Re: [PATCH] smp: Add bootcpus parameter to boot subset of CPUs

[Thomas Gleixner]

On Mon, Oct 26 2020 at 10:08, psodagud wrote:
> Based on my understanding with maxcpus option provides, maximum no of 
> CPUs are brough up during the device boot up. There is a different case, 
> in which we want to restrict which CPUs to be brough up.

Again: What for? Why?

> On a system with 8 cpus, if we set maxcpus as 3, cpu0, cpu1, and cpu2 
> are brough up during the bootup.  For example, if we want to bring 
> core0, core3 and core4 current maxcpu(as 3) setting would not help us.
> On some platform we want the flexibility on which CPUs to bring up 
> during the device bootup. bootcpus command line is helping to bring 
> specific CPUs and these patches are working downstream.

A lot of patches work downstream by some definition of work. But that
does not make an argument to bring them upstream.

Thanks,

        tglx