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[213.151.95.130]) by smtp.gmail.com with ESMTPSA id p7sm2687031wmp.31.2020.01.20.02.02.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Jan 2020 02:02:04 -0800 (PST) Date: Mon, 20 Jan 2020 11:02:03 +0100 From: Michal Hocko To: Wei Yang Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, yang.shi@linux.alibaba.com Subject: Re: [PATCH 7/8] mm/migrate.c: move page on next iteration Message-ID: <20200120100203.GR18451@dhcp22.suse.cz> References: <20200119030636.11899-1-richardw.yang@linux.intel.com> <20200119030636.11899-8-richardw.yang@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200119030636.11899-8-richardw.yang@linux.intel.com> User-Agent: Mutt/1.12.2 (2019-09-21) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun 19-01-20 11:06:35, Wei Yang wrote: > When page is not successfully queued for migration, we would move pages > on pagelist immediately. Actually, this could be done in the next > iteration by telling it we need some help. > > This patch adds a new variable need_move to be an indication. After > this, we only need to call move_pages_and_store_status() twice. No! Not another iterator. There are two and this makes the function quite hard to follow already. We do not want to add a third one. > Signed-off-by: Wei Yang > --- > mm/migrate.c | 18 +++++++++--------- > 1 file changed, 9 insertions(+), 9 deletions(-) > > diff --git a/mm/migrate.c b/mm/migrate.c > index aee5aeb082c4..2a857fec65b6 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1610,6 +1610,7 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, > LIST_HEAD(pagelist); > int start, i; > int err = 0, err1; > + int need_move = 0; > > migrate_prep(); > > @@ -1641,13 +1642,15 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, > if (current_node == NUMA_NO_NODE) { > current_node = node; > start = i; > - } else if (node != current_node) { > + } else if (node != current_node || need_move) { > err = move_pages_and_store_status(mm, current_node, > - &pagelist, status, start, i - start); > + &pagelist, status, start, > + i - start - need_move); > if (err) > goto out; > start = i; > current_node = node; > + need_move = 0; > } > > /* > @@ -1662,6 +1665,9 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, > continue; > } > > + /* Ask next iteration to move us */ > + need_move = 1; > + > /* > * Two possible cases for err here: > * == 0: page is already on the target node, then store > @@ -1671,17 +1677,11 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes, > err = store_status(status, i, err ? : current_node, 1); > if (err) > goto out_flush; > - > - err = move_pages_and_store_status(mm, current_node, &pagelist, > - status, start, i - start); > - if (err) > - goto out; > - current_node = NUMA_NO_NODE; > } > out_flush: > /* Make sure we do not overwrite the existing error */ > err1 = move_pages_and_store_status(mm, current_node, &pagelist, > - status, start, i - start); > + status, start, i - start - need_move); > if (err >= 0) > err = err1; > out: > -- > 2.17.1 > -- Michal Hocko SUSE Labs