Re: Migrate pages from a ccNUMA node to another - patch

[Zoltan Menyhart]

Hirokazu Takahashi wrote:

[...]
> 
> It's not hard to add "no-retry-mode" to "remap_onepage()" function
> if you want. It may skip to migrate some pages if they are accessed
> heavily. In paticular if you only want to care about anonymous pages,
> they will be handled very well.

Well, why not to give it a try ?
Yet your code is not really easy to read. :-)
I do not dare to adapt it on my own, I am afraid of breaking something.
Could you please provide me a modified version of your "remap_onepage()" ?
Can we move to 2.6.4 ?

In addition to "no-retry-mode", I need to specify where the new page
should be allocated from.

Here is my interface I need to implement with "remap_onepage()":

/*
 * Common part of checking & migrating the pages one by one.
 *
 * Arguments:	src_node:	Source NUMA node
 *		old_p:		-> old page structure
 *		node:		Destination NUMA node
 *		mm:		-> victim "mm_struct"
 *		pte:		-> PTE of the page to be moved
 *
 * Returns:	1:		Migration O. K.
 *		0:		Minor error, no actual migration has been done
 *		-Exxx:		Catastrophic error
 *
 * Notes:	- "mm->page_table_lock" and "mm->mmap_sem" have to be held.
 *		- The old page is "get_page()"-ed on entry to make sure it does not go
 *		  away in the mean time - on return it gets "put_page()"-ed.
 */
int
common_check_migrate_1_page(const int src_node, struct page * const old_p,
			const int node, struct mm_struct * const mm, pte_t * const pte)

Notes: "pte" can be NULL if I do not know it apriori
       I cannot release "mm->page_table_lock" otherwise I have to re-scan the "mm->pgd".

Thanks,

Zoltán Menyhárt
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