volatile long state;int exit_state;
state成员的可能取值如下:
- #define TASK_RUNNING 0
- #define TASK_INTERRUPTIBLE 1
- #define TASK_UNINTERRUPTIBLE 2
- #define __TASK_STOPPED 4
- #define __TASK_TRACED 8
-
- #define EXIT_ZOMBIE 16
- #define EXIT_DEAD 32
-
- #define TASK_DEAD 64
- #define TASK_WAKEKILL 128
- #define TASK_WAKING 256
#define TASK_RUNNING0#define TASK_INTERRUPTIBLE1#define TASK_UNINTERRUPTIBLE2#define __TASK_STOPPED4#define __TASK_TRACED8/* in tsk->exit_state */#define EXIT_ZOMBIE16#define EXIT_DEAD32/* in tsk->state again */#define TASK_DEAD64#define TASK_WAKEKILL128#define TASK_WAKING256
系统中的每个进程都必然处于以上所列进程状态中的一种。
TASK_RUNNING表示进程要么正在执行,要么正要准备执行。
TASK_INTERRUPTIBLE表示进程被阻塞(睡眠),直到某个条件变为真。条件一旦达成,进程的状态就被设置为TASK_RUNNING。
TASK_UNINTERRUPTIBLE的意义与TASK_INTERRUPTIBLE类似,除了不能通过接受一个信号来唤醒以外。
__TASK_STOPPED表示进程被停止执行。
__TASK_TRACED表示进程被debugger等进程监视。
EXIT_ZOMBIE表示进程的执行被终止,但是其父进程还没有使用wait()等系统调用来获知它的终止信息。
EXIT_DEAD表示进程的最终状态。
EXIT_ZOMBIE和EXIT_DEAD也可以存放在exit_state成员中。进程状态的切换过程和原因大致如下图(图片来自《Linux Kernel Development》):
2、进程标识符(PID)
pid_t pid;pid_t tgid;
在CONFIG_BASE_SMALL配置为0的情况下,PID的取值范围是0到32767,即系统中的进程数最大为32768个。
-
- #define PID_MAX_DEFAULT (CONFIG_BASE_SMALL ? 0x1000 : 0x8000)
/* linux-2.6.38.8/include/linux/threads.h */#define PID_MAX_DEFAULT (CONFIG_BASE_SMALL ? 0x1000 : 0x8000)
在Linux系统中,一个线程组中的所有线程使用和该线程组的领头线程(该组中的第一个轻量级进程)相同的PID,并被存放在tgid成员中。只有线程组的领头线程的pid成员才会被设置为与tgid相同的值。注意,getpid()系统调用返回的是当前进程的tgid值而不是pid值。
3、进程内核栈
void *stack;
进程通过alloc_thread_info函数分配它的内核栈,通过free_thread_info函数释放所分配的内核栈。
-
- static inline struct thread_info *alloc_thread_info(struct task_struct *tsk)
- {
- #ifdef CONFIG_DEBUG_STACK_USAGE
- gfp_t mask = GFP_KERNEL | __GFP_ZERO;
- #else
- gfp_t mask = GFP_KERNEL;
- #endif
- return (struct thread_info *)__get_free_pages(mask, THREAD_SIZE_ORDER);
- }
- static inline void free_thread_info(struct thread_info *ti)
- {
- free_pages((unsigned long)ti, THREAD_SIZE_ORDER);
- }
/* linux-2.6.38.8/kernel/fork.c */ static inline struct thread_info *alloc_thread_info(struct task_struct *tsk){#ifdef CONFIG_DEBUG_STACK_USAGEgfp_t mask = GFP_KERNEL | __GFP_ZERO;#elsegfp_t mask = GFP_KERNEL;#endifreturn (struct thread_info *)__get_free_pages(mask, THREAD_SIZE_ORDER);}static inline void free_thread_info(struct thread_info *ti){free_pages((unsigned long)ti, THREAD_SIZE_ORDER);}
其中,THREAD_SIZE_ORDER宏在linux-2.6.38.8/arch/arm/include/asm/thread_info.h文件中被定义为1,也就是说alloc_thread_info函数通过调用__get_free_pages函数分配2个页的内存(它的首地址是8192字节对齐的)。
Linux内核通过thread_union联合体来表示进程的内核栈,其中THREAD_SIZE宏的大小为8192。
- union thread_union {
- struct thread_info thread_info;
- unsigned long stack[THREAD_SIZE/sizeof(long)];
- };
union thread_union {struct thread_info thread_info;unsigned long stack[THREAD_SIZE/sizeof(long)];};
当进程从用户态切换到内核态时,进程的内核栈总是空的,所以ARM的sp寄存器指向这个栈的顶端。因此,内核能够轻易地通过sp寄存器获得当前正在CPU上运行的进程。
-
- static inline struct task_struct *get_current(void)
- {
- return current_thread_info()->task;
- }
-
- #define current (get_current())
-
-
- static inline struct thread_info *current_thread_info(void)
- {
- register unsigned long sp asm ("sp");
- return (struct thread_info *)(sp & ~(THREAD_SIZE - 1));
- }
/* linux-2.6.38.8/arch/arm/include/asm/current.h */static inline struct task_struct *get_current(void){return current_thread_info()->task;}#define current (get_current())/* linux-2.6.38.8/arch/arm/include/asm/thread_info.h */ static inline struct thread_info *current_thread_info(void){register unsigned long sp asm ("sp");return (struct thread_info *)(sp & ~(THREAD_SIZE - 1));}
进程内核栈与进程描述符的关系如下图:
4、标记
unsigned int flags;/* per process flags, defined below */
flags成员的可能取值如下:
- #define PF_KSOFTIRQD 0x00000001 /* I am ksoftirqd */
- #define PF_STARTING 0x00000002 /* being created */
- #define PF_EXITING 0x00000004 /* getting shut down */
- #define PF_EXITPIDONE 0x00000008 /* pi exit done on shut down */
- #define PF_VCPU 0x00000010 /* I'm a virtual CPU */
- #define PF_WQ_WORKER 0x00000020 /* I'm a workqueue worker */
- #define PF_FORKNOEXEC 0x00000040 /* forked but didn't exec */
- #define PF_MCE_PROCESS 0x00000080 /* process policy on mce errors */
- #define PF_SUPERPRIV 0x00000100 /* used super-user privileges */
- #define PF_DUMPCORE 0x00000200 /* dumped core */
- #define PF_SIGNALED 0x00000400 /* killed by a signal */
- #define PF_MEMALLOC 0x00000800 /* Allocating memory */
- #define PF_USED_MATH 0x00002000 /* if unset the fpu must be initialized before use */
- #define PF_FREEZING 0x00004000 /* freeze in progress. do not account to load */
- #define PF_NOFREEZE 0x00008000 /* this thread should not be frozen */
- #define PF_FROZEN 0x00010000 /* frozen for system suspend */
- #define PF_FSTRANS 0x00020000 /* inside a filesystem transaction */
- #define PF_KSWAPD 0x00040000 /* I am kswapd */
- #define PF_OOM_ORIGIN 0x00080000 /* Allocating much memory to others */
- #define PF_LESS_THROTTLE 0x00100000 /* Throttle me less: I clean memory */
- #define PF_KTHREAD 0x00200000 /* I am a kernel thread */
- #define PF_RANDOMIZE 0x00400000 /* randomize virtual address space */
- #define PF_SWAPWRITE 0x00800000 /* Allowed to write to swap */
- #define PF_SPREAD_PAGE 0x01000000 /* Spread page cache over cpuset */
- #define PF_SPREAD_SLAB 0x02000000 /* Spread some slab caches over cpuset */
- #define PF_THREAD_BOUND 0x04000000 /* Thread bound to specific cpu */
- #define PF_MCE_EARLY 0x08000000 /* Early kill for mce process policy */
- #define PF_MEMPOLICY 0x10000000 /* Non-default NUMA mempolicy */
- #define PF_MUTEX_TESTER 0x20000000 /* Thread belongs to the rt mutex tester */
- #define PF_FREEZER_SKIP 0x40000000 /* Freezer should not count it as freezable */
- #define PF_FREEZER_NOSIG 0x80000000 /* Freezer won't send signals to it */
#define PF_KSOFTIRQD0x00000001/* I am ksoftirqd */#define PF_STARTING0x00000002/* being created */#define PF_EXITING0x00000004/* getting shut down */#define PF_EXITPIDONE0x00000008/* pi exit done on shut down */#define PF_VCPU0x00000010/* I'm a virtual CPU */#define PF_WQ_WORKER0x00000020/* I'm a workqueue worker */#define PF_FORKNOEXEC0x00000040/* forked but didn't exec */#define PF_MCE_PROCESS 0x00000080 /* process policy on mce errors */#define PF_SUPERPRIV0x00000100/* used super-user privileges */#define PF_DUMPCORE0x00000200/* dumped core */#define PF_SIGNALED0x00000400/* killed by a signal */#define PF_MEMALLOC0x00000800/* Allocating memory */#define PF_USED_MATH0x00002000/* if unset the fpu must be initialized before use */#define PF_FREEZING0x00004000/* freeze in progress. do not account to load */#define PF_NOFREEZE0x00008000/* this thread should not be frozen */#define PF_FROZEN0x00010000/* frozen for system suspend */#define PF_FSTRANS0x00020000/* inside a filesystem transaction */#define PF_KSWAPD0x00040000/* I am kswapd */#define PF_OOM_ORIGIN0x00080000/* Allocating much memory to others */#define PF_LESS_THROTTLE 0x00100000/* Throttle me less: I clean memory */#define PF_KTHREAD0x00200000/* I am a kernel thread */#define PF_RANDOMIZE0x00400000/* randomize virtual address space */#define PF_SWAPWRITE0x00800000/* Allowed to write to swap */#define PF_SPREAD_PAGE0x01000000/* Spread page cache over cpuset */#define PF_SPREAD_SLAB0x02000000/* Spread some slab caches over cpuset */#define PF_THREAD_BOUND0x04000000/* Thread bound to specific cpu */#define PF_MCE_EARLY 0x08000000 /* Early kill for mce process policy */#define PF_MEMPOLICY0x10000000/* Non-default NUMA mempolicy */#define PF_MUTEX_TESTER0x20000000/* Thread belongs to the rt mutex tester */#define PF_FREEZER_SKIP0x40000000/* Freezer should not count it as freezable */#define PF_FREEZER_NOSIG 0x80000000/* Freezer won't send signals to it */
5、表示进程亲属关系的成员
- struct task_struct *real_parent;
- struct task_struct *parent;
- struct list_head children;
- struct list_head sibling;
- struct task_struct *group_leader;
struct task_struct *real_parent; /* real parent process */struct task_struct *parent; /* recipient of SIGCHLD, wait4() reports */struct list_head children;/* list of my children */struct list_head sibling;/* linkage in my parent's children list */struct task_struct *group_leader;/* threadgroup leader */
在Linux系统中,所有进程之间都有着直接或间接地联系,每个进程都有其父进程,也可能有零个或多个子进程。拥有同一父进程的所有进程具有兄弟关系。
real_parent指向其父进程,如果创建它的父进程不再存在,则指向PID为1的init进程。
parent指向其父进程,当它终止时,必须向它的父进程发送信号。它的值通常与real_parent相同。
children表示链表的头部,链表中的所有元素都是它的子进程。
sibling用于把当前进程插入到兄弟链表中。
group_leader指向其所在进程组的领头进程。
6、ptrace系统调用
- unsigned int ptrace;
- struct list_head ptraced;
- struct list_head ptrace_entry;
- unsigned long ptrace_message;
- siginfo_t *last_siginfo;
- ifdef CONFIG_HAVE_HW_BREAKPOINT
- atomic_t ptrace_bp_refcnt;
- endif
unsigned int ptrace;struct list_head ptraced;struct list_head ptrace_entry;unsigned long ptrace_message;siginfo_t *last_siginfo; /* For ptrace use. */#ifdef CONFIG_HAVE_HW_BREAKPOINTatomic_t ptrace_bp_refcnt;#endif
成员ptrace被设置为0时表示不需要被跟踪,它的可能取值如下:
-
- #define PT_PTRACED 0x00000001
- #define PT_DTRACE 0x00000002 /* delayed trace (used on m68k, i386) */
- #define PT_TRACESYSGOOD 0x00000004
- #define PT_PTRACE_CAP 0x00000008 /* ptracer can follow suid-exec */
- #define PT_TRACE_FORK 0x00000010
- #define PT_TRACE_VFORK 0x00000020
- #define PT_TRACE_CLONE 0x00000040
- #define PT_TRACE_EXEC 0x00000080
- #define PT_TRACE_VFORK_DONE 0x00000100
- #define PT_TRACE_EXIT 0x00000200
/* linux-2.6.38.8/include/linux/ptrace.h */#define PT_PTRACED0x00000001#define PT_DTRACE0x00000002/* delayed trace (used on m68k, i386) */#define PT_TRACESYSGOOD0x00000004#define PT_PTRACE_CAP0x00000008/* ptracer can follow suid-exec */#define PT_TRACE_FORK0x00000010#define PT_TRACE_VFORK0x00000020#define PT_TRACE_CLONE0x00000040#define PT_TRACE_EXEC0x00000080#define PT_TRACE_VFORK_DONE0x00000100#define PT_TRACE_EXIT0x00000200
7、Performance Event
- #ifdef CONFIG_PERF_EVENTS
- struct perf_event_context *perf_event_ctxp[perf_nr_task_contexts];
- struct mutex perf_event_mutex;
- struct list_head perf_event_list;
- #endif
#ifdef CONFIG_PERF_EVENTSstruct perf_event_context *perf_event_ctxp[perf_nr_task_contexts];struct mutex perf_event_mutex;struct list_head perf_event_list;#endif
Performance Event是一款随 Linux 内核代码一同发布和维护的性能诊断工具。这些成员用于帮助PerformanceEvent分析进程的性能问题。
关于Performance Event工具的介绍可参考文章http://www.ibm.com/developerworks/cn/linux/l-cn-perf1/index.html?ca=drs-#major1和http://www.ibm.com/developerworks/cn/linux/l-cn-perf2/index.html?ca=drs-#major1。
8、进程调度
- int prio, static_prio, normal_prio;
- unsigned int rt_priority;
- const struct sched_class *sched_class;
- struct sched_entity se;
- struct sched_rt_entity rt;
- unsigned int policy;
- cpumask_t cpus_allowed;
int prio, static_prio, normal_prio;unsigned int rt_priority;const struct sched_class *sched_class;struct sched_entity se;struct sched_rt_entity rt;unsigned int policy;cpumask_t cpus_allowed;
实时优先级范围是0到MAX_RT_PRIO-1(即99),而普通进程的静态优先级范围是从MAX_RT_PRIO到MAX_PRIO-1(即100到139)。值越大静态优先级越低。
-
- #define MAX_USER_RT_PRIO 100
- #define MAX_RT_PRIO MAX_USER_RT_PRIO
-
- #define MAX_PRIO (MAX_RT_PRIO + 40)
- #define DEFAULT_PRIO (MAX_RT_PRIO + 20)
/* linux-2.6.38.8/include/linux/sched.h */#define MAX_USER_RT_PRIO100#define MAX_RT_PRIOMAX_USER_RT_PRIO#define MAX_PRIO(MAX_RT_PRIO + 40)#define DEFAULT_PRIO(MAX_RT_PRIO + 20)
static_prio用于保存静态优先级,可以通过nice系统调用来进行修改。
rt_priority用于保存实时优先级。
normal_prio的值取决于静态优先级和调度策略。
prio用于保存动态优先级。
policy表示进程的调度策略,目前主要有以下五种:
- #define SCHED_NORMAL 0
- #define SCHED_FIFO 1
- #define SCHED_RR 2
- #define SCHED_BATCH 3
-
- #define SCHED_IDLE 5
#define SCHED_NORMAL0#define SCHED_FIFO1#define SCHED_RR2#define SCHED_BATCH3/* SCHED_ISO: reserved but not implemented yet */#define SCHED_IDLE5
SCHED_NORMAL用于普通进程,通过CFS调度器实现。SCHED_BATCH用于非交互的处理器消耗型进程。SCHED_IDLE是在系统负载很低时使用。
SCHED_FIFO(先入先出调度算法)和SCHED_RR(轮流调度算法)都是实时调度策略。
sched_class结构体表示调度类,目前内核中有实现以下四种:
-
- static const struct sched_class fair_sched_class;
-
- static const struct sched_class rt_sched_class;
-
- static const struct sched_class idle_sched_class;
-
- static const struct sched_class stop_sched_class;
/* linux-2.6.38.8/kernel/sched_fair.c */ static const struct sched_class fair_sched_class;/* linux-2.6.38.8/kernel/sched_rt.c */static const struct sched_class rt_sched_class;/* linux-2.6.38.8/kernel/sched_idletask.c */static const struct sched_class idle_sched_class;/* linux-2.6.38.8/kernel/sched_stoptask.c */static const struct sched_class stop_sched_class;
se和rt都是调用实体,一个用于普通进程,一个用于实时进程,每个进程都有其中之一的实体。
cpus_allowed用于控制进程可以在哪里处理器上运行。
9、进程地址空间
- struct mm_struct *mm, *active_mm;
- #ifdef CONFIG_COMPAT_BRK
- unsigned brk_randomized:1;
- #endif
- #if defined(SPLIT_RSS_COUNTING)
- struct task_rss_stat rss_stat;
- #endif
mm指向进程所拥有的内存描述符,而active_mm指向进程运行时所使用的内存描述符。对于普通进程而言,这两个指针变量的值相同。但是,内核线程不拥有任何内存描述符,所以它们的mm成员总是为NULL。当内核线程得以运行时,它的active_mm成员被初始化为前一个运行进程的active_mm值。
brk_randomized的用法在http://lkml.indiana.edu/hypermail/Linux/kernel/1104.1/00196.html上有介绍,用来确定对随机堆内存的探测。
rss_stat用来记录缓冲信息。
10、判断标志
- int exit_code, exit_signal;
- int pdeath_signal;
-
- unsigned int personality;
- unsigned did_exec:1;
- unsigned in_execve:1;
-
- unsigned in_iowait:1;
-
-
-
- unsigned sched_reset_on_fork:1;
exit_code用于设置进程的终止代号,这个值要么是_exit()或exit_group()系统调用参数(正常终止),要么是由内核提供的一个错误代号(异常终止)。
exit_signal被置为-1时表示是某个线程组中的一员。只有当线程组的最后一个成员终止时,才会产生一个信号,以通知线程组的领头进程的父进程。
pdeath_signal用于判断父进程终止时发送信号。
personality用于处理不同的ABI,它的可能取值如下:
- enum {
- PER_LINUX = 0x0000,
- PER_LINUX_32BIT = 0x0000 | ADDR_LIMIT_32BIT,
- PER_LINUX_FDPIC = 0x0000 | FDPIC_FUNCPTRS,
- PER_SVR4 = 0x0001 | STICKY_TIMEOUTS | MMAP_PAGE_ZERO,
- PER_SVR3 = 0x0002 | STICKY_TIMEOUTS | SHORT_INODE,
- PER_SCOSVR3 = 0x0003 | STICKY_TIMEOUTS |
- WHOLE_SECONDS | SHORT_INODE,
- PER_OSR5 = 0x0003 | STICKY_TIMEOUTS | WHOLE_SECONDS,
- PER_WYSEV386 = 0x0004 | STICKY_TIMEOUTS | SHORT_INODE,
- PER_ISCR4 = 0x0005 | STICKY_TIMEOUTS,
- PER_BSD = 0x0006,
- PER_SUNOS = 0x0006 | STICKY_TIMEOUTS,
- PER_XENIX = 0x0007 | STICKY_TIMEOUTS | SHORT_INODE,
- PER_LINUX32 = 0x0008,
- PER_LINUX32_3GB = 0x0008 | ADDR_LIMIT_3GB,
- PER_IRIX32 = 0x0009 | STICKY_TIMEOUTS,
- PER_IRIXN32 = 0x000a | STICKY_TIMEOUTS,
- PER_IRIX64 = 0x000b | STICKY_TIMEOUTS,
- PER_RISCOS = 0x000c,
- PER_SOLARIS = 0x000d | STICKY_TIMEOUTS,
- PER_UW7 = 0x000e | STICKY_TIMEOUTS | MMAP_PAGE_ZERO,
- PER_OSF4 = 0x000f,
- PER_HPUX = 0x0010,
- PER_MASK = 0x00ff,
- };
did_exec用于记录进程代码是否被execve()函数所执行。
in_execve用于通知LSM是否被do_execve()函数所调用。详见补丁说明:http://lkml.indiana.edu/hypermail/linux/kernel/0901.1/00014.html。
in_iowait用于判断是否进行iowait计数。
sched_reset_on_fork用于判断是否恢复默认的优先级或调度策略。
11、时间
- cputime_t utime, stime, utimescaled, stimescaled;
- cputime_t gtime;
- #ifndef CONFIG_VIRT_CPU_ACCOUNTING
- cputime_t prev_utime, prev_stime;
- #endif
- unsigned long nvcsw, nivcsw;
- struct timespec start_time;
- struct timespec real_start_time;
- struct task_cputime cputime_expires;
- struct list_head cpu_timers[3];
- #ifdef CONFIG_DETECT_HUNG_TASK
-
- unsigned long last_switch_count;
- #endif
utime/stime用于记录进程在用户态/内核态下所经过的节拍数(定时器)。prev_utime/prev_stime是先前的运行时间。
utimescaled/stimescaled也是用于记录进程在用户态/内核态的运行时间,但它们以处理器的频率为刻度。
gtime是以节拍计数的虚拟机运行时间(guest time)。
nvcsw/nivcsw是自愿(voluntary)/非自愿(involuntary)上下文切换计数。last_switch_count是nvcsw和nivcsw的总和。
start_time和real_start_time都是进程创建时间,real_start_time还包含了进程睡眠时间,常用于/proc/pid/stat。
cputime_expires用来统计进程或进程组被跟踪的处理器时间,其中的三个成员对应着cpu_timers[3]的三个链表。
12、信号处理
-
- struct signal_struct *signal;
- struct sighand_struct *sighand;
-
- sigset_t blocked, real_blocked;
- sigset_t saved_sigmask;
- struct sigpending pending;
-
- unsigned long sas_ss_sp;
- size_t sas_ss_size;
- int (*notifier)(void *priv);
- void *notifier_data;
- sigset_t *notifier_mask;
signal指向进程的信号描述符。
sighand指向进程的信号处理程序描述符。
blocked表示被阻塞信号的掩码,real_blocked表示临时掩码。
pending存放私有挂起信号的数据结构。
sas_ss_sp是信号处理程序备用堆栈的地址,sas_ss_size表示堆栈的大小。
设备驱动程序常用notifier指向的函数来阻塞进程的某些信号(notifier_mask是这些信号的位掩码),notifier_data指的是notifier所指向的函数可能使用的数据。
13、其他
(1)、用于保护资源分配或释放的自旋锁
-
-
- spinlock_t alloc_lock;
(2)、进程描述符使用计数,被置为2时,表示进程描述符正在被使用而且其相应的进程处于活动状态。
- atomic_t usage;
atomic_t usage;
(3)、用于表示获取大内核锁的次数,如果进程未获得过锁,则置为-1。
int lock_depth;/* BKL lock depth */
(4)、在SMP上帮助实现无加锁的进程切换(unlocked context switches)
- #ifdef CONFIG_SMP
- #ifdef __ARCH_WANT_UNLOCKED_CTXSW
- int oncpu;
- #endif
- #endif
#ifdef CONFIG_SMP#ifdef __ARCH_WANT_UNLOCKED_CTXSWint oncpu;#endif#endif
(5)、preempt_notifier结构体链表
- #ifdef CONFIG_PREEMPT_NOTIFIERS
-
- struct hlist_head preempt_notifiers;
- #endif
#ifdef CONFIG_PREEMPT_NOTIFIERS/* list of struct preempt_notifier: */struct hlist_head preempt_notifiers;#endif
(6)、FPU使用计数
- unsigned char fpu_counter;
unsigned char fpu_counter;
(7)、blktrace是一个针对Linux内核中块设备I/O层的跟踪工具。
- #ifdef CONFIG_BLK_DEV_IO_TRACE
- unsigned int btrace_seq;
- #endif
#ifdef CONFIG_BLK_DEV_IO_TRACEunsigned int btrace_seq;#endif
(8)、RCU同步原语
- #ifdef CONFIG_PREEMPT_RCU
- int rcu_read_lock_nesting;
- char rcu_read_unlock_special;
- struct list_head rcu_node_entry;
- #endif /* #ifdef CONFIG_PREEMPT_RCU */
- #ifdef CONFIG_TREE_PREEMPT_RCU
- struct rcu_node *rcu_blocked_node;
- #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
- #ifdef CONFIG_RCU_BOOST
- struct rt_mutex *rcu_boost_mutex;
- #endif /* #ifdef CONFIG_RCU_BOOST */
#ifdef CONFIG_PREEMPT_RCUint rcu_read_lock_nesting;char rcu_read_unlock_special;struct list_head rcu_node_entry;#endif /* #ifdef CONFIG_PREEMPT_RCU */#ifdef CONFIG_TREE_PREEMPT_RCUstruct rcu_node *rcu_blocked_node;#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */#ifdef CONFIG_RCU_BOOSTstruct rt_mutex *rcu_boost_mutex;#endif /* #ifdef CONFIG_RCU_BOOST */
(9)、用于调度器统计进程的运行信息
- #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
- struct sched_info sched_info;
- #endif
#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)struct sched_info sched_info;#endif
(10)、用于构建进程链表
struct list_head tasks;
(11)、to limit pushing to one attempt
- #ifdef CONFIG_SMP
- struct plist_node pushable_tasks;
- #endif
#ifdef CONFIG_SMPstruct plist_node pushable_tasks;#endif
补丁说明请参考:http://lkml.indiana.edu/hypermail/linux/kernel/0808.3/0503.html
(12)、防止内核堆栈溢出
- #ifdef CONFIG_CC_STACKPROTECTOR
-
- unsigned long stack_canary;
- #endif
#ifdef CONFIG_CC_STACKPROTECTOR/* Canary value for the -fstack-protector gcc feature */unsigned long stack_canary;#endif
在GCC编译内核时,需要加上-fstack-protector选项。
(13)、PID散列表和链表
-
- struct pid_link pids[PIDTYPE_MAX];
- struct list_head thread_group;
/* PID/PID hash table linkage. */struct pid_link pids[PIDTYPE_MAX];struct list_head thread_group; //线程组中所有进程的链表
(14)、do_fork函数
- struct completion *vfork_done;
- int __user *set_child_tid;
- int __user *clear_child_tid;
struct completion *vfork_done;/* for vfork() */int __user *set_child_tid;/* CLONE_CHILD_SETTID */int __user *clear_child_tid;/* CLONE_CHILD_CLEARTID */
在执行do_fork()时,如果给定特别标志,则vfork_done会指向一个特殊地址。
如果copy_process函数的clone_flags参数的值被置为CLONE_CHILD_SETTID或CLONE_CHILD_CLEARTID,则会把child_tidptr参数的值分别复制到set_child_tid和clear_child_tid成员。这些标志说明必须改变子进程用户态地址空间的child_tidptr所指向的变量的值。
(15)、缺页统计
-
- unsigned long min_flt, maj_flt;
/* mm fault and swap info: this can arguably be seen as either mm-specific or thread-specific */unsigned long min_flt, maj_flt;
(16)、进程权能
- const struct cred __rcu *real_cred;
-
- const struct cred __rcu *cred;
-
- struct cred *replacement_session_keyring;
const struct cred __rcu *real_cred; /* objective and real subjective task * credentials (COW) */const struct cred __rcu *cred;/* effective (overridable) subjective task * credentials (COW) */struct cred *replacement_session_keyring; /* for KEYCTL_SESSION_TO_PARENT */
(17)、相应的程序名
- char comm[TASK_COMM_LEN];
char comm[TASK_COMM_LEN];
(18)、文件
-
- int link_count, total_link_count;
-
- struct fs_struct *fs;
-
- struct files_struct *files;
/* file system info */int link_count, total_link_count;/* filesystem information */struct fs_struct *fs;/* open file information */struct files_struct *files;
fs用来表示进程与文件系统的联系,包括当前目录和根目录。
files表示进程当前打开的文件。
(19)、进程通信(SYSVIPC)
- #ifdef CONFIG_SYSVIPC
-
- struct sysv_sem sysvsem;
- #endif
#ifdef CONFIG_SYSVIPC/* ipc stuff */struct sysv_sem sysvsem;#endif
(20)、处理器特有数据
-
- struct thread_struct thread;
/* CPU-specific state of this task */struct thread_struct thread;
(21)、命名空间
/* namespaces */struct nsproxy *nsproxy;
(22)、进程审计
- struct audit_context *audit_context;
- #ifdef CONFIG_AUDITSYSCALL
- uid_t loginuid;
- unsigned int sessionid;
- #endif
struct audit_context *audit_context;#ifdef CONFIG_AUDITSYSCALLuid_t loginuid;unsigned int sessionid;#endif
(23)、secure computing
seccomp_t seccomp;
(24)、用于copy_process函数使用CLONE_PARENT 标记时
-
- u32 parent_exec_id;
- u32 self_exec_id;
/* Thread group tracking */ u32 parent_exec_id; u32 self_exec_id;
(25)、中断
- #ifdef CONFIG_GENERIC_HARDIRQS
-
- struct irqaction *irqaction;
- #endif
- #ifdef CONFIG_TRACE_IRQFLAGS
- unsigned int irq_events;
- unsigned long hardirq_enable_ip;
- unsigned long hardirq_disable_ip;
- unsigned int hardirq_enable_event;
- unsigned int hardirq_disable_event;
- int hardirqs_enabled;
- int hardirq_context;
- unsigned long softirq_disable_ip;
- unsigned long softirq_enable_ip;
- unsigned int softirq_disable_event;
- unsigned int softirq_enable_event;
- int softirqs_enabled;
- int softirq_context;
- #endif
#ifdef CONFIG_GENERIC_HARDIRQS/* IRQ handler threads */struct irqaction *irqaction;#endif#ifdef CONFIG_TRACE_IRQFLAGSunsigned int irq_events;unsigned long hardirq_enable_ip;unsigned long hardirq_disable_ip;unsigned int hardirq_enable_event;unsigned int hardirq_disable_event;int hardirqs_enabled;int hardirq_context;unsigned long softirq_disable_ip;unsigned long softirq_enable_ip;unsigned int softirq_disable_event;unsigned int softirq_enable_event;int softirqs_enabled;int softirq_context;#endif
(26)、task_rq_lock函数所使用的锁
/* Protection of the PI data structures: */raw_spinlock_t pi_lock;
(27)、基于PI协议的等待互斥锁,其中PI指的是priority inheritance(优先级继承)
- #ifdef CONFIG_RT_MUTEXES
-
- struct plist_head pi_waiters;
-
- struct rt_mutex_waiter *pi_blocked_on;
- #endif
#ifdef CONFIG_RT_MUTEXES/* PI waiters blocked on a rt_mutex held by this task */struct plist_head pi_waiters;/* Deadlock detection and priority inheritance handling */struct rt_mutex_waiter *pi_blocked_on;#endif
(28)、死锁检测
- #ifdef CONFIG_DEBUG_MUTEXES
-
- struct mutex_waiter *blocked_on;
- #endif
#ifdef CONFIG_DEBUG_MUTEXES/* mutex deadlock detection */struct mutex_waiter *blocked_on;#endif
(29)、lockdep
- #ifdef CONFIG_LOCKDEP
- # define MAX_LOCK_DEPTH 48UL
- u64 curr_chain_key;
- int lockdep_depth;
- unsigned int lockdep_recursion;
- struct held_lock held_locks[MAX_LOCK_DEPTH];
- gfp_t lockdep_reclaim_gfp;
- #endif
#ifdef CONFIG_LOCKDEP# define MAX_LOCK_DEPTH 48ULu64 curr_chain_key;int lockdep_depth;unsigned int lockdep_recursion;struct held_lock held_locks[MAX_LOCK_DEPTH];gfp_t lockdep_reclaim_gfp;#endif
(30)、JFS文件系统
/* journalling filesystem info */void *journal_info;
(31)、块设备链表
-
- struct bio_list *bio_list;
/* stacked block device info */struct bio_list *bio_list;
(32)、内存回收
- struct reclaim_state *reclaim_state;
struct reclaim_state *reclaim_state;
(33)、存放块设备I/O数据流量信息
- struct backing_dev_info *backing_dev_info;
struct backing_dev_info *backing_dev_info;
(34)、I/O调度器所使用的信息
- struct io_context *io_context;
struct io_context *io_context;
(35)、记录进程的I/O计数
- struct task_io_accounting ioac;
- if defined(CONFIG_TASK_XACCT)
- u64 acct_rss_mem1;
- u64 acct_vm_mem1;
- cputime_t acct_timexpd;
- endif
struct task_io_accounting ioac;#if defined(CONFIG_TASK_XACCT)u64 acct_rss_mem1;/* accumulated rss usage */u64 acct_vm_mem1;/* accumulated virtual memory usage */cputime_t acct_timexpd;/* stime + utime since last update */#endif
在Ubuntu 11.04上,执行cat获得进程1的I/O计数如下:
$ sudo cat /proc/1/io
- rchar: 164258906
- wchar: 455212837
- syscr: 388847
- syscw: 92563
- read_bytes: 439251968
- write_bytes: 14143488
- cancelled_write_bytes: 2134016
rchar: 164258906wchar: 455212837syscr: 388847syscw: 92563read_bytes: 439251968write_bytes: 14143488cancelled_write_bytes: 2134016
输出的数据项刚好是task_io_accounting结构体的所有成员。
(36)、CPUSET功能
- #ifdef CONFIG_CPUSETS
- nodemask_t mems_allowed;
- int mems_allowed_change_disable;
- int cpuset_mem_spread_rotor;
- int cpuset_slab_spread_rotor;
- #endif
#ifdef CONFIG_CPUSETSnodemask_t mems_allowed;/* Protected by alloc_lock */int mems_allowed_change_disable;int cpuset_mem_spread_rotor;int cpuset_slab_spread_rotor;#endif
(37)、Control Groups
- #ifdef CONFIG_CGROUPS
-
- struct css_set __rcu *cgroups;
-
- struct list_head cg_list;
- #endif
- #ifdef CONFIG_CGROUP_MEM_RES_CTLR /* memcg uses this to do batch job */
- struct memcg_batch_info {
- int do_batch;
- struct mem_cgroup *memcg;
- unsigned long bytes;
- unsigned long memsw_bytes;
- } memcg_batch;
- #endif
#ifdef CONFIG_CGROUPS/* Control Group info protected by css_set_lock */struct css_set __rcu *cgroups;/* cg_list protected by css_set_lock and tsk->alloc_lock */struct list_head cg_list;#endif#ifdef CONFIG_CGROUP_MEM_RES_CTLR /* memcg uses this to do batch job */struct memcg_batch_info {int do_batch;/* incremented when batch uncharge started */struct mem_cgroup *memcg; /* target memcg of uncharge */unsigned long bytes; /* uncharged usage */unsigned long memsw_bytes; /* uncharged mem+swap usage */} memcg_batch;#endif
(38)、futex同步机制
- #ifdef CONFIG_FUTEX
- struct robust_list_head __user *robust_list;
- #ifdef CONFIG_COMPAT
- struct compat_robust_list_head __user *compat_robust_list;
- #endif
- struct list_head pi_state_list;
- struct futex_pi_state *pi_state_cache;
- #endif
#ifdef CONFIG_FUTEXstruct robust_list_head __user *robust_list;#ifdef CONFIG_COMPATstruct compat_robust_list_head __user *compat_robust_list;#endifstruct list_head pi_state_list;struct futex_pi_state *pi_state_cache;#endif
(39)、非一致内存访问(NUMA Non-Uniform Memory Access)
- #ifdef CONFIG_NUMA
- struct mempolicy *mempolicy;
- short il_next;
- #endif
#ifdef CONFIG_NUMAstruct mempolicy *mempolicy;/* Protected by alloc_lock */short il_next;#endif
(40)、文件系统互斥资源
atomic_t fs_excl;/* holding fs exclusive resources */
(41)、RCU链表
struct rcu_head rcu;
(42)、管道
- struct pipe_inode_info *splice_pipe;
struct pipe_inode_info *splice_pipe;
(43)、延迟计数
- #ifdef CONFIG_TASK_DELAY_ACCT
- struct task_delay_info *delays;
- #endif
#ifdefCONFIG_TASK_DELAY_ACCTstruct task_delay_info *delays;#endif
(44)、fault injection
- #ifdef CONFIG_FAULT_INJECTION
- int make_it_fail;
- #endif
#ifdef CONFIG_FAULT_INJECTIONint make_it_fail;#endif
(45)、FLoating proportions
- struct prop_local_single dirties;
struct prop_local_single dirties;
(46)、Infrastructure for displayinglatency
- #ifdef CONFIG_LATENCYTOP
- int latency_record_count;
- struct latency_record latency_record[LT_SAVECOUNT];
- #endif
#ifdef CONFIG_LATENCYTOPint latency_record_count;struct latency_record latency_record[LT_SAVECOUNT];#endif
(47)、time slack values,常用于poll和select函数
- unsigned long timer_slack_ns;
- unsigned long default_timer_slack_ns;
unsigned long timer_slack_ns;unsigned long default_timer_slack_ns;
(48)、socket控制消息(control message)
- struct list_head *scm_work_list;
struct list_head*scm_work_list;
(49)、ftrace跟踪器
- #ifdef CONFIG_FUNCTION_GRAPH_TRACER
-
- int curr_ret_stack;
-
- struct ftrace_ret_stack *ret_stack;
-
- unsigned long long ftrace_timestamp;
-
-
-
-
- atomic_t trace_overrun;
-
- atomic_t tracing_graph_pause;
- #endif
- #ifdef CONFIG_TRACING
-
- unsigned long trace;
-
- unsigned long trace_recursion;
- #endif /* CONFIG_TRACING */
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