From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Hocko Subject: Re: [PATCH] mm/memcontrol.c: use list_{first,next}_entry Date: Thu, 3 Dec 2015 17:27:18 +0100 Message-ID: <20151203162718.GK9264@dhcp22.suse.cz> References: <9e62e3006561653fcbf0c49cf0b9c2b653a8ed0e.1449152124.git.geliangtang@163.com> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <9e62e3006561653fcbf0c49cf0b9c2b653a8ed0e.1449152124.git.geliangtang-9Onoh4P/yGk@public.gmane.org> Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Geliang Tang Cc: Johannes Weiner , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-mm-Bw31MaZKKs3YtjvyW6yDsg@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org On Thu 03-12-15 22:16:55, Geliang Tang wrote: > To make the intention clearer, use list_{first,next}_entry instead > of list_entry. Does this really help readability? This function simply uncharges the given list of pages. Why cannot we simply use list_for_each_entry instead... > Signed-off-by: Geliang Tang > --- > mm/memcontrol.c | 9 +++------ > 1 file changed, 3 insertions(+), 6 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index 79a29d5..a6301ea 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -5395,16 +5395,12 @@ static void uncharge_list(struct list_head *page_list) > unsigned long nr_file = 0; > unsigned long nr_huge = 0; > unsigned long pgpgout = 0; > - struct list_head *next; > struct page *page; > > - next = page_list->next; > + page = list_first_entry(page_list, struct page, lru); > do { > unsigned int nr_pages = 1; > > - page = list_entry(next, struct page, lru); > - next = page->lru.next; > - > VM_BUG_ON_PAGE(PageLRU(page), page); > VM_BUG_ON_PAGE(page_count(page), page); > > @@ -5440,7 +5436,8 @@ static void uncharge_list(struct list_head *page_list) > page->mem_cgroup = NULL; > > pgpgout++; > - } while (next != page_list); > + } while (!list_is_last(&page->lru, page_list) && > + (page = list_next_entry(page, lru))); > > if (memcg) > uncharge_batch(memcg, pgpgout, nr_anon, nr_file, > -- > 2.5.0 > -- Michal Hocko SUSE Labs