Re: [PATCH 01/28] mm, page_alloc: Only check PageCompound for high-order pages

[Vlastimil Babka]

On 04/26/2016 12:33 PM, Mel Gorman wrote:
> I dithered on this a bit and could not convince myself that the order
> case really is unlikely. It depends on the situation as we could be
> tearing down a large THP-backed mapping. SLUB is also using compound
> pages so it's both workload and configuration dependent whether this
> path is really likely or not.

Hmm I see. But e.g. buffered_rmqueue uses "if (likely(order == 0))" so it would 
be at least consistent. Also compound pages can amortize the extra cost over 
more base pages.