Re: [PATCH 1/4] [mm] buddy page allocator: add tunable big orderallocation

[KAMEZAWA Hiroyuki]

On Wed, 14 May 2008 12:22:35 +0800
"Bryan Wu" <cooloney@xxxxxxxxxx> wrote:

> On Tue, May 13, 2008 at 7:42 PM, Hennerich, Michael
> <Michael.Hennerich@xxxxxxxxxx> wrote:
> >
> >
> >  >-----Original Message-----
> >  >From: KAMEZAWA Hiroyuki [mailto:kamezawa.hiroyu@xxxxxxxxxxxxxx]
> >  >Sent: Dienstag, 13. Mai 2008 04:09
> >  >To: Bryan Wu
> >  >Cc: linux-kernel@xxxxxxxxxxxxxxx; linux-mm@xxxxxxxxx;
> >  dwmw2@xxxxxxxxxxxxx;
> >  >Michael Hennerich
> >  >Subject: Re: [PATCH 1/4] [mm] buddy page allocator: add tunable big
> >  order
> >  >allocation
> >  >
> >  >On Mon, 12 May 2008 18:32:02 +0800
> >  >Bryan Wu <cooloney@xxxxxxxxxx> wrote:
> >  >
> >  >> From: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
> >  >>
> >  >> Signed-off-by: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
> >  >> Signed-off-by: Bryan Wu <cooloney@xxxxxxxxxx>
> >  >
> >  >Does this really solve your problem ? possible hang-up is better than
> >  >page allocation failure ?
> >
> >  On nommu this helped quite a bit, when we run out of memory, eaten up by
> >  the page cache. But yes - with this option it's likely that we sit there
> >  and wait form memory that might never get available.
> >
> >  We now use a better workaround for freeing up "available" memory
> >  currently used as page cache.
> >
> >  I think we should drop this patch.
> >
> 
> OK, I dropped it. And do you think the limited page_cache patch is the
> replacement of this patch?
> 

I'm not so familiar with nommu environments but have some thoughts.

one idea is 
 - use memory resource controller.
   but this eats much amount of GFP_KERNEL memory and maybe not useful ;)
 - use ZONE_MOVABLE and set lowmem_reserve_ratio value to be suitable value.
   then, the page cache just uses MOVABLE zone...(maybe)

Thanks,
-Kame











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