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

[Andrew Morton]

On Wed, 19 Aug 2026 06:18:58 +0800 Lance Yang <lance.yang@xxxxxxxxx> 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).
> 
> Since cond_resched() is a scheduling no-op under LAZY/FULL anyway (only
> the __might_resched() debug check remains), why not take this upstream
> with Cc: stable?

I think so - as long as PREEPMT_NONE exists we should support it as
well as we can.  If the day comes that PREEMPT_NONE is removed, then we
get to remove lots of cond_resched()s.  mm/ has 200 of the things.

> Mainline scheduling stays unchanged, and stable can pick it up for old
> PREEMPT_NONE kernels. wdyt?

Addressing this issue in older kernels is another reason.