Re: [POC][RFC][PATCH v2] sched: Extended Scheduler Time Slice

[Steven Rostedt]

On Thu, 26 Oct 2023 14:59:13 -0400
Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> wrote:

> > for a rough implementation of a 'xchg()' without SMP coherency, just
> > cpu-local one (ie atomic wrt being preempted by the kernel, but not
> > atomic wrt other CPU's accessing the same variable concurrently)  
> 
> Actually Steven does not need a xchg to test-and-set a single bit which
> is only accessed concurrently between kernel and userspace from the same
> thread. Either "bts" or "andb" should work fine.

Hmm, how would bts work? Doesn't that just set a bit?

I need to clear one bit while seeing if another bit is set. I could also
use subl, as that would also atomically clear the bit.

-- Steve