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[195.135.220.15]) by mx.google.com with ESMTPS id y16si34136864edb.404.2019.08.07.04.01.48 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 07 Aug 2019 04:01:49 -0700 (PDT) Received-SPF: softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) client-ip=195.135.220.15; Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning mhocko@kernel.org does not designate 195.135.220.15 as permitted sender) smtp.mailfrom=mhocko@kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=kernel.org X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id F3BFCAE48; Wed, 7 Aug 2019 11:01:47 +0000 (UTC) Date: Wed, 7 Aug 2019 13:01:47 +0200 From: Michal Hocko To: john.hubbard@gmail.com Cc: Andrew Morton , Christoph Hellwig , Ira Weiny , Jan Kara , Jason Gunthorpe , Jerome Glisse , LKML , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, John Hubbard , Dan Williams , Daniel Black , Matthew Wilcox , Mike Kravetz Subject: Re: [PATCH 1/3] mm/mlock.c: convert put_page() to put_user_page*() Message-ID: <20190807110147.GT11812@dhcp22.suse.cz> References: <20190805222019.28592-1-jhubbard@nvidia.com> <20190805222019.28592-2-jhubbard@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190805222019.28592-2-jhubbard@nvidia.com> User-Agent: Mutt/1.10.1 (2018-07-13) 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: On Mon 05-08-19 15:20:17, john.hubbard@gmail.com wrote: > From: John Hubbard > > For pages that were retained via get_user_pages*(), release those pages > via the new put_user_page*() routines, instead of via put_page() or > release_pages(). Hmm, this is an interesting code path. There seems to be a mix of pages in the game. We get one page via follow_page_mask but then other pages in the range are filled by __munlock_pagevec_fill and that does a direct pte walk. Is using put_user_page correct in this case? Could you explain why in the changelog? > This is part a tree-wide conversion, as described in commit fc1d8e7cca2d > ("mm: introduce put_user_page*(), placeholder versions"). > > Cc: Dan Williams > Cc: Daniel Black > Cc: Jan Kara > Cc: Jérôme Glisse > Cc: Matthew Wilcox > Cc: Mike Kravetz > Signed-off-by: John Hubbard > --- > mm/mlock.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/mm/mlock.c b/mm/mlock.c > index a90099da4fb4..b980e6270e8a 100644 > --- a/mm/mlock.c > +++ b/mm/mlock.c > @@ -345,7 +345,7 @@ static void __munlock_pagevec(struct pagevec *pvec, struct zone *zone) > get_page(page); /* for putback_lru_page() */ > __munlock_isolated_page(page); > unlock_page(page); > - put_page(page); /* from follow_page_mask() */ > + put_user_page(page); /* from follow_page_mask() */ > } > } > } > @@ -467,7 +467,7 @@ void munlock_vma_pages_range(struct vm_area_struct *vma, > if (page && !IS_ERR(page)) { > if (PageTransTail(page)) { > VM_BUG_ON_PAGE(PageMlocked(page), page); > - put_page(page); /* follow_page_mask() */ > + put_user_page(page); /* follow_page_mask() */ > } else if (PageTransHuge(page)) { > lock_page(page); > /* > @@ -478,7 +478,7 @@ void munlock_vma_pages_range(struct vm_area_struct *vma, > */ > page_mask = munlock_vma_page(page); > unlock_page(page); > - put_page(page); /* follow_page_mask() */ > + put_user_page(page); /* follow_page_mask() */ > } else { > /* > * Non-huge pages are handled in batches via > -- > 2.22.0 -- Michal Hocko SUSE Labs