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

[Vlastimil Babka <vbabka@suse.cz>]

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.

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