Messages in this thread | | | Date | Wed, 11 Nov 2020 16:38:48 +0000 | From | Matthew Wilcox <> | Subject | Re: [PATCH V9 1/4] perf/core: Add PERF_SAMPLE_DATA_PAGE_SIZE |
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On Wed, Nov 11, 2020 at 04:57:24PM +0100, Peter Zijlstra wrote: > On Wed, Nov 11, 2020 at 03:30:22PM +0000, Matthew Wilcox wrote: > > This confuses me. Why only special-case hugetlbfs pages here? Should > > they really be treated differently from THP? If you want to consider > > that we might be mapping a page that's twice as big as a PUD entry and > > this is only half of it, then the simple way is: > > > > if (pud_leaf(pud)) { > > #ifdef pud_page > > page = compound_head(pud_page(*pud)); > > return page_size(page); > > Also; this is 'wrong'. The purpose of this function is to return the > hardware TLB size of a given address. The above will return the compound > size, for any random compound page, which would be myrads of reasons.
Oh, then the whole thing is overly-complicated. This should just be
if (pud_leaf(pud)) return PUD_SIZE;
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