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Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pSJoT-007a1r-Kt; Wed, 15 Feb 2023 15:35:17 +0000 Date: Wed, 15 Feb 2023 15:35:17 +0000 From: Matthew Wilcox To: Baolin Wang Cc: akpm@linux-foundation.org, torvalds@linux-foundation.org, sj@kernel.org, hannes@cmpxchg.org, mhocko@kernel.org, roman.gushchin@linux.dev, shakeelb@google.com, muchun.song@linux.dev, naoya.horiguchi@nec.com, linmiaohe@huawei.com, david@redhat.com, osalvador@suse.de, mike.kravetz@oracle.com, damon@lists.linux.dev, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 1/4] mm: change to return bool for folio_isolate_lru() Message-ID: References: <8a4e3679ed4196168efadf7ea36c038f2f7d5aa9.1676424378.git.baolin.wang@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8a4e3679ed4196168efadf7ea36c038f2f7d5aa9.1676424378.git.baolin.wang@linux.alibaba.com> X-Stat-Signature: xn9yebhtuup11wm6b75gc4zg3i551h1k X-Rspam-User: X-Rspamd-Queue-Id: 8D75820008 X-Rspamd-Server: rspam06 X-HE-Tag: 1676475687-211392 X-HE-Meta: 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 uWI30eOQ 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 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, Feb 15, 2023 at 06:39:34PM +0800, Baolin Wang wrote: > Now the folio_isolate_lru() did not return a boolean value to indicate > isolation success or not, however below code checking the return value > can make people think that it was a boolean success/failure thing, which > makes people easy to make mistakes (see the fix patch[1]). > > if (folio_isolate_lru(folio)) > continue; > > Thus it's better to check the negative error value expilictly returned by > folio_isolate_lru(), which makes code more clear per Linus's suggestion[2]. > Moreover Matthew suggested we can convert the isolation functions to return > a boolean[3], since most users did not care about the negative error value, > and can also remove the confusing of checking return value. > > So this patch converts the folio_isolate_lru() to return a boolean value, > which means return 'true' to indicate the folio isolation is successful, > and 'false' means a failure to isolation. Meanwhile changing all users' > logic of checking the isolation state. > > No functional changes intended. > > [1] https://lore.kernel.org/all/20230131063206.28820-1-Kuan-Ying.Lee@mediatek.com/T/#u > [2] https://lore.kernel.org/all/CAHk-=wiBrY+O-4=2mrbVyxR+hOqfdJ=Do6xoucfJ9_5az01L4Q@mail.gmail.com/ > [3] https://lore.kernel.org/all/Y+sTFqwMNAjDvxw3@casper.infradead.org/ > > Signed-off-by: Baolin Wang > Reviewed-by: SeongJae Park > Acked-by: David Hildenbrand Reviewed-by: Matthew Wilcox (Oracle)