From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx176.postini.com [74.125.245.176]) by kanga.kvack.org (Postfix) with SMTP id 0FCE86B0032 for ; Thu, 15 Aug 2013 06:47:31 -0400 (EDT) Date: Thu, 15 Aug 2013 11:47:27 +0100 From: Mel Gorman Subject: Re: kswapd skips compaction if reclaim order drops to zero? Message-ID: <20130815104727.GT2296@suse.de> References: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Hillf Danton Cc: Minchan Kim , LKML , Linux-MM On Thu, Aug 15, 2013 at 06:02:53PM +0800, Hillf Danton wrote: > If the allocation order is not high, direct compaction does nothing. > Can we skip compaction here if order drops to zero? > If the allocation order is not high then pgdat_needs_compaction == (order > 0) == false == no calling compact_pdatt In the case where order is reset to 0 due to fragmentation then it does call compact_pgdat but it does no work due to the cc->order check in __compact_pgdat. -- 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 From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754366Ab3HOKrd (ORCPT ); Thu, 15 Aug 2013 06:47:33 -0400 Received: from cantor2.suse.de ([195.135.220.15]:50076 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752579Ab3HOKrc (ORCPT ); Thu, 15 Aug 2013 06:47:32 -0400 Date: Thu, 15 Aug 2013 11:47:27 +0100 From: Mel Gorman To: Hillf Danton Cc: Minchan Kim , LKML , Linux-MM Subject: Re: kswapd skips compaction if reclaim order drops to zero? Message-ID: <20130815104727.GT2296@suse.de> References: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: 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 Thu, Aug 15, 2013 at 06:02:53PM +0800, Hillf Danton wrote: > If the allocation order is not high, direct compaction does nothing. > Can we skip compaction here if order drops to zero? > If the allocation order is not high then pgdat_needs_compaction == (order > 0) == false == no calling compact_pdatt In the case where order is reset to 0 due to fragmentation then it does call compact_pgdat but it does no work due to the cc->order check in __compact_pgdat. -- Mel Gorman SUSE Labs