Re: [PATCH 03/12] mm: Share the anon_vma ref counts between KSM andpage migration

[Rik van Riel]

On 02/18/2010 01:02 PM, Mel Gorman wrote:

>   struct anon_vma {
>   	spinlock_t lock;	/* Serialize access to vma list */
> -#ifdef CONFIG_KSM
> -	atomic_t ksm_refcount;
> -#endif
> -#ifdef CONFIG_MIGRATION
> -	atomic_t migrate_refcount;
> +#if defined(CONFIG_KSM) || defined(CONFIG_MIGRATION)
> +
> +	/*
> +	 * The refcount is taken by either KSM or page migration
> +	 * to take a reference to an anon_vma when there is no
> +	 * guarantee that the vma of page tables will exist for
> +	 * the duration of the operation. A caller that takes
> +	 * the reference is responsible for clearing up the
> +	 * anon_vma if they are the last user on release
> +	 */
> +	atomic_t refcount;

Calling it just refcount is probably confusing, since
the anon_vma is also referenced by being on the chain
with others.

Maybe "other_refcount" because it is refcounts taken
by things other than VMAs?  I am sure there is a better
name possible...

--
All rights reversed.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/