Re: [PATCH 3/5] mm/vmstat: use cmpxchg loop in cpu_vm_stats_fold

Christoph Lameter
2023-02-02T14:39:36Z

On Wed, 1 Feb 2023, Marcelo Tosatti wrote:

> In preparation to switch vmstat shepherd to flush
> per-CPU counters remotely, use a cmpxchg loop
> instead of a pair of read/write instructions.

You are mixing full atomic cmpxchg and per cpu atomic cmpxchg? That does
not work.

I thought you would only run this while the kernel is not active on the
remote cpu? Then you dont need any cmpxchg and you can leave the function
as is.