From: Michal Hocko <mhocko@suse.cz>
To: Hiroyuki Kamezawa <kamezawa.hiroyuki@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.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] Make is_mem_section_removable more conformable with offlining code
Date: Thu, 2 Sep 2010 15:18:55 +0200 [thread overview]
Message-ID: <20100902131855.GC10265@tiehlicka.suse.cz> (raw)
In-Reply-To: <AANLkTi=cLzRGPCc3gCubtU7Ggws7yyAK5c7tp4iocv6u@mail.gmail.com>
On Thu 02-09-10 20:19:45, Hiroyuki Kamezawa wrote:
> 2010/9/2 Michal Hocko <mhocko@suse.cz>:
> > On Thu 02-09-10 18:03:43, KAMEZAWA Hiroyuki wrote:
> >> On Thu, 2 Sep 2010 10:28:29 +0200
> >> Michal Hocko <mhocko@suse.cz> wrote:
> >>
> >> > On Thu 02-09-10 14:45:00, KAMEZAWA Hiroyuki wrote:
[...]
> >> > By the higher fragmentation you mean that all movable pageblocks (even
> >> > reclaimable) gets to MIGRATE_MOVABLE until we get first failure. In the
> >> > worst case, if we fail near the end of the zone then there is imbalance
> >> > in MIGRATE_MOVABLE vs. MIGRATE_RECALIMABLE. Is that what you are
> >> > thinking of? Doesn't this just gets the zone to the state after
> >> > onlining? Or is the problem if we fail somewhere in the middle?
> >> >
> >>
> >> No. My concern is pageblock type changes before/after memory hotplug failure.
> >> ? ? ? before isolation: MIGRATE_RECLAIMABLE
> >> ? ? ? after isolation failure : MIGRATE_MOVABLE
> >
> > Ahh, OK I can see your point now. unset_migratetype_isolate called on
> > the failure path sets migrate type unconditionally as it cannot know
> > what was the original migration type.
> >
> Right.
>
> > What about MIGRATE_RESERVE? Is there anything that can make those
> > allocations fail offlining?
> >
> MIGRATE_RESERVE can contain several typs of pages, mixture of movable/unmovable
> pages.
Ahh, ok. This is just a fallback zone. I see.
>
> IIRC, my 1st version of code of set_migratetype_isolate() just checks
> zone_idx and
> I think checking MIGRATE_TYPE is my mistake.
> (As Mel explained, it can be a mixture of several types.)
>
> So, how about using the latter half of set_migratetype_isolate()'s check ?
> It checks that the given range just includes free pages and LRU pages.
> It's 100% accurate and more trustable than migrate_type check.
>
> Whatever migratetype the pageblock has, if the block only contains free pages
> and lru pages, changing the type as MOVABLE (at failure) is not very bad.
>
> (Or, checking contents of pageblock in failure path and set proper
> MIGRATE type.)
>
> Anyway, not very difficult. Just a bit larger patch than you have.
What about this? Just compile tested.
---
next prev parent reply other threads:[~2010-09-02 13:18 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-20 14:14 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 [this message]
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
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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