[linux-next PATCH 1/2] mm: khugepaged: add exceed_max_ptes_* helpers

Yang Shi
2020-04-29T22:56:36Z

The max_ptes_{swap|none|shared} are defined to tune the behavior of
khugepaged. The are checked at a couple of places with open coding.
Replace the opencoding to exceed_pax_ptes_{swap|none_shared} helpers to
improve the readability.

Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
---
mm/khugepaged.c | 27 +++++++++++++++++++++------
1 file changed, 21 insertions(+), 6 deletions(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index a02a4c5..0c8d30b 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -339,6 +339,21 @@ struct attribute_group khugepaged_attr_group = {
};
#endif /* CONFIG_SYSFS */

+static inline bool exceed_max_ptes_none(unsigned int *nr_ptes)
+{
+ return (++(*nr_ptes) > khugepaged_max_ptes_none);
+}
+
+static inline bool exceed_max_ptes_swap(unsigned int *nr_ptes)
+{
+ return (++(*nr_ptes) > khugepaged_max_ptes_swap);
+}
+
+static inline bool exceed_max_ptes_shared(unsigned int *nr_ptes)
+{
+ return (++(*nr_ptes) > khugepaged_max_ptes_shared);
+}
+
int hugepage_madvise(struct vm_area_struct *vma,
unsigned long *vm_flags, int advice)
{
@@ -604,7 +619,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
if (pte_none(pteval) || (pte_present(pteval) &&
is_zero_pfn(pte_pfn(pteval)))) {
if (!userfaultfd_armed(vma) &&
- ++none_or_zero <= khugepaged_max_ptes_none) {
+ !exceed_max_ptes_none(&none_or_zero)) {
continue;
} else {
result = SCAN_EXCEED_NONE_PTE;
@@ -624,7 +639,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
VM_BUG_ON_PAGE(!PageAnon(page), page);

if (page_mapcount(page) > 1 &&
- ++shared > khugepaged_max_ptes_shared) {
+ exceed_max_ptes_shared(&shared)) {
result = SCAN_EXCEED_SHARED_PTE;
goto out;
}
@@ -1234,7 +1249,7 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
_pte++, _address += PAGE_SIZE) {
pte_t pteval = *_pte;
if (is_swap_pte(pteval)) {
- if (++unmapped <= khugepaged_max_ptes_swap) {
+ if (!exceed_max_ptes_swap(&unmapped)) {
/*
* Always be strict with uffd-wp
* enabled swap entries. Please see
@@ -1252,7 +1267,7 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
}
if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) {
if (!userfaultfd_armed(vma) &&
- ++none_or_zero <= khugepaged_max_ptes_none) {
+ !exceed_max_ptes_none(&none_or_zero)) {
continue;
} else {
result = SCAN_EXCEED_NONE_PTE;
@@ -1286,7 +1301,7 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
}

if (page_mapcount(page) > 1 &&
- ++shared > khugepaged_max_ptes_shared) {
+ exceed_max_ptes_shared(&shared)) {
result = SCAN_EXCEED_SHARED_PTE;
goto out_unmap;
}
@@ -1961,7 +1976,7 @@ static void khugepaged_scan_file(struct mm_struct *mm,
continue;

if (xa_is_value(page)) {
- if (++swap > khugepaged_max_ptes_swap) {
+ if (exceed_max_ptes_swap(&swap)) {
result = SCAN_EXCEED_SWAP_PTE;
break;
}
--
1.8.3.1