Re: [PATCH 19/27] mm: Move vmscan writes and file write accounting to the node

[Mel Gorman]

On Wed, Jun 22, 2016 at 04:40:39PM +0200, Michal Hocko wrote:
> On Tue 21-06-16 15:15:58, Mel Gorman wrote:
> > As reclaim is now node-based, it follows that page write activity
> > due to page reclaim should also be accounted for on the node. For
> > consistency, also account page writes and page dirtying on a per-node
> > basis.
> > 
> > After this patch, there are a few remaining zone counters that may
> > appear strange but are fine. NUMA stats are still per-zone as this is a
> > user-space interface that tools consume. NR_MLOCK, NR_SLAB_*, NR_PAGETABLE,
> > NR_KERNEL_STACK and NR_BOUNCE are all allocations that potentially pin
> > low memory and cannot trivially be reclaimed on demand. This information
> > is still useful for debugging a page allocation failure warning.
> 
> As I've said in other patch. I think we will need to provide
> /proc/nodeinfo to fill the gap.
> 

I added a patch on top that prints the node stats in zoneinfo but only
once for the first populated zone in a node. Doing this or creating a
new file are both potentially surprising but extending zoneinfo means
there is a greater chance that a user will spot the change.

-- 
Mel Gorman
SUSE Labs