From: Michal Hocko <mhocko@suse.cz>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hiroyuki Kamezawa <kamezawa.hiroyuki@gmail.com>,
Wu Fengguang <fengguang.wu@intel.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
"Kleen, Andi" <andi.kleen@intel.com>,
Haicheng Li <haicheng.li@linux.intel.com>,
Christoph Lameter <cl@linux-foundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Mel Gorman <mel@linux.vnet.ibm.com>
Subject: Re: [PATCH 2/2] Make is_mem_section_removable more conformable with offlining code
Date: Fri, 3 Sep 2010 13:01:14 +0200 [thread overview]
Message-ID: <20100903110114.GH10686@tiehlicka.suse.cz> (raw)
In-Reply-To: <20100903190520.8751aab6.kamezawa.hiroyu@jp.fujitsu.com>
On Fri 03-09-10 19:05:20, KAMEZAWA Hiroyuki wrote:
> On Fri, 3 Sep 2010 11:50:49 +0200
> Michal Hocko <mhocko@suse.cz> wrote:
>
> > On Fri 03-09-10 18:13:27, KAMEZAWA Hiroyuki wrote:
> > > On Fri, 3 Sep 2010 10:25:58 +0200
> > > Michal Hocko <mhocko@suse.cz> wrote:
> > >
> > > > On Fri 03-09-10 12:14:52, KAMEZAWA Hiroyuki wrote:
> > > > [...]
> > [...]
> > > > Cannot ZONE_MOVABLE contain different MIGRATE_types?
> > > >
> > > never.
> >
> > Then I am terribly missing something. Zone contains free lists for
> > different MIGRATE_TYPES, doesn't it? Pages allocated from those free
> > lists keep the migration type of the list, right?
> >
> > ZONE_MOVABLE just says whether it makes sense to move pages in that zone
> > at all, right?
> >
>
> ZONE_MOVABLE means "it only contains MOVABLE pages."
> So, we can ignore migrate-type.
Ahh. OK, it seems that I have to look over movable related code once
again. Maybe I just got confused from my experience when ZONE_MOVABLE
zone contained MIGRATE_RESERVE pages but now I can see that this is OK
and doesn't have anything to do with other migrate types.
Anyway, thank you for clarification.
[...]
> > > > Isn't this a problem? The function is triggered from userspace by sysfs
> > > > (0444 file) and holds the lock for pageblock_nr_pages. So someone can
> > > > simply read the file and block the zone->lock preventing/delaying
> > > > allocations for the rest of the system.
> > > >
> > > But we need to take this. Maybe no panic you'll see even if no-lock.
> >
> > Yes, I think that this can only lead to a false possitive in sysfs
> > interface. Isolating code holds the lock.
> >
>
> ok, let's go step by step.
>
> I'm ok that your new patch to be merged. I'll post some clean up and small
> bugfix (not related to your patch), later.
> (I'll be very busy in this weekend, sorry.)
OK, no problem, we are not in hurry ;)
>
>
> Thanks,
> -Kame
>
Thanks!
--
Michal Hocko
L3 team
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
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next prev parent reply other threads:[~2010-09-03 11:01 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-20 14:14 [PATCH] " Michal Hocko
2010-08-22 0:42 ` Wu Fengguang
2010-08-23 9:22 ` Michal Hocko
2010-08-31 12:30 ` Michal Hocko
2010-08-31 14:19 ` Wu Fengguang
2010-08-31 14:36 ` Wu Fengguang
2010-08-31 14:59 ` Wu Fengguang
2010-09-01 1:19 ` KAMEZAWA Hiroyuki
2010-09-01 12:19 ` Michal Hocko
2010-09-01 12:41 ` Michal Hocko
2010-09-02 5:45 ` KAMEZAWA Hiroyuki
2010-09-02 8:28 ` Michal Hocko
2010-09-02 9:03 ` KAMEZAWA Hiroyuki
2010-09-02 9:24 ` Michal Hocko
2010-09-02 11:19 ` Hiroyuki Kamezawa
2010-09-02 13:18 ` Michal Hocko
2010-09-02 14:19 ` Hiroyuki Kamezawa
2010-09-02 14:39 ` Michal Hocko
2010-09-02 15:05 ` Michal Hocko
2010-09-03 3:10 ` [PATCH 0/2 v2] " KAMEZAWA Hiroyuki
2010-09-03 3:11 ` [PATCH 1/2][BUGFIX] fix next active pageblock calculation KAMEZAWA Hiroyuki
2010-09-03 3:14 ` [PATCH 2/2] Make is_mem_section_removable more conformable with offlining code KAMEZAWA Hiroyuki
2010-09-03 8:25 ` Michal Hocko
2010-09-03 9:13 ` KAMEZAWA Hiroyuki
2010-09-03 9:50 ` Michal Hocko
2010-09-03 10:05 ` KAMEZAWA Hiroyuki
2010-09-03 11:01 ` Michal Hocko [this message]
2010-09-03 11:42 ` [PATCH 2/2] Make is_mem_section_removable more conformable with offlining code v3 Michal Hocko
2010-09-04 2:55 ` Wu Fengguang
2010-09-06 9:16 ` Michal Hocko
2010-09-03 9:15 ` [PATCH 2/2] Make is_mem_section_removable more conformable with offlining code Michal Hocko
2010-09-03 9:24 ` KAMEZAWA Hiroyuki
2010-09-03 7:54 ` [PATCH 0/2 v2] " Michal Hocko
2010-09-03 7:57 ` [PATCH 3/2][BUGFIX] fix memory isolation notifier return value check KAMEZAWA Hiroyuki
2010-09-03 20:48 ` Andrew Morton
2010-09-03 22:05 ` Hiroyuki Kamezawa
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