From: Oleg Nesterov <oleg@redhat.com>
To: Pavel Emelyanov <xemul@parallels.com>
Cc: Tejun Heo <tj@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Cyrill Gorcunov <gorcunov@openvz.org>,
Glauber Costa <glommer@parallels.com>,
Nathan Lynch <ntl@pobox.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Serge Hallyn <serue@us.ibm.com>,
Daniel Lezcano <dlezcano@fr.ibm.com>
Subject: Re: [PATCH 3/3] pids: Make it possible to clone tasks with given pids
Date: Fri, 11 Nov 2011 17:48:00 +0100 [thread overview]
Message-ID: <20111111164800.GA27245@redhat.com> (raw)
In-Reply-To: <4EBD4A7E.7060102@parallels.com>
On 11/11, Pavel Emelyanov wrote:
>
> First of all - let's imagine that we just want to clone a set of tasks. Then
> each of them will have to fork its kids, then report first of them that he's
> OK to fork and wait for it to report back, that forking is done. Then do the
> same for the rest of them. This is not impossible, but painful.
Why we should wait/report? They can do this in parallel, only
"set_last_pid + fork" needs the synchronization or "check + retry".
> Next - let's consider we have some tasks sharing various resources, e.g. mm-s
> or fd-tables. This means, that these tasks should be cloned in the carefully
> calculated sequence with CLONE_XXX flags set. In this case the described above
> scheme with fork() serialization simply won't work and we'll have to invent
> some fancy messaging with "now X fork with Y pid" and "X done with forking,
> please go on" messages.
Can't understand...
Oleg.
next prev parent reply other threads:[~2011-11-11 16:52 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-10 17:15 [PATCH 0/3] Introduce the cloning with pids functionality Pavel Emelyanov
2011-11-10 17:15 ` [PATCH 1/3] pids: Make alloc_pid return error Pavel Emelyanov
2011-11-10 18:00 ` Oleg Nesterov
2011-11-11 10:02 ` Pavel Emelyanov
2011-11-10 17:15 ` [PATCH 2/3] pids: Split alloc_pidmap into parts Pavel Emelyanov
2011-11-10 18:12 ` Oleg Nesterov
2011-11-10 17:16 ` [PATCH 3/3] pids: Make it possible to clone tasks with given pids Pavel Emelyanov
2011-11-10 17:30 ` Tejun Heo
2011-11-10 17:36 ` Pavel Emelyanov
2011-11-10 17:45 ` Tejun Heo
2011-11-11 10:04 ` Pavel Emelyanov
2011-11-10 18:46 ` Oleg Nesterov
2011-11-10 18:56 ` Oleg Nesterov
2011-11-11 10:11 ` Pavel Emelyanov
2011-11-11 15:25 ` Oleg Nesterov
2011-11-11 15:58 ` Pavel Emelyanov
2011-11-11 16:06 ` Tejun Heo
2011-11-11 16:10 ` Tejun Heo
2011-11-11 16:18 ` Pavel Emelyanov
2011-11-11 16:22 ` Tejun Heo
2011-11-11 16:49 ` Pavel Emelyanov
2011-11-11 17:02 ` Tejun Heo
2011-11-11 17:13 ` Pavel Emelyanov
2011-11-13 19:28 ` Oleg Nesterov
2011-11-14 10:28 ` Pavel Emelyanov
2011-11-11 16:17 ` Pavel Emelyanov
2011-11-11 16:48 ` Oleg Nesterov [this message]
2011-11-11 16:39 ` Oleg Nesterov
2011-11-11 16:55 ` Pavel Emelyanov
2011-11-13 18:59 ` Oleg Nesterov
-- strict thread matches above, loose matches on Subject: below --
2011-11-17 11:41 [RFC][PATCH 0/3] fork: Add the ability to create " Pavel Emelyanov
2011-11-17 11:43 ` [PATCH 3/3] pids: Make it possible to clone " Pavel Emelyanov
2011-11-17 15:32 ` Oleg Nesterov
2011-11-17 15:49 ` Pavel Emelyanov
2011-11-17 16:00 ` Oleg Nesterov
2011-11-17 17:28 ` Linus Torvalds
2011-11-17 19:04 ` Oleg Nesterov
2011-11-17 18:36 ` Oleg Nesterov
2011-11-18 10:05 ` Pavel Emelyanov
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