.com with ESMTPS id s2si3065435plr.110.2019.04.18.13.17.14 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 18 Apr 2019 13:17:14 -0700 (PDT) Received-SPF: pass (google.com: domain of yang.shi@linux.alibaba.com designates 115.124.30.57 as permitted sender) client-ip=115.124.30.57; Authentication-Results: mx.google.com; spf=pass (google.com: domain of yang.shi@linux.alibaba.com designates 115.124.30.57 as permitted sender) smtp.mailfrom=yang.shi@linux.alibaba.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=alibaba.com X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R191e4;CH=green;DM=||false|;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04426;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=10;SR=0;TI=SMTPD_---0TPfSgC1_1555618625; Received: from e19h19392.et15sqa.tbsite.net(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0TPfSgC1_1555618625) by smtp.aliyun-inc.com(127.0.0.1); Fri, 19 Apr 2019 04:17:13 +0800 From: Yang Shi To: mhocko@suse.com, kirill.shutemov@linux.intel.com, ziy@nvidia.com, rppt@linux.vnet.ibm.com, corbet@lwn.net, akpm@linux-foundation.org Cc: yang.shi@linux.alibaba.com, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] doc: mm: migration doesn't use FOLL_SPLIT anymore Date: Fri, 19 Apr 2019 04:17:04 +0800 Message-Id: <1555618624-23957-1-git-send-email-yang.shi@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 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: X-Virus-Scanned: ClamAV using ClamSMTP When demonstrating FOLL_SPLIT in transhuge document, migration is used as an example. But, since commit 94723aafb9e7 ("mm: unclutter THP migration"), the way of THP migration is totally changed. FOLL_SPLIT is not used by migration anymore due to the change. Remove the obsolete example to avoid confusion. Cc: Michal Hocko Cc: Kirill A. Shutemov Cc: Zi Yan Cc: Mike Rapoport Signed-off-by: Yang Shi Reviewed-by: Zi Yan --- Documentation/vm/transhuge.rst | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/Documentation/vm/transhuge.rst b/Documentation/vm/transhuge.rst index a8cf680..8df3806 100644 --- a/Documentation/vm/transhuge.rst +++ b/Documentation/vm/transhuge.rst @@ -55,13 +55,7 @@ prevent page from being split by anyone. In case you can't handle compound pages if they're returned by follow_page, the FOLL_SPLIT bit can be specified as parameter to follow_page, so that it will split the hugepages before returning -them. Migration for example passes FOLL_SPLIT as parameter to -follow_page because it's not hugepage aware and in fact it can't work -at all on hugetlbfs (but it instead works fine on transparent -hugepages thanks to FOLL_SPLIT). migration simply can't deal with -hugepages being returned (as it's not only checking the pfn of the -page and pinning it during the copy but it pretends to migrate the -memory in regular page sizes and with regular pte/pmd mappings). +them. Graceful fallback =================