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-rw-r--r--mm/khugepaged.c16
1 files changed, 7 insertions, 9 deletions
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 5cb401aa2b9d..79be13133322 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1460,14 +1460,6 @@ int collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr,
if (!hugepage_vma_check(vma, vma->vm_flags, false, false, false))
return SCAN_VMA_CHECK;
- /*
- * Symmetry with retract_page_tables(): Exclude MAP_PRIVATE mappings
- * that got written to. Without this, we'd have to also lock the
- * anon_vma if one exists.
- */
- if (vma->anon_vma)
- return SCAN_VMA_CHECK;
-
/* Keep pmd pgtable for uffd-wp; see comment in retract_page_tables() */
if (userfaultfd_wp(vma))
return SCAN_PTE_UFFD_WP;
@@ -1567,8 +1559,14 @@ int collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr,
}
/* step 4: remove pte entries */
+ /* we make no change to anon, but protect concurrent anon page lookup */
+ if (vma->anon_vma)
+ anon_vma_lock_write(vma->anon_vma);
+
collapse_and_free_pmd(mm, vma, haddr, pmd);
+ if (vma->anon_vma)
+ anon_vma_unlock_write(vma->anon_vma);
i_mmap_unlock_write(vma->vm_file->f_mapping);
maybe_install_pmd:
@@ -2649,7 +2647,7 @@ int madvise_collapse(struct vm_area_struct *vma, struct vm_area_struct **prev,
goto out_nolock;
}
- hend = vma->vm_end & HPAGE_PMD_MASK;
+ hend = min(hend, vma->vm_end & HPAGE_PMD_MASK);
}
mmap_assert_locked(mm);
memset(cc->node_load, 0, sizeof(cc->node_load));