On 2024/4/17 16:23, Kefeng Wang wrote:
Directly call vmf_orig_pte_uffd_wp() in do_anonymous_page() and
set_pte_range() to save a uffd_wp and add userfaultfd_wp() check
in vmf_orig_pte_uffd_wp() to avoid the unnecessary function calls
in the most sense, lat_pagefault testcase does show improvement
though very small(~1%).
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
mm/memory.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index 5ae2409d3cb9..a6afc96001e6 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -117,6 +117,9 @@ static bool vmf_orig_pte_uffd_wp(struct vm_fault *vmf)
if (!IS_ENABLED(CONFIG_PTE_MARKER_UFFD_WP))
return false;
Will add config check too,
if (!(vmf->flags & FAULT_FLAG_ORIG_PTE_VALID))
return false;
+ if (!userfaultfd_wp(vmf->vma))
+ return false;
+
but wait for review.
return pte_marker_uffd_wp(vmf->orig_pte);
}
@@ -4388,7 +4391,6 @@ static struct folio *alloc_anon_folio(struct vm_fault *vmf)
*/
static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
{
- bool uffd_wp = vmf_orig_pte_uffd_wp(vmf);
struct vm_area_struct *vma = vmf->vma;
unsigned long addr = vmf->address;
struct folio *folio;
@@ -4488,7 +4490,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
folio_add_new_anon_rmap(folio, vma, addr);
folio_add_lru_vma(folio, vma);
setpte:
- if (uffd_wp)
+ if (vmf_orig_pte_uffd_wp(vmf))
entry = pte_mkuffd_wp(entry);
set_ptes(vma->vm_mm, addr, vmf->pte, entry, nr_pages);
@@ -4663,7 +4665,6 @@ void set_pte_range(struct vm_fault *vmf, struct folio *folio,
struct page *page, unsigned int nr, unsigned long addr)
{
struct vm_area_struct *vma = vmf->vma;
- bool uffd_wp = vmf_orig_pte_uffd_wp(vmf);
bool write = vmf->flags & FAULT_FLAG_WRITE;
bool prefault = in_range(vmf->address, addr, nr * PAGE_SIZE);
pte_t entry;
@@ -4678,7 +4679,7 @@ void set_pte_range(struct vm_fault *vmf, struct folio *folio,
if (write)
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
- if (unlikely(uffd_wp))
+ if (unlikely(vmf_orig_pte_uffd_wp(vmf)))
entry = pte_mkuffd_wp(entry);
/* copy-on-write page */
if (write && !(vma->vm_flags & VM_SHARED)) {
