From: Andrea Arcangeli <aarcange@redhat.com>
To: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Pavel Emelyanov <xemul@virtuozzo.com>,
linux-mm@kvack.org
Subject: Re: [PATCH for 4.11] userfaultfd: report actual registered features in fdinfo
Date: Mon, 3 Apr 2017 18:30:34 +0200 [thread overview]
Message-ID: <20170403163034.GD5107@redhat.com> (raw)
In-Reply-To: <20170403151024.GA14802@rapoport-lnx>
Hello Mike,
On Mon, Apr 03, 2017 at 06:10:24PM +0300, Mike Rapoport wrote:
> Actually, I've found these details in /proc useful when I was experimenting
> with checkpoint-restore of an application that uses userfaultfd. With
> interface in /proc/<pid>/ we know exactly which process use userfaultfd and
> can act appropriately.
You've to be somewhat serialized by other means though, because
"exactly" has a limit with fdinfo. For example by the time read()
returns, the uffd may have been closed already by the app (just the
uffd isn't ->release()d yet as the last fput has yet to run, the
fdinfo runs the last fput in such case). As long as you can cope with
this and you've a stable fdinfo it's ok.
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next prev parent reply other threads:[~2017-04-03 16:30 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-02 13:36 [PATCH for 4.11] userfaultfd: report actual registered features in fdinfo Mike Rapoport
2017-04-03 14:35 ` Andrea Arcangeli
2017-04-03 15:10 ` Mike Rapoport
2017-04-03 16:30 ` Andrea Arcangeli [this message]
2017-04-04 7:46 ` Mike Rapoport
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