Re: [RFC-PATCH 1/2] mm: Add __GFP_NO_LOCKS flag

[Michal Hocko]

On Thu 13-08-20 20:31:21, Peter Zijlstra wrote:
> On Thu, Aug 13, 2020 at 09:29:04AM -0700, Paul E. McKenney wrote:
[...]
> > 3.	Reusing existing GFP_ flags/values/whatever to communicate
> > 	the raw-context information that was to be communicated by
> > 	the new GFP_ flag.
> > 
> > 4.	Making lockdep forgive acquiring spinlocks while holding
> > 	raw spinlocks, but only in CONFIG_PREEMPT_NONE=y kernels.
> > 
> > Am I missing anything?
> 
> How would 4 solve anything?

Nothing on its own but along with http://lkml.kernel.org/r/20200813075027.GD9477@xxxxxxxxxxxxxx
it would allow at least _some_ NOWAIT semantic for RT atomic contexts
and prevent from lockdep false positives for !RT trees.
-- 
Michal Hocko
SUSE Labs