Re: [PATCH v8 10/12] blk-mq: use hk cpus only when isolcpus=io_queue is enabled

[Daniel Wagner]

On Mon, Sep 08, 2025 at 09:51:34AM +0200, Hannes Reinecke wrote:
> Wouldn't it be better to call 'cpumask_zero' before 'cpumask_and'?

I don't think this is necessary, from the docs :

  cpumask_and - *dstp = *src1p & *src2p

cpumask_and call bitmap_and which is:

static __always_inline
bool bitmap_and(unsigned long *dst, const unsigned long *src1,
		const unsigned long *src2, unsigned int nbits)
{
	if (small_const_nbits(nbits))
		return (*dst = *src1 & *src2 & BITMAP_LAST_WORD_MASK(nbits)) != 0;
	return __bitmap_and(dst, src1, src2, nbits);
}