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Sun, 19 Jan 2020 14:14:29 -0800 (PST) Received: from [2620:15c:17:3:3a5:23a7:5e32:4598] ([2620:15c:17:3:3a5:23a7:5e32:4598]) by smtp.gmail.com with ESMTPSA id n4sm34595568pgg.88.2020.01.19.14.14.29 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 19 Jan 2020 14:14:29 -0800 (PST) Date: Sun, 19 Jan 2020 14:14:28 -0800 (PST) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Wei Yang cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, mhocko@suse.com, yang.shi@linux.alibaba.com Subject: Re: [PATCH 2/8] mm/migrate.c: not necessary to check start and i In-Reply-To: <20200119030636.11899-3-richardw.yang@linux.intel.com> Message-ID: References: <20200119030636.11899-1-richardw.yang@linux.intel.com> <20200119030636.11899-3-richardw.yang@linux.intel.com> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII 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 Sun, 19 Jan 2020, Wei Yang wrote: > diff --git a/mm/migrate.c b/mm/migrate.c > index ba7cf4fa43a0..c3ef70de5876 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1664,11 +1664,9 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, > err = do_move_pages_to_node(mm, &pagelist, current_node); > if (err) > goto out; > - if (i > start) { > - err = store_status(status, start, current_node, i - start); > - if (err) > - goto out; > - } > + err = store_status(status, start, current_node, i - start); > + if (err) > + goto out; > current_node = NUMA_NO_NODE; > } > out_flush: Not sure this is useful, it relies on the implementation of store_status() when i == start and the overhead of the function call should actually be slower than the simple conditional to avoid it in that case?