Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754877Ab1EAPJ2 (ORCPT ); Sun, 1 May 2011 11:09:28 -0400 Received: from mail-qw0-f46.google.com ([209.85.216.46]:37174 "EHLO mail-qw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753372Ab1EAPJ1 convert rfc822-to-8bit (ORCPT ); Sun, 1 May 2011 11:09:27 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=OiVeVbnVURWE/UpWtO00/sXPvovdcKtes1TnPYyva6G++v3Zfx9/ukPgjHXOIqxrjQ oKq5lQFYvQTp1ETfk6dLUhIBnOQ/wmnsjIivutmw7X6Y3vL1g629pVen8FMi5L3NkkTM s3WfwlhXIW9dfqsUh1SMIKrpWsp1G+E3ClugM= MIME-Version: 1.0 In-Reply-To: <20110501222117.75E8.A69D9226@jp.fujitsu.com> References: <20110428105027.GT4658@suse.de> <20110501222117.75E8.A69D9226@jp.fujitsu.com> Date: Mon, 2 May 2011 00:09:26 +0900 Message-ID: Subject: Re: [RFC 5/8] compaction: remove active list counting From: Minchan Kim To: KOSAKI Motohiro Cc: Mel Gorman , Andrew Morton , linux-mm , LKML , Christoph Lameter , Johannes Weiner , KAMEZAWA Hiroyuki , Rik van Riel , Andrea Arcangeli Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2108 Lines: 57 On Sun, May 1, 2011 at 10:19 PM, KOSAKI Motohiro wrote: >> On Thu, Apr 28, 2011 at 7:50 PM, Mel Gorman wrote: >> > On Wed, Apr 27, 2011 at 01:25:22AM +0900, Minchan Kim wrote: >> >> acct_isolated of compaction uses page_lru_base_type which returns only >> >> base type of LRU list so it never returns LRU_ACTIVE_ANON or LRU_ACTIVE_FILE. >> >> So it's pointless to add lru[LRU_ACTIVE_[ANON|FILE]] to get sum. >> >> >> >> Cc: KOSAKI Motohiro >> >> Cc: Mel Gorman >> >> Cc: Rik van Riel >> >> Cc: Andrea Arcangeli >> >> Signed-off-by: Minchan Kim >> > >> > hmm, isolate_migratepages() is doing a linear scan of PFNs and is >> > calling __isolate_lru_page(..ISOLATE_BOTH..). Using page_lru_base_type >> > happens to work because we're only interested in the number of isolated >> > pages and your patch still covers that. Using page_lru might be more >> > accurate in terms of accountancy but does not seem necessary. >> >> True. >> >> > >> > Adding a comment explaining why we account for it as inactive and why >> > that's ok would be nice although I admit this is something I should have >> > done when acct_isolated() was introduced. >> >> When Kame pointed out comment, I wanted to avoid unnecessary comment >> so decided changing it with page_lru although it adds overhead a >> little bit. But Hannes, you and maybe Kame don't want it. I don't mind >> adding comment. >> Okay. fix it in next version. > > Or > >        unsigned int count[2]; > >        list_for_each_entry(page, &cc->migratepages, lru) { >                count[page_is_file_cache(page)]++; >        } > > is also clear to me. > That's very clear to me, too. Thanks, KOSAKI. -- 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/