Christophe Leroy <christophe.le...@c-s.fr> writes:
> Function store_updates_sp() checks whether the faulting
> instruction is a store updating r1. Therefore we can limit its calls
> to stores exceptions.
>
> This patch is an improvement of commit a7a9dcd882a67 ("powerpc: Avoid
> taking a data miss on every userspace instruction miss")
>
> With the same microbenchmark app, run with 500 as argument, on an
> MPC885 we get:
>
> Before this patch: 152000 DTLB misses
> After this patch: 147000 DTLB misses
>
Reviewed-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com>
> Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr>
> ---
> arch/powerpc/mm/fault.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
> index 3a7d580fdc59..67fefb59d40e 100644
> --- a/arch/powerpc/mm/fault.c
> +++ b/arch/powerpc/mm/fault.c
> @@ -287,7 +287,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long
> address,
> * can result in fault, which will cause a deadlock when called with
> * mmap_sem held
> */
> - if (!is_exec && user_mode(regs))
> + if (is_write && user_mode(regs))
> store_update_sp = store_updates_sp(regs);
>
> if (user_mode(regs))
> --
> 2.12.0
