Re: [PATCH] cgroup/rstat: avoid disabling irqs for O(num_cpu)

[Tejun Heo]

On Wed, Mar 19, 2025 at 11:47:32AM +0100, Mateusz Guzik wrote:
...
> Is not this going a little too far?
> 
> the lock + irq trip is quite expensive in its own right and now is
> going to be paid for each cpu, as in the total time spent executing
> cgroup_rstat_flush_locked is going to go up.

Lock/unlock when the cacheline is already on the cpu is pretty cheap and on
modern x86 cpus at least irq on/off are also only a few cycles, so you
probably wouldn't be able to tell the difference.

Thanks.

-- 
tejun