[PATCHv5 07/11] mm, thp: do not access mm->pmd_huge_pte directly

Kirill A. Shutemov
2013-10-07T13:54:47Z

Currently mm->pmd_huge_pte protected by page table lock. It will not
work with split lock. We have to have per-pmd pmd_huge_pte for proper
access serialization.

For now, let's just introduce wrapper to access mm->pmd_huge_pte.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Tested-by: Alex Thorlton <athorlton@sgi.com>
---
arch/s390/mm/pgtable.c | 12 ++++++------
arch/sparc/mm/tlb.c | 12 ++++++------
include/linux/mm.h | 1 +
mm/pgtable-generic.c | 12 ++++++------
4 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/arch/s390/mm/pgtable.c b/arch/s390/mm/pgtable.c
index de8cbc30dc..c463e5cd3b 100644
--- a/arch/s390/mm/pgtable.c
+++ b/arch/s390/mm/pgtable.c
@@ -1225,11 +1225,11 @@ void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
assert_spin_locked(&mm->page_table_lock);

/* FIFO */
- if (!mm->pmd_huge_pte)
+ if (!pmd_huge_pte(mm, pmdp))
INIT_LIST_HEAD(lh);
else
- list_add(lh, (struct list_head *) mm->pmd_huge_pte);
- mm->pmd_huge_pte = pgtable;
+ list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
+ pmd_huge_pte(mm, pmdp) = pgtable;
}

pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
@@ -1241,12 +1241,12 @@ pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
assert_spin_locked(&mm->page_table_lock);

/* FIFO */
- pgtable = mm->pmd_huge_pte;
+ pgtable = pmd_huge_pte(mm, pmdp);
lh = (struct list_head *) pgtable;
if (list_empty(lh))
- mm->pmd_huge_pte = NULL;
+ pmd_huge_pte(mm, pmdp) = NULL;
else {
- mm->pmd_huge_pte = (pgtable_t) lh->next;
+ pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
list_del(lh);
}
ptep = (pte_t *) pgtable;
diff --git a/arch/sparc/mm/tlb.c b/arch/sparc/mm/tlb.c
index 7a91f288c7..656cc46a81 100644
--- a/arch/sparc/mm/tlb.c
+++ b/arch/sparc/mm/tlb.c
@@ -196,11 +196,11 @@ void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
assert_spin_locked(&mm->page_table_lock);

/* FIFO */
- if (!mm->pmd_huge_pte)
+ if (!pmd_huge_pte(mm, pmdp))
INIT_LIST_HEAD(lh);
else
- list_add(lh, (struct list_head *) mm->pmd_huge_pte);
- mm->pmd_huge_pte = pgtable;
+ list_add(lh, (struct list_head *) pmd_huge_pte(mm, pmdp));
+ pmd_huge_pte(mm, pmdp) = pgtable;
}

pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
@@ -211,12 +211,12 @@ pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
assert_spin_locked(&mm->page_table_lock);

/* FIFO */
- pgtable = mm->pmd_huge_pte;
+ pgtable = pmd_huge_pte(mm, pmdp);
lh = (struct list_head *) pgtable;
if (list_empty(lh))
- mm->pmd_huge_pte = NULL;
+ pmd_huge_pte(mm, pmdp) = NULL;
else {
- mm->pmd_huge_pte = (pgtable_t) lh->next;
+ pmd_huge_pte(mm, pmdp) = (pgtable_t) lh->next;
list_del(lh);
}
pte_val(pgtable[0]) = 0;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index e3481c6b52..b96aac9622 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1299,6 +1299,7 @@ static inline spinlock_t *pmd_lockptr(struct mm_struct *mm, pmd_t *pmd)
return &mm->page_table_lock;
}

+#define pmd_huge_pte(mm, pmd) ((mm)->pmd_huge_pte)

static inline spinlock_t *pmd_lock(struct mm_struct *mm, pmd_t *pmd)
{
diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
index 3929a40bd6..41fee3e5d5 100644
--- a/mm/pgtable-generic.c
+++ b/mm/pgtable-generic.c
@@ -154,11 +154,11 @@ void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
assert_spin_locked(&mm->page_table_lock);

/* FIFO */
- if (!mm->pmd_huge_pte)
+ if (!pmd_huge_pte(mm, pmdp))
INIT_LIST_HEAD(&pgtable->lru);
else
- list_add(&pgtable->lru, &mm->pmd_huge_pte->lru);
- mm->pmd_huge_pte = pgtable;
+ list_add(&pgtable->lru, &pmd_huge_pte(mm, pmdp)->lru);
+ pmd_huge_pte(mm, pmdp) = pgtable;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif
@@ -173,11 +173,11 @@ pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
assert_spin_locked(&mm->page_table_lock);

/* FIFO */
- pgtable = mm->pmd_huge_pte;
+ pgtable = pmd_huge_pte(mm, pmdp);
if (list_empty(&pgtable->lru))
- mm->pmd_huge_pte = NULL;
+ pmd_huge_pte(mm, pmdp) = NULL;
else {
- mm->pmd_huge_pte = list_entry(pgtable->lru.next,
+ pmd_huge_pte(mm, pmdp) = list_entry(pgtable->lru.next,
struct page, lru);
list_del(&pgtable->lru);
}
--
1.8.4.rc3