On mips platform, hw PTE entry valid bit is set in pte_mkyoung function, it is used to set physical page with readable privilege. Here add pte_mkyoung function to make page readable on MIPS platform during page fault handling. This patch improves page fault latency about 10% on my MIPS machine with lmbench lat_pagefault case. Signed-off-by: Bibo Mao <maobibo@xxxxxxxxxxx> --- mm/memory.c | 3 +++ mm/mprotect.c | 2 ++ 2 files changed, 5 insertions(+) diff --git a/mm/memory.c b/mm/memory.c index 2eb59a9..2399dcb 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2704,6 +2704,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf) } flush_cache_page(vma, vmf->address, pte_pfn(vmf->orig_pte)); entry = mk_pte(new_page, vma->vm_page_prot); + entry = pte_mkyoung(entry); entry = maybe_mkwrite(pte_mkdirty(entry), vma); /* * Clear the pte entry and flush it first, before updating the @@ -3378,6 +3379,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf) __SetPageUptodate(page); entry = mk_pte(page, vma->vm_page_prot); + entry = pte_mkyoung(entry); if (vma->vm_flags & VM_WRITE) entry = pte_mkwrite(pte_mkdirty(entry)); @@ -3660,6 +3662,7 @@ vm_fault_t alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg, flush_icache_page(vma, page); entry = mk_pte(page, vma->vm_page_prot); + entry = pte_mkyoung(entry); if (write) entry = maybe_mkwrite(pte_mkdirty(entry), vma); /* copy-on-write page */ diff --git a/mm/mprotect.c b/mm/mprotect.c index 494192ca..673f1cd 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -131,6 +131,8 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, ptent = pte_clear_uffd_wp(ptent); } + if (vma->vm_flags & VM_READ) + ptent = pte_mkyoung(ptent); /* Avoid taking write faults for known dirty pages */ if (dirty_accountable && pte_dirty(ptent) && (pte_soft_dirty(ptent) || -- 1.8.3.1
