From: John Hubbard <jhubbard@nvidia.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Matthew Wilcox <willy@infradead.org>, <linux-mm@kvack.org>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH] mm: Improve dump_page() for compound pages
Date: Mon, 10 Feb 2020 14:00:39 -0800 [thread overview]
Message-ID: <1d2ceaff-2cd5-8a03-97d0-556c1b48a69f@nvidia.com> (raw)
In-Reply-To: <20200210215449.ao7q5x4no5y2j6pc@box>
On 2/10/20 1:54 PM, Kirill A. Shutemov wrote:
> On Mon, Feb 10, 2020 at 01:33:22PM -0800, John Hubbard wrote:
>>> PageSlab() can be called for the head page.
>>
>>
>> It's not clear to me whether it's safer to use the...user-provided page, or the
>> head page, for checking PageSlab()--it's probably set on both head and non-head
>> pages, right?
>
> PageSlab() will call compound_head() inside.
>
>> I guess you're saying it should be like this:
>>
>> mapcount = PageSlab(head) ? 0 : page_mapcount(page);
>>
>> ...yes?
>
> Yes.
>
OK very good, thanks for walking me through it. :)
Matthew, if you like I'll just fix it up like that for my v6 posting of the
patchset, since it's such a small change.
thanks,
--
John Hubbard
NVIDIA
next prev parent reply other threads:[~2020-02-10 22:00 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-08 4:44 Matthew Wilcox
2020-02-08 4:48 ` Matthew Wilcox
2020-02-09 1:09 ` John Hubbard
2020-02-09 1:12 ` Matthew Wilcox
2020-02-09 1:18 ` John Hubbard
2020-02-10 12:42 ` Kirill A. Shutemov
2020-02-10 19:50 ` John Hubbard
2020-02-10 21:21 ` Kirill A. Shutemov
2020-02-10 21:33 ` John Hubbard
2020-02-10 21:54 ` Kirill A. Shutemov
2020-02-10 22:00 ` John Hubbard [this message]
2020-02-10 22:02 ` Matthew Wilcox
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