Re: [PATCH] hugetlb: add cond_resched() to __unmap_hugepage_range()

[Michal Hocko]

On Wed 19-08-26 09:53:25, David Hildenbrand wrote:
> On 8/18/26 20:55, Andrew Morton wrote:
> > On Tue, 18 Aug 2026 20:21:37 +0200 "David Hildenbrand (Arm)" <david@xxxxxxxxxx> wrote:
> > 
> >>>
> >>> That's pretty bad behavior and we might want to fix it in earlier
> >>> kernels.  Is PREEMPT_NONE effectively dead in 6.18.x and its
> >>> existing users?
> >>>
> >>> If yes, we do want to fix older kernels then we should merge this.
> >>>
> >>
> >> Okay, but that would be stable-only fixes?
> > 
> > Not understanding.
> > 
> > Maybe you refer to adding a patch to -stable but not to -linus?  That's
> > against the -stable rules
> > (Documentation/process/stable-kernel-rules.rst).
> 
> It's tricky: if a problem only exists in stable (there is nothing to fix in
> Linus' tree), then a stable-only fix is acceptable.

The crucial quiestion is whether this is something that needs a code fix
or a configuration fix. Really fighting for low latencies with
PREEMPT_NONE is a kinda lost battle. You might want to play whack a
mole...

-- 
Michal Hocko
SUSE Labs