From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail138.messagelabs.com (mail138.messagelabs.com [216.82.249.35]) by kanga.kvack.org (Postfix) with SMTP id 348BE6B006A for ; Mon, 11 Jan 2010 21:35:01 -0500 (EST) Date: Tue, 12 Jan 2010 10:27:08 +0800 From: Wu Fengguang Subject: Re: [PATCH 4/4] mm/page_alloc : relieve zone->lock's pressure for memory free Message-ID: <20100112022708.GA21621@localhost> References: <1263184634-15447-4-git-send-email-shijie8@gmail.com> <1263191277-30373-1-git-send-email-shijie8@gmail.com> <20100111153802.f3150117.minchan.kim@barrios-desktop> <20100112094708.d09b01ea.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100112094708.d09b01ea.kamezawa.hiroyu@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: Minchan Kim , Huang Shijie , akpm@linux-foundation.org, mel@csn.ul.ie, kosaki.motohiro@jp.fujitsu.com, linux-mm@kvack.org, Rik van Riel List-ID: On Tue, Jan 12, 2010 at 09:47:08AM +0900, KAMEZAWA Hiroyuki wrote: > > Thanks, Huang. > > > > Frankly speaking, I am not sure this ir right way. > > This patch is adding to fine-grained locking overhead > > > > As you know, this functions are one of hot pathes. > > In addition, we didn't see the any problem, until now. > > It means out of synchronization in ZONE_ALL_UNRECLAIMABLE > > and pages_scanned are all right? > > > > If it is, we can move them out of zone->lock, too. > > If it isn't, we need one more lock, then. > > > I don't want to see additional spin_lock, here. > > About ZONE_ALL_UNRECLAIMABLE, it's not necessary to be handled in atomic way. > If you have concerns with other flags, please modify this with single word, > instead of a bit field. I'd second it. It's not a big problem to reset ZONE_ALL_UNRECLAIMABLE and pages_scanned outside of zone->lru_lock. Clear of ZONE_ALL_UNRECLAIMABLE is already atomic; if we lose one pages_scanned=0 due to races, there are plenty of page free events ahead to reset it, before pages_scanned hit the huge zone_reclaimable_pages() * 6. Thanks, Fengguang -- 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