From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: [PATCH] memory hotplug: run lru_add_drain_all() on each cpu From: Lee Schermerhorn In-Reply-To: <20081207133450.53D8.KOSAKI.MOTOHIRO@jp.fujitsu.com> References: <1228482500.8392.15.camel@t60p> <1228509818.12681.21.camel@nimitz> <20081207133450.53D8.KOSAKI.MOTOHIRO@jp.fujitsu.com> Content-Type: text/plain Date: Mon, 08 Dec 2008 08:56:28 -0500 Message-Id: <1228744588.22647.32.camel@lts-notebook> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: KOSAKI Motohiro Cc: Dave Hansen , gerald.schaefer@de.ibm.com, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, kamezawa.hiroyu@jp.fujitsu.com, y-goto@jp.fujitsu.com, npiggin@suse.de List-ID: On Sun, 2008-12-07 at 13:43 +0900, KOSAKI Motohiro wrote: > CC to Lee Schermerhorn > > > > On Fri, 2008-12-05 at 14:08 +0100, Gerald Schaefer wrote: > > > > > > As explained above, the per-cpu pagevec layout should be independent > > > from NUMA or UNEVICTABLE_LRU, so I guess the right thing to do here > > > is completely remove the #ifdef as in the patch from Kosaki Motohiro > > > (or at least replace it with a CONFIG_SMP as suggested by Kamezawa > > > Hiroyuki). > > > > Thanks for looking into it deeper. That CONFIG_SMP thing really does > > look like the right solution. > > Lee, Could you read this thread and explain why you add ifdef CONFIG_UNEVICTABLE_LRU? > I am not sure about that Dave's proposal is safe change. (but I guess he is right) I added that back in Patch 17/25 "Mlocked Pages are non-reclaimable" [before nonreclaimable became unevictable". I did this because "lru_add_drain_all()" was only used by numa code prior to this, and was under #ifdef CONFIG_NUMA". I called lru_add_drain_all() from __mlock_vma_pages_range() [since removed] and I wanted the nonreclaimable/unevictable mlocked pages feature to be independent of numa. So, I had to ensure that we defined the function for nonreclaimable/unevictable lru as well as numa. Now it appears that hotplug and memcg also depend on lru_add_drain_all(), so making it depend on 'SMP looks reasonable to me. Lee -- 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/ . Don't email: email@kvack.org