Re: [PATCH 2/2] sched/topology: Expose numa_mask set/clear functions to arch

* Peter Zijlstra [off-list ref] [2018-08-31 13:26:39]:

On Fri, Aug 31, 2018 at 01:12:53PM +0200, Peter Zijlstra wrote:

quoted

NAK, not until you've fixed every cpu_to_node() user in the kernel to
deal with that mask changing.

Also, what happens if userspace reads that information; uses libnuma and
then you go and shift the world underneath their feet?

quoted

This is absolutely insane.

The topology events are suppose to be very rare.

From whatever small experiments I have done till now, unless tasks are

bound to both cpu and memory, they seem to be coping well with topology
updates. I know things weren't optimal after a topology change but they
worked. Now after 051f3ca02e46 "Introduce NUMA identity node sched
domain", systems stall. I am only exploring at ways to keep them working
as much as they were before that commit.

-- 
Thanks and Regards
Srikar Dronamraju