From: Christoph Lameter <cl@gentwo.org>
To: Pavel Emelyanov <xemul@parallels.com>
Cc: Pekka Enberg <penberg@kernel.org>, Matt Mackall <mpm@selenic.com>,
linux-mm@kvack.org, Glauber Costa <glommer@parallels.com>,
Cyrill Gorcunov <gorcunov@openvz.org>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 0/5] Slab objects identifiers
Date: Fri, 7 Oct 2011 12:03:43 -0500 (CDT) [thread overview]
Message-ID: <alpine.DEB.2.00.1110071159540.11042@router.home> (raw)
In-Reply-To: <4E8DD5B9.4060905@parallels.com>
On Thu, 6 Oct 2011, Pavel Emelyanov wrote:
> While doing the checkpoint-restore in the userspace we need to determine
> whether various kernel objects (like mm_struct-s of file_struct-s) are shared
> between tasks and restore this state.
>
> The 2nd step can for now be solved by using respective CLONE_XXX flags and
> the unshare syscall, while there's currently no ways for solving the 1st one.
>
> One of the ways for checking whether two tasks share e.g. an mm_struct is to
> provide some mm_struct ID of a task to its proc file. The best from the
> performance point of view ID is the object address in the kernel, but showing
> them to the userspace is not good for performance reasons. Thus the ID should
> not be calculated based on the object address.
If two tasks share an mm_struct then the mm_struct pointer (task->mm) will
point to the same address. Objects are already uniquely identified by
their address. If you store the physical address with the object content
when transferring then you can verify that they share the mm_struct.
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next prev parent reply other threads:[~2011-10-07 17:03 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-06 16:22 Pavel Emelyanov
2011-10-06 16:23 ` [PATCH 1/5] slab: Tossing bits around Pavel Emelyanov
2011-10-06 16:23 ` [PATCH 2/5] slab_id: Generic slab ID infrastructure Pavel Emelyanov
2011-10-07 8:27 ` Glauber Costa
2011-10-07 8:31 ` Pavel Emelyanov
2011-10-06 16:23 ` [PATCH 3/5] slab_id: Slab support for IDs Pavel Emelyanov
2011-10-06 16:24 ` [PATCH 4/5] slab_id: Slub " Pavel Emelyanov
2011-10-06 16:24 ` [PATCH 5/5] slab_id: Show the task's mm ID in proc Pavel Emelyanov
2011-10-07 17:03 ` Christoph Lameter [this message]
2011-10-10 10:20 ` [PATCH 0/5] Slab objects identifiers Pavel Emelyanov
2011-10-10 15:24 ` Christoph Lameter
2011-10-10 15:46 ` Pavel Emelyanov
2011-10-13 7:12 ` Pekka Enberg
2011-10-13 11:25 ` Pavel Emelyanov
2011-10-13 12:12 ` Pekka Enberg
2011-10-13 12:23 ` Pavel Emelyanov
2011-10-10 18:59 ` Matt Helsley
2011-10-11 7:50 ` Pavel Emelyanov
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