Replaces 5 calls to compound_head(), and removes 1466 bytes of kernel
text.
Previously, to determine if any pte was shared, the page mapcount
corresponding exactly to the pte was checked. This gave us a precise
number of shared ptes. Using folio_estimated_sharers() instead uses
the mapcount of the head page, giving us an estimate for tail page ptes.
This means if a tail page's mapcount is greater than its head page's
mapcount, folio_estimated_sharers() would be underestimating the number of
shared ptes, and vice versa.
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@xxxxxxxxx>
---
mm/khugepaged.c | 26 ++++++++++++--------------
1 file changed, 12 insertions(+), 14 deletions(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 7a552fe16c92..67aac53b31c8 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1245,7 +1245,7 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm,
pte_t *pte, *_pte;
int result = SCAN_FAIL, referenced = 0;
int none_or_zero = 0, shared = 0;
- struct page *page = NULL;
+ struct folio *folio = NULL;
unsigned long _address;
spinlock_t *ptl;
int node = NUMA_NO_NODE, unmapped = 0;
@@ -1316,13 +1316,13 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm,
if (pte_write(pteval))
writable = true;
- page = vm_normal_page(vma, _address, pteval);
- if (unlikely(!page) || unlikely(is_zone_device_page(page))) {
+ folio = vm_normal_folio(vma, _address, pteval);
+ if (unlikely(!folio) || unlikely(folio_is_zone_device(folio))) {
result = SCAN_PAGE_NULL;
goto out_unmap;
}
- if (page_mapcount(page) > 1) {
+ if (folio_estimated_sharers(folio) > 1) {
++shared;
if (cc->is_khugepaged &&
shared > khugepaged_max_ptes_shared) {
@@ -1332,29 +1332,27 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm,
}
}
- page = compound_head(page);
-
/*
* Record which node the original page is from and save this
* information to cc->node_load[].
* Khugepaged will allocate hugepage from the node has the max
* hit record.
*/
- node = page_to_nid(page);
+ node = folio_nid(folio);
if (hpage_collapse_scan_abort(node, cc)) {
result = SCAN_SCAN_ABORT;
goto out_unmap;
}
cc->node_load[node]++;
- if (!PageLRU(page)) {
+ if (!folio_test_lru(folio)) {
result = SCAN_PAGE_LRU;
goto out_unmap;
}
- if (PageLocked(page)) {
+ if (folio_test_locked(folio)) {
result = SCAN_PAGE_LOCK;
goto out_unmap;
}
- if (!PageAnon(page)) {
+ if (!folio_test_anon(folio)) {
result = SCAN_PAGE_ANON;
goto out_unmap;
}
@@ -1369,7 +1367,7 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm,
* has excessive GUP pins (i.e. 512). Anyway the same check
* will be done again later the risk seems low.
*/
- if (!is_refcount_suitable(page)) {
+ if (!is_refcount_suitable(&folio->page)) {
result = SCAN_PAGE_COUNT;
goto out_unmap;
}
@@ -1379,8 +1377,8 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm,
* 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,
+ (pte_young(pteval) || folio_test_young(folio) ||
+ folio_test_referenced(folio) || mmu_notifier_test_young(vma->vm_mm,
address)))
referenced++;
}
@@ -1402,7 +1400,7 @@ static int hpage_collapse_scan_pmd(struct mm_struct *mm,
*mmap_locked = false;
}
out:
- trace_mm_khugepaged_scan_pmd(mm, page, writable, referenced,
+ trace_mm_khugepaged_scan_pmd(mm, &folio->page, writable, referenced,
none_or_zero, result, unmapped);
return result;
}
--
2.40.1
