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From: Matthew Wilcox <willy@infradead.org>
To: Daniel Colascione <dancol@google.com>
Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
	timmurray@google.com, primiano@google.com, joelaf@google.com,
	Jonathan Corbet <corbet@lwn.net>,
	Andrew Morton <akpm@linux-foundation.org>,
	Mike Rapoport <rppt@linux.vnet.ibm.com>,
	Roman Gushchin <guro@fb.com>, Vlastimil Babka <vbabka@suse.cz>,
	"Dennis Zhou (Facebook)" <dennisszhou@gmail.com>,
	Prashant Dhamdhere <pdhamdhe@redhat.com>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	"Steven Rostedt (VMware)" <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@kernel.org>,
	Dominik Brodowski <linux@dominikbrodowski.net>,
	Pavel Tatashin <pasha.tatashin@oracle.com>,
	Josh Poimboeuf <jpoimboe@redhat.com>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Michal Hocko <mhocko@suse.com>,
	David Howells <dhowells@redhat.com>,
	KJ Tsanaktsidis <ktsanaktsidis@zendesk.com>,
	"open list:DOCUMENTATION" <linux-doc@vger.kernel.org>
Subject: Re: [PATCH] Add /proc/pid_generation
Date: Wed, 21 Nov 2018 12:31:50 -0800	[thread overview]
Message-ID: <20181121203150.GK3065@bombadil.infradead.org> (raw)
In-Reply-To: <20181121201452.77173-1-dancol@google.com>

On Wed, Nov 21, 2018 at 12:14:44PM -0800, Daniel Colascione wrote:
> This change adds a per-pid-namespace 64-bit generation number,
> incremented on PID rollover, and exposes it via a new proc file
> /proc/pid_generation. By examining this file before and after /proc
> enumeration, user code can detect the potential reuse of a PID and
> restart the task enumeration process, repeating until it gets a
> coherent snapshot.
> 
> PID rollover ought to be rare, so in practice, scan repetitions will
> be rare.

Then why does it need to be 64-bit?

  reply	other threads:[~2018-11-21 20:31 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-21 20:14 [PATCH] Add /proc/pid_generation Daniel Colascione
2018-11-21 20:31 ` Matthew Wilcox [this message]
2018-11-21 20:38   ` Daniel Colascione
2018-11-22  2:06     ` Matthew Wilcox
2018-11-25 22:55       ` Pavel Machek
2018-11-21 20:54 ` [PATCH v2] Add /proc/pid_gen Daniel Colascione
2018-11-21 22:12   ` Andrew Morton
2018-11-21 22:40     ` Daniel Colascione
2018-11-21 22:48       ` Jann Horn
2018-11-21 22:52         ` Daniel Colascione
2018-11-21 22:50       ` Andrew Morton
2018-11-21 23:21         ` Daniel Colascione
2018-11-21 23:35           ` Andy Lutomirski
2018-11-22  0:21             ` Daniel Colascione
2018-11-22 13:58             ` Cyrill Gorcunov
2018-11-22  0:22           ` Andrew Morton
2018-11-22  0:28             ` Daniel Colascione
2018-11-22  0:30               ` Daniel Colascione
2018-11-22 15:27                 ` Mathieu Desnoyers
2018-11-22  0:57               ` Andrew Morton
2018-11-22  1:08                 ` Daniel Colascione
2018-11-22  1:29                   ` Andrew Morton
2018-11-22  2:35                     ` Tim Murray
2018-11-22  5:30                       ` Daniel Colascione
2018-11-22 11:19 ` [PATCH] Add /proc/pid_generation Kevin Easton
2018-11-23 11:14   ` David Laight
2018-11-25 23:00     ` Pavel Machek

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