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From: Yasunori Goto <y-goto@jp.fujitsu.com>
To: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: mgross@linux.intel.com, pbadari@gmail.com, linux-mm@kvack.org
Subject: Re: Hotplug memory remove
Date: Tue, 09 Oct 2007 19:51:59 +0900	[thread overview]
Message-ID: <20071009193217.4270.Y-GOTO@jp.fujitsu.com> (raw)
In-Reply-To: <20071009101003.cb9fdc9f.kamezawa.hiroyu@jp.fujitsu.com>


> > > One idea is to ignore memory of some PXMs specified by kerenel boot param.
> > > Later, you can hot-add specified PXM memory as MOVABLE.
> > > Then, boot sequence will be
> > > --
> > >    bootstrap , ignore some memory here.
> > >    init memory, driver, etc
> > >    hot-add ignored memory
> > >    online hot-added memory by user scripts. (from rc script ?)
> > > --y
> > > For doing this, we need
> > >  - a switch to hot-add memory as MOVABLE (will be easy patch)
> > >  - a code for ignoring memory at boot but remember them for later hotadd
> > >    (maybe needs arch specific codes)
> > >  - a code for hot add memory before rc script (initcall is suitable ?) 
> > > 
> > > Needs some amount of arch-specific codes, but maybe simple.
> > > Why I recommend above is it will be complex to avoid some PXM's memory
> > > to be used as bootmem or for some other purpose(slab, hash, etc...).
> > 
> > I have the boot memory allocations or off-lineable-memory taken care of.
> > I can see how the above would work, but I worry that it feels a bit
> > hackish.   
> > 
> > BTW Is this how memory hot remove is expected to be used?
> > 
> I think above is a simple way to go. How about you ? > Goto-san.
> I don't want to make memory-initialization too complicated.

Hmm. At first, I agreed with you. But I'm a bit worry about it too now.

When movable-memory is specified by boot option, I guess something
wrong case will occur like followings.

  ex) Movable node is specified by boot-option as "movable_node=2" on 
      4 node box.

    1) boot up with 2 movable node and 2 non-movable node.
    2) remove those 2 nodes physically.
    3) system must be removed by some reasons.
    4) system can't boot up due to only 2 MOVABLE nodes!

It depends how "movable area" is specified. please take care.

Bye.

-- 
Yasunori Goto 


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      reply	other threads:[~2007-10-09 10:51 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-10-01 15:37 Badari Pulavarty
2007-10-01 16:14 ` KAMEZAWA Hiroyuki
2007-10-01 17:49   ` Badari Pulavarty
2007-10-02  0:52     ` KAMEZAWA Hiroyuki
2007-10-02 14:58       ` Badari Pulavarty
2007-10-02 17:17       ` Badari Pulavarty
2007-10-03  1:07         ` KAMEZAWA Hiroyuki
2007-10-05 17:21   ` Mark Gross
2007-10-06  0:41     ` KAMEZAWA Hiroyuki
2007-10-08 19:01       ` Mark Gross
2007-10-09  1:10         ` KAMEZAWA Hiroyuki
2007-10-09 10:51           ` Yasunori Goto [this message]

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