From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751329Ab2CCI1q (ORCPT ); Sat, 3 Mar 2012 03:27:46 -0500 Received: from mail-bk0-f46.google.com ([209.85.214.46]:38039 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750716Ab2CCI1o (ORCPT ); Sat, 3 Mar 2012 03:27:44 -0500 Authentication-Results: mr.google.com; spf=pass (google.com: domain of koct9i@gmail.com designates 10.205.122.144 as permitted sender) smtp.mail=koct9i@gmail.com; dkim=pass header.i=koct9i@gmail.com Message-ID: <4F51D5FB.4050106@openvz.org> Date: Sat, 03 Mar 2012 12:27:39 +0400 From: Konstantin Khlebnikov User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.19) Gecko/20120201 Iceape/2.0.14 MIME-Version: 1.0 To: Hugh Dickins CC: Andrew Morton , Johannes Weiner , KAMEZAWA Hiroyuki , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 3/7] mm: rework __isolate_lru_page() file/anon filter References: <20120229090748.29236.35489.stgit@zurg> <20120229091547.29236.28230.stgit@zurg> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hugh Dickins wrote: > On Wed, 29 Feb 2012, Konstantin Khlebnikov wrote: > >> This patch adds file/anon filter bits into isolate_mode_t, >> this allows to simplify checks in __isolate_lru_page(). >> >> Signed-off-by: Konstantin Khlebnikov > > Almost-Acked-by: Hugh Dickins > > with one whitespace nit, and one functional addition requested. > > I'm perfectly happy with your :?s myself, but some people do dislike > them. I'm happy with the switch alternative if it's as efficient: > something that surprised me very much when trying to get convincing > performance numbers for per-memcg per-zone lru_lock at home... > > ... __isolate_lru_page() featured astonishly high on the perf report > of streaming from files on ext4 on /dev/ram0 to /dev/null, coming > immediately below the obvious zeroing and copying: okay, the zeroing > and copying were around 30% each, and __isolate_lru_page() down around > 2% or below, but even so it seemed very odd that it should feature so > high, and any optimizations to it very welcome - unless it was purely > some bogus result. Actually ANON/FILE ACTIVE/INACTIVE checks does not required at non-lumpy reclaim (all pages are picked from right lru list) and compaction (it does not care). But seems like removing these two bit-checks cannot give noticeable performance gain. This patch can be postponed. It does not so important and it does not share context with other patches in this set. > >> --- >> include/linux/mmzone.h | 4 ++++ >> include/linux/swap.h | 2 +- >> mm/compaction.c | 5 +++-- >> mm/vmscan.c | 27 +++++++++++++-------------- >> 4 files changed, 21 insertions(+), 17 deletions(-) >> >> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h >> index eff4918..2fed935 100644 >> --- a/include/linux/mmzone.h >> +++ b/include/linux/mmzone.h >> @@ -193,6 +193,10 @@ struct lruvec { >> #define ISOLATE_UNMAPPED ((__force isolate_mode_t)0x8) >> /* Isolate for asynchronous migration */ >> #define ISOLATE_ASYNC_MIGRATE ((__force isolate_mode_t)0x10) >> +/* Isolate swap-backed pages */ >> +#define ISOLATE_ANON ((__force isolate_mode_t)0x20) >> +/* Isolate file-backed pages */ >> +#define ISOLATE_FILE ((__force isolate_mode_t)0x40) > > From the patch you can see that the #defines above yours used a > space where you have used a tab: better to use a space as above. > >> @@ -375,7 +376,7 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone, >> mode |= ISOLATE_ASYNC_MIGRATE; >> >> /* Try isolate the page */ >> - if (__isolate_lru_page(page, mode, 0) != 0) >> + if (__isolate_lru_page(page, mode) != 0) >> continue; > > I thought you were missing something there, but no, that's rather > the case you are simplifying. However... > >> diff --git a/mm/vmscan.c b/mm/vmscan.c >> index af6cfe7..1b70338 100644 >> --- a/mm/vmscan.c >> +++ b/mm/vmscan.c >> @@ -1520,6 +1511,10 @@ shrink_inactive_list(unsigned long nr_to_scan, struct mem_cgroup_zone *mz, >> isolate_mode |= ISOLATE_UNMAPPED; >> if (!sc->may_writepage) >> isolate_mode |= ISOLATE_CLEAN; >> + if (file) >> + isolate_mode |= ISOLATE_FILE; >> + else >> + isolate_mode |= ISOLATE_ANON; > > Above here, under "if (sc->reclaim_mode& RECLAIM_MODE_LUMPYRECLAIM)", > don't you need > > isolate_mode |= ISOLATE_ACTIVE | ISOLATE_FILE | ISOLATE_ANON; > > now to reproduce the same "all_lru_mode" behaviour as before? Yes, I missed this. Thanks. > > Hugh