From: Matthew Wilcox <willy@infradead.org>
To: Peng Zhang <zhangpeng362@huawei.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
akpm@linux-foundation.org, mike.kravetz@oracle.com,
muchun.song@linux.dev, sidhartha.kumar@oracle.com,
vishal.moola@gmail.com, wangkefeng.wang@huawei.com,
sunnanyong@huawei.com
Subject: Re: [PATCH 2/2] mm/hugetlb: Use a folio in hugetlb_wp()
Date: Fri, 2 Jun 2023 21:17:08 +0100 [thread overview]
Message-ID: <ZHpORDg3JltVUwNb@casper.infradead.org> (raw)
In-Reply-To: <20230602015408.376149-3-zhangpeng362@huawei.com>
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.
next prev parent reply other threads:[~2023-06-02 20:18 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-02 1:54 [PATCH 0/2] Convert two functions in hugetlb.c to use a folio Peng Zhang
2023-06-02 1:54 ` [PATCH 1/2] mm/hugetlb: Use a folio in copy_hugetlb_page_range() Peng Zhang
2023-06-02 3:14 ` Muchun Song
2023-06-02 16:44 ` Sidhartha Kumar
2023-06-02 1:54 ` [PATCH 2/2] mm/hugetlb: Use a folio in hugetlb_wp() Peng Zhang
2023-06-02 3:17 ` Muchun Song
2023-06-02 17:47 ` Sidhartha Kumar
2023-06-02 20:17 ` Matthew Wilcox [this message]
2023-06-02 20:52 ` Mike Kravetz
2023-06-05 11:15 ` zhangpeng (AS)
2023-06-05 11:15 ` zhangpeng (AS)
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