From 68662f85f3c3ea8a6fb61586a05955ab51bbb9e6 Mon Sep 17 00:00:00 2001
From: Nicholas Piggin <npiggin@gmail.com>
Date: Fri, 1 Jun 2018 20:01:18 +1000
Subject: [PATCH] powerpc/64s/radix: prefetch user address in update_mmu_cache
References: bsc#1055117
Patch-mainline: v4.18-rc1
Git-commit: 68662f85f3c3ea8a6fb61586a05955ab51bbb9e6
Prefetch the faulting address in update_mmu_cache to give the page
table walker perhaps 100 cycles head start as locks are dropped and
the interrupt completed.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
arch/powerpc/mm/mem.c | 4 +++-
arch/powerpc/mm/pgtable-book3s64.c | 3 ++-
2 files changed, 5 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index c3c39b02b2ba..8cecda4bd66a 100644
--- a/arch/powerpc/mm/mem.c
+++ b/arch/powerpc/mm/mem.c
@@ -509,8 +509,10 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address,
*/
unsigned long access, trap;
- if (radix_enabled())
+ if (radix_enabled()) {
+ prefetch((void *)address);
return;
+ }
/* We only want HPTEs for linux PTEs that have _PAGE_ACCESSED set */
if (!pte_young(*ptep) || address >= TASK_SIZE)
diff --git a/arch/powerpc/mm/pgtable-book3s64.c b/arch/powerpc/mm/pgtable-book3s64.c
index 82fed87289de..c1f4ca45c93a 100644
--- a/arch/powerpc/mm/pgtable-book3s64.c
+++ b/arch/powerpc/mm/pgtable-book3s64.c
@@ -152,7 +152,8 @@ pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
void update_mmu_cache_pmd(struct vm_area_struct *vma, unsigned long addr,
pmd_t *pmd)
{
- return;
+ if (radix_enabled())
+ prefetch((void *)addr);
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
--
2.21.0