lkml.org 
[lkml]   [2006]   [Aug]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] BC: resource beancounters (v2)
On Fri, 25 Aug 2006 15:49:15 +0400
Kirill Korotaev <dev@sw.ru> wrote:

> > We need to go over this work before we can commit to the BC
> > core. Last time I looked at the VM accounting patch it
> > seemed rather unpleasing from a maintainability POV.
> hmmm... in which regard?

Little changes all over the MM code which might get accidentally broken.

> > And, if I understand it correctly, the only response to a job
> > going over its VM limits is to kill it, rather than trimming
> > it. Which sounds like a big problem?
> No, UBC virtual memory management refuses occur on mmap()'s.

That's worse, isn't it? Firstly it rules out big sparse mappings and secondly

mmap_and_use(80% of container size)
fork_and_immediately_exec(/bin/true)

will fail at the fork?


> Andrey Savochkin wrote already a brief summary on vm resource management:
>
> ------------- cut ----------------
> The task of limiting a container to 4.5GB of memory bottles down to the
> question: what to do when the container starts to use more than assigned
> 4.5GB of memory?
>
> At this moment there are only 3 viable alternatives.
>
> A) Have separate memory management for each container,
> with separate buddy allocator, lru lists, page replacement mechanism.
> That implies a considerable overhead, and the main challenge there
> is sharing of pages between these separate memory managers.
>
> B) Return errors on extension of mappings, but not on page faults, where
> memory is actually consumed.
> In this case it makes sense to take into account not only the size of used
> memory, but the size of created mappings as well.
> This is approximately what "privvmpages" accounting/limiting provides in
> UBC.
>
> C) Rely on OOM killer.
> This is a fall-back method in UBC, for the case "privvmpages" limits
> still leave the possibility to overload the system.
>

D) Virtual scan of mm's in the over-limit container

E) Modify existing physical scanner to be able to skip pages which
belong to not-over-limit containers.

F) Something else ;)


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-08-25 16:33    [W:0.116 / U:29.168 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site