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Tue, 10 Mar 2020 02:09:50 -0700 (PDT) Received: from localhost ([43.224.245.179]) by smtp.gmail.com with ESMTPSA id k3sm4850471pfp.142.2020.03.10.02.09.49 (version=TLS1_2 cipher=AES128-SHA bits=128/128); Tue, 10 Mar 2020 02:09:49 -0700 (PDT) Date: Tue, 10 Mar 2020 17:09:47 +0800 From: chenqiwu To: Vlastimil Babka Cc: akpm@linux-foundation.org, pankaj.gupta.linux@gmail.com, alexander.duyck@gmail.com, willy@infradead.org, bhe@redhat.com, linux-mm@kvack.org, chenqiwu Subject: Re: [PATCH v2] mm/page_alloc: simplify page_is_buddy() for better code readability Message-ID: <20200310090947.GA14219@cqw-OptiPlex-7050> References: <1583807664-10343-1-git-send-email-qiwuchen55@gmail.com> <30f98262-2686-c717-8b0c-fd90c204b35d@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <30f98262-2686-c717-8b0c-fd90c204b35d@suse.cz> User-Agent: Mutt/1.5.21 (2010-09-15) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Mar 10, 2020 at 09:28:46AM +0100, Vlastimil Babka wrote: > On 3/10/20 3:34 AM, qiwuchen55@gmail.com wrote: > > From: chenqiwu > > > > Simplify page_is_buddy() to reduce the redundant code for better code > > readability. > > > > Signed-off-by: chenqiwu > > I would personally keep testing the page type first, and even switch it so that > PageBuddy is tested before page_is_guard (but it only matters on debugging kernels). > > I can only speculate which will have better performance (if any), but it's more > logical to test the type first. Both orders should be safe though as we have the > zone lock. Yes, I have ignored the iegality of the page must be checked first. Thanks for your review!