Re: [v3 9/9] s390: teach platforms not to zero struct pages memory

[Heiko Carstens]

On Fri, May 05, 2017 at 01:03:16PM -0400, Pavel Tatashin wrote:
> If we are using deferred struct page initialization feature, most of
> "struct page"es are getting initialized after other CPUs are started, and
> hence we are benefiting from doing this job in parallel. However, we are
> still zeroing all the memory that is allocated for "struct pages" using the
> boot CPU.  This patch solves this problem, by deferring zeroing "struct
> pages" to only when they are initialized on s390 platforms.
> 
> Signed-off-by: Pavel Tatashin <pasha.tatas...@oracle.com>
> Reviewed-by: Shannon Nelson <shannon.nel...@oracle.com>
> ---
>  arch/s390/mm/vmem.c |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
> index 9c75214..ffe9ba1 100644
> --- a/arch/s390/mm/vmem.c
> +++ b/arch/s390/mm/vmem.c
> @@ -252,7 +252,7 @@ int __meminit vmemmap_populate(unsigned long start, 
> unsigned long end, int node)
>                               void *new_page;
>  
>                               new_page = vmemmap_alloc_block(PMD_SIZE, node,
> -                                                            true);
> +                                                            VMEMMAP_ZERO);
>                               if (!new_page)
>                                       goto out;
>                               pmd_val(*pm_dir) = __pa(new_page) | sgt_prot;

If you add the hunk below then this is

Acked-by: Heiko Carstens <heiko.carst...@de.ibm.com>

diff --git a/arch/s390/mm/vmem.c b/arch/s390/mm/vmem.c
index ffe9ba1aec8b..bf88a8b9c24d 100644
--- a/arch/s390/mm/vmem.c
+++ b/arch/s390/mm/vmem.c
@@ -272,7 +272,7 @@ int __meminit vmemmap_populate(unsigned long start, 
unsigned long end, int node)
                if (pte_none(*pt_dir)) {
                        void *new_page;
 
-                       new_page = vmemmap_alloc_block(PAGE_SIZE, node, true);
+                       new_page = vmemmap_alloc_block(PAGE_SIZE, node, 
VMEMMAP_ZERO);
                        if (!new_page)
                                goto out;
                        pte_val(*pt_dir) = __pa(new_page) | pgt_prot;