Re: [patch 3/9] mm: shmem: save one radix tree lookup whentruncating swapped pages

[Minchan Kim]

On Sun, Nov 24, 2013 at 06:38:22PM -0500, Johannes Weiner wrote:
> Page cache radix tree slots are usually stabilized by the page lock,
> but shmem's swap cookies have no such thing.  Because the overall
> truncation loop is lockless, the swap entry is currently confirmed by
> a tree lookup and then deleted by another tree lookup under the same
> tree lock region.
> 
> Use radix_tree_delete_item() instead, which does the verification and
> deletion with only one lookup.  This also allows removing the
> delete-only special case from shmem_radix_tree_replace().
> 
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Reviewed-by: Minchan Kim <minchan@xxxxxxxxxx>

Nice cleanup!

-- 
Kind regards,
Minchan Kim
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