Re: [PATCH 1/3] mm: introduce VM_MAYBE_GUARD and make visible for guard regions

[Lorenzo Stoakes]

On Wed, Oct 29, 2025 at 12:50:18PM -0700, Randy Dunlap wrote:
>
> On 10/29/25 9:50 AM, Lorenzo Stoakes wrote:
>
> > diff --git a/mm/memory.c b/mm/memory.c
> > index 4c3a7e09a159..a2c79ee43d68 100644
> > --- a/mm/memory.c
> > +++ b/mm/memory.c
> > @@ -1478,6 +1478,10 @@ vma_needs_copy(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma)
> >  	if (src_vma->anon_vma)
> >  		return true;
> >
> > +	/* Guard regions have momdified page tables that require copying. */
>
> 	                      modified

I appear to have entered some kind of typo nirvana in this series it seems :)

Thanks, will fix!

>
> > +	if (src_vma->vm_flags & VM_MAYBE_GUARD)
> > +		return true;
> > +
> >  	/*
> >  	 * Don't copy ptes where a page fault will fill them correctly.  Fork
> >  	 * becomes much lighter when there are big shared or private readonly
> --
> ~Randy
>

Cheers, Lorenzo