Re: [PATCH] per-cgroup tcp buffer limitation

From: Glauber Costa
Date: Tue Sep 13 2011 - 15:09:33 EST


On 09/13/2011 03:46 PM, Paul Menage wrote:
On Tue, Sep 13, 2011 at 11:11 AM, Glauber Costa<glommer@xxxxxxxxxxxxx> wrote:

What if they are all updated under the same lock ?

Right, that would be the kind of optimization that would remove the
need for worrying about whether or not to account it. It would
probably mean creating some memcg-specific structures like
res-counters that could handle multiple values, since you'd need to
update both the kernel charge and the total charge, in this cgroup
*and* its ancestors.

Paul
If we do that, we may have to commit to an intermediary user interface - with controls to to determine if kernel memory is billed to kernel or total, a enable/disable file, just to later render it pointless by a new optimization - that we seem to agree that seems possible.

I think it is preferred to always assume kernel memory is accounted to the kernel, and when we optimize it, no changes are made to what's exposed to userspace.
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