Re: [PATCH 07/13] s390: make setup_zero_pages() use memblock

[Mike Rapoport <rppt@kernel.org>]

On Wed, Mar 12, 2025 at 04:56:59PM +0100, Ard Biesheuvel wrote:
> On Tue, 11 Mar 2025 at 06:56, Mike Rapoport <rppt@kernel.org> wrote:
> >
> > On Fri, Mar 07, 2025 at 04:28:15PM +0100, Heiko Carstens wrote:
> > > On Thu, Mar 06, 2025 at 08:51:17PM +0200, Mike Rapoport wrote:
> > > > From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
> > > >
> > > > Allocating the zero pages from memblock is simpler because the memory is
> > > > already reserved.
> > > >
> > > > This will also help with pulling out memblock_free_all() to the generic
> > > > code and reducing code duplication in arch::mem_init().
> > > >
> > > > Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> > > > ---
> > > >  arch/s390/mm/init.c | 14 +++-----------
> > > >  1 file changed, 3 insertions(+), 11 deletions(-)
> > >
> > > Acked-by: Heiko Carstens <hca@linux.ibm.com>
> > >
> > > > -   empty_zero_page = __get_free_pages(GFP_KERNEL | __GFP_ZERO, order);
> > > > +   empty_zero_page = (unsigned long)memblock_alloc(PAGE_SIZE << order, order);
> > > >     if (!empty_zero_page)
> > > >             panic("Out of memory in setup_zero_pages");
> > >
> > > This could have been converted to memblock_alloc_or_panic(), but I
> > > guess this can also be done at a later point in time.
> >
> > Duh, I should have remembered about memblock_alloc_or_panic() :)
> >
> > @Andrew, can you please pick this as a fixup?
> >
> > From 344fec8519e5152c25809c9277b54a68f9cde0e9 Mon Sep 17 00:00:00 2001
> > From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
> > Date: Tue, 11 Mar 2025 07:51:27 +0200
> > Subject: [PATCH] s390: use memblock_alloc_or_panic() in setup_zero_page()
> >
> > Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> > ---
> >  arch/s390/mm/init.c | 4 +---
> >  1 file changed, 1 insertion(+), 3 deletions(-)
> >
> > diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
> > index ab8ece3c41f1..c6a97329d7e7 100644
> > --- a/arch/s390/mm/init.c
> > +++ b/arch/s390/mm/init.c
> > @@ -81,9 +81,7 @@ static void __init setup_zero_pages(void)
> >         while (order > 2 && (total_pages >> 10) < (1UL << order))
> >                 order--;
> >
> > -       empty_zero_page = (unsigned long)memblock_alloc(PAGE_SIZE << order, order);
> > -       if (!empty_zero_page)
> > -               panic("Out of memory in setup_zero_pages");
> > +       empty_zero_page = (unsigned long)memblock_alloc_or_panic(PAGE_SIZE << order, order);
> >
> 
> memblock_alloc_or_panic() takes the alignment is in bytes, no? So
> shouldn't the second argument be BIT(order)?

The second argument should be PAGE_SIZE. Thanks for catching that!

-- 
Sincerely yours,
Mike.