Re: [PATCH -mm] autonuma: Fix scan period updating

[Mel Gorman]

On Mon, Jun 24, 2019 at 10:56:04AM +0800, Huang Ying wrote:
> The autonuma scan period should be increased (scanning is slowed down)
> if the majority of the page accesses are shared with other processes.
> But in current code, the scan period will be decreased (scanning is
> speeded up) in that situation.
> 
> This patch fixes the code.  And this has been tested via tracing the
> scan period changing and /proc/vmstat numa_pte_updates counter when
> running a multi-threaded memory accessing program (most memory
> areas are accessed by multiple threads).
> 

The patch somewhat flips the logic on whether shared or private is
considered and it's not immediately obvious why that was required. That
aside, other than the impact on numa_pte_updates, what actual
performance difference was measured and on on what workloads?

-- 
Mel Gorman
SUSE Labs