1、linux 內(nèi)核源碼分析進(jìn)程管理（一）郭海林2012.9.29linux 內(nèi)核源碼分析進(jìn)程管理（一）重要數(shù)據(jù)結(jié)構(gòu)雙向鏈表（1）結(jié)構(gòu)體定義：struct list_head struct list_head *next, *prev;list_headlist_headlist_headlist_headnextprevnextprevnextprevnextprev重要數(shù)據(jù)結(jié)構(gòu)雙向鏈表（1）結(jié)構(gòu)體定義：list_head重要數(shù)據(jù)結(jié)構(gòu)雙向鏈表（2）為什么要使用這種結(jié)構(gòu)？容器機(jī)制將對象嵌入到另一個對象中怎樣通過鏈表元素找到容器對象的實(shí)例？nextprevtask_structlist_headne

2、xtprevtask_structlist_headnextprevtask_structlist_head重要數(shù)據(jù)結(jié)構(gòu)雙向鏈表（2）為什么要使用這種結(jié)構(gòu)？next重要數(shù)據(jù)結(jié)構(gòu)雙向鏈表（3）./include/linux/list.hlist_entry(p, t, m) 已知類型為t的數(shù)據(jù)結(jié)構(gòu)包含了一個list_head字段，該字段的名字是m，地址為p，返回類型為t的數(shù)據(jù)結(jié)構(gòu)地址list_entry(0 x., struct task_struct, tasks)重要數(shù)據(jù)結(jié)構(gòu)雙向鏈表（3）./include/lin重要數(shù)據(jù)結(jié)構(gòu)散列表（1）結(jié)構(gòu)體定義表頭：struct hlist_head s

3、truct hlist_node *first;節(jié)點(diǎn)：struct hlist_node struct hlist_node *next, *pprev;重要數(shù)據(jù)結(jié)構(gòu)散列表（1）結(jié)構(gòu)體定義重要數(shù)據(jù)結(jié)構(gòu)散列表（2）pprevnexthlist_headhlist_nodenullfirstfirstfirsthlist_nodepprevnextpprevnexthlist_nodenull重要數(shù)據(jù)結(jié)構(gòu)散列表（2）pprevnexthlist_h為什么要這么定義？進(jìn)程結(jié)構(gòu)體剖析（1）struct task_struct volatile long state;/* -1 unrunnable,

4、0 runnable, 0 stopped */.long exit_state;/.進(jìn)程的狀態(tài)宏定義：#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/.為什么要這么定義？進(jìn)程結(jié)構(gòu)體剖析（1）struct task進(jìn)程結(jié)構(gòu)體剖析（2）struct task_struct /.st

5、ruct list_head tasks; /將系統(tǒng)中所有進(jìn)程通過雙向鏈表鏈接起來！/.怎樣訪問所有的進(jìn)程呢？#define for_each_process(p) for (p = &init_task ; (p = next_task(p) != &init_task ; )#define next_task(p) list_entry_rcu(p)-tasks.next, struct task_struct, tasks)給出全局pid號，怎么找到相應(yīng)進(jìn)程的task_struct？進(jìn)程結(jié)構(gòu)體剖析（2）struct task_struct 進(jìn)程結(jié)構(gòu)體剖析（3）struct task_st

6、ruct /.pid_t pid; /進(jìn)程標(biāo)識符（線程）pid_t tgid; /線程組的領(lǐng)頭線程IDstruct task_struct *group_leader; / threadgroup leader/. 系統(tǒng)調(diào)用 getpid() 返回什么？進(jìn)程結(jié)構(gòu)體剖析（3）struct task_struct 進(jìn)程結(jié)構(gòu)體剖析（4.1）struct task_struct /.struct task_struct _rcu *real_parent; /* real parent process */struct task_struct _rcu *parent; /* recipient of

7、 SIGCHLD, wait4() reports */struct list_head children; /* list of my children */struct list_head sibling; /* linkage in my parents children list */.進(jìn)程之間的關(guān)系：父子關(guān)系兄弟關(guān)系進(jìn)程結(jié)構(gòu)體剖析（4.1）struct task_structchildrensiblingchildrensiblingchildrensiblingchildrensiblingchildrensiblingADCBEPNNPPPNNP進(jìn)程結(jié)構(gòu)體剖析（4.2）假設(shè)現(xiàn)在有

8、進(jìn)程A，生成三個子進(jìn)程B、C、D，B進(jìn)程又生成一個子進(jìn)程E。五個task_struct怎么進(jìn)行鏈接？childrensiblingchildrensibling進(jìn)程結(jié)構(gòu)體剖析（5.1）struct task_struct /./* PID/PID hash table linkage. */struct pid_link pidsPIDTYPE_MAX;/.enum pid_typePIDTYPE_PID,PIDTYPE_PGID,PIDTYPE_SID,PIDTYPE_MAX;/進(jìn)程PID/線程組領(lǐng)頭線程PID/會話領(lǐng)頭進(jìn)程ID/類型個數(shù)pids0pids1pids2進(jìn)程結(jié)構(gòu)體剖析（5.1）

9、struct task_struct關(guān)鍵結(jié)構(gòu)體struct upid int nr;struct pid_namespace *ns;struct hlist_node pid_chain;struct pid_link struct hlist_node node; struct pid *pid;struct pid atomic_t count; unsigned int level; struct hlist_head tasksPIDTYPE_MAX; struct rcu_head rcu; struct upid numbers1;countlevertask0task1task

10、2nrnodepidnodepidnspid_chain 關(guān)鍵結(jié)構(gòu)體struct upid struct pid_l213pid命名空間（1）123456781092131lever 0lever 1lever 2213pid命名空間（1）123456781092131lepid命名空間（2）struct nsproxy atomic_t count;struct uts_namespace *uts_ns;struct ipc_namespace *ipc_ns;struct mnt_namespace *mnt_ns;struct pid_namespace *pid_ns;struct

11、net *net_ns;struct pid_namespace /. unsigned int level; struct pid_namespace *parent; /.;pid命名空間（2）struct nsproxy stru結(jié)構(gòu)圖見板書.結(jié)構(gòu)圖見板書.重要函數(shù)（1）根據(jù)進(jìn)程的命名空間ns以及局部PID號nr，怎么找到進(jìn)程的task_struct?nr,ns - upid - pid - task_structstruct pid *find_pid_ns(int nr, struct pid_namespace *ns)struct task_struct *pid_task(struct pid *pid, enum pid_type type)重要函數(shù)（1）根據(jù)進(jìn)程的命名空間ns以及局部PID號nr，怎重要函數(shù)（2）給出task_struct、ID類型、命名空間，怎么取得命名空間局部的ID號？task_struct - pid - upid - nrstruct pid *task_pid(struct task_struct *task)pid_t pid_nr_ns(struct pi