Re: [PATCH] hugetlb: Do not account hugetlb pages as NR_FILE_PAGES

Vlastimil Babka
2015-05-25T15:24:34Z

On 05/22/2015 04:35 PM, Mel Gorman wrote:
>>
>> Thanks!
>>
>> > This makes a lot of sense to me. The only thing I worry about is the
>> > proliferation of PageHuge(), a function call, in relatively hot paths.
>>
>> I've tried that (see the patch below) but it enlarged the code by almost
>> 1k
>> text data bss dec hex filename
>> 510323 74273 44440 629036 9992c mm/built-in.o.before
>> 511248 74273 44440 629961 99cc9 mm/built-in.o.after
>>
>> I am not sure the code size increase is worth it. Maybe we can reduce
>> the check to only PageCompound(page) as huge pages are no in the page
>> cache (yet).
>>
>
> That would be a more sensible route because it also avoids exposing the
> hugetlbfs destructor unnecessarily.

You could maybe do test such as (PageCompound(page) && PageHuge(page)) to
short-circuit the call while remaining future-proof.