diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 849f70af557f0e7ec0054bae43f395a90af5dcc9..4661441375ea92b99dd90da405610f845caa79e2 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -73,6 +73,8 @@ static DECLARE_WAIT_QUEUE_HEAD(khugepaged_wait);
* default collapse hugepages if there is at least one pte mapped like
* it would have happened if the vma was large enough during page
* fault.
+ *
+ * Note that these are only respected if collapse was initiated by khugepaged.
*/
static unsigned int khugepaged_max_ptes_none __read_mostly;
static unsigned int khugepaged_max_ptes_swap __read_mostly;
@@ -86,6 +88,8 @@ static struct kmem_cache *mm_slot_cache __read_mostly;
#define MAX_PTE_MAPPED_THP 8
struct collapse_control {
+ bool is_khugepaged;
+
/* Num pages scanned per node */
u32 node_load[MAX_NUMNODES];
@@ -554,6 +558,7 @@ static bool is_refcount_suitable(struct page *page)
static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
unsigned long address,
pte_t *pte,
+ struct collapse_control *cc,
struct list_head *compound_pagelist)
{
struct page *page = NULL;
@@ -566,8 +571,10 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
pte_t pteval = *_pte;
if (pte_none(pteval) || (pte_present(pteval) &&
is_zero_pfn(pte_pfn(pteval)))) {
+ ++none_or_zero;
if (!userfaultfd_armed(vma) &&
- ++none_or_zero <= khugepaged_max_ptes_none) {
+ (!cc->is_khugepaged ||
+ none_or_zero <= khugepaged_max_ptes_none)) {
continue;
} else {
result = SCAN_EXCEED_NONE_PTE;
@@ -587,11 +594,14 @@ 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) {
- result = SCAN_EXCEED_SHARED_PTE;
- count_vm_event(THP_SCAN_EXCEED_SHARED_PTE);
- goto out;
+ if (page_mapcount(page) > 1) {
+ ++shared;
+ if (cc->is_khugepaged &&
+ shared > khugepaged_max_ptes_shared) {
+ result = SCAN_EXCEED_SHARED_PTE;
+ count_vm_event(THP_SCAN_EXCEED_SHARED_PTE);
+ goto out;
+ }
}
if (PageCompound(page)) {
@@ -654,10 +664,14 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
if (PageCompound(page))
list_add_tail(&page->lru, compound_pagelist);
next:
- /* There should be enough young pte to collapse the page */
- if (pte_young(pteval) ||
- page_is_young(page) || PageReferenced(page) ||
- mmu_notifier_test_young(vma->vm_mm, address))
+ /*
+ * If collapse was initiated by khugepaged, check that there is
+ * enough young pte to justify collapsing the page
+ */
+ if (cc->is_khugepaged &&
+ (pte_young(pteval) || page_is_young(page) ||
+ PageReferenced(page) || mmu_notifier_test_young(vma->vm_mm,
+ address)))
referenced++;
if (pte_write(pteval))
@@ -666,7 +680,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
if (unlikely(!writable)) {
result = SCAN_PAGE_RO;
- } else if (unlikely(!referenced)) {
+ } else if (unlikely(cc->is_khugepaged && !referenced)) {
result = SCAN_LACK_REFERENCED_PAGE;
} else {
result = SCAN_SUCCEED;
@@ -745,6 +759,7 @@ static void khugepaged_alloc_sleep(void)
struct collapse_control khugepaged_collapse_control = {
+ .is_khugepaged = true,
.last_target_node = NUMA_NO_NODE,
};
@@ -1025,7 +1040,7 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address,
mmu_notifier_invalidate_range_end(&range);
spin_lock(pte_ptl);
- result = __collapse_huge_page_isolate(vma, address, pte,
+ result = __collapse_huge_page_isolate(vma, address, pte, cc,
&compound_pagelist);
spin_unlock(pte_ptl);
@@ -1116,7 +1131,9 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, struct vm_area_struct *vma,
_pte++, _address += PAGE_SIZE) {
pte_t pteval = *_pte;
if (is_swap_pte(pteval)) {
- if (++unmapped <= khugepaged_max_ptes_swap) {
+ ++unmapped;
+ if (!cc->is_khugepaged ||
+ unmapped <= khugepaged_max_ptes_swap) {
/*
* Always be strict with uffd-wp
* enabled swap entries. Please see
@@ -1134,8 +1151,10 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, struct vm_area_struct *vma,
}
}
if (pte_none(pteval) || is_zero_pfn(pte_pfn(pteval))) {
+ ++none_or_zero;
if (!userfaultfd_armed(vma) &&
- ++none_or_zero <= khugepaged_max_ptes_none) {
+ (!cc->is_khugepaged ||
+ none_or_zero <= khugepaged_max_ptes_none)) {
continue;
} else {
result = SCAN_EXCEED_NONE_PTE;
@@ -1165,11 +1184,14 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, struct vm_area_struct *vma,
goto out_unmap;
}
- if (page_mapcount(page) > 1 &&
- ++shared > khugepaged_max_ptes_shared) {
- result = SCAN_EXCEED_SHARED_PTE;
- count_vm_event(THP_SCAN_EXCEED_SHARED_PTE);
- goto out_unmap;
+ if (page_mapcount(page) > 1) {
+ ++shared;
+ if (cc->is_khugepaged &&
+ shared > khugepaged_max_ptes_shared) {
+ result = SCAN_EXCEED_SHARED_PTE;
+ count_vm_event(THP_SCAN_EXCEED_SHARED_PTE);
+ goto out_unmap;
+ }
}
page = compound_head(page);
@@ -1220,14 +1242,22 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, struct vm_area_struct *vma,
result = SCAN_PAGE_COUNT;
goto out_unmap;
}
- if (pte_young(pteval) ||
- page_is_young(page) || PageReferenced(page) ||
- mmu_notifier_test_young(vma->vm_mm, address))
+
+ /*
+ * If collapse was initiated by khugepaged, check that there is
+ * enough young pte to justify collapsing the page
+ */
+ if (cc->is_khugepaged &&
+ (pte_young(pteval) || page_is_young(page) ||
+ PageReferenced(page) || mmu_notifier_test_young(vma->vm_mm,
+ address)))
referenced++;
}
if (!writable) {
result = SCAN_PAGE_RO;
- } else if (!referenced || (unmapped && referenced < HPAGE_PMD_NR/2)) {
+ } else if (cc->is_khugepaged &&
+ (!referenced ||
+ (unmapped && referenced < HPAGE_PMD_NR / 2))) {
result = SCAN_LACK_REFERENCED_PAGE;
} else {
result = SCAN_SUCCEED;
@@ -1896,7 +1926,9 @@ static int khugepaged_scan_file(struct mm_struct *mm, struct file *file,
continue;
if (xa_is_value(page)) {
- if (++swap > khugepaged_max_ptes_swap) {
+ ++swap;
+ if (cc->is_khugepaged &&
+ swap > khugepaged_max_ptes_swap) {
result = SCAN_EXCEED_SWAP_PTE;
count_vm_event(THP_SCAN_EXCEED_SWAP_PTE);
break;
@@ -1947,7 +1979,8 @@ static int khugepaged_scan_file(struct mm_struct *mm, struct file *file,
rcu_read_unlock();
if (result == SCAN_SUCCEED) {
- if (present < HPAGE_PMD_NR - khugepaged_max_ptes_none) {
+ if (cc->is_khugepaged &&
+ present < HPAGE_PMD_NR - khugepaged_max_ptes_none) {
result = SCAN_EXCEED_NONE_PTE;
count_vm_event(THP_SCAN_EXCEED_NONE_PTE);
} else {