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mm: fix atomic_t overflow in vm

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The atomic_t type is 32bit but a 64bit system can have more than 2^32
pages of virtual address space available.  Without this we overflow on
ludicrously large mappings

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Alan Cox 2008-05-23 13:04:31 -07:00 committed by Linus Torvalds
parent 6c7c6afbb8
commit 80119ef5c8
5 changed files with 9 additions and 9 deletions
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2
fs/proc/proc_misc.c
View File

@ -139,7 +139,7 @@ static int meminfo_read_proc(char *page, char **start, off_t off,
#define K(x) ((x) << (PAGE_SHIFT - 10))
si_meminfo(&i);
si_swapinfo(&i);
committed = atomic_read(&vm_committed_space);
committed = atomic_long_read(&vm_committed_space);
allowed = ((totalram_pages - hugetlb_total_pages())
* sysctl_overcommit_ratio / 100) + total_swap_pages;

4
include/linux/mman.h
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@ -17,14 +17,14 @@
extern int sysctl_overcommit_memory;
extern int sysctl_overcommit_ratio;
extern atomic_t vm_committed_space;
extern atomic_long_t vm_committed_space;
#ifdef CONFIG_SMP
extern void vm_acct_memory(long pages);
#else
static inline void vm_acct_memory(long pages)
{
atomic_add(pages, &vm_committed_space);
atomic_long_add(pages, &vm_committed_space);
}
#endif

4
mm/mmap.c
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@ -80,7 +80,7 @@ EXPORT_SYMBOL(vm_get_page_prot);
int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
int sysctl_overcommit_ratio = 50; /* default is 50% */
int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
atomic_t vm_committed_space = ATOMIC_INIT(0);
atomic_long_t vm_committed_space = ATOMIC_LONG_INIT(0);
/*
* Check that a process has enough memory to allocate a new virtual
@ -177,7 +177,7 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
* cast `allowed' as a signed long because vm_committed_space
* sometimes has a negative value
*/
if (atomic_read(&vm_committed_space) < (long)allowed)
if (atomic_long_read(&vm_committed_space) < (long)allowed)
return 0;
error:
vm_unacct_memory(pages);

4
mm/nommu.c
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@ -39,7 +39,7 @@ struct page *mem_map;
unsigned long max_mapnr;
unsigned long num_physpages;
unsigned long askedalloc, realalloc;
atomic_t vm_committed_space = ATOMIC_INIT(0);
atomic_long_t vm_committed_space = ATOMIC_LONG_INIT(0);
int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
int sysctl_overcommit_ratio = 50; /* default is 50% */
int sysctl_max_map_count = DEFAULT_MAX_MAP_COUNT;
@ -1410,7 +1410,7 @@ int __vm_enough_memory(struct mm_struct *mm, long pages, int cap_sys_admin)
* cast `allowed' as a signed long because vm_committed_space
* sometimes has a negative value
*/
if (atomic_read(&vm_committed_space) < (long)allowed)
if (atomic_long_read(&vm_committed_space) < (long)allowed)
return 0;
error:
vm_unacct_memory(pages);

4
mm/swap.c
View File

@ -503,7 +503,7 @@ void vm_acct_memory(long pages)
local = &__get_cpu_var(committed_space);
*local += pages;
if (*local > ACCT_THRESHOLD || *local < -ACCT_THRESHOLD) {
atomic_add(*local, &vm_committed_space);
atomic_long_add(*local, &vm_committed_space);
*local = 0;
}
preempt_enable();
@ -520,7 +520,7 @@ static int cpu_swap_callback(struct notifier_block *nfb,
committed = &per_cpu(committed_space, (long)hcpu);
if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
atomic_add(*committed, &vm_committed_space);
atomic_long_add(*committed, &vm_committed_space);
*committed = 0;
drain_cpu_pagevecs((long)hcpu);
}