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Subject[RFC PATCH 15/31] mm: thp: add 1GB THP split_huge_pud_page() function.
Date
From: Zi Yan <ziy@nvidia.com>

It mimics PMD-level THP split. In addition, to support PMD-mapped PUD
THP, PMDPageInPUD() is used. For the mapcount of PMD-mapped PUD THP,
sub_compound_mapcount() is used, which uses
(head_page+3).compound_mapcount, since each base page's mapcount is used
for PTE mapping. PagePUDDoubleMap() is used for both PUD-mapped and
PMD-mapped PUD THPs.

page_xxx_rmap() functions now have an extra page order parameter to
distinguish different THP sizes.

Signed-off-by: Zi Yan <ziy@nvidia.com>
---
arch/x86/include/asm/pgtable.h | 15 +
include/asm-generic/pgtable.h | 83 ++++
include/linux/huge_mm.h | 31 +-
include/linux/memcontrol.h | 5 +
include/linux/mm.h | 18 +
include/linux/page-flags.h | 79 +++-
include/linux/rmap.h | 9 +-
include/linux/swap.h | 2 +
include/linux/vm_event_item.h | 4 +
kernel/events/uprobes.c | 4 +-
mm/huge_memory.c | 695 ++++++++++++++++++++++++++++++---
mm/hugetlb.c | 4 +-
mm/khugepaged.c | 4 +-
mm/ksm.c | 4 +-
mm/memcontrol.c | 13 +
mm/memory.c | 16 +-
mm/migrate.c | 8 +-
mm/page_alloc.c | 18 +-
mm/pgtable-generic.c | 11 +
mm/rmap.c | 108 +++--
mm/swap.c | 38 ++
mm/swapfile.c | 4 +-
mm/userfaultfd.c | 2 +-
mm/util.c | 7 +
mm/vmstat.c | 4 +
25 files changed, 1079 insertions(+), 107 deletions(-)

diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
index f99ce657d282..4a6805f8f128 100644
--- a/arch/x86/include/asm/pgtable.h
+++ b/arch/x86/include/asm/pgtable.h
@@ -1269,6 +1269,21 @@ static inline p4d_t *user_to_kernel_p4dp(p4d_t *p4dp)
}
#endif /* CONFIG_PAGE_TABLE_ISOLATION */

+#ifndef pudp_establish
+#define pudp_establish pudp_establish
+static inline pud_t pudp_establish(struct vm_area_struct *vma,
+ unsigned long address, pud_t *pudp, pud_t pud)
+{
+ if (IS_ENABLED(CONFIG_SMP)) {
+ return xchg(pudp, pud);
+ } else {
+ pud_t old = *pudp;
+ *pudp = pud;
+ return old;
+ }
+}
+#endif
+
/*
* clone_pgd_range(pgd_t *dst, pgd_t *src, int count);
*
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index 682531e0d55c..1ae33b6590b8 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -346,6 +346,11 @@ extern pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
pmd_t *pmdp);
#endif

+#ifndef __HAVE_ARCH_PUDP_INVALIDATE
+extern pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
+ pud_t *pudp);
+#endif
+
#ifndef __HAVE_ARCH_PTE_SAME
static inline int pte_same(pte_t pte_a, pte_t pte_b)
{
@@ -941,6 +946,18 @@ static inline pmd_t pmd_read_atomic(pmd_t *pmdp)
}
#endif

+#ifndef pud_read_atomic
+static inline pud_t pud_read_atomic(pud_t *pudp)
+{
+ /*
+ * Depend on compiler for an atomic pmd read. NOTE: this is
+ * only going to work, if the pmdval_t isn't larger than
+ * an unsigned long.
+ */
+ return *pudp;
+}
+#endif
+
#ifndef arch_needs_pgtable_deposit
#define arch_needs_pgtable_deposit() (false)
#endif
@@ -1032,6 +1049,72 @@ static inline int pmd_trans_unstable(pmd_t *pmd)
#endif
}

+static inline int pud_none_or_trans_huge_or_clear_bad(pud_t *pud)
+{
+ pud_t pudval = pud_read_atomic(pud);
+ /*
+ * The barrier will stabilize the pmdval in a register or on
+ * the stack so that it will stop changing under the code.
+ *
+ * When CONFIG_TRANSPARENT_HUGEPAGE=y on x86 32bit PAE,
+ * pmd_read_atomic is allowed to return a not atomic pmdval
+ * (for example pointing to an hugepage that has never been
+ * mapped in the pmd). The below checks will only care about
+ * the low part of the pmd with 32bit PAE x86 anyway, with the
+ * exception of pmd_none(). So the important thing is that if
+ * the low part of the pmd is found null, the high part will
+ * be also null or the pmd_none() check below would be
+ * confused.
+ */
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ barrier();
+#endif
+ /*
+ * !pmd_present() checks for pmd migration entries
+ *
+ * The complete check uses is_pmd_migration_entry() in linux/swapops.h
+ * But using that requires moving current function and pmd_trans_unstable()
+ * to linux/swapops.h to resovle dependency, which is too much code move.
+ *
+ * !pmd_present() is equivalent to is_pmd_migration_entry() currently,
+ * because !pmd_present() pages can only be under migration not swapped
+ * out.
+ *
+ * pmd_none() is preseved for future condition checks on pmd migration
+ * entries and not confusing with this function name, although it is
+ * redundant with !pmd_present().
+ */
+ if (pud_none(pudval) || pud_trans_huge(pudval))
+ return 1;
+ if (unlikely(pud_bad(pudval))) {
+ pud_clear_bad(pud);
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * This is a noop if Transparent Hugepage Support is not built into
+ * the kernel. Otherwise it is equivalent to
+ * pmd_none_or_trans_huge_or_clear_bad(), and shall only be called in
+ * places that already verified the pmd is not none and they want to
+ * walk ptes while holding the mmap sem in read mode (write mode don't
+ * need this). If THP is not enabled, the pmd can't go away under the
+ * code even if MADV_DONTNEED runs, but if THP is enabled we need to
+ * run a pmd_trans_unstable before walking the ptes after
+ * split_huge_page_pmd returns (because it may have run when the pmd
+ * become null, but then a page fault can map in a THP and not a
+ * regular page).
+ */
+static inline int pud_trans_unstable(pud_t *pud)
+{
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ return pud_none_or_trans_huge_or_clear_bad(pud);
+#else
+ return 0;
+#endif
+}
+
#ifndef CONFIG_NUMA_BALANCING
/*
* Technically a PTE can be PROTNONE even when not doing NUMA balancing but
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index 02419fa91e12..bd5cc5e65de8 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -178,17 +178,27 @@ void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
void split_huge_pmd_address(struct vm_area_struct *vma, unsigned long address,
bool freeze, struct page *page);

+bool can_split_huge_pud_page(struct page *page, int *pextra_pins);
+int split_huge_pud_page_to_list(struct page *page, struct list_head *list);
+static inline int split_huge_pud_page(struct page *page)
+{
+ return split_huge_pud_page_to_list(page, NULL);
+}
void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud,
- unsigned long address);
+ unsigned long address, bool freeze, struct page *page);

#define split_huge_pud(__vma, __pud, __address) \
do { \
pud_t *____pud = (__pud); \
if (pud_trans_huge(*____pud) \
|| pud_devmap(*____pud)) \
- __split_huge_pud(__vma, __pud, __address); \
+ __split_huge_pud(__vma, __pud, __address, \
+ false, NULL); \
} while (0)

+void split_huge_pud_address(struct vm_area_struct *vma, unsigned long address,
+ bool freeze, struct page *page);
+
extern int hugepage_madvise(struct vm_area_struct *vma,
unsigned long *vm_flags, int advice);
extern void vma_adjust_trans_huge(struct vm_area_struct *vma,
@@ -319,8 +329,25 @@ static inline void __split_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
static inline void split_huge_pmd_address(struct vm_area_struct *vma,
unsigned long address, bool freeze, struct page *page) {}

+static inline bool
+can_split_huge_pud_page(struct page *page, int *pextra_pins)
+{
+ BUILD_BUG();
+ return false;
+}
+static inline int
+split_huge_pud_page_to_list(struct page *page, struct list_head *list)
+{
+ return 0;
+}
+static inline int split_huge_pud_page(struct page *page)
+{
+ return 0;
+}
#define split_huge_pud(__vma, __pmd, __address) \
do { } while (0)
+static inline void split_huge_pud_address(struct vm_area_struct *vma,
+ unsigned long address, bool freeze, struct page *page) {}

static inline int hugepage_madvise(struct vm_area_struct *vma,
unsigned long *vm_flags, int advice)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 83ae11cbd12c..fd362559d4b7 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -790,6 +790,7 @@ static inline void memcg_memory_event_mm(struct mm_struct *mm,

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
void mem_cgroup_split_huge_fixup(struct page *head);
+void mem_cgroup_split_huge_pud_fixup(struct page *head);
#endif

#else /* CONFIG_MEMCG */
@@ -1098,6 +1099,10 @@ static inline void mem_cgroup_split_huge_fixup(struct page *head)
{
}

+static inline void mem_cgroup_split_huge_pud_fixup(struct page *head)
+{
+}
+
static inline void count_memcg_events(struct mem_cgroup *memcg,
enum vm_event_item idx,
unsigned long count)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index d10dc9db2311..af6257d05189 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -652,6 +652,24 @@ static inline int compound_mapcount(struct page *page)
return atomic_read(compound_mapcount_ptr(page)) + 1;
}

+static inline unsigned int compound_order(struct page *page);
+static inline atomic_t *sub_compound_mapcount_ptr(struct page *page, int sub_level)
+{
+ struct page *head = compound_head(page);
+
+ VM_BUG_ON_PAGE(!PageCompound(page), page);
+ VM_BUG_ON_PAGE(compound_order(head) != HPAGE_PUD_ORDER, page);
+ VM_BUG_ON_PAGE((page - head) % HPAGE_PMD_NR, page);
+ VM_BUG_ON_PAGE(sub_level != 1, page);
+ return &page[2 + sub_level].compound_mapcount;
+}
+
+/* Only works for PUD pages */
+static inline int sub_compound_mapcount(struct page *page)
+{
+ return atomic_read(sub_compound_mapcount_ptr(page, 1)) + 1;
+}
+
/*
* The atomic page->_mapcount, starts from -1: so that transitions
* both from it and to it can be tracked, using atomic_inc_and_test
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 39b4494e29f1..480e091f52ac 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -607,6 +607,23 @@ static inline int PageTransTail(struct page *page)
return PageTail(page);
}

+#define HPAGE_PMD_SHIFT PMD_SHIFT
+#define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
+#define HPAGE_PMD_NR (1<<HPAGE_PMD_ORDER)
+
+#define HPAGE_PUD_SHIFT PUD_SHIFT
+#define HPAGE_PUD_ORDER (HPAGE_PUD_SHIFT-PAGE_SHIFT)
+#define HPAGE_PUD_NR (1<<HPAGE_PUD_ORDER)
+
+static inline unsigned int compound_order(struct page *page);
+
+static inline int PMDPageInPUD(struct page *page)
+{
+ struct page *head = compound_head(page);
+ return (PageCompound(page) && compound_order(head) == HPAGE_PUD_ORDER &&
+ ((page - head) % HPAGE_PMD_NR == 0));
+}
+
/*
* PageDoubleMap indicates that the compound page is mapped with PTEs as well
* as PMDs.
@@ -622,30 +639,72 @@ static inline int PageTransTail(struct page *page)
*/
static inline int PageDoubleMap(struct page *page)
{
- return PageHead(page) && test_bit(PG_double_map, &page[1].flags);
+ return (PageHead(page) || PMDPageInPUD(page)) &&
+ test_bit(PG_double_map, &compound_head(page)[1].flags);
}

static inline void SetPageDoubleMap(struct page *page)
{
- VM_BUG_ON_PAGE(!PageHead(page), page);
- set_bit(PG_double_map, &page[1].flags);
+ VM_BUG_ON_PAGE(!PageHead(page) && !PMDPageInPUD(page), page);
+ set_bit(PG_double_map, &compound_head(page)[1].flags);
}

static inline void ClearPageDoubleMap(struct page *page)
{
- VM_BUG_ON_PAGE(!PageHead(page), page);
- clear_bit(PG_double_map, &page[1].flags);
+ VM_BUG_ON_PAGE(!PageHead(page) && !PMDPageInPUD(page), page);
+ clear_bit(PG_double_map, &compound_head(page)[1].flags);
}
static inline int TestSetPageDoubleMap(struct page *page)
{
- VM_BUG_ON_PAGE(!PageHead(page), page);
- return test_and_set_bit(PG_double_map, &page[1].flags);
+ VM_BUG_ON_PAGE(!PageHead(page) && !PMDPageInPUD(page), page);
+ return test_and_set_bit(PG_double_map, &compound_head(page)[1].flags);
}

static inline int TestClearPageDoubleMap(struct page *page)
+{
+ VM_BUG_ON_PAGE(!PageHead(page) && !PMDPageInPUD(page), page);
+ return test_and_clear_bit(PG_double_map, &compound_head(page)[1].flags);
+}
+
+/*
+ * PagePUDDoubleMap indicates that the compound page is mapped with PMDs as well
+ * as PUDs.
+ *
+ * This is required for optimization of rmap operations for THP: we can postpone
+ * per small page mapcount accounting (and its overhead from atomic operations)
+ * until the first PMD split.
+ *
+ * For the page PageDoubleMap means ->_mapcount in all sub-pages is offset up
+ * by one. This reference will go away with last compound_mapcount.
+ *
+ * See also __split_huge_pmd_locked() and page_remove_anon_compound_rmap().
+ */
+static inline int PagePUDDoubleMap(struct page *page)
+{
+ return PageHead(page) && test_bit(PG_double_map, &page[2].flags);
+}
+
+static inline void SetPagePUDDoubleMap(struct page *page)
+{
+ VM_BUG_ON_PAGE(!PageHead(page), page);
+ set_bit(PG_double_map, &page[2].flags);
+}
+
+static inline void ClearPagePUDDoubleMap(struct page *page)
+{
+ VM_BUG_ON_PAGE(!PageHead(page), page);
+ clear_bit(PG_double_map, &page[2].flags);
+}
+static inline int TestSetPagePUDDoubleMap(struct page *page)
+{
+ VM_BUG_ON_PAGE(!PageHead(page), page);
+ return test_and_set_bit(PG_double_map, &page[2].flags);
+}
+
+static inline int TestClearPagePUDDoubleMap(struct page *page)
{
VM_BUG_ON_PAGE(!PageHead(page), page);
- return test_and_clear_bit(PG_double_map, &page[1].flags);
+ return test_and_clear_bit(PG_double_map, &page[2].flags);
}

#else
@@ -653,9 +712,13 @@ TESTPAGEFLAG_FALSE(TransHuge)
TESTPAGEFLAG_FALSE(TransCompound)
TESTPAGEFLAG_FALSE(TransCompoundMap)
TESTPAGEFLAG_FALSE(TransTail)
+TESTPAGEFLAG_FALSE(PMDPageInPUD)
PAGEFLAG_FALSE(DoubleMap)
TESTSETFLAG_FALSE(DoubleMap)
TESTCLEARFLAG_FALSE(DoubleMap)
+PAGEFLAG_FALSE(PUDDoubleMap)
+ TESTSETFLAG_FALSE(PUDDoubleMap)
+ TESTCLEARFLAG_FALSE(PUDDoubleMap)
#endif

/*
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 2b566736e3c2..6adb6e835b30 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -99,6 +99,7 @@ enum ttu_flags {
TTU_RMAP_LOCKED = 0x80, /* do not grab rmap lock:
* caller holds it */
TTU_SPLIT_FREEZE = 0x100, /* freeze pte under splitting thp */
+ TTU_SPLIT_HUGE_PUD = 0x200, /* split huge PUD if any */
};

#ifdef CONFIG_MMU
@@ -171,13 +172,13 @@ struct anon_vma *page_get_anon_vma(struct page *page);
*/
void page_move_anon_rmap(struct page *, struct vm_area_struct *);
void page_add_anon_rmap(struct page *, struct vm_area_struct *,
- unsigned long, bool);
+ unsigned long, bool, int);
void do_page_add_anon_rmap(struct page *, struct vm_area_struct *,
- unsigned long, int);
+ unsigned long, int, int);
void page_add_new_anon_rmap(struct page *, struct vm_area_struct *,
- unsigned long, bool);
+ unsigned long, bool, int);
void page_add_file_rmap(struct page *, bool);
-void page_remove_rmap(struct page *, bool);
+void page_remove_rmap(struct page *, bool, int);

void hugepage_add_anon_rmap(struct page *, struct vm_area_struct *,
unsigned long);
diff --git a/include/linux/swap.h b/include/linux/swap.h
index 622025ac1461..1a6bac77c854 100644
--- a/include/linux/swap.h
+++ b/include/linux/swap.h
@@ -333,6 +333,8 @@ extern void lru_cache_add_anon(struct page *page);
extern void lru_cache_add_file(struct page *page);
extern void lru_add_page_tail(struct page *page, struct page *page_tail,
struct lruvec *lruvec, struct list_head *head);
+extern void lru_add_pud_page_tail(struct page *page, struct page *page_tail,
+ struct lruvec *lruvec, struct list_head *head);
extern void activate_page(struct page *);
extern void mark_page_accessed(struct page *);
extern void lru_add_drain(void);
diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index 4550667b2274..df619262b1b4 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -85,6 +85,10 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
THP_FAULT_ALLOC_PUD,
THP_FAULT_FALLBACK_PUD,
THP_SPLIT_PUD,
+ THP_SPLIT_PUD_PAGE,
+ THP_SPLIT_PUD_PAGE_FAILED,
+ THP_ZERO_PUD_PAGE_ALLOC,
+ THP_ZERO_PUD_PAGE_ALLOC_FAILED,
#endif
THP_ZERO_PAGE_ALLOC,
THP_ZERO_PAGE_ALLOC_FAILED,
diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 8aef47ee7bfa..e4819fef634f 100644
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -195,7 +195,7 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
VM_BUG_ON_PAGE(addr != pvmw.address, old_page);

get_page(new_page);
- page_add_new_anon_rmap(new_page, vma, addr, false);
+ page_add_new_anon_rmap(new_page, vma, addr, false, 0);
mem_cgroup_commit_charge(new_page, memcg, false, false);
lru_cache_add_active_or_unevictable(new_page, vma);

@@ -209,7 +209,7 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr,
set_pte_at_notify(mm, addr, pvmw.pte,
mk_pte(new_page, vma->vm_page_prot));

- page_remove_rmap(old_page, false);
+ page_remove_rmap(old_page, false, 0);
if (!page_mapped(old_page))
try_to_free_swap(old_page);
page_vma_mapped_walk_done(&pvmw);
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 0a006592f3fe..5f83f4c5eac7 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -121,10 +121,10 @@ static struct page *get_huge_pud_zero_page(void)
zero_page = alloc_pages((GFP_TRANSHUGE | __GFP_ZERO) & ~__GFP_MOVABLE,
HPAGE_PUD_ORDER);
if (!zero_page) {
- count_vm_event(THP_ZERO_PAGE_ALLOC_FAILED);
+ count_vm_event(THP_ZERO_PUD_PAGE_ALLOC_FAILED);
return NULL;
}
- count_vm_event(THP_ZERO_PAGE_ALLOC);
+ count_vm_event(THP_ZERO_PUD_PAGE_ALLOC);
preempt_disable();
if (cmpxchg(&huge_pud_zero_page, NULL, zero_page)) {
preempt_enable();
@@ -660,7 +660,7 @@ static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf,

entry = mk_huge_pmd(page, vma->vm_page_prot);
entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
- page_add_new_anon_rmap(page, vma, haddr, true);
+ page_add_new_anon_rmap(page, vma, haddr, true, HPAGE_PMD_ORDER);
mem_cgroup_commit_charge(page, memcg, false, true);
lru_cache_add_active_or_unevictable(page, vma);
pgtable_trans_huge_deposit(vma->vm_mm, vmf->pmd, pgtable);
@@ -969,7 +969,7 @@ static int __do_huge_pud_anonymous_page(struct vm_fault *vmf, struct page *page,

entry = mk_huge_pud(page, vma->vm_page_prot);
entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma);
- page_add_new_anon_rmap(page, vma, haddr, true);
+ page_add_new_anon_rmap(page, vma, haddr, true, HPAGE_PUD_ORDER);
mem_cgroup_commit_charge(page, memcg, false, true);
lru_cache_add_active_or_unevictable(page, vma);
pgtable_trans_huge_pud_deposit(vma->vm_mm, vmf->pud,
@@ -1463,7 +1463,7 @@ static int do_huge_pud_wp_page_fallback(struct vm_fault *vmf, pud_t orig_pud,
entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
memcg = (void *)page_private(pages[i]);
set_page_private(pages[i], 0);
- page_add_new_anon_rmap(pages[i], vmf->vma, haddr, true);
+ page_add_new_anon_rmap(pages[i], vmf->vma, haddr, true, HPAGE_PMD_ORDER);
mem_cgroup_commit_charge(pages[i], memcg, false, true);
lru_cache_add_active_or_unevictable(pages[i], vma);
vmf->pmd = pmd_offset(&_pud, haddr);
@@ -1475,7 +1475,7 @@ static int do_huge_pud_wp_page_fallback(struct vm_fault *vmf, pud_t orig_pud,

smp_wmb(); /* make pte visible before pmd */
pud_populate_with_pgtable(vma->vm_mm, vmf->pud, pgtable);
- page_remove_rmap(page, true);
+ page_remove_rmap(page, true, HPAGE_PUD_ORDER);
spin_unlock(vmf->ptl);

/*
@@ -1566,13 +1566,13 @@ int do_huge_pud_wp_page(struct vm_fault *vmf, pud_t orig_pud)
prep_transhuge_page(new_page);
} else {
if (!page) {
- WARN(1, "%s: split_huge_page\n", __func__);
+ /*WARN(1, "%s: split_huge_page\n", __func__);*/
split_huge_pud(vma, vmf->pud, vmf->address);
ret |= VM_FAULT_FALLBACK;
} else {
ret = do_huge_pud_wp_page_fallback(vmf, orig_pud, page);
if (ret & VM_FAULT_OOM) {
- WARN(1, "%s: split_huge_page after wp fallback\n", __func__);
+ /*WARN(1, "%s: split_huge_page after wp fallback\n", __func__);*/
split_huge_pud(vma, vmf->pud, vmf->address);
ret |= VM_FAULT_FALLBACK;
}
@@ -1585,7 +1585,7 @@ int do_huge_pud_wp_page(struct vm_fault *vmf, pud_t orig_pud)
if (unlikely(mem_cgroup_try_charge(new_page, vma->vm_mm,
huge_gfp, &memcg, true))) {
put_page(new_page);
- WARN(1, "%s: split_huge_page after mem cgroup failed\n", __func__);
+ /*WARN(1, "%s: split_huge_page after mem cgroup failed\n", __func__);*/
split_huge_pud(vma, vmf->pud, vmf->address);
if (page)
put_page(page);
@@ -1620,7 +1620,7 @@ int do_huge_pud_wp_page(struct vm_fault *vmf, pud_t orig_pud)
entry = mk_huge_pud(new_page, vma->vm_page_prot);
entry = maybe_pud_mkwrite(pud_mkdirty(entry), vma);
pudp_huge_clear_flush_notify(vma, haddr, vmf->pud);
- page_add_new_anon_rmap(new_page, vma, haddr, true);
+ page_add_new_anon_rmap(new_page, vma, haddr, true, HPAGE_PUD_ORDER);
mem_cgroup_commit_charge(new_page, memcg, false, true);
lru_cache_add_active_or_unevictable(new_page, vma);
set_pud_at(vma->vm_mm, haddr, vmf->pud, entry);
@@ -1629,7 +1629,7 @@ int do_huge_pud_wp_page(struct vm_fault *vmf, pud_t orig_pud)
add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PUD_NR);
} else {
VM_BUG_ON_PAGE(!PageHead(page), page);
- page_remove_rmap(page, true);
+ page_remove_rmap(page, true, HPAGE_PUD_ORDER);
put_page(page);
}
ret |= VM_FAULT_WRITE;
@@ -1748,7 +1748,7 @@ static vm_fault_t do_huge_pmd_wp_page_fallback(struct vm_fault *vmf,
entry = maybe_mkwrite(pte_mkdirty(entry), vma);
memcg = (void *)page_private(pages[i]);
set_page_private(pages[i], 0);
- page_add_new_anon_rmap(pages[i], vmf->vma, haddr, false);
+ page_add_new_anon_rmap(pages[i], vmf->vma, haddr, false, 0);
mem_cgroup_commit_charge(pages[i], memcg, false, false);
lru_cache_add_active_or_unevictable(pages[i], vma);
vmf->pte = pte_offset_map(&_pmd, haddr);
@@ -1760,7 +1760,7 @@ static vm_fault_t do_huge_pmd_wp_page_fallback(struct vm_fault *vmf,

smp_wmb(); /* make pte visible before pmd */
pmd_populate(vma->vm_mm, vmf->pmd, pgtable);
- page_remove_rmap(page, true);
+ page_remove_rmap(page, true, HPAGE_PMD_ORDER);
spin_unlock(vmf->ptl);

/*
@@ -1900,7 +1900,7 @@ vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd)
entry = mk_huge_pmd(new_page, vma->vm_page_prot);
entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);
pmdp_huge_clear_flush_notify(vma, haddr, vmf->pmd);
- page_add_new_anon_rmap(new_page, vma, haddr, true);
+ page_add_new_anon_rmap(new_page, vma, haddr, true, HPAGE_PMD_ORDER);
mem_cgroup_commit_charge(new_page, memcg, false, true);
lru_cache_add_active_or_unevictable(new_page, vma);
set_pmd_at(vma->vm_mm, haddr, vmf->pmd, entry);
@@ -1909,7 +1909,7 @@ vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd)
add_mm_counter(vma->vm_mm, MM_ANONPAGES, HPAGE_PMD_NR);
} else {
VM_BUG_ON_PAGE(!PageHead(page), page);
- page_remove_rmap(page, true);
+ page_remove_rmap(page, true, HPAGE_PMD_ORDER);
put_page(page);
}
ret |= VM_FAULT_WRITE;
@@ -2282,9 +2282,9 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,

if (pmd_present(orig_pmd)) {
page = pmd_page(orig_pmd);
- page_remove_rmap(page, true);
+ page_remove_rmap(page, true, HPAGE_PMD_ORDER);
VM_BUG_ON_PAGE(page_mapcount(page) < 0, page);
- VM_BUG_ON_PAGE(!PageHead(page), page);
+ VM_BUG_ON_PAGE(!PageHead(page) && !PMDPageInPUD(page), page);
} else if (thp_migration_supported()) {
swp_entry_t entry;

@@ -2560,7 +2560,7 @@ int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma,

if (pud_present(orig_pud)) {
page = pud_page(orig_pud);
- page_remove_rmap(page, true);
+ page_remove_rmap(page, true, HPAGE_PUD_ORDER);
VM_BUG_ON_PAGE(page_mapcount(page) < 0, page);
VM_BUG_ON_PAGE(!PageHead(page), page);
} else
@@ -2582,9 +2582,60 @@ int zap_huge_pud(struct mmu_gather *tlb, struct vm_area_struct *vma,
return 1;
}

+static void __split_huge_zero_page_pmd(struct vm_area_struct *vma,
+ unsigned long haddr, pmd_t *pmd);
+
+static void __split_huge_zero_page_pud(struct vm_area_struct *vma,
+ unsigned long haddr, pud_t *pud)
+{
+ struct mm_struct *mm = vma->vm_mm;
+ pgtable_t pgtable;
+ pud_t _pud;
+ int i;
+
+ /*
+ * Leave pmd empty until pte is filled note that it is fine to delay
+ * notification until mmu_notifier_invalidate_range_end() as we are
+ * replacing a zero pmd write protected page with a zero pte write
+ * protected page.
+ *
+ * See Documentation/vm/mmu_notifier.txt
+ */
+ pudp_huge_clear_flush(vma, haddr, pud);
+
+ pgtable = pgtable_trans_huge_pud_withdraw(mm, pud);
+ pud_populate_with_pgtable(mm, &_pud, pgtable);
+
+ for (i = 0; i < (1<<(HPAGE_PUD_ORDER-HPAGE_PMD_ORDER));
+ i++, haddr += PMD_SIZE) {
+ pmd_t *pmd = pmd_offset(&_pud, haddr), entry;
+ struct page *zero_page = mm_get_huge_zero_page(mm);
+
+ if (unlikely(!zero_page)) {
+ VM_BUG_ON(1);
+ __split_huge_zero_page_pmd(vma, haddr, pmd);
+ continue;
+ }
+
+ VM_BUG_ON(!pmd_none(*pmd));
+ entry = mk_huge_pmd(zero_page, vma->vm_page_prot);
+ set_pmd_at(mm, haddr, pmd, entry);
+ }
+ smp_wmb(); /* make pte visible before pmd */
+ pud_populate_with_pgtable(mm, pud, pgtable);
+}
+
static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud,
- unsigned long haddr)
+ unsigned long haddr, bool freeze)
{
+ struct mm_struct *mm = vma->vm_mm;
+ struct page *page;
+ pgtable_t pgtable;
+ pud_t _pud, old_pud;
+ bool young, write, dirty, soft_dirty;
+ unsigned long addr;
+ int i;
+
VM_BUG_ON(haddr & ~HPAGE_PUD_MASK);
VM_BUG_ON_VMA(vma->vm_start > haddr, vma);
VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PUD_SIZE, vma);
@@ -2592,22 +2643,149 @@ static void __split_huge_pud_locked(struct vm_area_struct *vma, pud_t *pud,

count_vm_event(THP_SPLIT_PUD);

- pudp_huge_clear_flush_notify(vma, haddr, pud);
+ if (!vma_is_anonymous(vma)) {
+ _pud = pudp_huge_clear_flush_notify(vma, haddr, pud);
+ /*
+ * We are going to unmap this huge page. So
+ * just go ahead and zap it
+ */
+ if (arch_needs_pgtable_deposit())
+ zap_pud_deposited_table(mm, pud);
+ if (vma_is_dax(vma))
+ return;
+ page = pud_page(_pud);
+ if (!PageReferenced(page) && pud_young(_pud))
+ SetPageReferenced(page);
+ page_remove_rmap(page, true, HPAGE_PUD_ORDER);
+ put_page(page);
+ add_mm_counter(mm, MM_FILEPAGES, -HPAGE_PUD_NR);
+ return;
+ } else if (is_huge_zero_pud(*pud)) {
+ /*
+ * FIXME: Do we want to invalidate secondary mmu by calling
+ * mmu_notifier_invalidate_range() see comments below inside
+ * __split_huge_pmd() ?
+ *
+ * We are going from a zero huge page write protected to zero
+ * small page also write protected so it does not seems useful
+ * to invalidate secondary mmu at this time.
+ */
+ return __split_huge_zero_page_pud(vma, haddr, pud);
+ }
+
+ /* See the comment above pmdp_invalidate() in __split_huge_pmd_locked() */
+ old_pud = pudp_invalidate(vma, haddr, pud);
+
+ page = pud_page(old_pud);
+ VM_BUG_ON_PAGE(!page_count(page), page);
+ page_ref_add(page, (1<<(HPAGE_PUD_ORDER-HPAGE_PMD_ORDER)) - 1);
+ if (pud_dirty(old_pud))
+ SetPageDirty(page);
+ write = pud_write(old_pud);
+ young = pud_young(old_pud);
+ dirty = pud_dirty(old_pud);
+ soft_dirty = pud_soft_dirty(old_pud);
+
+ pgtable = pgtable_trans_huge_pud_withdraw(mm, pud);
+ pud_populate_with_pgtable(mm, &_pud, pgtable);
+
+ for (i = 0, addr = haddr; i < HPAGE_PUD_NR;
+ i += HPAGE_PMD_NR, addr += PMD_SIZE) {
+ pmd_t entry, *pmd;
+ /*
+ * Note that NUMA hinting access restrictions are not
+ * transferred to avoid any possibility of altering
+ * permissions across VMAs.
+ */
+ if (freeze) {
+ swp_entry_t swp_entry;
+
+ swp_entry = make_migration_entry(page + i, write);
+ entry = swp_entry_to_pmd(swp_entry);
+ if (soft_dirty)
+ entry = pmd_swp_mksoft_dirty(entry);
+ } else {
+ entry = mk_huge_pmd(page + i, READ_ONCE(vma->vm_page_prot));
+ entry = maybe_pmd_mkwrite(entry, vma);
+ if (!write)
+ entry = pmd_wrprotect(entry);
+ if (!young)
+ entry = pmd_mkold(entry);
+ if (soft_dirty)
+ entry = pmd_mksoft_dirty(entry);
+ }
+ pmd = pmd_offset(&_pud, addr);
+ VM_BUG_ON(!pmd_none(*pmd));
+ set_pmd_at(mm, addr, pmd, entry);
+ /* distinguish between pud compound_mapcount and pmd compound_mapcount */
+ if (atomic_inc_and_test(sub_compound_mapcount_ptr(&page[i], 1)))
+ /* first pmd-mapped pud page */
+ __inc_node_page_state(page, NR_ANON_THPS);
+ }
+
+ /*
+ * Set PG_double_map before dropping compound_mapcount to avoid
+ * false-negative page_mapped().
+ */
+ if (compound_mapcount(page) > 1 && !TestSetPagePUDDoubleMap(page)) {
+ for (i = 0; i < HPAGE_PUD_NR; i += HPAGE_PMD_NR)
+ /* distinguish between pud compound_mapcount and pmd compound_mapcount */
+ atomic_inc(sub_compound_mapcount_ptr(&page[i], 1));
+ }
+
+ if (atomic_add_negative(-1, compound_mapcount_ptr(page))) {
+ /* Last compound_mapcount is gone. */
+ __dec_node_page_state(page, NR_ANON_THPS_PUD);
+ if (TestClearPagePUDDoubleMap(page)) {
+ /* No need in mapcount reference anymore */
+ for (i = 0; i < HPAGE_PUD_NR; i += HPAGE_PMD_NR)
+ /* distinguish between pud compound_mapcount and pmd compound_mapcount */
+ atomic_dec(sub_compound_mapcount_ptr(&page[i], 1));
+ }
+ }
+
+ smp_wmb(); /* make pte visible before pmd */
+ pud_populate_with_pgtable(mm, pud, pgtable);
+
+ if (freeze) {
+ for (i = 0; i < HPAGE_PUD_NR; i += HPAGE_PMD_NR) {
+ /*page_remove_rmap(page + i, true, HPAGE_PMD_ORDER);*/
+ atomic_dec(sub_compound_mapcount_ptr(&page[i], 1));
+ __dec_node_page_state(page, NR_ANON_THPS);
+ __mod_node_page_state(page_pgdat(page), NR_ANON_MAPPED, -HPAGE_PMD_NR);
+ put_page(page + i);
+ }
+ }
}

void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud,
- unsigned long address)
+ unsigned long address, bool freeze, struct page *page)
{
spinlock_t *ptl;
+ struct mm_struct *mm = vma->vm_mm;
+ unsigned long haddr = address & HPAGE_PUD_MASK;
struct mmu_notifier_range range;

mmu_notifier_range_init(&range, vma->vm_mm, address & HPAGE_PUD_MASK,
(address & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE);
mmu_notifier_invalidate_range_start(&range);
- ptl = pud_lock(vma->vm_mm, pud);
- if (unlikely(!pud_trans_huge(*pud) && !pud_devmap(*pud)))
+ ptl = pud_lock(mm, pud);
+
+ /*
+ * If caller asks to setup a migration entries, we need a page to check
+ * pmd against. Otherwise we can end up replacing wrong page.
+ */
+ VM_BUG_ON(freeze && !page);
+ if (page && page != pud_page(*pud))
goto out;
- __split_huge_pud_locked(vma, pud, range.start);
+
+ if (pud_trans_huge(*pud)) {
+ page = pud_page(*pud);
+ if (PageMlocked(page))
+ clear_page_mlock(page);
+ } else if (unlikely(!pud_devmap(*pud)))
+ goto out;
+ __split_huge_pud_locked(vma, pud, haddr, freeze);

out:
spin_unlock(ptl);
@@ -2617,6 +2795,369 @@ void __split_huge_pud(struct vm_area_struct *vma, pud_t *pud,
*/
mmu_notifier_invalidate_range_only_end(&range);
}
+
+void split_huge_pud_address(struct vm_area_struct *vma, unsigned long address,
+ bool freeze, struct page *page)
+{
+ pgd_t *pgd;
+ p4d_t *p4d;
+ pud_t *pud;
+
+ pgd = pgd_offset(vma->vm_mm, address);
+ if (!pgd_present(*pgd))
+ return;
+
+ p4d = p4d_offset(pgd, address);
+ if (!p4d_present(*p4d))
+ return;
+
+ pud = pud_offset(p4d, address);
+
+ __split_huge_pud(vma, pud, address, freeze, page);
+}
+
+static void freeze_pud_page(struct page *page)
+{
+ enum ttu_flags ttu_flags = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS |
+ TTU_RMAP_LOCKED | TTU_SPLIT_HUGE_PUD;
+ bool unmap_success;
+
+ VM_BUG_ON_PAGE(!PageHead(page), page);
+
+ if (PageAnon(page))
+ ttu_flags |= TTU_SPLIT_FREEZE;
+
+ unmap_success = try_to_unmap(page, ttu_flags);
+ VM_BUG_ON_PAGE(!unmap_success, page);
+}
+
+static void unfreeze_pud_page(struct page *page)
+{
+ int i;
+
+ VM_BUG_ON(!PageTransHuge(page));
+ if (compound_order(page) == HPAGE_PUD_ORDER) {
+ remove_migration_ptes(page, page, true);
+ } else if (compound_order(page) == HPAGE_PMD_ORDER) {
+ for (i = 0; i < HPAGE_PUD_NR; i += HPAGE_PMD_NR)
+ remove_migration_ptes(page + i, page + i, true);
+ } else
+ VM_BUG_ON_PAGE(1, page);
+}
+
+static void __split_huge_pud_page_tail(struct page *head, int tail,
+ struct lruvec *lruvec, struct list_head *list)
+{
+ struct page *page_tail = head + tail;
+ /*int page_tail_mapcount = sub_compound_mapcount(page_tail);*/
+
+ VM_BUG_ON_PAGE(page_ref_count(page_tail) != 0, page_tail);
+
+ /*atomic_set(sub_compound_mapcount_ptr(page_tail, 1), -1);*/
+
+ clear_compound_head(page_tail);
+ prep_compound_page(page_tail, HPAGE_PMD_ORDER);
+ prep_transhuge_page(page_tail);
+
+ /* move sub PMD page mapcount */
+ /*atomic_set(compound_mapcount_ptr(page_tail), page_tail_mapcount);*/
+ /*
+ * tail_page->_refcount is zero and not changing from under us. But
+ * get_page_unless_zero() may be running from under us on the
+ * tail_page. If we used atomic_set() below instead of atomic_inc() or
+ * atomic_add(), we would then run atomic_set() concurrently with
+ * get_page_unless_zero(), and atomic_set() is implemented in C not
+ * using locked ops. spin_unlock on x86 sometime uses locked ops
+ * because of PPro errata 66, 92, so unless somebody can guarantee
+ * atomic_set() here would be safe on all archs (and not only on x86),
+ * it's safer to use atomic_inc()/atomic_add().
+ */
+ if (PageAnon(head) && !PageSwapCache(head)) {
+ page_ref_inc(page_tail);
+ } else {
+ VM_BUG_ON(1);
+ /* Additional pin to radix tree */
+ page_ref_add(page_tail, 2);
+ }
+
+ page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP;
+ page_tail->flags |= (head->flags &
+ ((1L << PG_referenced) |
+ (1L << PG_swapbacked) |
+ (1L << PG_swapcache) |
+ (1L << PG_mlocked) |
+ (1L << PG_uptodate) |
+ (1L << PG_active) |
+ (1L << PG_locked) |
+ (1L << PG_unevictable) |
+ (1L << PG_dirty) |
+ /* preserve THP */
+ (1L << PG_head)));
+
+ /*
+ * After clearing PageTail the gup refcount can be released.
+ * Page flags also must be visible before we make the page non-compound.
+ */
+ smp_wmb();
+
+ if (page_is_young(head))
+ set_page_young(page_tail);
+ if (page_is_idle(head))
+ set_page_idle(page_tail);
+
+ /* ->mapping in first tail page is compound_mapcount */
+ VM_BUG_ON_PAGE(tail > 2 && page_tail->mapping != TAIL_MAPPING,
+ page_tail);
+ page_tail->mapping = head->mapping;
+
+ page_tail->index = head->index + tail;
+ page_cpupid_xchg_last(page_tail, page_cpupid_last(head));
+ lru_add_pud_page_tail(head, page_tail, lruvec, list);
+}
+
+static void __split_huge_pud_page(struct page *page, struct list_head *list,
+ unsigned long flags)
+{
+ struct page *head = compound_head(page);
+ struct zone *zone = page_zone(head);
+ struct lruvec *lruvec;
+ pgoff_t end = -1;
+ int i;
+
+ lruvec = mem_cgroup_page_lruvec(head, zone->zone_pgdat);
+
+ /* complete memcg works before add pages to LRU */
+ mem_cgroup_split_huge_pud_fixup(head);
+
+ if (!PageAnon(page)) {
+ VM_BUG_ON(1);
+ end = DIV_ROUND_UP(i_size_read(head->mapping->host), PAGE_SIZE);
+ }
+
+ for (i = HPAGE_PUD_NR - HPAGE_PMD_NR; i >= 1; i -= HPAGE_PMD_NR) {
+ __split_huge_pud_page_tail(head, i, lruvec, list);
+ /* Some pages can be beyond i_size: drop them from page cache */
+ if (head[i].index >= end) {
+ VM_BUG_ON(1);
+ __ClearPageDirty(head + i);
+ __delete_from_page_cache(head + i, NULL);
+ if (IS_ENABLED(CONFIG_SHMEM) && PageSwapBacked(head))
+ shmem_uncharge(head->mapping->host, 1);
+ put_page(head + i);
+ }
+ }
+ /* reset head page order */
+ prep_compound_page(head, HPAGE_PMD_ORDER);
+ prep_transhuge_page(head);
+
+ /* See comment in __split_huge_page_tail() */
+ if (PageAnon(head)) {
+ /* Additional pin to radix tree of swap cache */
+ if (PageSwapCache(head)) {
+ VM_BUG_ON(1);
+ page_ref_add(head, 2);
+ } else
+ page_ref_inc(head);
+ } else {
+ VM_BUG_ON(1);
+ /* Additional pin to radix tree */
+ page_ref_add(head, 2);
+ xa_unlock(&head->mapping->i_pages);
+ }
+
+ spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags);
+
+ unfreeze_pud_page(head);
+
+ for (i = 0; i < HPAGE_PUD_NR; i += HPAGE_PMD_NR) {
+ struct page *subpage = head + i;
+
+ if (subpage == page)
+ continue;
+ unlock_page(subpage);
+
+ /*
+ * Subpages may be freed if there wasn't any mapping
+ * like if add_to_swap() is running on a lru page that
+ * had its mapping zapped. And freeing these pages
+ * requires taking the lru_lock so we do the put_page
+ * of the tail pages after the split is complete.
+ */
+ put_page(subpage);
+ }
+}
+/* Racy check whether the huge page can be split */
+bool can_split_huge_pud_page(struct page *page, int *pextra_pins)
+{
+ int extra_pins;
+
+ /* Additional pins from radix tree */
+ if (PageAnon(page))
+ extra_pins = PageSwapCache(page) ? HPAGE_PUD_NR : 0;
+ else
+ extra_pins = HPAGE_PUD_NR;
+ if (pextra_pins)
+ *pextra_pins = extra_pins;
+ return total_mapcount(page) == page_count(page) - extra_pins - 1;
+}
+
+/*
+ * This function splits huge page into normal pages. @page can point to any
+ * subpage of huge page to split. Split doesn't change the position of @page.
+ *
+ * Only caller must hold pin on the @page, otherwise split fails with -EBUSY.
+ * The huge page must be locked.
+ *
+ * If @list is null, tail pages will be added to LRU list, otherwise, to @list.
+ *
+ * Both head page and tail pages will inherit mapping, flags, and so on from
+ * the hugepage.
+ *
+ * GUP pin and PG_locked transferred to @page. Rest subpages can be freed if
+ * they are not mapped.
+ *
+ * Returns 0 if the hugepage is split successfully.
+ * Returns -EBUSY if the page is pinned or if anon_vma disappeared from under
+ * us.
+ */
+int split_huge_pud_page_to_list(struct page *page, struct list_head *list)
+{
+ struct page *head = compound_head(page);
+ struct pglist_data *pgdata = NODE_DATA(page_to_nid(head));
+ struct anon_vma *anon_vma = NULL;
+ struct address_space *mapping = NULL;
+ int count, mapcount, extra_pins, ret;
+ bool mlocked;
+ unsigned long flags;
+
+ VM_BUG_ON_PAGE(is_huge_zero_page(page), page);
+ VM_BUG_ON_PAGE(!PageLocked(page), page);
+ VM_BUG_ON_PAGE(!PageCompound(page), page);
+
+ if (PageWriteback(page))
+ return -EBUSY;
+
+ if (PageAnon(head)) {
+ /*
+ * The caller does not necessarily hold an mmap_sem that would
+ * prevent the anon_vma disappearing so we first we take a
+ * reference to it and then lock the anon_vma for write. This
+ * is similar to page_lock_anon_vma_read except the write lock
+ * is taken to serialise against parallel split or collapse
+ * operations.
+ */
+ anon_vma = page_get_anon_vma(head);
+ if (!anon_vma) {
+ ret = -EBUSY;
+ goto out;
+ }
+ mapping = NULL;
+ anon_vma_lock_write(anon_vma);
+ } else {
+ VM_BUG_ON(1);
+ mapping = head->mapping;
+
+ /* Truncated ? */
+ if (!mapping) {
+ ret = -EBUSY;
+ goto out;
+ }
+
+ anon_vma = NULL;
+ i_mmap_lock_read(mapping);
+ }
+
+ /*
+ * Racy check if we can split the page, before freeze_pud_page() will
+ * split PUDs
+ */
+ if (!can_split_huge_pud_page(head, &extra_pins)) {
+ ret = -EBUSY;
+ goto out_unlock;
+ }
+
+ mlocked = PageMlocked(page);
+ freeze_pud_page(head);
+ VM_BUG_ON_PAGE(compound_mapcount(head), head);
+
+ /* Make sure the page is not on per-CPU pagevec as it takes pin */
+ if (mlocked)
+ lru_add_drain();
+
+ /* prevent PageLRU to go away from under us, and freeze lru stats */
+ spin_lock_irqsave(zone_lru_lock(page_zone(head)), flags);
+
+ if (mapping) {
+ void **pslot;
+
+ VM_BUG_ON(1);
+
+ xa_lock(&mapping->i_pages);
+ pslot = radix_tree_lookup_slot(&mapping->i_pages,
+ page_index(head));
+ /*
+ * Check if the head page is present in radix tree.
+ * We assume all tail are present too, if head is there.
+ */
+ if (radix_tree_deref_slot_protected(pslot,
+ &mapping->i_pages.xa_lock) != head)
+ goto fail;
+ }
+
+ /* Prevent deferred_split_scan() touching ->_refcount */
+ spin_lock(&pgdata->split_queue_lock);
+ count = page_count(head);
+ mapcount = total_mapcount(head);
+ if (!mapcount && page_ref_freeze(head, 1 + extra_pins)) {
+ if (!list_empty(page_deferred_list(head))) {
+ pgdata->split_queue_len--;
+ list_del(page_deferred_list(head));
+ }
+ if (mapping) {
+ VM_BUG_ON(1);
+ __dec_node_page_state(page, NR_SHMEM_THPS);
+ }
+ spin_unlock(&pgdata->split_queue_lock);
+ __split_huge_pud_page(page, list, flags);
+ if (PageSwapCache(head)) {
+ swp_entry_t entry = { .val = page_private(head) };
+
+ VM_BUG_ON(1);
+
+ ret = split_swap_cluster(entry);
+ } else
+ ret = 0;
+ } else {
+ if (IS_ENABLED(CONFIG_DEBUG_VM) && mapcount) {
+ pr_alert("total_mapcount: %u, page_count(): %u\n",
+ mapcount, count);
+ if (PageTail(page))
+ dump_page(head, NULL);
+ dump_page(page, "total_mapcount(head) > 0");
+ VM_BUG_ON(1);
+ }
+ spin_unlock(&pgdata->split_queue_lock);
+fail:
+ if (mapping) {
+ VM_BUG_ON(1);
+ xa_unlock(&mapping->i_pages);
+ }
+ spin_unlock_irqrestore(zone_lru_lock(page_zone(head)), flags);
+ unfreeze_pud_page(head);
+ ret = -EBUSY;
+ }
+
+out_unlock:
+ if (anon_vma) {
+ anon_vma_unlock_write(anon_vma);
+ put_anon_vma(anon_vma);
+ }
+ if (mapping)
+ i_mmap_unlock_read(mapping);
+out:
+ count_vm_event(!ret ? THP_SPLIT_PUD_PAGE : THP_SPLIT_PUD_PAGE_FAILED);
+ return ret;
+}
#endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */

static void __split_huge_zero_page_pmd(struct vm_area_struct *vma,
@@ -2687,7 +3228,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
set_page_dirty(page);
if (!PageReferenced(page) && pmd_young(_pmd))
SetPageReferenced(page);
- page_remove_rmap(page, true);
+ page_remove_rmap(page, true, HPAGE_PMD_ORDER);
put_page(page);
add_mm_counter(mm, mm_counter_file(page), -HPAGE_PMD_NR);
return;
@@ -2787,12 +3328,19 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
* Set PG_double_map before dropping compound_mapcount to avoid
* false-negative page_mapped().
*/
- if (compound_mapcount(page) > 1 && !TestSetPageDoubleMap(page)) {
+ if (((PMDPageInPUD(page) &&
+ sub_compound_mapcount(page) >
+ (1 + PagePUDDoubleMap(compound_head(page)))) ||
+ compound_mapcount(page) > 1)
+ && !TestSetPageDoubleMap(page)) {
for (i = 0; i < HPAGE_PMD_NR; i++)
atomic_inc(&page[i]._mapcount);
}

- if (atomic_add_negative(-1, compound_mapcount_ptr(page))) {
+ if ((PMDPageInPUD(page) &&
+ atomic_add_negative(-(1 + PagePUDDoubleMap(compound_head(page))),
+ sub_compound_mapcount_ptr(page, 1))) ||
+ atomic_add_negative(-1, compound_mapcount_ptr(page))) {
/* Last compound_mapcount is gone. */
__dec_node_page_state(page, NR_ANON_THPS);
if (TestClearPageDoubleMap(page)) {
@@ -2807,7 +3355,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,

if (freeze) {
for (i = 0; i < HPAGE_PMD_NR; i++) {
- page_remove_rmap(page + i, false);
+ page_remove_rmap(page + i, false, 0);
put_page(page + i);
}
}
@@ -2892,6 +3440,11 @@ void vma_adjust_trans_huge(struct vm_area_struct *vma,
* previously contain an hugepage: check if we need to split
* an huge pmd.
*/
+ if (start & ~HPAGE_PUD_MASK &&
+ (start & HPAGE_PUD_MASK) >= vma->vm_start &&
+ (start & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE <= vma->vm_end)
+ split_huge_pud_address(vma, start, false, NULL);
+
if (start & ~HPAGE_PMD_MASK &&
(start & HPAGE_PMD_MASK) >= vma->vm_start &&
(start & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end)
@@ -2902,6 +3455,11 @@ void vma_adjust_trans_huge(struct vm_area_struct *vma,
* previously contain an hugepage: check if we need to split
* an huge pmd.
*/
+ if (end & ~HPAGE_PUD_MASK &&
+ (end & HPAGE_PUD_MASK) >= vma->vm_start &&
+ (end & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE <= vma->vm_end)
+ split_huge_pud_address(vma, end, false, NULL);
+
if (end & ~HPAGE_PMD_MASK &&
(end & HPAGE_PMD_MASK) >= vma->vm_start &&
(end & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= vma->vm_end)
@@ -2916,6 +3474,11 @@ void vma_adjust_trans_huge(struct vm_area_struct *vma,
struct vm_area_struct *next = vma->vm_next;
unsigned long nstart = next->vm_start;
nstart += adjust_next << PAGE_SHIFT;
+ if (nstart & ~HPAGE_PUD_MASK &&
+ (nstart & HPAGE_PUD_MASK) >= next->vm_start &&
+ (nstart & HPAGE_PUD_MASK) + HPAGE_PUD_SIZE <= next->vm_end)
+ split_huge_pud_address(next, nstart, false, NULL);
+
if (nstart & ~HPAGE_PMD_MASK &&
(nstart & HPAGE_PMD_MASK) >= next->vm_start &&
(nstart & HPAGE_PMD_MASK) + HPAGE_PMD_SIZE <= next->vm_end)
@@ -3084,12 +3647,23 @@ int total_mapcount(struct page *page)
if (PageHuge(page))
return compound;
ret = compound;
- for (i = 0; i < HPAGE_PMD_NR; i++)
- ret += atomic_read(&page[i]._mapcount) + 1;
+ /* if PMD, read all base page, if PUD, read the sub_compound_mapcount()*/
+ if (compound_order(page) == HPAGE_PMD_ORDER) {
+ for (i = 0; i < hpage_nr_pages(page); i++)
+ ret += atomic_read(&page[i]._mapcount) + 1;
+ } else if (compound_order(page) == HPAGE_PUD_ORDER) {
+ for (i = 0; i < HPAGE_PUD_NR; i += HPAGE_PMD_NR)
+ ret += sub_compound_mapcount(&page[i]);
+ for (i = 0; i < hpage_nr_pages(page); i++)
+ ret += atomic_read(&page[i]._mapcount) + 1;
+ } else
+ VM_BUG_ON_PAGE(1, page);
/* File pages has compound_mapcount included in _mapcount */
+ /* both PUD and PMD has HPAGE_PMD_NR sub pages */
if (!PageAnon(page))
return ret - compound * HPAGE_PMD_NR;
- if (PageDoubleMap(page))
+ /* both PUD and PMD has HPAGE_PMD_NR sub pages */
+ if (PagePUDDoubleMap(page) || PageDoubleMap(page))
ret -= HPAGE_PMD_NR;
return ret;
}
@@ -3135,13 +3709,38 @@ int page_trans_huge_mapcount(struct page *page, int *total_mapcount)
page = compound_head(page);

_total_mapcount = ret = 0;
- for (i = 0; i < HPAGE_PMD_NR; i++) {
- mapcount = atomic_read(&page[i]._mapcount) + 1;
- ret = max(ret, mapcount);
- _total_mapcount += mapcount;
- }
- if (PageDoubleMap(page)) {
+ /* if PMD, read all base page, if PUD, read the sub_compound_mapcount()*/
+ if (compound_order(page) == HPAGE_PMD_ORDER) {
+ for (i = 0; i < hpage_nr_pages(page); i++) {
+ mapcount = atomic_read(&page[i]._mapcount) + 1;
+ ret = max(ret, mapcount);
+ _total_mapcount += mapcount;
+ }
+ } else if (compound_order(page) == HPAGE_PUD_ORDER) {
+ for (i = 0; i < HPAGE_PUD_NR; i += HPAGE_PMD_NR) {
+ int j;
+
+ mapcount = sub_compound_mapcount(&page[i]);
+ ret = max(ret, mapcount);
+ _total_mapcount += mapcount;
+
+ /* Triple mapped at base page size */
+ for (j = 0; j < HPAGE_PMD_NR; j++) {
+ mapcount = atomic_read(&page[i + j]._mapcount) + 1;
+ ret = max(ret, mapcount);
+ _total_mapcount += mapcount;
+ }
+
+ if (PageDoubleMap(&page[i])) {
+ ret -= 1;
+ _total_mapcount -= HPAGE_PMD_NR;
+ }
+ }
+ } else
+ VM_BUG_ON_PAGE(1, page);
+ if (PageDoubleMap(page) || PagePUDDoubleMap(page)) {
ret -= 1;
+ /* both PUD and PMD has HPAGE_PMD_NR sub pages */
_total_mapcount -= HPAGE_PMD_NR;
}
mapcount = compound_mapcount(page);
@@ -3360,6 +3959,9 @@ static unsigned long deferred_split_count(struct shrinker *shrink,
return READ_ONCE(pgdata->split_queue_len);
}

+#define deferred_list_entry(x) (compound_head(list_entry((void *)x, \
+ struct page, mapping)))
+
static unsigned long deferred_split_scan(struct shrinker *shrink,
struct shrink_control *sc)
{
@@ -3372,8 +3974,7 @@ static unsigned long deferred_split_scan(struct shrinker *shrink,
spin_lock_irqsave(&pgdata->split_queue_lock, flags);
/* Take pin on all head pages to avoid freeing them under us */
list_for_each_safe(pos, next, &pgdata->split_queue) {
- page = list_entry((void *)pos, struct page, mapping);
- page = compound_head(page);
+ page = deferred_list_entry(pos);
if (get_page_unless_zero(page)) {
list_move(page_deferred_list(page), &list);
} else {
@@ -3387,12 +3988,18 @@ static unsigned long deferred_split_scan(struct shrinker *shrink,
spin_unlock_irqrestore(&pgdata->split_queue_lock, flags);

list_for_each_safe(pos, next, &list) {
- page = list_entry((void *)pos, struct page, mapping);
+ page = deferred_list_entry(pos);
if (!trylock_page(page))
goto next;
/* split_huge_page() removes page from list on success */
- if (!split_huge_page(page))
- split++;
+ if (compound_order(page) == HPAGE_PUD_ORDER) {
+ if (!split_huge_pud_page(page))
+ split++;
+ } else if (compound_order(page) == HPAGE_PMD_ORDER) {
+ if (!split_huge_page(page))
+ split++;
+ } else
+ VM_BUG_ON_PAGE(1, page);
unlock_page(page);
next:
put_page(page);
@@ -3499,7 +4106,7 @@ void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw,
if (pmd_soft_dirty(pmdval))
pmdswp = pmd_swp_mksoft_dirty(pmdswp);
set_pmd_at(mm, address, pvmw->pmd, pmdswp);
- page_remove_rmap(page, true);
+ page_remove_rmap(page, true, HPAGE_PMD_ORDER);
put_page(page);
}

@@ -3525,7 +4132,7 @@ void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new)

flush_cache_range(vma, mmun_start, mmun_start + HPAGE_PMD_SIZE);
if (PageAnon(new))
- page_add_anon_rmap(new, vma, mmun_start, true);
+ page_add_anon_rmap(new, vma, mmun_start, true, HPAGE_PMD_ORDER);
else
page_add_file_rmap(new, true);
set_pmd_at(mm, mmun_start, pvmw->pmd, pmde);
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index afef61656c1e..0db6c31440e8 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -3418,7 +3418,7 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
set_page_dirty(page);

hugetlb_count_sub(pages_per_huge_page(h), mm);
- page_remove_rmap(page, true);
+ page_remove_rmap(page, true, huge_page_order(h));

spin_unlock(ptl);
tlb_remove_page_size(tlb, page, huge_page_size(h));
@@ -3643,7 +3643,7 @@ static vm_fault_t hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma,
mmu_notifier_invalidate_range(mm, range.start, range.end);
set_huge_pte_at(mm, haddr, ptep,
make_huge_pte(vma, new_page, 1));
- page_remove_rmap(old_page, true);
+ page_remove_rmap(old_page, true, huge_page_order(h));
hugepage_add_new_anon_rmap(new_page, vma, haddr);
/* Make the old page be freed below */
new_page = old_page;
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index aedaa9f75806..3acfddcba714 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -674,7 +674,7 @@ static void __collapse_huge_page_copy(pte_t *pte, struct page *page,
* superfluous.
*/
pte_clear(vma->vm_mm, address, _pte);
- page_remove_rmap(src_page, false);
+ page_remove_rmap(src_page, false, 0);
spin_unlock(ptl);
free_page_and_swap_cache(src_page);
}
@@ -1073,7 +1073,7 @@ static void collapse_huge_page(struct mm_struct *mm,

spin_lock(pmd_ptl);
BUG_ON(!pmd_none(*pmd));
- page_add_new_anon_rmap(new_page, vma, address, true);
+ page_add_new_anon_rmap(new_page, vma, address, true, HPAGE_PMD_ORDER);
mem_cgroup_commit_charge(new_page, memcg, false, true);
lru_cache_add_active_or_unevictable(new_page, vma);
pgtable_trans_huge_deposit(mm, pmd, pgtable);
diff --git a/mm/ksm.c b/mm/ksm.c
index dc1ec06b71a0..68f1d0f8be22 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -1154,7 +1154,7 @@ static int replace_page(struct vm_area_struct *vma, struct page *page,
*/
if (!is_zero_pfn(page_to_pfn(kpage))) {
get_page(kpage);
- page_add_anon_rmap(kpage, vma, addr, false);
+ page_add_anon_rmap(kpage, vma, addr, false, 0);
newpte = mk_pte(kpage, vma->vm_page_prot);
} else {
newpte = pte_mkspecial(pfn_pte(page_to_pfn(kpage),
@@ -1178,7 +1178,7 @@ static int replace_page(struct vm_area_struct *vma, struct page *page,
ptep_clear_flush(vma, addr, ptep);
set_pte_at_notify(mm, addr, ptep, newpte);

- page_remove_rmap(page, false);
+ page_remove_rmap(page, false, 0);
if (!page_mapped(page))
try_to_free_swap(page);
put_page(page);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index af7f18b32389..ae3ff6a4da8c 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2678,6 +2678,19 @@ void mem_cgroup_split_huge_fixup(struct page *head)

__mod_memcg_state(head->mem_cgroup, MEMCG_RSS_HUGE, -HPAGE_PMD_NR);
}
+
+void mem_cgroup_split_huge_pud_fixup(struct page *head)
+{
+ int i;
+
+ if (mem_cgroup_disabled())
+ return;
+
+ for (i = HPAGE_PMD_NR; i < HPAGE_PUD_NR; i += HPAGE_PMD_NR)
+ head[i].mem_cgroup = head->mem_cgroup;
+
+ /*__mod_memcg_state(head->mem_cgroup, MEMCG_RSS_HUGE, -HPAGE_PUD_NR);*/
+}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

#ifdef CONFIG_MEMCG_SWAP
diff --git a/mm/memory.c b/mm/memory.c
index 3608b5436519..c875cc1a2600 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1088,7 +1088,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
mark_page_accessed(page);
}
rss[mm_counter(page)]--;
- page_remove_rmap(page, false);
+ page_remove_rmap(page, false, 0);
if (unlikely(page_mapcount(page) < 0))
print_bad_pte(vma, addr, ptent, page);
if (unlikely(__tlb_remove_page(tlb, page))) {
@@ -1116,7 +1116,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,

pte_clear_not_present_full(mm, addr, pte, tlb->fullmm);
rss[mm_counter(page)]--;
- page_remove_rmap(page, false);
+ page_remove_rmap(page, false, 0);
put_page(page);
continue;
}
@@ -2300,7 +2300,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
* thread doing COW.
*/
ptep_clear_flush_notify(vma, vmf->address, vmf->pte);
- page_add_new_anon_rmap(new_page, vma, vmf->address, false);
+ page_add_new_anon_rmap(new_page, vma, vmf->address, false, 0);
mem_cgroup_commit_charge(new_page, memcg, false, false);
lru_cache_add_active_or_unevictable(new_page, vma);
/*
@@ -2333,7 +2333,7 @@ static vm_fault_t wp_page_copy(struct vm_fault *vmf)
* mapcount is visible. So transitively, TLBs to
* old page will be flushed before it can be reused.
*/
- page_remove_rmap(old_page, false);
+ page_remove_rmap(old_page, false, 0);
}

/* Free the old page.. */
@@ -2816,11 +2816,11 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)

/* ksm created a completely new copy */
if (unlikely(page != swapcache && swapcache)) {
- page_add_new_anon_rmap(page, vma, vmf->address, false);
+ page_add_new_anon_rmap(page, vma, vmf->address, false, 0);
mem_cgroup_commit_charge(page, memcg, false, false);
lru_cache_add_active_or_unevictable(page, vma);
} else {
- do_page_add_anon_rmap(page, vma, vmf->address, exclusive);
+ do_page_add_anon_rmap(page, vma, vmf->address, exclusive, 0);
mem_cgroup_commit_charge(page, memcg, true, false);
activate_page(page);
}
@@ -2967,7 +2967,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
}

inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
- page_add_new_anon_rmap(page, vma, vmf->address, false);
+ page_add_new_anon_rmap(page, vma, vmf->address, false, 0);
mem_cgroup_commit_charge(page, memcg, false, false);
lru_cache_add_active_or_unevictable(page, vma);
setpte:
@@ -3241,7 +3241,7 @@ vm_fault_t alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg,
/* copy-on-write page */
if (write && !(vma->vm_flags & VM_SHARED)) {
inc_mm_counter_fast(vma->vm_mm, MM_ANONPAGES);
- page_add_new_anon_rmap(page, vma, vmf->address, false);
+ page_add_new_anon_rmap(page, vma, vmf->address, false, 0);
mem_cgroup_commit_charge(page, memcg, false, false);
lru_cache_add_active_or_unevictable(page, vma);
} else {
diff --git a/mm/migrate.c b/mm/migrate.c
index b8c79aa62134..f7e5d88210ee 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -268,7 +268,7 @@ static bool remove_migration_pte(struct page *page, struct vm_area_struct *vma,
set_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte);

if (PageAnon(new))
- page_add_anon_rmap(new, vma, pvmw.address, false);
+ page_add_anon_rmap(new, vma, pvmw.address, false, 0);
else
page_add_file_rmap(new, false);
}
@@ -2067,7 +2067,7 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,

page_ref_unfreeze(page, 2);
mlock_migrate_page(new_page, page);
- page_remove_rmap(page, true);
+ page_remove_rmap(page, true, HPAGE_PMD_ORDER);
set_page_owner_migrate_reason(new_page, MR_NUMA_MISPLACED);

spin_unlock(ptl);
@@ -2297,7 +2297,7 @@ static int migrate_vma_collect_pmd(pmd_t *pmdp,
* drop page refcount. Page won't be freed, as we took
* a reference just above.
*/
- page_remove_rmap(page, false);
+ page_remove_rmap(page, false, 0);
put_page(page);

if (pte_present(pte))
@@ -2688,7 +2688,7 @@ static void migrate_vma_insert_page(struct migrate_vma *migrate,
}

inc_mm_counter(mm, MM_ANONPAGES);
- page_add_new_anon_rmap(page, vma, addr, false);
+ page_add_new_anon_rmap(page, vma, addr, false, 0);
mem_cgroup_commit_charge(page, memcg, false, false);
if (!is_zone_device_page(page))
lru_cache_add_active_or_unevictable(page, vma);
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index a3b295ea7348..dbcccc022b30 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -626,6 +626,9 @@ void prep_compound_page(struct page *page, unsigned int order)
set_compound_head(p, page);
}
atomic_set(compound_mapcount_ptr(page), -1);
+ if (order == HPAGE_PUD_ORDER)
+ for (i = 0; i < HPAGE_PUD_NR; i += HPAGE_PMD_NR)
+ atomic_set(sub_compound_mapcount_ptr(&page[i], 1), -1);
}

#ifdef CONFIG_DEBUG_PAGEALLOC
@@ -1001,6 +1004,13 @@ static int free_tail_pages_check(struct page *head_page, struct page *page)
*/
break;
default:
+ /* sub_compound_map_ptr store here */
+ if (compound_order(head_page) == HPAGE_PUD_ORDER &&
+ (page - head_page) % HPAGE_PMD_NR == 3) {
+ if (unlikely(atomic_read(&page->compound_mapcount) != -1))
+ bad_page(page, "nonzero sub_compound_mapcount", 0);
+ break;
+ }
if (page->mapping != TAIL_MAPPING) {
bad_page(page, "corrupted mapping in tail page", 0);
goto out;
@@ -1041,8 +1051,14 @@ static __always_inline bool free_pages_prepare(struct page *page,

VM_BUG_ON_PAGE(compound && compound_order(page) != order, page);

- if (compound)
+ if (compound) {
ClearPageDoubleMap(page);
+ if (order == HPAGE_PUD_ORDER) {
+ ClearPagePUDDoubleMap(page);
+ for (i = 0; i < HPAGE_PUD_NR; i += HPAGE_PMD_NR)
+ ClearPageDoubleMap(&page[i]);
+ }
+ }
for (i = 1; i < (1 << order); i++) {
if (compound)
bad += free_tail_pages_check(page, page + i);
diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index 0b79568fba1c..95af1d67f209 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -236,6 +236,17 @@ pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
}
#endif

+#ifndef __HAVE_ARCH_PUDP_INVALIDATE
+pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
+ pud_t *pudp)
+{
+ pud_t old = pudp_establish(vma, address, pudp, pud_mknotpresent(*pudp));
+
+ flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
+ return old;
+}
+#endif
+
#ifndef pmdp_collapse_flush
pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
pmd_t *pmdp)
diff --git a/mm/rmap.c b/mm/rmap.c
index f69d81d4a956..79908cfc518a 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1097,9 +1097,9 @@ static void __page_check_anon_rmap(struct page *page,
* (but PageKsm is never downgraded to PageAnon).
*/
void page_add_anon_rmap(struct page *page,
- struct vm_area_struct *vma, unsigned long address, bool compound)
+ struct vm_area_struct *vma, unsigned long address, bool compound, int order)
{
- do_page_add_anon_rmap(page, vma, address, compound ? RMAP_COMPOUND : 0);
+ do_page_add_anon_rmap(page, vma, address, compound ? RMAP_COMPOUND : 0, order);
}

/*
@@ -1108,7 +1108,7 @@ void page_add_anon_rmap(struct page *page,
* Everybody else should continue to use page_add_anon_rmap above.
*/
void do_page_add_anon_rmap(struct page *page,
- struct vm_area_struct *vma, unsigned long address, int flags)
+ struct vm_area_struct *vma, unsigned long address, int flags, int order)
{
bool compound = flags & RMAP_COMPOUND;
bool first;
@@ -1117,7 +1117,18 @@ void do_page_add_anon_rmap(struct page *page,
atomic_t *mapcount;
VM_BUG_ON_PAGE(!PageLocked(page), page);
VM_BUG_ON_PAGE(!PageTransHuge(page), page);
- mapcount = compound_mapcount_ptr(page);
+ if (compound_order(page) == HPAGE_PUD_ORDER) {
+ if (order == HPAGE_PUD_ORDER) {
+ mapcount = compound_mapcount_ptr(page);
+ } else if (order == HPAGE_PMD_ORDER) {
+ VM_BUG_ON(!PMDPageInPUD(page));
+ mapcount = sub_compound_mapcount_ptr(page, 1);
+ } else
+ VM_BUG_ON(1);
+ } else if (compound_order(page) == HPAGE_PMD_ORDER) {
+ mapcount = compound_mapcount_ptr(page);
+ } else
+ VM_BUG_ON(1);
first = atomic_inc_and_test(mapcount);
} else {
first = atomic_inc_and_test(&page->_mapcount);
@@ -1132,7 +1143,7 @@ void do_page_add_anon_rmap(struct page *page,
* disabled.
*/
if (compound) {
- if (nr == HPAGE_PMD_NR)
+ if (order == HPAGE_PMD_ORDER)
__inc_node_page_state(page, NR_ANON_THPS);
else
__inc_node_page_state(page, NR_ANON_THPS_PUD);
@@ -1164,7 +1175,7 @@ void do_page_add_anon_rmap(struct page *page,
* Page does not have to be locked.
*/
void page_add_new_anon_rmap(struct page *page,
- struct vm_area_struct *vma, unsigned long address, bool compound)
+ struct vm_area_struct *vma, unsigned long address, bool compound, int order)
{
int nr = compound ? hpage_nr_pages(page) : 1;

@@ -1174,10 +1185,15 @@ void page_add_new_anon_rmap(struct page *page,
VM_BUG_ON_PAGE(!PageTransHuge(page), page);
/* increment count (starts at -1) */
atomic_set(compound_mapcount_ptr(page), 0);
- if (nr == HPAGE_PMD_NR)
- __inc_node_page_state(page, NR_ANON_THPS);
- else
+ if (order == HPAGE_PUD_ORDER) {
+ VM_BUG_ON(compound_order(page) != HPAGE_PUD_ORDER);
+ /* Anon THP always mapped first with PMD */
__inc_node_page_state(page, NR_ANON_THPS_PUD);
+ } else if (order == HPAGE_PMD_ORDER) {
+ VM_BUG_ON(compound_order(page) != HPAGE_PMD_ORDER);
+ __inc_node_page_state(page, NR_ANON_THPS);
+ } else
+ VM_BUG_ON(1);
} else {
/* Anon THP always mapped first with PMD */
VM_BUG_ON_PAGE(PageTransCompound(page), page);
@@ -1268,12 +1284,40 @@ static void page_remove_file_rmap(struct page *page, bool compound)
unlock_page_memcg(page);
}

-static void page_remove_anon_compound_rmap(struct page *page)
+static void page_remove_anon_compound_rmap(struct page *page, int order)
{
- int i, nr;
-
- if (!atomic_add_negative(-1, compound_mapcount_ptr(page)))
- return;
+ int i, nr = 0;
+ struct page *head = compound_head(page);
+
+ if (compound_order(head) == HPAGE_PUD_ORDER) {
+ if (order == HPAGE_PMD_ORDER) {
+ VM_BUG_ON(!PMDPageInPUD(page));
+ if (atomic_add_negative(-1, sub_compound_mapcount_ptr(page, 1))) {
+ if (TestClearPageDoubleMap(page)) {
+ /*
+ * Subpages can be mapped with PTEs too. Check how many of
+ * themi are still mapped.
+ */
+ for (i = 0; i < hpage_nr_pages(head); i++) {
+ if (atomic_add_negative(-1, &head[i]._mapcount))
+ nr++;
+ }
+ }
+ __dec_node_page_state(page, NR_ANON_THPS);
+ }
+ nr += HPAGE_PMD_NR;
+ __mod_node_page_state(page_pgdat(head), NR_ANON_MAPPED, -nr);
+ return;
+ } else {
+ VM_BUG_ON(order != HPAGE_PUD_ORDER);
+ if (!atomic_add_negative(-1, compound_mapcount_ptr(page)))
+ return;
+ }
+ } else if (compound_order(head) == HPAGE_PMD_ORDER) {
+ if (!atomic_add_negative(-1, compound_mapcount_ptr(page)))
+ return;
+ } else
+ VM_BUG_ON_PAGE(1, page);

/* Hugepages are not counted in NR_ANON_PAGES for now. */
if (unlikely(PageHuge(page)))
@@ -1282,30 +1326,44 @@ static void page_remove_anon_compound_rmap(struct page *page)
if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
return;

- if (hpage_nr_pages(page) == HPAGE_PMD_NR)
+ if (order == HPAGE_PMD_ORDER)
__dec_node_page_state(page, NR_ANON_THPS);
- else
+ else if (order == HPAGE_PUD_ORDER)
__dec_node_page_state(page, NR_ANON_THPS_PUD);
+ else
+ VM_BUG_ON(1);

- if (TestClearPageDoubleMap(page)) {
+ /* PMD-mapped PUD THP is handled above */
+ if (TestClearPagePUDDoubleMap(head)) {
+ VM_BUG_ON(!(compound_order(head) == HPAGE_PUD_ORDER || head == page));
+ /*
+ * Subpages can be mapped with PMDs too. Check how many of
+ * themi are still mapped.
+ */
+ for (i = 0, nr = 0; i < HPAGE_PUD_NR; i += HPAGE_PMD_NR) {
+ if (atomic_add_negative(-1, sub_compound_mapcount_ptr(&head[i], 1)))
+ nr += HPAGE_PMD_NR;
+ }
+ } else if (TestClearPageDoubleMap(head)) {
+ VM_BUG_ON(compound_order(head) != HPAGE_PMD_ORDER);
/*
* Subpages can be mapped with PTEs too. Check how many of
* themi are still mapped.
*/
- for (i = 0, nr = 0; i < hpage_nr_pages(page); i++) {
- if (atomic_add_negative(-1, &page[i]._mapcount))
+ for (i = 0, nr = 0; i < hpage_nr_pages(head); i++) {
+ if (atomic_add_negative(-1, &head[i]._mapcount))
nr++;
}
} else {
- nr = hpage_nr_pages(page);
+ nr = hpage_nr_pages(head);
}

if (unlikely(PageMlocked(page)))
clear_page_mlock(page);

if (nr) {
- __mod_node_page_state(page_pgdat(page), NR_ANON_MAPPED, -nr);
- deferred_split_huge_page(page);
+ __mod_node_page_state(page_pgdat(head), NR_ANON_MAPPED, -nr);
+ deferred_split_huge_page(head);
}
}

@@ -1316,13 +1374,13 @@ static void page_remove_anon_compound_rmap(struct page *page)
*
* The caller needs to hold the pte lock.
*/
-void page_remove_rmap(struct page *page, bool compound)
+void page_remove_rmap(struct page *page, bool compound, int order)
{
if (!PageAnon(page))
return page_remove_file_rmap(page, compound);

if (compound)
- return page_remove_anon_compound_rmap(page);
+ return page_remove_anon_compound_rmap(page, order);

/* page still mapped by someone else? */
if (!atomic_add_negative(-1, &page->_mapcount))
@@ -1672,7 +1730,7 @@ static bool try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
*
* See Documentation/vm/mmu_notifier.rst
*/
- page_remove_rmap(subpage, PageHuge(page));
+ page_remove_rmap(subpage, PageHuge(page), 0);
put_page(page);
}

diff --git a/mm/swap.c b/mm/swap.c
index 4929bc1be60e..79de59875280 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -851,6 +851,44 @@ void lru_add_page_tail(struct page *page, struct page *page_tail,
if (!PageUnevictable(page))
update_page_reclaim_stat(lruvec, file, PageActive(page_tail));
}
+
+/* used by __split_pud_huge_page_tail() */
+void lru_add_pud_page_tail(struct page *page, struct page *page_tail,
+ struct lruvec *lruvec, struct list_head *list)
+{
+ const int file = 0;
+
+ VM_BUG_ON_PAGE(!PageHead(page), page);
+ VM_BUG_ON_PAGE(PageLRU(page_tail), page);
+ VM_BUG_ON(NR_CPUS != 1 &&
+ !spin_is_locked(&lruvec_pgdat(lruvec)->lru_lock));
+
+ if (!list)
+ SetPageLRU(page_tail);
+
+ if (likely(PageLRU(page)))
+ list_add_tail(&page_tail->lru, &page->lru);
+ else if (list) {
+ /* page reclaim is reclaiming a huge page */
+ get_page(page_tail);
+ list_add_tail(&page_tail->lru, list);
+ } else {
+ struct list_head *list_head;
+ /*
+ * Head page has not yet been counted, as an hpage,
+ * so we must account for each subpage individually.
+ *
+ * Use the standard add function to put page_tail on the list,
+ * but then correct its position so they all end up in order.
+ */
+ add_page_to_lru_list(page_tail, lruvec, page_lru(page_tail));
+ list_head = page_tail->lru.prev;
+ list_move_tail(&page_tail->lru, list_head);
+ }
+
+ if (!PageUnevictable(page))
+ update_page_reclaim_stat(lruvec, file, PageActive(page_tail));
+}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec,
diff --git a/mm/swapfile.c b/mm/swapfile.c
index dbac1d49469d..742caaea2aa5 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1775,10 +1775,10 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
set_pte_at(vma->vm_mm, addr, pte,
pte_mkold(mk_pte(page, vma->vm_page_prot)));
if (page == swapcache) {
- page_add_anon_rmap(page, vma, addr, false);
+ page_add_anon_rmap(page, vma, addr, false, 0);
mem_cgroup_commit_charge(page, memcg, true, false);
} else { /* ksm created a completely new copy */
- page_add_new_anon_rmap(page, vma, addr, false);
+ page_add_new_anon_rmap(page, vma, addr, false, 0);
mem_cgroup_commit_charge(page, memcg, false, false);
lru_cache_add_active_or_unevictable(page, vma);
}
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index d59b5a73dfb3..e49537f6000e 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -90,7 +90,7 @@ static int mcopy_atomic_pte(struct mm_struct *dst_mm,
goto out_release_uncharge_unlock;

inc_mm_counter(dst_mm, MM_ANONPAGES);
- page_add_new_anon_rmap(page, dst_vma, dst_addr, false);
+ page_add_new_anon_rmap(page, dst_vma, dst_addr, false, 0);
mem_cgroup_commit_charge(page, memcg, false, false);
lru_cache_add_active_or_unevictable(page, dst_vma);

diff --git a/mm/util.c b/mm/util.c
index 1ea055138043..1b1b6dd386d1 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -536,8 +536,15 @@ struct address_space *page_mapping_file(struct page *page)
int __page_mapcount(struct page *page)
{
int ret;
+ struct page *head = compound_head(page);

ret = atomic_read(&page->_mapcount) + 1;
+ if (compound_order(head) == HPAGE_PUD_ORDER) {
+ struct page *sub_compound_page = head +
+ (((page - head) / HPAGE_PMD_NR) * HPAGE_PMD_NR);
+
+ ret += sub_compound_mapcount(sub_compound_page);
+ }
/*
* For file THP page->_mapcount contains total number of mapping
* of the page: no need to look into compound_mapcount.
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 25a88693e417..1d185cf748a6 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1263,6 +1263,10 @@ const char * const vmstat_text[] = {
"thp_fault_alloc_pud",
"thp_fault_fallback_pud",
"thp_split_pud",
+ "thp_split_pud_page",
+ "thp_split_pud_page_failed",
+ "thp_zero_pud_page_alloc",
+ "thp_zero_pud_page_alloc_failed",
#endif
"thp_zero_page_alloc",
"thp_zero_page_alloc_failed",
--
2.20.1
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