From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta7.messagelabs.com (mail6.bemta7.messagelabs.com [216.82.255.55]) by kanga.kvack.org (Postfix) with ESMTP id 32E0F6B0169 for ; Mon, 8 Aug 2011 08:23:00 -0400 (EDT) Date: Mon, 8 Aug 2011 14:22:55 +0200 From: Michal Hocko Subject: Re: [PATCH v2] vmscan: reverse lru scanning order Message-ID: <20110808122255.GC14803@tiehlicka.suse.cz> References: <20110727111002.9985.94938.stgit@localhost6> <20110808110207.30777.30800.stgit@localhost6> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110808110207.30777.30800.stgit@localhost6> Sender: owner-linux-mm@kvack.org List-ID: To: Konstantin Khlebnikov Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , KAMEZAWA Hiroyuki On Mon 08-08-11 15:02:07, Konstantin Khlebnikov wrote: > LRU scanning order was accidentially changed in commit v2.6.27-5584-gb69408e: > "vmscan: Use an indexed array for LRU variables". > Before that commit reclaimer always scan active lists first. > > This patch just reverse it back. I am still not sure I see why the ordering matters that much. One thing that might matter is that shrink_list moves some pages from active to inactive list if inactive is low so it makes sense to try to shrink active before inactive. It would be a problem if inactive was almost empty. Then we would just waste time by shrinking inactive first. I am not sure how real problem is that, though. Whatever is the reason, I think it should be documented in the changelog. The change makes sense to me. > > Signed-off-by: Konstantin Khlebnikov > --- > include/linux/mmzone.h | 3 ++- > 1 files changed, 2 insertions(+), 1 deletions(-) > > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > index be1ac8d..0094389 100644 > --- a/include/linux/mmzone.h > +++ b/include/linux/mmzone.h > @@ -141,7 +141,8 @@ enum lru_list { > > #define for_each_lru(l) for (l = 0; l < NR_LRU_LISTS; l++) > > -#define for_each_evictable_lru(l) for (l = 0; l <= LRU_ACTIVE_FILE; l++) > +#define for_each_evictable_lru(l) \ > + for (l = LRU_ACTIVE_FILE; (int)l >= LRU_INACTIVE_ANON; l--) > > static inline int is_file_lru(enum lru_list l) > { > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@kvack.org. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ > Don't email: email@kvack.org -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org