lkml.org 
[lkml]   [2011]   [Dec]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCHSET] block, mempool, percpu: implement percpu mempool and fix blkcg percpu alloc deadlock
Hello, Andrew.

On Tue, Dec 27, 2011 at 02:21:56PM -0800, Andrew Morton wrote:
> <autorepeat>For those users who don't want the stats, stats shouldn't
> consume any resources at all.

Hmmm.... For common use cases - a few cgroups doing IOs to most likely
single physical device and maybe a couple virtual ones, I don't think
this would show up anywhere both in terms of memory and process
overhead. While avoding it would be nice, I don't think that should
be the focus of optimization or design decisions.

> And I bet that the majority of the minority who want stats simply want
> to know "how much IO is this cgroup doing", and don't need per-cgroup,
> per-device accounting.
>
> And it could be that the minority of the minority who want per-device,
> per-cgroup stats only want those for a minority of the time.
>
> IOW, what happens if we give 'em atomic_add() and be done with it?

I really don't know. That surely is an enticing idea tho. Jens,
Vivek, can you guys chime in? Is gutting out (or drastically
simplifying) cgroup-dev stats an option? Are there users who are
actually interested in this stuff?

Thanks.

--
tejun


\
 
 \ /
  Last update: 2011-12-27 23:33    [W:0.070 / U:0.268 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site