From: David Hildenbrand <david@redhat.com>
To: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>,
Matthew Wilcox <willy@infradead.org>
Cc: Barry Song <21cnbao@gmail.com>,
Nicolas Geoffray <ngeoffray@google.com>,
Lokesh Gidra <lokeshgidra@google.com>,
Harry Yoo <harry.yoo@oracle.com>,
Suren Baghdasaryan <surenb@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Rik van Riel <riel@surriel.com>,
"Liam R . Howlett" <Liam.Howlett@oracle.com>,
Vlastimil Babka <vbabka@suse.cz>, Jann Horn <jannh@google.com>,
Linux-MM <linux-mm@kvack.org>,
Kalesh Singh <kaleshsingh@google.com>,
SeongJae Park <sj@kernel.org>, Barry Song <v-songbaohua@oppo.com>,
Peter Xu <peterx@redhat.com>
Subject: Re: [DISCUSSION] anon_vma root lock contention and per anon_vma lock
Date: Mon, 15 Sep 2025 12:41:52 +0200 [thread overview]
Message-ID: <88258e24-60d2-4068-8d26-bec51c94a650@redhat.com> (raw)
In-Reply-To: <b6d5c607-a9d9-4c1b-b4ac-41fcaa2e696d@lucifer.local>
>>
>> Another point in favour of COW_NOW or EAGER_COW is that we can choose to
>> allocate folios of the appropriate size at that time. Unless something's
>> changed, I think we always COW individual pages rather than multiple
>> pages at once.
>>
>
> I don't think there's any practical way to do it any differently because
> you don't know what's mapped/not at the point of fault.
>
> How expensive would it be to have xarray for anon, I wonder... :)
We had a proposal least year I think where someone wanted to bring some
weird FreeBSD semantics into Linux MM and proposed a secondary tracking
structure for anon.
Tracking twice is obviously more expensive than tracking once, so I am
quite convinced that no, we never want that.
--
Cheers
David / dhildenb
next prev parent reply other threads:[~2025-09-15 10:42 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-11 7:17 Barry Song
2025-09-11 8:14 ` David Hildenbrand
2025-09-11 8:34 ` Lorenzo Stoakes
2025-09-11 9:18 ` Barry Song
2025-09-11 10:47 ` Lorenzo Stoakes
2025-09-11 8:28 ` Lorenzo Stoakes
2025-09-11 18:22 ` Jann Horn
2025-09-12 4:49 ` Lorenzo Stoakes
2025-09-12 11:37 ` Jann Horn
2025-09-12 11:56 ` Lorenzo Stoakes
2025-09-14 23:53 ` Matthew Wilcox
2025-09-15 0:23 ` Barry Song
2025-09-15 1:47 ` Suren Baghdasaryan
2025-09-15 8:41 ` Lorenzo Stoakes
2025-09-15 2:50 ` Matthew Wilcox
2025-09-15 5:17 ` David Hildenbrand
2025-09-15 9:42 ` Lorenzo Stoakes
2025-09-15 10:29 ` David Hildenbrand
2025-09-15 10:56 ` Lorenzo Stoakes
2025-09-15 9:22 ` Lorenzo Stoakes
2025-09-15 10:41 ` David Hildenbrand [this message]
2025-09-15 10:51 ` Lorenzo Stoakes
2025-09-15 8:57 ` Lorenzo Stoakes
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