From: Peter Xu <peterx@redhat.com>
To: David Hildenbrand <david@redhat.com>
Cc: Suren Baghdasaryan <surenb@google.com>,
akpm@linux-foundation.org, viro@zeniv.linux.org.uk,
brauner@kernel.org, shuah@kernel.org, aarcange@redhat.com,
lokeshgidra@google.com, hughd@google.com, mhocko@suse.com,
axelrasmussen@google.com, rppt@kernel.org, willy@infradead.org,
Liam.Howlett@oracle.com, jannh@google.com,
zhangpeng362@huawei.com, bgeffon@google.com,
kaleshsingh@google.com, ngeoffray@google.com, jdduke@google.com,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
kernel-team@android.com
Subject: Re: [PATCH v2 1/3] userfaultfd: UFFDIO_REMAP: rmap preparation
Date: Mon, 2 Oct 2023 11:23:05 -0400 [thread overview]
Message-ID: <ZRrgWVgjVfQu4RGX@x1n> (raw)
In-Reply-To: <27f177c9-1035-3277-cd62-dc81c12acec4@redhat.com>
On Mon, Oct 02, 2023 at 04:42:50PM +0200, David Hildenbrand wrote:
> On 23.09.23 03:31, Suren Baghdasaryan wrote:
> > From: Andrea Arcangeli <aarcange@redhat.com>
> >
> > As far as the rmap code is concerned, UFFDIO_REMAP only alters the
> > page->mapping and page->index. It does it while holding the page
> > lock. However folio_referenced() is doing rmap walks without taking the
> > folio lock first, so folio_lock_anon_vma_read() must be updated to
> > re-check that the folio->mapping didn't change after we obtained the
> > anon_vma read lock.
>
> I'm curious: why don't we need this for existing users of
> page_move_anon_rmap()? What's special about UFFDIO_REMAP?
Totally no expert on anon vma so I'm prone to errors, but IIUC the
difference here is root anon vma cannot change in page_move_anon_rmap(),
while UFFDIO_REMAP can.
Thanks,
--
Peter Xu
next prev parent reply other threads:[~2023-10-02 15:24 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-09-23 1:31 [PATCH v2 0/3] userfaultfd remap option Suren Baghdasaryan
2023-09-23 1:31 ` [PATCH v2 1/3] userfaultfd: UFFDIO_REMAP: rmap preparation Suren Baghdasaryan
2023-09-28 16:23 ` Peter Xu
2023-09-28 20:03 ` Suren Baghdasaryan
2023-10-02 14:42 ` David Hildenbrand
2023-10-02 15:23 ` Peter Xu [this message]
2023-10-02 17:30 ` David Hildenbrand
2023-10-03 17:56 ` Suren Baghdasaryan
2023-09-23 1:31 ` [PATCH v2 2/3] userfaultfd: UFFDIO_REMAP uABI Suren Baghdasaryan
2023-09-27 10:06 ` potential new userfaultfd vs khugepaged conflict [was: Re: [PATCH v2 2/3] userfaultfd: UFFDIO_REMAP uABI] Jann Horn
2023-09-27 17:12 ` Suren Baghdasaryan
2023-09-28 15:29 ` Jann Horn
2023-09-27 12:47 ` [PATCH v2 2/3] userfaultfd: UFFDIO_REMAP uABI Jann Horn
2023-09-27 13:29 ` David Hildenbrand
2023-09-27 18:25 ` Suren Baghdasaryan
2023-09-28 16:28 ` Peter Xu
2023-09-28 17:15 ` David Hildenbrand
2023-09-28 18:32 ` Suren Baghdasaryan
2023-09-28 20:11 ` Suren Baghdasaryan
2023-09-28 19:00 ` Peter Xu
2023-10-02 7:49 ` David Hildenbrand
2023-09-28 16:24 ` Peter Xu
2023-09-28 17:05 ` David Hildenbrand
2023-09-28 17:21 ` Peter Xu
2023-09-28 17:51 ` David Hildenbrand
2023-09-28 18:34 ` Peter Xu
2023-09-28 19:47 ` Suren Baghdasaryan
2023-10-02 8:00 ` David Hildenbrand
2023-10-02 15:21 ` Peter Xu
2023-10-02 15:46 ` Lokesh Gidra
2023-10-02 15:55 ` Lokesh Gidra
2023-10-02 17:43 ` David Hildenbrand
2023-10-02 19:33 ` Lokesh Gidra
2023-10-03 20:04 ` Suren Baghdasaryan
2023-10-03 20:21 ` Peter Xu
2023-10-03 21:08 ` David Hildenbrand
2023-10-03 21:20 ` Peter Xu
2023-10-03 22:26 ` Suren Baghdasaryan
2023-10-03 23:39 ` Lokesh Gidra
2023-10-06 12:30 ` David Hildenbrand
2023-10-06 15:02 ` Suren Baghdasaryan
2023-10-03 21:04 ` David Hildenbrand
2023-10-02 17:33 ` David Hildenbrand
2023-10-02 17:36 ` David Hildenbrand
2023-09-27 18:07 ` Suren Baghdasaryan
2023-09-27 20:04 ` Jann Horn
2023-09-27 20:42 ` Suren Baghdasaryan
2023-09-27 21:08 ` Suren Baghdasaryan
2023-09-27 22:48 ` Jann Horn
2023-09-28 15:36 ` Suren Baghdasaryan
2023-09-28 17:09 ` Peter Xu
2023-09-28 18:23 ` Suren Baghdasaryan
2023-09-28 18:43 ` Peter Xu
2023-09-28 19:50 ` Suren Baghdasaryan
2023-09-23 1:31 ` [PATCH v2 3/3] selftests/mm: add UFFDIO_REMAP ioctl test Suren Baghdasaryan
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=ZRrgWVgjVfQu4RGX@x1n \
--to=peterx@redhat.com \
--cc=Liam.Howlett@oracle.com \
--cc=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=axelrasmussen@google.com \
--cc=bgeffon@google.com \
--cc=brauner@kernel.org \
--cc=david@redhat.com \
--cc=hughd@google.com \
--cc=jannh@google.com \
--cc=jdduke@google.com \
--cc=kaleshsingh@google.com \
--cc=kernel-team@android.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-kselftest@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=lokeshgidra@google.com \
--cc=mhocko@suse.com \
--cc=ngeoffray@google.com \
--cc=rppt@kernel.org \
--cc=shuah@kernel.org \
--cc=surenb@google.com \
--cc=viro@zeniv.linux.org.uk \
--cc=willy@infradead.org \
--cc=zhangpeng362@huawei.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.