[PATCH v2 6/7] powerpc/64s/radix: prefetch user address in update_mmu_cache
From: Nicholas Piggin <npiggin@gmail.com>
Date: 2018-05-20 00:44:13
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
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> --- 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 994492453f0e..7ce889a7e5ce 100644
--- a/arch/powerpc/mm/pgtable-book3s64.c
+++ b/arch/powerpc/mm/pgtable-book3s64.c@@ -145,7 +145,8 @@ 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 */
--
2.17.0