Re: [PATCH 2.6.12-rc5 5/10] mm: manual page migration-rc3 -- sys_migrate_pages-mempolicy-migration-rc3.patch

[Andi Kleen <ak@suse.de>]

On Wed, Jun 22, 2005 at 09:39:41AM -0700, Ray Bryant wrote:
> This patch adds code that translates the memory policy structures
> as they are encountered so that they continue to represent where
> memory should be allocated after the page migration has completed.


That won't work for shared memory objects though (which store
their mempolicies separately). Is that intended?

> +
> +	if (task->mempolicy->policy == MPOL_INTERLEAVE) {
> +		/*
> +		 * If the task is still running and allocating storage, this
> +		 * is racy, but there is not much that can be done about it.
> +		 */
> +		tmp = task->il_next;
> +		if (node_map[tmp] >= 0)
> +			task->il_next = node_map[tmp];

RCU (synchronize_kernel) could do better, but that might be slow. However the 
code might BUG when il_next ends up in a node that is not part of 
the policy anymore. Have you checked that?  

-Andi
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