Re: 2.6.14-rc2-mm1

["Seth, Rohit" <rohit.seth@intel.com>]

On Sat, Sep 24, 2005 at 11:23:39AM -0700, Andrew Morton wrote:
> > 
> > ...
> >  exim4: page allocation failure. order:1, mode:0x80000020
> 
> Yes, it's expected that
> mm-try-to-allocate-higher-order-pages-in-rmqueue_bulk.patch will cause more
> fragmentation and will hence cause higher-order allocation attempts to
> fail.
> 
> I think I'll drop that one.

Seems like from the log messages that quite a few pages are hanging in the cpu's cold pcp list even with the low memory conditions.  Below is the patch to reduce the higher bound in cold pcp list (...this got increased with my previous change).  

I think we should also drain the CPU's hot and cold pcps for the GFP_KERNEL page requests (in the event the higher order request is not able to get serviced otherwise).  This will still only drains the current CPUs pcps in an MP environment (leaving the other CPUs with their lists intact).  I will send this patch later today.

	[PATCH]: Reduce the high mark in cpu's cold pcp list.

	Signed-off-by: Rohit Seth <rohit.seth@intel.com>


--- linux-2.6.13.old/mm/page_alloc.c	2005-09-26 10:57:07.000000000 -0700
+++ linux-2.6.13.work/mm/page_alloc.c	2005-09-26 10:47:57.000000000 -0700
@@ -1749,7 +1749,7 @@
 	pcp = &p->pcp[1];		/* cold*/
 	pcp->count = 0;
 	pcp->low = 0;
-	pcp->high = 2 * batch;
+	pcp->high = batch / 2;
 	pcp->batch = max(1UL, batch/2);
 	INIT_LIST_HEAD(&pcp->list);
 }
-
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