lkml.org 
[lkml]   [2006]   [Oct]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [ckrm-tech] RFC: Memory Controller
On 10/31/06, Balbir Singh <balbir@in.ibm.com> wrote:
>
> I am still a little concerned about how limit size changes will be implemented.
> Will the cpuset "mems" field change to reflect the changed limits?

That's how we've been doing it - increasing limits is easy, shrinking
them is harder ...

> > Page cache control is actually more essential that RSS control, in our
> > experience - it's pretty easy to track RSS values from userspace, and
> > react reasonably quickly to kill things that go over their limit, but
> > determining page cache usage (i.e. determining which job on the system
> > is flooding the page cache with dirty buffers) is pretty much
> > impossible currently.
> >
>
> Hmm... interesting. Why do you think its impossible, what are the kinds of
> issues you've run into?
>

Issues such as:

- determining from userspace how much of the page cache is really
"free" memory that can be given out to new jobs without impacting the
performance of existing jobs

- determining which job on the system is flooding the page cache with
dirty buffers

- accounting the active pagecache usage of a job as part of its memory
footprint (if a process is only 1MB large but is seeking randomly
through a 1GB file, treating it as only using/needing 1MB isn't
practical).

Paul
-
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: 2006-10-31 18:25    [W:2.128 / U:0.004 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site