In madvise collapse context, we optionally want to be able to ignore
advice from MADV_NOHUGEPAGE-marked regions.
Add a vm_flags_ignore argument to hugepage_vma_revalidate_pmd_count()
which can be used to ignore vm flags used when considering thp
eligibility.
Signed-off-by: Zach O'Keefe <zokeefe@xxxxxxxxxx>
---
mm/khugepaged.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 1d20be47bcea..ecbd3fc41c80 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -964,10 +964,14 @@ khugepaged_alloc_page(struct page **hpage, gfp_t gfp, int node)
#endif
/*
- * Revalidate a vma's eligibility to collapse nr hugepages.
+ * Revalidate a vma's eligibility to collapse nr hugepages. vm_flags_ignore
+ * can be used to ignore certain vma_flags that would otherwise be checked -
+ * the principal example being VM_NOHUGEPAGE which is ignored in madvise
+ * collapse context.
*/
static int hugepage_vma_revalidate_pmd_count(struct mm_struct *mm,
unsigned long address, int nr,
+ unsigned long vm_flags_ignore,
struct vm_area_struct **vmap)
{
struct vm_area_struct *vma;
@@ -986,7 +990,7 @@ static int hugepage_vma_revalidate_pmd_count(struct mm_struct *mm,
hend = vma->vm_end & HPAGE_PMD_MASK;
if (address < hstart || (address + nr * HPAGE_PMD_SIZE) > hend)
return SCAN_ADDRESS_RANGE;
- if (!hugepage_vma_check(vma, vma->vm_flags))
+ if (!hugepage_vma_check(vma, vma->vm_flags & ~vm_flags_ignore))
return SCAN_VMA_CHECK;
/* Anon VMA expected */
if (!vma->anon_vma || vma->vm_ops)
@@ -1000,9 +1004,11 @@ static int hugepage_vma_revalidate_pmd_count(struct mm_struct *mm,
*/
static int hugepage_vma_revalidate(struct mm_struct *mm, unsigned long address,
+ unsigned long vm_flags_ignore,
struct vm_area_struct **vmap)
{
- return hugepage_vma_revalidate_pmd_count(mm, address, 1, vmap);
+ return hugepage_vma_revalidate_pmd_count(mm, address, 1,
+ vm_flags_ignore, vmap);
}
/*
@@ -1043,7 +1049,7 @@ static bool __collapse_huge_page_swapin(struct mm_struct *mm,
/* do_swap_page returns VM_FAULT_RETRY with released mmap_lock */
if (ret & VM_FAULT_RETRY) {
mmap_read_lock(mm);
- if (hugepage_vma_revalidate(mm, haddr, &vma)) {
+ if (hugepage_vma_revalidate(mm, haddr, VM_NONE, &vma)) {
/* vma is no longer available, don't continue to swapin */
trace_mm_collapse_huge_page_swapin(mm, swapped_in, referenced, 0);
return false;
@@ -1200,7 +1206,7 @@ static void collapse_huge_page(struct mm_struct *mm,
count_memcg_page_event(new_page, THP_COLLAPSE_ALLOC);
mmap_read_lock(mm);
- result = hugepage_vma_revalidate(mm, address, &vma);
+ result = hugepage_vma_revalidate(mm, address, VM_NONE, &vma);
if (result) {
mmap_read_unlock(mm);
goto out_nolock;
@@ -1232,7 +1238,7 @@ static void collapse_huge_page(struct mm_struct *mm,
*/
mmap_write_lock(mm);
- result = hugepage_vma_revalidate(mm, address, &vma);
+ result = hugepage_vma_revalidate(mm, address, VM_NONE, &vma);
if (result)
goto out_up_write;
/* check if the pmd is still valid */
--
2.35.1.616.g0bdcbb4464-goog
