From: "Yin, Fengwei" <fengwei.yin@intel.com>
To: Zi Yan <ziy@nvidia.com>
Cc: David Hildenbrand <david@redhat.com>,
Matthew Wilcox <willy@infradead.org>, <linux-mm@kvack.org>,
Vishal Moola <vishal.moola@gmail.com>,
Hugh Dickins <hughd@google.com>, Rik van Riel <riel@surriel.com>
Subject: Re: Folio mapcount
Date: Tue, 4 Jul 2023 09:22:07 +0800 [thread overview]
Message-ID: <83534eb4-cf18-b594-98c7-1ca2b6cc3db8@intel.com> (raw)
In-Reply-To: <2AE20377-9111-4BCF-879E-7414808BDBA4@nvidia.com>
On 7/3/2023 9:24 PM, Zi Yan wrote:
> On 2 Jul 2023, at 21:09, Yin, Fengwei wrote:
>
>> On 7/3/2023 3:51 AM, Zi Yan wrote:
>>>> (3) Mapcount of first (or any other) subpage (compount+subpage): for
>>>> folio_estimated_sharers().
>>> This is another estimation. I wonder if we can use a different estimation
>>> like total_mapcount() > folio_nr_pages() instead.
>> Considering the partial folio mapping, I suppose we should use
>> total_mapcount() > folio->_nr_pages_mapped
>> as folio_estimated_sharers().
>
> What you propose is to get a precise check instead of estimate, and you assume no PMD mapping and still require per-page mapcount.
>
> What I am proposing is to get rid of per-page mapcount, which is my goal, and use a single mapcount to do a rough estimate.
O. Sorry. I didn't notice your goal. So if the rough estimate is enough,
total_mapcount() > folio_nr_pages() works.
Do we need to check all the cases to make sure the rough estimation is
enough for all of them?
Regards
Yin, Fengwei
>
> --
> Best Regards,
> Yan, Zi
next prev parent reply other threads:[~2023-07-04 1:22 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-24 18:13 Matthew Wilcox
2023-01-24 18:35 ` David Hildenbrand
2023-01-24 18:37 ` David Hildenbrand
2023-01-24 18:35 ` Yang Shi
2023-02-02 3:45 ` Mike Kravetz
2023-02-02 15:31 ` Matthew Wilcox
2023-02-07 16:19 ` Zi Yan
2023-02-07 16:44 ` Matthew Wilcox
2023-02-06 20:34 ` Matthew Wilcox
2023-02-06 22:55 ` Yang Shi
2023-02-06 23:09 ` Matthew Wilcox
2023-02-07 3:06 ` Yin, Fengwei
2023-02-07 4:08 ` Matthew Wilcox
2023-02-07 22:39 ` Peter Xu
2023-02-07 23:27 ` Matthew Wilcox
2023-02-08 19:40 ` Peter Xu
2023-02-08 20:25 ` Matthew Wilcox
2023-02-08 20:58 ` Peter Xu
2023-02-09 15:10 ` Chih-En Lin
2023-02-09 15:43 ` Peter Xu
2023-02-07 22:56 ` James Houghton
2023-02-07 23:08 ` Matthew Wilcox
2023-02-07 23:27 ` James Houghton
2023-02-07 23:35 ` Matthew Wilcox
2023-02-08 0:35 ` James Houghton
2023-02-08 2:26 ` Matthew Wilcox
2023-02-07 16:23 ` Zi Yan
2023-02-07 16:51 ` Matthew Wilcox
2023-02-08 19:36 ` Zi Yan
2023-02-08 19:54 ` Matthew Wilcox
2023-02-10 15:15 ` Zi Yan
2023-03-29 14:02 ` Yin, Fengwei
2023-07-01 1:17 ` Zi Yan
2023-07-02 9:50 ` Yin, Fengwei
2023-07-02 11:45 ` David Hildenbrand
2023-07-02 12:26 ` Matthew Wilcox
2023-07-03 20:54 ` David Hildenbrand
2023-07-02 19:51 ` Zi Yan
2023-07-03 1:09 ` Yin, Fengwei
2023-07-03 13:24 ` Zi Yan
2023-07-03 20:46 ` David Hildenbrand
2023-07-04 1:22 ` Yin, Fengwei [this message]
2023-07-04 2:25 ` Matthew Wilcox
2023-07-03 21:09 ` David Hildenbrand
-- strict thread matches above, loose matches on Subject: below --
2021-12-15 21:55 folio mapcount Matthew Wilcox
2021-12-16 9:37 ` Kirill A. Shutemov
2021-12-16 13:56 ` Matthew Wilcox
2021-12-16 15:19 ` Jason Gunthorpe
2021-12-16 15:54 ` Matthew Wilcox
2021-12-16 16:45 ` David Hildenbrand
2021-12-16 17:01 ` Jason Gunthorpe
2021-12-16 18:56 ` Kirill A. Shutemov
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