Re: [RFC 08/20] mm: store completed TLB generation

[Peter Zijlstra <peterz@xxxxxxxxxxxxx>]

On Sat, Jan 30, 2021 at 04:11:20PM -0800, Nadav Amit wrote:
> +static inline void tlb_update_generation(atomic64_t *gen, u64 new_gen)
> +{
> +	u64 cur_gen = atomic64_read(gen);
> +
> +	while (cur_gen < new_gen) {
> +		u64 old_gen = atomic64_cmpxchg(gen, cur_gen, new_gen);
> +
> +		/* Check if we succeeded in the cmpxchg */
> +		if (likely(cur_gen == old_gen))
> +			break;
> +
> +		cur_gen = old_gen;
> +	};
> +}

	u64 cur_gen = atomic64_read(gen);
	while (cur_gen < new_gen && !atomic64_try_cmpxchg(gen, &cur_gen, new_gen))
		;