TTU_MIGRATION is used to convert pte into migration entry until thp split
completes. This behavior conflicts with thp migration added later patches,
so let's introduce a new TTU flag specifically for freezing.
Signed-off-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
---
include/linux/rmap.h | 1 +
mm/huge_memory.c | 2 +-
mm/rmap.c | 8 +++++---
3 files changed, 7 insertions(+), 4 deletions(-)
diff --git v4.9-rc2-mmotm-2016-10-27-18-27/include/linux/rmap.h v4.9-rc2-mmotm-2016-10-27-18-27_patched/include/linux/rmap.h
index b46bb56..a2fa425 100644
--- v4.9-rc2-mmotm-2016-10-27-18-27/include/linux/rmap.h
+++ v4.9-rc2-mmotm-2016-10-27-18-27_patched/include/linux/rmap.h
@@ -87,6 +87,7 @@ enum ttu_flags {
TTU_MUNLOCK = 4, /* munlock mode */
TTU_LZFREE = 8, /* lazy free mode */
TTU_SPLIT_HUGE_PMD = 16, /* split huge PMD if any */
+ TTU_SPLIT_FREEZE = 32, /* freeze pte under splitting thp */
TTU_IGNORE_MLOCK = (1 << 8), /* ignore mlock */
TTU_IGNORE_ACCESS = (1 << 9), /* don't age */
diff --git v4.9-rc2-mmotm-2016-10-27-18-27/mm/huge_memory.c v4.9-rc2-mmotm-2016-10-27-18-27_patched/mm/huge_memory.c
index 2d1d6bb..0509d17 100644
--- v4.9-rc2-mmotm-2016-10-27-18-27/mm/huge_memory.c
+++ v4.9-rc2-mmotm-2016-10-27-18-27_patched/mm/huge_memory.c
@@ -1794,7 +1794,7 @@ static void freeze_page(struct page *page)
VM_BUG_ON_PAGE(!PageHead(page), page);
if (PageAnon(page))
- ttu_flags |= TTU_MIGRATION;
+ ttu_flags |= TTU_SPLIT_FREEZE;
/* We only need TTU_SPLIT_HUGE_PMD once */
ret = try_to_unmap(page, ttu_flags | TTU_SPLIT_HUGE_PMD);
diff --git v4.9-rc2-mmotm-2016-10-27-18-27/mm/rmap.c v4.9-rc2-mmotm-2016-10-27-18-27_patched/mm/rmap.c
index 1ef3640..a4be307 100644
--- v4.9-rc2-mmotm-2016-10-27-18-27/mm/rmap.c
+++ v4.9-rc2-mmotm-2016-10-27-18-27_patched/mm/rmap.c
@@ -1449,7 +1449,7 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
if (flags & TTU_SPLIT_HUGE_PMD) {
split_huge_pmd_address(vma, address,
- flags & TTU_MIGRATION, page);
+ flags & TTU_SPLIT_FREEZE, page);
/* check if we have anything to do after split */
if (page_mapcount(page) == 0)
goto out;
@@ -1527,7 +1527,8 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
* will take care of the rest.
*/
dec_mm_counter(mm, mm_counter(page));
- } else if (IS_ENABLED(CONFIG_MIGRATION) && (flags & TTU_MIGRATION)) {
+ } else if (IS_ENABLED(CONFIG_MIGRATION) &&
+ (flags & (TTU_MIGRATION|TTU_SPLIT_FREEZE))) {
swp_entry_t entry;
pte_t swp_pte;
/*
@@ -1649,7 +1650,8 @@ int try_to_unmap(struct page *page, enum ttu_flags flags)
* locking requirements of exec(), migration skips
* temporary VMAs until after exec() completes.
*/
- if ((flags & TTU_MIGRATION) && !PageKsm(page) && PageAnon(page))
+ if ((flags & (TTU_MIGRATION|TTU_SPLIT_FREEZE))
+ && !PageKsm(page) && PageAnon(page))
rwc.invalid_vma = invalid_migration_vma;
if (flags & TTU_RMAP_LOCKED)
--
2.7.0
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