From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: David Rientjes <rientjes@google.com>
Cc: kosaki.motohiro@jp.fujitsu.com,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Wu Fengguang <fengguang.wu@intel.com>,
Minchan Kim <minchan.kim@gmail.com>,
Huang Shijie <shijie8@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mel@csn.ul.ie>,
linux-mm@kvack.org, Rik van Riel <riel@redhat.com>
Subject: Re: [PATCH 4/4] mm/page_alloc : relieve zone->lock's pressure for memory free
Date: Tue, 12 Jan 2010 17:56:28 +0900 (JST) [thread overview]
Message-ID: <20100112175027.B3BC.A69D9226@jp.fujitsu.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1001112335001.12808@chino.kir.corp.google.com>
> On Tue, 12 Jan 2010, KOSAKI Motohiro wrote:
>
> > From 751f197ad256c7245151681d7aece591b1dab343 Mon Sep 17 00:00:00 2001
> > From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
> > Date: Tue, 12 Jan 2010 13:53:47 +0900
> > Subject: [PATCH] mm: Restore zone->all_unreclaimable to independence word
> >
> > commit e815af95 (change all_unreclaimable zone member to flags) chage
> > all_unreclaimable member to bit flag. but It have undesireble side
> > effect.
> > free_one_page() is one of most hot path in linux kernel and increasing
> > atomic ops in it can reduce kernel performance a bit.
> >
>
> Could you please elaborate on "a bit" in the changelog with some data? If
> it's so egregious, it should be easily be quantifiable.
Unfortunately I can't. atomic ops is mainly the issue of large machine. but
I can't access such machine now. but I'm sure we shouldn't take unnecessary
atomic ops.
That's fundamental space vs performance tradeoff thing. if we talked about
struct page or similar lots created struct, space efficient is very important.
but struct zone isn't such one.
Or, do you have strong argue to use bitops without space efficiency?
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next prev parent reply other threads:[~2010-01-12 8:56 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-11 4:37 [PATCH 1/4] mm/page_alloc : rename rmqueue_bulk to rmqueue_single Huang Shijie
2010-01-11 4:37 ` [PATCH 2/4] mm/page_alloc : relieve the zone->lock's pressure for allocation Huang Shijie
2010-01-11 4:37 ` [PATCH 3/4] mm/page_alloc : modify the return type of __free_one_page Huang Shijie
2010-01-11 4:37 ` [PATCH 4/4] mm/page_alloc : relieve zone->lock's pressure for memory free Huang Shijie
2010-01-11 5:20 ` Minchan Kim
2010-01-11 6:01 ` Huang Shijie
2010-01-11 6:27 ` Huang Shijie
2010-01-11 6:38 ` Minchan Kim
2010-01-11 6:59 ` Huang Shijie
2010-01-12 0:47 ` KAMEZAWA Hiroyuki
2010-01-12 2:02 ` Huang Shijie
2010-01-12 2:07 ` KAMEZAWA Hiroyuki
2010-01-12 2:32 ` Huang Shijie
2010-01-12 2:27 ` Wu Fengguang
2010-01-12 2:56 ` KOSAKI Motohiro
2010-01-12 3:02 ` Huang Shijie
2010-01-12 4:05 ` Minchan Kim
2010-01-12 4:21 ` Wu Fengguang
2010-01-12 4:32 ` KAMEZAWA Hiroyuki
2010-01-12 4:59 ` Wu Fengguang
2010-01-12 5:09 ` Wu Fengguang
2010-01-12 5:10 ` KOSAKI Motohiro
2010-01-12 7:36 ` David Rientjes
2010-01-12 8:56 ` KOSAKI Motohiro [this message]
2010-01-12 21:39 ` David Rientjes
2010-01-13 0:01 ` KOSAKI Motohiro
2010-01-12 4:48 ` Minchan Kim
2010-01-12 2:51 ` Huang Shijie
2010-01-12 3:03 ` Wu Fengguang
2010-01-12 3:05 ` KOSAKI Motohiro
2010-01-11 5:04 ` [PATCH 3/4] mm/page_alloc : modify the return type of __free_one_page Minchan Kim
2010-01-12 2:56 ` KOSAKI Motohiro
2010-01-18 11:25 ` Mel Gorman
2010-01-19 1:49 ` Huang Shijie
2010-01-11 5:02 ` [PATCH 2/4] mm/page_alloc : relieve the zone->lock's pressure for allocation Minchan Kim
2010-01-11 5:13 ` Huang Shijie
2010-01-12 2:54 ` KOSAKI Motohiro
2010-01-18 11:24 ` Mel Gorman
2010-01-11 5:00 ` [PATCH 1/4] mm/page_alloc : rename rmqueue_bulk to rmqueue_single Minchan Kim
2010-01-12 2:52 ` KOSAKI Motohiro
2010-01-18 11:21 ` Mel Gorman
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