alistair23-linux/include/linux/types.h
David Rientjes e1e12d2f31 mm, oom: fix race when specifying a thread as the oom origin
test_set_oom_score_adj() and compare_swap_oom_score_adj() are used to
specify that current should be killed first if an oom condition occurs in
between the two calls.

The usage is

	short oom_score_adj = test_set_oom_score_adj(OOM_SCORE_ADJ_MAX);
	...
	compare_swap_oom_score_adj(OOM_SCORE_ADJ_MAX, oom_score_adj);

to store the thread's oom_score_adj, temporarily change it to the maximum
score possible, and then restore the old value if it is still the same.

This happens to still be racy, however, if the user writes
OOM_SCORE_ADJ_MAX to /proc/pid/oom_score_adj in between the two calls.
The compare_swap_oom_score_adj() will then incorrectly reset the old value
prior to the write of OOM_SCORE_ADJ_MAX.

To fix this, introduce a new oom_flags_t member in struct signal_struct
that will be used for per-thread oom killer flags.  KSM and swapoff can
now use a bit in this member to specify that threads should be killed
first in oom conditions without playing around with oom_score_adj.

This also allows the correct oom_score_adj to always be shown when reading
/proc/pid/oom_score.

Signed-off-by: David Rientjes <rientjes@google.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: Anton Vorontsov <anton.vorontsov@linaro.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-12-11 17:22:27 -08:00

217 lines
4.5 KiB
C

#ifndef _LINUX_TYPES_H
#define _LINUX_TYPES_H
#define __EXPORTED_HEADERS__
#include <uapi/linux/types.h>
#ifndef __ASSEMBLY__
#define DECLARE_BITMAP(name,bits) \
unsigned long name[BITS_TO_LONGS(bits)]
typedef __u32 __kernel_dev_t;
typedef __kernel_fd_set fd_set;
typedef __kernel_dev_t dev_t;
typedef __kernel_ino_t ino_t;
typedef __kernel_mode_t mode_t;
typedef unsigned short umode_t;
typedef __u32 nlink_t;
typedef __kernel_off_t off_t;
typedef __kernel_pid_t pid_t;
typedef __kernel_daddr_t daddr_t;
typedef __kernel_key_t key_t;
typedef __kernel_suseconds_t suseconds_t;
typedef __kernel_timer_t timer_t;
typedef __kernel_clockid_t clockid_t;
typedef __kernel_mqd_t mqd_t;
typedef _Bool bool;
typedef __kernel_uid32_t uid_t;
typedef __kernel_gid32_t gid_t;
typedef __kernel_uid16_t uid16_t;
typedef __kernel_gid16_t gid16_t;
typedef unsigned long uintptr_t;
#ifdef CONFIG_UID16
/* This is defined by include/asm-{arch}/posix_types.h */
typedef __kernel_old_uid_t old_uid_t;
typedef __kernel_old_gid_t old_gid_t;
#endif /* CONFIG_UID16 */
#if defined(__GNUC__)
typedef __kernel_loff_t loff_t;
#endif
/*
* The following typedefs are also protected by individual ifdefs for
* historical reasons:
*/
#ifndef _SIZE_T
#define _SIZE_T
typedef __kernel_size_t size_t;
#endif
#ifndef _SSIZE_T
#define _SSIZE_T
typedef __kernel_ssize_t ssize_t;
#endif
#ifndef _PTRDIFF_T
#define _PTRDIFF_T
typedef __kernel_ptrdiff_t ptrdiff_t;
#endif
#ifndef _TIME_T
#define _TIME_T
typedef __kernel_time_t time_t;
#endif
#ifndef _CLOCK_T
#define _CLOCK_T
typedef __kernel_clock_t clock_t;
#endif
#ifndef _CADDR_T
#define _CADDR_T
typedef __kernel_caddr_t caddr_t;
#endif
/* bsd */
typedef unsigned char u_char;
typedef unsigned short u_short;
typedef unsigned int u_int;
typedef unsigned long u_long;
/* sysv */
typedef unsigned char unchar;
typedef unsigned short ushort;
typedef unsigned int uint;
typedef unsigned long ulong;
#ifndef __BIT_TYPES_DEFINED__
#define __BIT_TYPES_DEFINED__
typedef __u8 u_int8_t;
typedef __s8 int8_t;
typedef __u16 u_int16_t;
typedef __s16 int16_t;
typedef __u32 u_int32_t;
typedef __s32 int32_t;
#endif /* !(__BIT_TYPES_DEFINED__) */
typedef __u8 uint8_t;
typedef __u16 uint16_t;
typedef __u32 uint32_t;
#if defined(__GNUC__)
typedef __u64 uint64_t;
typedef __u64 u_int64_t;
typedef __s64 int64_t;
#endif
/* this is a special 64bit data type that is 8-byte aligned */
#define aligned_u64 __u64 __attribute__((aligned(8)))
#define aligned_be64 __be64 __attribute__((aligned(8)))
#define aligned_le64 __le64 __attribute__((aligned(8)))
/**
* The type used for indexing onto a disc or disc partition.
*
* Linux always considers sectors to be 512 bytes long independently
* of the devices real block size.
*
* blkcnt_t is the type of the inode's block count.
*/
#ifdef CONFIG_LBDAF
typedef u64 sector_t;
typedef u64 blkcnt_t;
#else
typedef unsigned long sector_t;
typedef unsigned long blkcnt_t;
#endif
/*
* The type of an index into the pagecache. Use a #define so asm/types.h
* can override it.
*/
#ifndef pgoff_t
#define pgoff_t unsigned long
#endif
#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
typedef u64 dma_addr_t;
#else
typedef u32 dma_addr_t;
#endif /* dma_addr_t */
#ifdef __CHECKER__
#else
#endif
#ifdef __CHECK_ENDIAN__
#else
#endif
typedef unsigned __bitwise__ gfp_t;
typedef unsigned __bitwise__ fmode_t;
typedef unsigned __bitwise__ oom_flags_t;
#ifdef CONFIG_PHYS_ADDR_T_64BIT
typedef u64 phys_addr_t;
#else
typedef u32 phys_addr_t;
#endif
typedef phys_addr_t resource_size_t;
/*
* This type is the placeholder for a hardware interrupt number. It has to be
* big enough to enclose whatever representation is used by a given platform.
*/
typedef unsigned long irq_hw_number_t;
typedef struct {
int counter;
} atomic_t;
#ifdef CONFIG_64BIT
typedef struct {
long counter;
} atomic64_t;
#endif
struct list_head {
struct list_head *next, *prev;
};
struct hlist_head {
struct hlist_node *first;
};
struct hlist_node {
struct hlist_node *next, **pprev;
};
struct ustat {
__kernel_daddr_t f_tfree;
__kernel_ino_t f_tinode;
char f_fname[6];
char f_fpack[6];
};
/**
* struct callback_head - callback structure for use with RCU and task_work
* @next: next update requests in a list
* @func: actual update function to call after the grace period.
*/
struct callback_head {
struct callback_head *next;
void (*func)(struct callback_head *head);
};
#define rcu_head callback_head
#endif /* __ASSEMBLY__ */
#endif /* _LINUX_TYPES_H */