Messages in this thread |  | | | Date | Fri, 19 Feb 2010 21:58:26 +0000 | | From | Mel Gorman <> | | Subject | Re: [PATCH 03/12] mm: Share the anon_vma ref counts between KSM and page migration |
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On Fri, Feb 19, 2010 at 04:42:18PM -0500, Rik van Riel wrote: > 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... >
external_refcount is about as good as I can think of to explain what's going on :/
-- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab
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