From: Guo Ren <guoren@xxxxxxxxxxxxxxxxx> C-SKY MMU would pre-fetch invalid pte entries, and it could work with flush_tlb_fix_spurious_fault, but the additional page fault exceptions would reduce performance. So flushing the entry of the TLB would prevent the following spurious page faults. Here is the test code: define DATA_LEN 4096 define COPY_NUM (504*100) unsigned char src[DATA_LEN*COPY_NUM] = {0}; unsigned char dst[DATA_LEN*COPY_NUM] = {0}; unsigned char func_src[DATA_LEN*COPY_NUM] = {0}; unsigned char func_dst[DATA_LEN*COPY_NUM] = {0}; void main(void) { int j; for (j = 0; j < COPY_NUM; j++) memcpy(&dst[j*DATA_LEN], &src[j*DATA_LEN], 4); } perf stat -e page-faults ./main.elf The amount of page fault traps would be reduced in half with the patch. Signed-off-by: Guo Ren <guoren@xxxxxxxxxxxxxxxxx> Signed-off-by: Guo Ren <guoren@xxxxxxxxxx> --- arch/csky/abiv1/cacheflush.c | 2 ++ arch/csky/abiv2/cacheflush.c | 2 ++ 2 files changed, 4 insertions(+) diff --git a/arch/csky/abiv1/cacheflush.c b/arch/csky/abiv1/cacheflush.c index fb91b069dc69..6f38cc7944e1 100644 --- a/arch/csky/abiv1/cacheflush.c +++ b/arch/csky/abiv1/cacheflush.c @@ -40,6 +40,8 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long addr, unsigned long pfn = pte_pfn(*ptep); struct page *page; + flush_tlb_page(vma, addr); + if (!pfn_valid(pfn)) return; diff --git a/arch/csky/abiv2/cacheflush.c b/arch/csky/abiv2/cacheflush.c index 39c51399dd81..ff39c897c820 100644 --- a/arch/csky/abiv2/cacheflush.c +++ b/arch/csky/abiv2/cacheflush.c @@ -12,6 +12,8 @@ void update_mmu_cache(struct vm_area_struct *vma, unsigned long address, unsigned long addr; struct page *page; + flush_tlb_page(vma, address); + if (!pfn_valid(pte_pfn(*pte))) return; -- 2.36.1