mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-22 20:23:57 +08:00
00a62ce91e
The Committed_AS field can underflow in certain situations: > # while true; do cat /proc/meminfo | grep _AS; sleep 1; done | uniq -c > 1 Committed_AS: 18446744073709323392 kB > 11 Committed_AS: 18446744073709455488 kB > 6 Committed_AS: 35136 kB > 5 Committed_AS: 18446744073709454400 kB > 7 Committed_AS: 35904 kB > 3 Committed_AS: 18446744073709453248 kB > 2 Committed_AS: 34752 kB > 9 Committed_AS: 18446744073709453248 kB > 8 Committed_AS: 34752 kB > 3 Committed_AS: 18446744073709320960 kB > 7 Committed_AS: 18446744073709454080 kB > 3 Committed_AS: 18446744073709320960 kB > 5 Committed_AS: 18446744073709454080 kB > 6 Committed_AS: 18446744073709320960 kB Because NR_CPUS can be greater than 1000 and meminfo_proc_show() does not check for underflow. But NR_CPUS proportional isn't good calculation. In general, possibility of lock contention is proportional to the number of online cpus, not theorical maximum cpus (NR_CPUS). The current kernel has generic percpu-counter stuff. using it is right way. it makes code simplify and percpu_counter_read_positive() don't make underflow issue. Reported-by: Dave Hansen <dave@linux.vnet.ibm.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Eric B Munson <ebmunson@us.ibm.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: <stable@kernel.org> [All kernel versions] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
94 lines
2.2 KiB
C
94 lines
2.2 KiB
C
#ifndef _LINUX_MMAN_H
|
|
#define _LINUX_MMAN_H
|
|
|
|
#include <asm/mman.h>
|
|
|
|
#define MREMAP_MAYMOVE 1
|
|
#define MREMAP_FIXED 2
|
|
|
|
#define OVERCOMMIT_GUESS 0
|
|
#define OVERCOMMIT_ALWAYS 1
|
|
#define OVERCOMMIT_NEVER 2
|
|
|
|
#ifdef __KERNEL__
|
|
#include <linux/mm.h>
|
|
#include <linux/percpu_counter.h>
|
|
|
|
#include <asm/atomic.h>
|
|
|
|
extern int sysctl_overcommit_memory;
|
|
extern int sysctl_overcommit_ratio;
|
|
extern struct percpu_counter vm_committed_as;
|
|
|
|
static inline void vm_acct_memory(long pages)
|
|
{
|
|
percpu_counter_add(&vm_committed_as, pages);
|
|
}
|
|
|
|
static inline void vm_unacct_memory(long pages)
|
|
{
|
|
vm_acct_memory(-pages);
|
|
}
|
|
|
|
/*
|
|
* Allow architectures to handle additional protection bits
|
|
*/
|
|
|
|
#ifndef arch_calc_vm_prot_bits
|
|
#define arch_calc_vm_prot_bits(prot) 0
|
|
#endif
|
|
|
|
#ifndef arch_vm_get_page_prot
|
|
#define arch_vm_get_page_prot(vm_flags) __pgprot(0)
|
|
#endif
|
|
|
|
#ifndef arch_validate_prot
|
|
/*
|
|
* This is called from mprotect(). PROT_GROWSDOWN and PROT_GROWSUP have
|
|
* already been masked out.
|
|
*
|
|
* Returns true if the prot flags are valid
|
|
*/
|
|
static inline int arch_validate_prot(unsigned long prot)
|
|
{
|
|
return (prot & ~(PROT_READ | PROT_WRITE | PROT_EXEC | PROT_SEM)) == 0;
|
|
}
|
|
#define arch_validate_prot arch_validate_prot
|
|
#endif
|
|
|
|
/*
|
|
* Optimisation macro. It is equivalent to:
|
|
* (x & bit1) ? bit2 : 0
|
|
* but this version is faster.
|
|
* ("bit1" and "bit2" must be single bits)
|
|
*/
|
|
#define _calc_vm_trans(x, bit1, bit2) \
|
|
((bit1) <= (bit2) ? ((x) & (bit1)) * ((bit2) / (bit1)) \
|
|
: ((x) & (bit1)) / ((bit1) / (bit2)))
|
|
|
|
/*
|
|
* Combine the mmap "prot" argument into "vm_flags" used internally.
|
|
*/
|
|
static inline unsigned long
|
|
calc_vm_prot_bits(unsigned long prot)
|
|
{
|
|
return _calc_vm_trans(prot, PROT_READ, VM_READ ) |
|
|
_calc_vm_trans(prot, PROT_WRITE, VM_WRITE) |
|
|
_calc_vm_trans(prot, PROT_EXEC, VM_EXEC) |
|
|
arch_calc_vm_prot_bits(prot);
|
|
}
|
|
|
|
/*
|
|
* Combine the mmap "flags" argument into "vm_flags" used internally.
|
|
*/
|
|
static inline unsigned long
|
|
calc_vm_flag_bits(unsigned long flags)
|
|
{
|
|
return _calc_vm_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN ) |
|
|
_calc_vm_trans(flags, MAP_DENYWRITE, VM_DENYWRITE ) |
|
|
_calc_vm_trans(flags, MAP_EXECUTABLE, VM_EXECUTABLE) |
|
|
_calc_vm_trans(flags, MAP_LOCKED, VM_LOCKED );
|
|
}
|
|
#endif /* __KERNEL__ */
|
|
#endif /* _LINUX_MMAN_H */
|