[RFC 02/11] khugepaged: refactor madvise_collapse and khugepaged_scan_mm_slot

Nico Pache
2025-01-08T23:33:21Z

Now that we have a khugepaged_collapse_single_pmd, lets use that code
in madvise_collapse and khugepaged_scan_mm_slot to create a single entry
point.

Signed-off-by: Nico Pache <npache@redhat.com>
---
mm/khugepaged.c | 50 ++++---------------------------------------------
1 file changed, 4 insertions(+), 46 deletions(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 4d932839ff1d..ba85a8fcee88 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -2468,33 +2468,9 @@ static unsigned int khugepaged_scan_mm_slot(unsigned int pages, int *result,
VM_BUG_ON(khugepaged_scan.address < hstart ||
khugepaged_scan.address + HPAGE_PMD_SIZE >
hend);
- if (IS_ENABLED(CONFIG_SHMEM) && vma->vm_file) {
- struct file *file = get_file(vma->vm_file);
- pgoff_t pgoff = linear_page_index(vma,
- khugepaged_scan.address);

- mmap_read_unlock(mm);
- mmap_locked = false;
- *result = hpage_collapse_scan_file(mm,
- khugepaged_scan.address, file, pgoff, cc);
- fput(file);
- if (*result == SCAN_PTE_MAPPED_HUGEPAGE) {
- mmap_read_lock(mm);
- if (hpage_collapse_test_exit_or_disable(mm))
- goto breakouterloop;
- *result = collapse_pte_mapped_thp(mm,
- khugepaged_scan.address, false);
- if (*result == SCAN_PMD_MAPPED)
- *result = SCAN_SUCCEED;
- mmap_read_unlock(mm);
- }
- } else {
- *result = hpage_collapse_scan_pmd(mm, vma,
- khugepaged_scan.address, &mmap_locked, cc);
- }
-
- if (*result == SCAN_SUCCEED)
- ++khugepaged_pages_collapsed;
+ *result = khugepaged_collapse_single_pmd(khugepaged_scan.address,
+ mm, vma, &mmap_locked, cc);

/* move to next address */
khugepaged_scan.address += HPAGE_PMD_SIZE;
@@ -2814,36 +2790,18 @@ int madvise_collapse(struct vm_area_struct *vma, struct vm_area_struct **prev,
mmap_assert_locked(mm);
memset(cc->node_load, 0, sizeof(cc->node_load));
nodes_clear(cc->alloc_nmask);
- if (IS_ENABLED(CONFIG_SHMEM) && vma->vm_file) {
- struct file *file = get_file(vma->vm_file);
- pgoff_t pgoff = linear_page_index(vma, addr);

- mmap_read_unlock(mm);
- mmap_locked = false;
- result = hpage_collapse_scan_file(mm, addr, file, pgoff,
- cc);
- fput(file);
- } else {
- result = hpage_collapse_scan_pmd(mm, vma, addr,
- &mmap_locked, cc);
- }
+ result = khugepaged_collapse_single_pmd(addr, mm, vma, &mmap_locked, cc);
+
if (!mmap_locked)
*prev = NULL; /* Tell caller we dropped mmap_lock */

-handle_result:
switch (result) {
case SCAN_SUCCEED:
case SCAN_PMD_MAPPED:
++thps;
break;
case SCAN_PTE_MAPPED_HUGEPAGE:
- BUG_ON(mmap_locked);
- BUG_ON(*prev);
- mmap_read_lock(mm);
- result = collapse_pte_mapped_thp(mm, addr, true);
- mmap_read_unlock(mm);
- goto handle_result;
- /* Whitelisted set of results where continuing OK */
case SCAN_PMD_NULL:
case SCAN_PTE_NON_PRESENT:
case SCAN_PTE_UFFD_WP:
--
2.47.1