lkml.org 
[lkml]   [2016]   [Jun]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 01/27] mm, vmstat: Add infrastructure for per-node vmstats
On Mon, Jun 13, 2016 at 12:26:13PM -0500, Christoph Lameter wrote:
> On Thu, 9 Jun 2016, Mel Gorman wrote:
>
> > VM statistic counters for reclaim decisions are zone-based. If the kernel
> > is to reclaim on a per-node basis then we need to track per-node statistics
> > but there is no infrastructure for that. The most notable change is that
>
> There is node_page_state() so the value of any counter per node is already
> available. Note that some of the counters (NUMA_xx) for example do not
> make much sense as per zone counters and are effectively used as per node
> counters.
>
> So the main effect you are looking for is to have the counters stored in
> the per node structure as opposed to the per zone struct in order to
> avoid the summing?

Yes.

> Doing so duplicates a large amount of code it seems.
>

Also yes. I considered macro magic to cover it but it turned into a
major mess. They could always be summed so it would be a minor
performance dent and a heavier cache footprint.

> If you do this then also move over certain counters that have more of a
> per node use from per zone to per node. Like the NUMA_xxx counters.
>

As the NUMA counters are consumed by userspace, I worried that it would
break some tools. If the rest of the series gets solidified then I will
do it as a single patch on top so it can be reverted if necessary
relatively easily.

--
Mel Gorman
SUSE Labs

\
 
 \ /
  Last update: 2016-06-14 17:01    [W:0.086 / U:0.092 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site