Re: [patch 8/8] mm: reduce rmap overhead for ex-KSM page copies createdon swap faults

[Rik van Riel]

On 12/12/2012 04:43 PM, Johannes Weiner wrote:
> When ex-KSM pages are faulted from swap cache, the fault handler is
> not capable of re-establishing anon_vma-spanning KSM pages.  In this
> case, a copy of the page is created instead, just like during a COW
> break.
>
> These freshly made copies are known to be exclusive to the faulting
> VMA and there is no reason to go look for this page in parent and
> sibling processes during rmap operations.
>
> Use page_add_new_anon_rmap() for these copies.  This also puts them on
> the proper LRU lists and marks them SwapBacked, so we can get rid of
> doing this ad-hoc in the KSM copy code.
>
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>

Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>

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