Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754068AbaFKBuS (ORCPT ); Tue, 10 Jun 2014 21:50:18 -0400 Received: from lgeamrelo02.lge.com ([156.147.1.126]:60534 "EHLO lgeamrelo02.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752718AbaFKBuQ (ORCPT ); Tue, 10 Jun 2014 21:50:16 -0400 X-Original-SENDERIP: 10.177.220.169 X-Original-MAILFROM: minchan@kernel.org Date: Wed, 11 Jun 2014 10:50:20 +0900 From: Minchan Kim To: Vlastimil Babka Cc: David Rientjes , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Andrew Morton , Greg Thelen , Mel Gorman , Michal Nazarewicz , Naoya Horiguchi , Christoph Lameter , Rik van Riel Subject: Re: [PATCH 04/10] mm, compaction: skip rechecks when lock was already held Message-ID: <20140611015020.GE15630@bbox> References: <1402305982-6928-1-git-send-email-vbabka@suse.cz> <1402305982-6928-4-git-send-email-vbabka@suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1402305982-6928-4-git-send-email-vbabka@suse.cz> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jun 09, 2014 at 11:26:16AM +0200, Vlastimil Babka wrote: > Compaction scanners try to lock zone locks as late as possible by checking > many page or pageblock properties opportunistically without lock and skipping > them if not unsuitable. For pages that pass the initial checks, some properties > have to be checked again safely under lock. However, if the lock was already > held from a previous iteration in the initial checks, the rechecks are > unnecessary. > > This patch therefore skips the rechecks when the lock was already held. This is > now possible to do, since we don't (potentially) drop and reacquire the lock > between the initial checks and the safe rechecks anymore. > > Signed-off-by: Vlastimil Babka Acked-by: Minchan Kim -- Kind regards, Minchan Kim -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/