[Devel] Re: [PATCH 00/11] kmem controller for memcg: stripped down version
glommer at parallels.com
Wed Jun 27 01:39:54 PDT 2012
On 06/27/2012 05:08 AM, David Rientjes wrote:
> On Tue, 26 Jun 2012, Andrew Morton wrote:
>> mm, maybe. Kernel developers tend to look at code from the point of
>> view "does it work as designed", "is it clean", "is it efficient", "do
>> I understand it", etc. We often forget to step back and really
>> consider whether or not it should be merged at all.
> It's appropriate for true memory isolation so that applications cannot
> cause an excess of slab to be consumed. This allows other applications to
> have higher reservations without the risk of incurring a global oom
> condition as the result of the usage of other memcgs.
Just a note for Andrew, we we're in the same page: The slab cache
limitation is not included in *this* particular series. The goal was
always to have other kernel resources limited as well, and the general
argument from David holds: we want a set of applications to run truly
independently from others, without creating memory pressure on the
The way history develop in this series, I started from the slab cache,
and a page-level tracking appeared on that series. I then figured it
would be better to start tracking something that is totally page-based,
such as the stack - that already accounts for 70 % of the
infrastructure, and then merge the slab code later. In this sense, it
was just a strategy inversion. But both are, and were, in the goals.
> I'm not sure whether it would ever be appropriate to limit the amount of
> slab for an individual slab cache, however, instead of limiting the sum of
> all slab for a set of processes. With cache merging in slub this would
> seem to be difficult to do correctly.
Yes, I do agree.
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