Re: [PATCH] x86,tlb: update mm_cpumask lazily

[Dave Hansen]

On 11/8/24 11:31, Rik van Riel wrote:
>  		/* Start receiving IPIs and then read tlb_gen (and LAM below) */
> -		if (next != &init_mm)
> +		if (next != &init_mm && !cpumask_test_cpu(cpu, mm_cpumask(next)))
>  			cpumask_set_cpu(cpu, mm_cpumask(next));
>  		next_tlb_gen = atomic64_read(&next->context.tlb_gen);

If we're worried about contention on mm_cpumask(), then this hunk makes
sense independently of the lazy updating. We might want to take this
hunk forward before we do the rest because this seems like a no-brainer.