Re: [RFCv2][PATCH 2/5] make 'struct page' and swp_entry_t variantsof swapcache_free().

From: Mel Gorman
Date: Fri May 17 2013 - 09:27:23 EST

On Thu, May 16, 2013 at 01:34:29PM -0700, Dave Hansen wrote:
> From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
> swapcache_free() takes two arguments:
> void swapcache_free(swp_entry_t entry, struct page *page)
> Most of its callers (5/7) are from error handling paths haven't even
> instantiated a page, so they pass page=NULL. Both of the callers
> that call in with a 'struct page' create and pass in a temporary
> swp_entry_t.
> Now that we are deferring clearing page_private() until after
> swapcache_free() has been called, we can just create a variant
> that takes a 'struct page' and does the temporary variable in
> the helper.
> That leaves all the other callers doing
> swapcache_free(entry, NULL)
> so create another helper for them that makes it clear that they
> need only pass in a swp_entry_t.
> One downside here is that delete_from_swap_cache() now does
> an extra swap_address_space() call. But, those are pretty
> cheap (just some array index arithmetic).
> Signed-off-by: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>

Acked-by: Mel Gorman <mgorman@xxxxxxx>

Mel Gorman
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