Messages in this thread | | | From | Naoya Horiguchi <> | Subject | Re: [PATCHv12 26/37] mm: rework mapcount accounting to enable 4k mapping of THPs | Date | Fri, 30 Oct 2015 08:33:48 +0000 |
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On Thu, Oct 29, 2015 at 11:50:47PM +0200, Kirill A. Shutemov wrote: ... > > Okay, the problem is that the page was freed under stable_page_flags(). > > Is the code performance sensitive? Can we get reference to the page before > touching it? If not, we can rewrite the helper like this: > > static inline int PageDoubleMap(struct page *page) > { > return PageHead(page) && test_bit(PG_double_map, &page[1].flags); > } > > Just dropping the check would be wrong, I think, as we access the next > page. >
I don't think this interface is performance sensitive, but hopefully the impact on other workload is minimum. So I like the above rewritten one.
Thanks, Naoya Horiguchi
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