From: Peter Xu <peterx@redhat.com>
To: David Hildenbrand <david@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 11:51:04 -0500 [thread overview]
Message-ID: <ZAi8+PCsIzExWPQN@x1n> (raw)
In-Reply-To: <83b3f3ad-19a2-3737-77dd-3c3f9db82194@redhat.com>
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..
Pagemap may bring overhead constantly though, not sure when vs page faults.
May relevant to num of missing pages.
It's just that we may still want pte markers to avoid losing MISSING+WP
(with WP_UNPOPULATED) use case, which you rightfully pointed out before.
--
Peter Xu
next prev parent reply other threads:[~2023-03-08 16:51 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 [this message]
2023-03-08 17:04 ` David Hildenbrand
2023-03-06 21:39 ` [PATCH v3 2/2] selftests/mm: Smoke test WP_UNPOPULATED Peter Xu
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