From: "zhangpeng (AS)" <zhangpeng362@huawei.com>
To: Matthew Wilcox <willy@infradead.org>
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: Mon, 5 Jun 2023 19:15:02 +0800 [thread overview]
Message-ID: <188bd60a-e58a-a0f7-727f-bb2ce2a40d94@huawei.com> (raw)
In-Reply-To: <ZHpORDg3JltVUwNb@casper.infradead.org>
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
prev parent reply other threads:[~2023-06-05 11:15 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
2023-06-02 20:52 ` Mike Kravetz
2023-06-05 11:15 ` zhangpeng (AS)
2023-06-05 11:15 ` zhangpeng (AS) [this message]
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