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-rw-r--r--mm/memory.c104
1 files changed, 32 insertions, 72 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 4bdd1186b43b..a40e4b1cee4f 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -282,14 +282,11 @@ void free_pgtables(struct mmu_gather **tlb, struct vm_area_struct *vma,
int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
{
- struct page *new;
-
- spin_unlock(&mm->page_table_lock);
- new = pte_alloc_one(mm, address);
- spin_lock(&mm->page_table_lock);
+ struct page *new = pte_alloc_one(mm, address);
if (!new)
return -ENOMEM;
+ spin_lock(&mm->page_table_lock);
if (pmd_present(*pmd)) /* Another has populated it */
pte_free(new);
else {
@@ -297,6 +294,7 @@ int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address)
inc_page_state(nr_page_table_pages);
pmd_populate(mm, pmd, new);
}
+ spin_unlock(&mm->page_table_lock);
return 0;
}
@@ -344,9 +342,6 @@ void print_bad_pte(struct vm_area_struct *vma, pte_t pte, unsigned long vaddr)
* copy one vm_area from one task to the other. Assumes the page tables
* already present in the new task to be cleared in the whole range
* covered by this vma.
- *
- * dst->page_table_lock is held on entry and exit,
- * but may be dropped within p[mg]d_alloc() and pte_alloc_map().
*/
static inline void
@@ -419,17 +414,19 @@ static int copy_pte_range(struct mm_struct *dst_mm, struct mm_struct *src_mm,
unsigned long addr, unsigned long end)
{
pte_t *src_pte, *dst_pte;
+ spinlock_t *src_ptl, *dst_ptl;
int progress = 0;
int rss[2];
again:
rss[1] = rss[0] = 0;
- dst_pte = pte_alloc_map(dst_mm, dst_pmd, addr);
+ dst_pte = pte_alloc_map_lock(dst_mm, dst_pmd, addr, &dst_ptl);
if (!dst_pte)
return -ENOMEM;
src_pte = pte_offset_map_nested(src_pmd, addr);
+ src_ptl = &src_mm->page_table_lock;
+ spin_lock(src_ptl);
- spin_lock(&src_mm->page_table_lock);
do {
/*
* We are holding two locks at this point - either of them
@@ -438,8 +435,8 @@ again:
if (progress >= 32) {
progress = 0;
if (need_resched() ||
- need_lockbreak(&src_mm->page_table_lock) ||
- need_lockbreak(&dst_mm->page_table_lock))
+ need_lockbreak(src_ptl) ||
+ need_lockbreak(dst_ptl))
break;
}
if (pte_none(*src_pte)) {
@@ -449,12 +446,12 @@ again:
copy_one_pte(dst_mm, src_mm, dst_pte, src_pte, vma, addr, rss);
progress += 8;
} while (dst_pte++, src_pte++, addr += PAGE_SIZE, addr != end);
- spin_unlock(&src_mm->page_table_lock);
+ spin_unlock(src_ptl);
pte_unmap_nested(src_pte - 1);
- pte_unmap(dst_pte - 1);
add_mm_rss(dst_mm, rss[0], rss[1]);
- cond_resched_lock(&dst_mm->page_table_lock);
+ pte_unmap_unlock(dst_pte - 1, dst_ptl);
+ cond_resched();
if (addr != end)
goto again;
return 0;
@@ -1049,8 +1046,9 @@ static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd,
unsigned long addr, unsigned long end, pgprot_t prot)
{
pte_t *pte;
+ spinlock_t *ptl;
- pte = pte_alloc_map(mm, pmd, addr);
+ pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
if (!pte)
return -ENOMEM;
do {
@@ -1062,7 +1060,7 @@ static int zeromap_pte_range(struct mm_struct *mm, pmd_t *pmd,
BUG_ON(!pte_none(*pte));
set_pte_at(mm, addr, pte, zero_pte);
} while (pte++, addr += PAGE_SIZE, addr != end);
- pte_unmap(pte - 1);
+ pte_unmap_unlock(pte - 1, ptl);
return 0;
}
@@ -1112,14 +1110,12 @@ int zeromap_page_range(struct vm_area_struct *vma,
BUG_ON(addr >= end);
pgd = pgd_offset(mm, addr);
flush_cache_range(vma, addr, end);
- spin_lock(&mm->page_table_lock);
do {
next = pgd_addr_end(addr, end);
err = zeromap_pud_range(mm, pgd, addr, next, prot);
if (err)
break;
} while (pgd++, addr = next, addr != end);
- spin_unlock(&mm->page_table_lock);
return err;
}
@@ -1133,8 +1129,9 @@ static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
unsigned long pfn, pgprot_t prot)
{
pte_t *pte;
+ spinlock_t *ptl;
- pte = pte_alloc_map(mm, pmd, addr);
+ pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
if (!pte)
return -ENOMEM;
do {
@@ -1142,7 +1139,7 @@ static int remap_pte_range(struct mm_struct *mm, pmd_t *pmd,
set_pte_at(mm, addr, pte, pfn_pte(pfn, prot));
pfn++;
} while (pte++, addr += PAGE_SIZE, addr != end);
- pte_unmap(pte - 1);
+ pte_unmap_unlock(pte - 1, ptl);
return 0;
}
@@ -1210,7 +1207,6 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
pfn -= addr >> PAGE_SHIFT;
pgd = pgd_offset(mm, addr);
flush_cache_range(vma, addr, end);
- spin_lock(&mm->page_table_lock);
do {
next = pgd_addr_end(addr, end);
err = remap_pud_range(mm, pgd, addr, next,
@@ -1218,7 +1214,6 @@ int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
if (err)
break;
} while (pgd++, addr = next, addr != end);
- spin_unlock(&mm->page_table_lock);
return err;
}
EXPORT_SYMBOL(remap_pfn_range);
@@ -1985,17 +1980,9 @@ static int do_file_page(struct mm_struct *mm, struct vm_area_struct *vma,
* with external mmu caches can use to update those (ie the Sparc or
* PowerPC hashed page tables that act as extended TLBs).
*
- * Note the "page_table_lock". It is to protect against kswapd removing
- * pages from under us. Note that kswapd only ever _removes_ pages, never
- * adds them. As such, once we have noticed that the page is not present,
- * we can drop the lock early.
- *
- * The adding of pages is protected by the MM semaphore (which we hold),
- * so we don't need to worry about a page being suddenly been added into
- * our VM.
- *
- * We enter with the pagetable spinlock held, we are supposed to
- * release it when done.
+ * We enter with non-exclusive mmap_sem (to exclude vma changes,
+ * but allow concurrent faults), and pte mapped but not yet locked.
+ * We return with mmap_sem still held, but pte unmapped and unlocked.
*/
static inline int handle_pte_fault(struct mm_struct *mm,
struct vm_area_struct *vma, unsigned long address,
@@ -2003,6 +1990,7 @@ static inline int handle_pte_fault(struct mm_struct *mm,
{
pte_t entry;
+ spin_lock(&mm->page_table_lock);
entry = *pte;
if (!pte_present(entry)) {
if (pte_none(entry)) {
@@ -2051,30 +2039,18 @@ int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
if (unlikely(is_vm_hugetlb_page(vma)))
return hugetlb_fault(mm, vma, address, write_access);
- /*
- * We need the page table lock to synchronize with kswapd
- * and the SMP-safe atomic PTE updates.
- */
pgd = pgd_offset(mm, address);
- spin_lock(&mm->page_table_lock);
-
pud = pud_alloc(mm, pgd, address);
if (!pud)
- goto oom;
-
+ return VM_FAULT_OOM;
pmd = pmd_alloc(mm, pud, address);
if (!pmd)
- goto oom;
-
+ return VM_FAULT_OOM;
pte = pte_alloc_map(mm, pmd, address);
if (!pte)
- goto oom;
-
- return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
+ return VM_FAULT_OOM;
- oom:
- spin_unlock(&mm->page_table_lock);
- return VM_FAULT_OOM;
+ return handle_pte_fault(mm, vma, address, pte, pmd, write_access);
}
#ifndef __PAGETABLE_PUD_FOLDED
@@ -2084,24 +2060,16 @@ int __handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
*/
int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
{
- pud_t *new;
-
- if (mm != &init_mm) /* Temporary bridging hack */
- spin_unlock(&mm->page_table_lock);
- new = pud_alloc_one(mm, address);
- if (!new) {
- if (mm != &init_mm) /* Temporary bridging hack */
- spin_lock(&mm->page_table_lock);
+ pud_t *new = pud_alloc_one(mm, address);
+ if (!new)
return -ENOMEM;
- }
spin_lock(&mm->page_table_lock);
if (pgd_present(*pgd)) /* Another has populated it */
pud_free(new);
else
pgd_populate(mm, pgd, new);
- if (mm == &init_mm) /* Temporary bridging hack */
- spin_unlock(&mm->page_table_lock);
+ spin_unlock(&mm->page_table_lock);
return 0;
}
#endif /* __PAGETABLE_PUD_FOLDED */
@@ -2113,16 +2081,9 @@ int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address)
*/
int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
{
- pmd_t *new;
-
- if (mm != &init_mm) /* Temporary bridging hack */
- spin_unlock(&mm->page_table_lock);
- new = pmd_alloc_one(mm, address);
- if (!new) {
- if (mm != &init_mm) /* Temporary bridging hack */
- spin_lock(&mm->page_table_lock);
+ pmd_t *new = pmd_alloc_one(mm, address);
+ if (!new)
return -ENOMEM;
- }
spin_lock(&mm->page_table_lock);
#ifndef __ARCH_HAS_4LEVEL_HACK
@@ -2136,8 +2097,7 @@ int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address)
else
pgd_populate(mm, pud, new);
#endif /* __ARCH_HAS_4LEVEL_HACK */
- if (mm == &init_mm) /* Temporary bridging hack */
- spin_unlock(&mm->page_table_lock);
+ spin_unlock(&mm->page_table_lock);
return 0;
}
#endif /* __PAGETABLE_PMD_FOLDED */
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-16 22:05:38 +0000