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Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1pRnGx-006OMR-1R; Tue, 14 Feb 2023 04:50:31 +0000 Date: Tue, 14 Feb 2023 04:50:30 +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, damon@lists.linux.dev, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 0/3] Some cleanups for page isolation Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: C836C40013 X-Stat-Signature: pisn18xdo9skttoe5ft4jx3xajkcgoz4 X-Rspam-User: X-HE-Tag: 1676350249-361470 X-HE-Meta: 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 qcsFX27x M/jDPCww89KsIB9lnF2d94gHNg9CxhMX1vanL95T+lX+NyXovjskE+9zgomnU1fORL4Dkt3zgGv8ay+V55CNQGuRWUUPSdBjgAmBtV5mQLXHsWlhwohxxpt2G/8znEY7hTZK/ef0EVBDUgvla27owlvETB+O06dg1FvF5 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 Tue, Feb 14, 2023 at 11:18:05AM +0800, Baolin Wang wrote: > The page isolation functions did not return a boolean to indicate > success or not, instead it will return a negative error when failed > to isolate a page. So it's better to check the negative error explicitly > for isolation to make the code more clear per Linus's suggestion in [1]. Only one caller of isolate_lru_page() or folio_isolate_lru() actually uses the errno. And the errno can only be 0 or -EBUSY. It'd be better to change the three functions to return bool and fix add_page_for_migration() to set the errno to -EBUSY itself.