The patch titled
Subject: mm, dax: dax-pmd vs thp-pmd vs hugetlbfs-pmd
has been removed from the -mm tree. Its filename was
mm-dax-dax-pmd-vs-thp-pmd-vs-hugetlbfs-pmd.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
From: Dan Williams <dan.j.williams@xxxxxxxxx>
Subject: mm, dax: dax-pmd vs thp-pmd vs hugetlbfs-pmd
A dax-huge-page mapping while it uses some thp helpers is ultimately not a
transparent huge page. The distinction is especially important in the
get_user_pages() path. pmd_devmap() is used to distinguish dax-pmds from
pmd_huge() and pmd_trans_huge() which have slightly different semantics.
Explicitly mark the pmd_trans_huge() helpers that dax needs by adding
pmd_devmap() checks.
[kirill.shutemov@xxxxxxxxxxxxxxx: fix regression in handling mlocked pages in __split_huge_pmd()]
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Dave Hansen <dave@xxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxxxx>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/pgtable.h | 9 ++++++-
include/linux/huge_mm.h | 5 ++--
include/linux/mm.h | 7 +++++
mm/huge_memory.c | 38 +++++++++++++++++--------------
mm/memory.c | 8 +++---
mm/mprotect.c | 5 ++--
mm/pgtable-generic.c | 2 -
7 files changed, 47 insertions(+), 27 deletions(-)
diff -puN arch/x86/include/asm/pgtable.h~mm-dax-dax-pmd-vs-thp-pmd-vs-hugetlbfs-pmd arch/x86/include/asm/pgtable.h
--- a/arch/x86/include/asm/pgtable.h~mm-dax-dax-pmd-vs-thp-pmd-vs-hugetlbfs-pmd
+++ a/arch/x86/include/asm/pgtable.h
@@ -164,13 +164,20 @@ static inline int pmd_large(pmd_t pte)
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
static inline int pmd_trans_huge(pmd_t pmd)
{
- return pmd_val(pmd) & _PAGE_PSE;
+ return (pmd_val(pmd) & (_PAGE_PSE|_PAGE_DEVMAP)) == _PAGE_PSE;
}
static inline int has_transparent_hugepage(void)
{
return cpu_has_pse;
}
+
+#ifdef __HAVE_ARCH_PTE_DEVMAP
+static inline int pmd_devmap(pmd_t pmd)
+{
+ return !!(pmd_val(pmd) & _PAGE_DEVMAP);
+}
+#endif
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
static inline pte_t pte_set_flags(pte_t pte, pteval_t set)
diff -puN include/linux/huge_mm.h~mm-dax-dax-pmd-vs-thp-pmd-vs-hugetlbfs-pmd include/linux/huge_mm.h
--- a/include/linux/huge_mm.h~mm-dax-dax-pmd-vs-thp-pmd-vs-hugetlbfs-pmd
+++ a/include/linux/huge_mm.h
@@ -104,7 +104,8 @@ void __split_huge_pmd(struct vm_area_str
#define split_huge_pmd(__vma, __pmd, __address) \
do { \
pmd_t *____pmd = (__pmd); \
- if (pmd_trans_huge(*____pmd)) \
+ if (pmd_trans_huge(*____pmd) \
+ || pmd_devmap(*____pmd)) \
__split_huge_pmd(__vma, __pmd, __address); \
} while (0)
@@ -124,7 +125,7 @@ static inline bool pmd_trans_huge_lock(p
spinlock_t **ptl)
{
VM_BUG_ON_VMA(!rwsem_is_locked(&vma->vm_mm->mmap_sem), vma);
- if (pmd_trans_huge(*pmd))
+ if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd))
return __pmd_trans_huge_lock(pmd, vma, ptl);
else
return false;
diff -puN include/linux/mm.h~mm-dax-dax-pmd-vs-thp-pmd-vs-hugetlbfs-pmd include/linux/mm.h
--- a/include/linux/mm.h~mm-dax-dax-pmd-vs-thp-pmd-vs-hugetlbfs-pmd
+++ a/include/linux/mm.h
@@ -329,6 +329,13 @@ struct inode;
#define page_private(page) ((page)->private)
#define set_page_private(page, v) ((page)->private = (v))
+#if !defined(__HAVE_ARCH_PTE_DEVMAP) || !defined(CONFIG_TRANSPARENT_HUGEPAGE)
+static inline int pmd_devmap(pmd_t pmd)
+{
+ return 0;
+}
+#endif
+
/*
* FIXME: take this include out, include page-flags.h in
* files which need it (119 of them)
diff -puN mm/huge_memory.c~mm-dax-dax-pmd-vs-thp-pmd-vs-hugetlbfs-pmd mm/huge_memory.c
--- a/mm/huge_memory.c~mm-dax-dax-pmd-vs-thp-pmd-vs-hugetlbfs-pmd
+++ a/mm/huge_memory.c
@@ -995,7 +995,7 @@ int copy_huge_pmd(struct mm_struct *dst_
ret = -EAGAIN;
pmd = *src_pmd;
- if (unlikely(!pmd_trans_huge(pmd))) {
+ if (unlikely(!pmd_trans_huge(pmd) && !pmd_devmap(pmd))) {
pte_free(dst_mm, pgtable);
goto out_unlock;
}
@@ -1018,17 +1018,20 @@ int copy_huge_pmd(struct mm_struct *dst_
goto out_unlock;
}
- src_page = pmd_page(pmd);
- VM_BUG_ON_PAGE(!PageHead(src_page), src_page);
- get_page(src_page);
- page_dup_rmap(src_page, true);
- add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR);
+ if (pmd_trans_huge(pmd)) {
+ /* thp accounting separate from pmd_devmap accounting */
+ src_page = pmd_page(pmd);
+ VM_BUG_ON_PAGE(!PageHead(src_page), src_page);
+ get_page(src_page);
+ page_dup_rmap(src_page, true);
+ add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR);
+ atomic_long_inc(&dst_mm->nr_ptes);
+ pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable);
+ }
pmdp_set_wrprotect(src_mm, addr, src_pmd);
pmd = pmd_mkold(pmd_wrprotect(pmd));
- pgtable_trans_huge_deposit(dst_mm, dst_pmd, pgtable);
set_pmd_at(dst_mm, addr, dst_pmd, pmd);
- atomic_long_inc(&dst_mm->nr_ptes);
ret = 0;
out_unlock:
@@ -1716,7 +1719,7 @@ bool __pmd_trans_huge_lock(pmd_t *pmd, s
spinlock_t **ptl)
{
*ptl = pmd_lock(vma->vm_mm, pmd);
- if (likely(pmd_trans_huge(*pmd)))
+ if (likely(pmd_trans_huge(*pmd) || pmd_devmap(*pmd)))
return true;
spin_unlock(*ptl);
return false;
@@ -2788,7 +2791,7 @@ static void __split_huge_pmd_locked(stru
VM_BUG_ON(haddr & ~HPAGE_PMD_MASK);
VM_BUG_ON_VMA(vma->vm_start > haddr, vma);
VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma);
- VM_BUG_ON(!pmd_trans_huge(*pmd));
+ VM_BUG_ON(!pmd_trans_huge(*pmd) && !pmd_devmap(*pmd));
count_vm_event(THP_SPLIT_PMD);
@@ -2901,14 +2904,15 @@ void __split_huge_pmd(struct vm_area_str
mmu_notifier_invalidate_range_start(mm, haddr, haddr + HPAGE_PMD_SIZE);
ptl = pmd_lock(mm, pmd);
- if (unlikely(!pmd_trans_huge(*pmd)))
+ if (pmd_trans_huge(*pmd)) {
+ page = pmd_page(*pmd);
+ if (PageMlocked(page))
+ get_page(page);
+ else
+ page = NULL;
+ } else if (!pmd_devmap(*pmd))
goto out;
- page = pmd_page(*pmd);
__split_huge_pmd_locked(vma, pmd, haddr, false);
- if (PageMlocked(page))
- get_page(page);
- else
- page = NULL;
out:
spin_unlock(ptl);
mmu_notifier_invalidate_range_end(mm, haddr, haddr + HPAGE_PMD_SIZE);
@@ -2938,7 +2942,7 @@ static void split_huge_pmd_address(struc
return;
pmd = pmd_offset(pud, address);
- if (!pmd_present(*pmd) || !pmd_trans_huge(*pmd))
+ if (!pmd_present(*pmd) || (!pmd_trans_huge(*pmd) && !pmd_devmap(*pmd)))
return;
/*
* Caller holds the mmap_sem write mode, so a huge pmd cannot
diff -puN mm/memory.c~mm-dax-dax-pmd-vs-thp-pmd-vs-hugetlbfs-pmd mm/memory.c
--- a/mm/memory.c~mm-dax-dax-pmd-vs-thp-pmd-vs-hugetlbfs-pmd
+++ a/mm/memory.c
@@ -950,7 +950,7 @@ static inline int copy_pmd_range(struct
src_pmd = pmd_offset(src_pud, addr);
do {
next = pmd_addr_end(addr, end);
- if (pmd_trans_huge(*src_pmd)) {
+ if (pmd_trans_huge(*src_pmd) || pmd_devmap(*src_pmd)) {
int err;
VM_BUG_ON(next-addr != HPAGE_PMD_SIZE);
err = copy_huge_pmd(dst_mm, src_mm,
@@ -1177,7 +1177,7 @@ static inline unsigned long zap_pmd_rang
pmd = pmd_offset(pud, addr);
do {
next = pmd_addr_end(addr, end);
- if (pmd_trans_huge(*pmd)) {
+ if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) {
if (next - addr != HPAGE_PMD_SIZE) {
#ifdef CONFIG_DEBUG_VM
if (!rwsem_is_locked(&tlb->mm->mmap_sem)) {
@@ -3375,7 +3375,7 @@ static int __handle_mm_fault(struct mm_s
int ret;
barrier();
- if (pmd_trans_huge(orig_pmd)) {
+ if (pmd_trans_huge(orig_pmd) || pmd_devmap(orig_pmd)) {
unsigned int dirty = flags & FAULT_FLAG_WRITE;
if (pmd_protnone(orig_pmd))
@@ -3404,7 +3404,7 @@ static int __handle_mm_fault(struct mm_s
unlikely(__pte_alloc(mm, vma, pmd, address)))
return VM_FAULT_OOM;
/* if an huge pmd materialized from under us just retry later */
- if (unlikely(pmd_trans_huge(*pmd)))
+ if (unlikely(pmd_trans_huge(*pmd) || pmd_devmap(*pmd)))
return 0;
/*
* A regular pmd is established and it can't morph into a huge pmd
diff -puN mm/mprotect.c~mm-dax-dax-pmd-vs-thp-pmd-vs-hugetlbfs-pmd mm/mprotect.c
--- a/mm/mprotect.c~mm-dax-dax-pmd-vs-thp-pmd-vs-hugetlbfs-pmd
+++ a/mm/mprotect.c
@@ -149,7 +149,8 @@ static inline unsigned long change_pmd_r
unsigned long this_pages;
next = pmd_addr_end(addr, end);
- if (!pmd_trans_huge(*pmd) && pmd_none_or_clear_bad(pmd))
+ if (!pmd_trans_huge(*pmd) && !pmd_devmap(*pmd)
+ && pmd_none_or_clear_bad(pmd))
continue;
/* invoke the mmu notifier if the pmd is populated */
@@ -158,7 +159,7 @@ static inline unsigned long change_pmd_r
mmu_notifier_invalidate_range_start(mm, mni_start, end);
}
- if (pmd_trans_huge(*pmd)) {
+ if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) {
if (next - addr != HPAGE_PMD_SIZE)
split_huge_pmd(vma, pmd, addr);
else {
diff -puN mm/pgtable-generic.c~mm-dax-dax-pmd-vs-thp-pmd-vs-hugetlbfs-pmd mm/pgtable-generic.c
--- a/mm/pgtable-generic.c~mm-dax-dax-pmd-vs-thp-pmd-vs-hugetlbfs-pmd
+++ a/mm/pgtable-generic.c
@@ -132,7 +132,7 @@ pmd_t pmdp_huge_clear_flush(struct vm_ar
{
pmd_t pmd;
VM_BUG_ON(address & ~HPAGE_PMD_MASK);
- VM_BUG_ON(!pmd_trans_huge(*pmdp));
+ VM_BUG_ON(!pmd_trans_huge(*pmdp) && !pmd_devmap(*pmdp));
pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
return pmd;
_
Patches currently in -mm which might be from dan.j.williams@xxxxxxxxx are
dax-add-support-for-fsync-sync-v6-fix.patch
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