Re: [PATCH 0/3] x86: add cpuset_scnprintf function

Paul Jackson
2008-04-02T10:40:01Z

Mike wrote:
> I wanted to not break current apps unmercifully, but perhaps I should
> default it to the "non-compatible" mode (and adjust the schedstat version
> to indicate this)? [It's the only output that I found that seemed to care.]

It doesn't matter which way you set the default. My concerns apply
either way. I don't think your reply addressed my concerns.

> I know if I'm a user and I'm really interested in understanding
> the outputs when there's hundreds and hundreds of cpus, then the
> more compact format is much more useful.

That's not sufficient reason to change an API visible across the
kernel-user boundary.

> Plus I was under the impression that one of the basic tenets of Linux
> was that API's can and will change?

Kernel internals have a relatively lower barrier to API changes.

Kernel API's visible to kernel drivers or loadable modules have a
higher barrier to change.

Kernel API's visible to user space, such as this one, have a much
higher barrier to incompatible change.

I hesitate to NAQ patches because I strike out more often than someone
like Al Viro. But I'm getting tempted on this one.

Perhaps you could write yourself a user utility that scanned its input
for masks in legacy format, converted them to list format, and passed
all else unscathed?

--
I won't rest till it's the best ...
Programmer, Linux Scalability
Paul Jackson <pj@sgi.com> 1.940.382.4214