Messages in this thread | | | Date | Mon, 5 Jun 2023 19:15:02 +0800 | Subject | Re: [PATCH 2/2] mm/hugetlb: Use a folio in hugetlb_wp() | From | "zhangpeng (AS)" <> |
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On 2023/6/3 4:17, Matthew Wilcox wrote:
> On Fri, Jun 02, 2023 at 09:54:08AM +0800, Peng Zhang wrote: >> From: ZhangPeng <zhangpeng362@huawei.com> >> >> We can replace nine implict calls to compound_head() with one by using >> old_folio. However, we still need to keep old_page because we need to >> know which page in the folio we are copying. > Do we? It's my understanding (and I am far from an expert here ...) > that the 'pte_t *' we are passed *inside hugetlbfs* is not in fact a pte > pointer at all but actually a pmd or pud pointer. See how we do this: > > pte_t pte = huge_ptep_get(ptep); > > and so the page we get back is always a head page, and we can go > directly to a folio. ie this is different from the THP cases.
Yes, I'll remove ptepage and old_page in a v2. Thanks.
Best Regards, Peng
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