From: David Hildenbrand <david@redhat.com>
To: Peter Xu <peterx@redhat.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Muhammad Usama Anjum <usama.anjum@collabora.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Axel Rasmussen <axelrasmussen@google.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Nadav Amit <nadav.amit@gmail.com>,
Paul Gofman <pgofman@codeweavers.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH v3 1/2] mm/uffd: UFFD_FEATURE_WP_UNPOPULATED
Date: Wed, 8 Mar 2023 18:04:22 +0100 [thread overview]
Message-ID: <fd206791-aa8a-5cd8-2606-58d395f2c995@redhat.com> (raw)
In-Reply-To: <ZAi8+PCsIzExWPQN@x1n>
On 08.03.23 17:51, Peter Xu wrote:
> On Wed, Mar 08, 2023 at 04:57:55PM +0100, David Hildenbrand wrote:
>> Oh, my thinking was that with markers you postpone placing the shared
>> zeropage. So the next read access will require a pagefault to map the shared
>> zeropage. Your v1 would have performed best in that case I guess.
>
> Ah, so I misunderstood because the sentence being quote was in another
> context I think..
Sorry, I might have messed up the quoting.
>
> Pagemap may bring overhead constantly though, not sure when vs page faults.
> May relevant to num of missing pages.
Right, one idea (raised by Dave G. IIRC) was to to the pagemap scanning
concurrently from another thread and avoid most of the shared-zeropage
dance.
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2023-03-08 17:04 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-06 21:39 [PATCH v3 0/2] mm/uffd: Add feature bit UFFD_FEATURE_WP_UNPOPULATED Peter Xu
2023-03-06 21:39 ` [PATCH v3 1/2] mm/uffd: UFFD_FEATURE_WP_UNPOPULATED Peter Xu
2023-03-07 16:11 ` David Hildenbrand
2023-03-08 15:31 ` Peter Xu
2023-03-08 15:57 ` David Hildenbrand
2023-03-08 16:51 ` Peter Xu
2023-03-08 17:04 ` David Hildenbrand [this message]
2023-03-06 21:39 ` [PATCH v3 2/2] selftests/mm: Smoke test WP_UNPOPULATED Peter Xu
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