Re: [PATCH v2 2/3] vmstat: skip periodic vmstat update for nohz full CPUs

[Marcelo Tosatti]

On Mon, Jun 05, 2023 at 08:57:15PM +0200, Michal Hocko wrote:
> > Guest initiated I/O, since the host CPU is isolated.
> 
> Make it explicit in the changelog.

I think better use of our time would be to focus on

https://lkml.iu.edu/hypermail/linux/kernel/2209.1/01263.html

1) Operate in terms of add CPU, remove CPU on sysfs (to avoid races).
2) Don't allow all CPUs to be marked as "block_interf".
3) Remove percpu rwsem lock.

> I am just wondering how you can achieve your strict deadlines when IO is
> involved but that is another story I guess.

IO can be submitted when the ELF binary and libraries are read
from the virtual disk, for example.