Re: [PATCH-cgroup 2/2] cgroup/cpuset: Include isolated cpuset CPUs in cpu_is_isolated() check

[Tejun Heo]

Hello,

On Sun, Nov 26, 2023 at 11:19:56PM -0500, Waiman Long wrote:
> +bool cpuset_cpu_is_isolated(int cpu)
> +{
> +	unsigned int seq;
> +	bool ret;
> +
> +	do {
> +		seq = read_seqcount_begin(&isolcpus_seq);
> +		ret = cpumask_test_cpu(cpu, isolated_cpus);
> +	} while (read_seqcount_retry(&isolcpus_seq, seq));
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(cpuset_cpu_is_isolated);

We're testing a bit in a bitmask. I don't think we need to worry about value
integrity from RMW updates being broken up. ie. We can just test the bit
without seqlock and drop the first patch?

Thanks.

-- 
tejun