From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx172.postini.com [74.125.245.172]) by kanga.kvack.org (Postfix) with SMTP id 363836B006C for ; Mon, 10 Sep 2012 04:12:23 -0400 (EDT) Date: Mon, 10 Sep 2012 09:12:18 +0100 From: Mel Gorman Subject: Re: [patch 2/2 v2]compaction: check lock contention first before taking lock Message-ID: <20120910081218.GE11266@suse.de> References: <20120910011850.GD3715@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20120910011850.GD3715@kernel.org> Sender: owner-linux-mm@kvack.org List-ID: To: Shaohua Li Cc: linux-mm@kvack.org, akpm@linux-foundation.org, aarcange@redhat.com On Mon, Sep 10, 2012 at 09:18:50AM +0800, Shaohua Li wrote: > isolate_migratepages_range will take zone->lru_lock first and check if the lock > is contented, if yes, it will release the lock. This isn't efficient. If the > lock is truly contented, a lock/unlock pair will increase the lock contention. > We'd better check if the lock is contended first. compact_trylock_irqsave > perfectly meets the requirement. > > V2: > leave cond_resched() pointed out by Mel. > > Signed-off-by: Shaohua Li Acked-by: Mel Gorman -- Mel Gorman SUSE Labs -- 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