Re: [RFC V2 12/12] mm: Tag VMA with VM_CDM flag explicitly during mbind(MPOL_BIND)

[Dave Hansen]

On 01/29/2017 07:35 PM, Anshuman Khandual wrote:
> +		if ((new_pol->mode == MPOL_BIND)
> +			&& nodemask_has_cdm(new_pol->v.nodes))
> +			set_vm_cdm(vma);

So, if you did:

	mbind(addr, PAGE_SIZE, MPOL_BIND, all_nodes, ...);
	mbind(addr, PAGE_SIZE, MPOL_BIND, one_non_cdm_node, ...);

You end up with a VMA that can never have KSM done on it, etc...  Even
though there's no good reason for it.  I guess /proc/$pid/smaps might be
able to help us figure out what was going on here, but that still seems
like an awful lot of damage.