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Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pAf24-009R8A-8c; Wed, 28 Dec 2022 22:36:20 +0000 Date: Wed, 28 Dec 2022 22:36:20 +0000 From: Matthew Wilcox To: Kefeng Wang Cc: Andrew Morton , SeongJae Park , damon@lists.linux.dev, linux-mm@kvack.org, vishal.moola@gmail.com, david@redhat.com Subject: Re: [PATCH -next v3 2/7] mm/damon: introduce damon_get_folio() Message-ID: References: <20221228113413.10329-1-wangkefeng.wang@huawei.com> <20221228113413.10329-3-wangkefeng.wang@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221228113413.10329-3-wangkefeng.wang@huawei.com> X-Rspamd-Queue-Id: 8C4E14000C X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: eie9ay6gp39fh1gasawsgmt85b6c7ede X-HE-Tag: 1672266987-927256 X-HE-Meta: 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 7xuTZ9mf KnXPE 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 Wed, Dec 28, 2022 at 07:34:08PM +0800, Kefeng Wang wrote: > +static inline struct page *damon_get_page(unsigned long pfn) > +{ > + struct folio *folio = damon_get_folio(pfn); > + > + /* when folio is NULL, return &(0->page) mean return NULL */ > + return &folio->page; I really don't think this comment is needed. This is the standard idiom for converting from a folio to its head page.