Thomas Gleixner [off-list ref] 于2019年6月25日周二 下午3:36写道：

MIng,

On Tue, 25 Jun 2019, Ming Lei wrote:

quoted

On Mon, Jun 24, 2019 at 05:42:39PM +0200, Thomas Gleixner wrote:

quoted

On Mon, 24 Jun 2019, Weiping Zhang wrote:

quoted

The driver may implement multiple affinity set, and some of
are empty, for this case we just skip them.

Why? What's the point of creating empty sets? Just because is not a real
good justification.

Patch 5 will add 4 new sets for supporting NVMe's weighted round robin
arbitration. It can be a headache to manage so many irq sets(now the total
sets can become 6) dynamically since size of anyone in the new 4 sets can
be zero, so each particular set is assigned one static index for avoiding
the management trouble, then empty set will be seen by
irq_create_affinity_masks().

So looks skipping the empty set makes sense because the API will become
easier to use than before.

Hello Ming,
Thanks your detail explanation.

That makes sense, but at least some of that information wants to be in the
change log and not some uninformative description of what the patch does.

I was not Cc'ed on the rest of the patches so I had exactly zero context.

Hello Thomas,

I am sorry I didn't cc you the full patchset, I will add more detail
description in
commit message at V4.

Thanks,

        tglx