Commit dfc7ab57 authored by Baolin Wang's avatar Baolin Wang Committed by Andrew Morton
Browse files

mm: rmap: use flush_cache_range() to flush cache for hugetlb pages 

Now we will use flush_cache_page() to flush cache for anonymous hugetlb
pages when unmapping or migrating a hugetlb page mapping, but the
flush_cache_page() only handles a PAGE_SIZE range on some architectures
(like arm32, arc and so on), which will cause potential cache issues. 
Thus change to use flush_cache_range() to cover the whole size of a
hugetlb page.

Link: https://lkml.kernel.org/r/dc903b378d1e2d26bbbe85409ab9d009631f175c.1651056365.git.baolin.wang@linux.alibaba.com


Signed-off-by: default avatarBaolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: default avatarMike Kravetz <mike.kravetz@oracle.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 54205e9c

mm/rmap.c

+48 −42
Original line number Diff line number Diff line
@@ -1525,13 +1525,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, 
		anon_exclusive = folio_test_anon(folio) &&

				 PageAnonExclusive(subpage);



		if (folio_test_hugetlb(folio) && !folio_test_anon(folio)) {

			/*

			 * To call huge_pmd_unshare, i_mmap_rwsem must be

			 * held in write mode.  Caller needs to explicitly

			 * do this outside rmap routines.

			 */

			VM_BUG_ON(!(flags & TTU_RMAP_LOCKED));

		if (folio_test_hugetlb(folio)) {

			/*

			 * huge_pmd_unshare may unmap an entire PMD page.

			 * There is no way of knowing exactly which PMDs may
@@ -1541,6 +1535,14 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, 
			 */

			flush_cache_range(vma, range.start, range.end);



			if (!folio_test_anon(folio)) {

				/*

				 * To call huge_pmd_unshare, i_mmap_rwsem must be

				 * held in write mode.  Caller needs to explicitly

				 * do this outside rmap routines.

				 */

				VM_BUG_ON(!(flags & TTU_RMAP_LOCKED));



				if (huge_pmd_unshare(mm, vma, &address, pvmw.pte)) {

					flush_tlb_range(vma, range.start, range.end);

					mmu_notifier_invalidate_range(mm, range.start,
@@ -1558,6 +1560,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, 
					page_vma_mapped_walk_done(&pvmw);

					break;

				}

			}

		} else {

			flush_cache_page(vma, address, pte_pfn(*pvmw.pte));

		}
@@ -1879,13 +1882,7 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, 
		anon_exclusive = folio_test_anon(folio) &&

				 PageAnonExclusive(subpage);



		if (folio_test_hugetlb(folio) && !folio_test_anon(folio)) {

			/*

			 * To call huge_pmd_unshare, i_mmap_rwsem must be

			 * held in write mode.  Caller needs to explicitly

			 * do this outside rmap routines.

			 */

			VM_BUG_ON(!(flags & TTU_RMAP_LOCKED));

		if (folio_test_hugetlb(folio)) {

			/*

			 * huge_pmd_unshare may unmap an entire PMD page.

			 * There is no way of knowing exactly which PMDs may
@@ -1895,6 +1892,14 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, 
			 */

			flush_cache_range(vma, range.start, range.end);



			if (!folio_test_anon(folio)) {

				/*

				 * To call huge_pmd_unshare, i_mmap_rwsem must be

				 * held in write mode.  Caller needs to explicitly

				 * do this outside rmap routines.

				 */

				VM_BUG_ON(!(flags & TTU_RMAP_LOCKED));



				if (huge_pmd_unshare(mm, vma, &address, pvmw.pte)) {

					flush_tlb_range(vma, range.start, range.end);

					mmu_notifier_invalidate_range(mm, range.start,
@@ -1912,6 +1917,7 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, 
					page_vma_mapped_walk_done(&pvmw);

					break;

				}

			}

		} else {

			flush_cache_page(vma, address, pte_pfn(*pvmw.pte));

		}