Re: [PATCH -mm] autonuma: Fix scan period updating
From: Mel Gorman
Date: Mon Jun 24 2019 - 10:09:56 EST
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?