Messages in this thread | | | Date | Sun, 17 May 2015 02:17:32 +0300 | From | "Kirill A. Shutemov" <> | Subject | Re: [PATCHv5 03/28] memcg: adjust to support new THP refcounting |
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On Fri, May 15, 2015 at 07:57:39AM -0700, Dave Hansen wrote: > On 05/15/2015 04:18 AM, Kirill A. Shutemov wrote: > >> > But same question about whether it should be using hpage_nr_pages() instead > >> > of a constant. > > No. Compiler woundn't be able to optimize HPAGE_PMD_NR away for THP=n, > > since compound value cross compilation unit barrier. > > What code are you talking about here, specifically? This? > > static inline int hpage_nr_pages(struct page *page) > { > if (unlikely(PageTransHuge(page))) > return HPAGE_PMD_NR; > return 1; > }
No. See for instance mem_cgroup_try_charge(). Vlastimil would like to replace hpage_nr_pages() call with plain HPAGE_PMD_NR.
-- Kirill A. Shutemov
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