On Tue 31-07-12 22:45:43, Larry Woodman wrote:

On 07/31/2012 04:06 PM, Michal Hocko wrote:

quoted

On Tue 31-07-12 13:49:21, Larry Woodman wrote:

quoted

On 07/31/2012 08:46 AM, Mel Gorman wrote:

quoted

Fundamentally I think the problem is that we are not correctly detecting
that page table sharing took place during huge_pte_alloc(). This patch is
longer and makes an API change but if I'm right, it addresses the underlying
problem. The first VM_MAYSHARE patch is still necessary but would you mind
testing this on top please?

Hi Mel, yes this does work just fine.  It ran for hours without a panic so
I'll Ack this one if you send it to the list.

Hi Larry, thanks for testing! I have a different patch which tries to
address this very same issue. I am not saying it is better or that it
should be merged instead of Mel's one but I would be really happy if you
could give it a try. We can discuss (dis)advantages of both approaches
later.

Thanks!

Hi Michal, the system hung when I tested this patch on top of the
latest 3.5 kernel.  I wont have AltSysrq access to the system until
tomorrow AM.  

Please hold on. The patch is crap. I forgot about 
if (!vma_shareable(vma, addr))
	return;

case so somebody got an uninitialized pmd. The patch bellow handles
that.

Sorry about that and thanks to Mel to notice this.
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