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authorOleg Nesterov <oleg@tv-sign.ru>2006-03-28 19:11:25 -0500
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-28 21:36:44 -0500
commit47e65328a7b1cdfc4e3102e50d60faf94ebba7d3 (patch)
tree78e00a5321cca87767806a91e623e71b5c6637c7
parent88531f725bd52e37a7be726860e4ff3f09031d89 (diff)
[PATCH] pids: kill PIDTYPE_TGID
This patch kills PIDTYPE_TGID pid_type thus saving one hash table in kernel/pid.c and speeding up subthreads create/destroy a bit. It is also a preparation for the further tref/pids rework. This patch adds 'struct list_head thread_group' to 'struct task_struct' instead. We don't detach group leader from PIDTYPE_PID namespace until another thread inherits it's ->pid == ->tgid, so we are safe wrt premature free_pidmap(->tgid) call. Currently there are no users of find_task_by_pid_type(PIDTYPE_TGID). Should the need arise, we can use find_task_by_pid()->group_leader. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Acked-By: Eric Biederman <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--include/linux/pid.h1
-rw-r--r--include/linux/sched.h11
-rw-r--r--kernel/exit.c10
-rw-r--r--kernel/fork.c4
4 files changed, 12 insertions, 14 deletions
diff --git a/include/linux/pid.h b/include/linux/pid.h
index 099e70ecf7c7..5b9082cc600f 100644
--- a/include/linux/pid.h
+++ b/include/linux/pid.h
@@ -4,7 +4,6 @@
4enum pid_type 4enum pid_type
5{ 5{
6 PIDTYPE_PID, 6 PIDTYPE_PID,
7 PIDTYPE_TGID,
8 PIDTYPE_PGID, 7 PIDTYPE_PGID,
9 PIDTYPE_SID, 8 PIDTYPE_SID,
10 PIDTYPE_MAX 9 PIDTYPE_MAX
diff --git a/include/linux/sched.h b/include/linux/sched.h
index a913fca9e70d..99855f694ebd 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -752,6 +752,7 @@ struct task_struct {
752 752
753 /* PID/PID hash table linkage. */ 753 /* PID/PID hash table linkage. */
754 struct pid pids[PIDTYPE_MAX]; 754 struct pid pids[PIDTYPE_MAX];
755 struct list_head thread_group;
755 756
756 struct completion *vfork_done; /* for vfork() */ 757 struct completion *vfork_done; /* for vfork() */
757 int __user *set_child_tid; /* CLONE_CHILD_SETTID */ 758 int __user *set_child_tid; /* CLONE_CHILD_SETTID */
@@ -1192,13 +1193,17 @@ extern void wait_task_inactive(task_t * p);
1192#define while_each_thread(g, t) \ 1193#define while_each_thread(g, t) \
1193 while ((t = next_thread(t)) != g) 1194 while ((t = next_thread(t)) != g)
1194 1195
1195extern task_t * FASTCALL(next_thread(const task_t *p));
1196
1197#define thread_group_leader(p) (p->pid == p->tgid) 1196#define thread_group_leader(p) (p->pid == p->tgid)
1198 1197
1198static inline task_t *next_thread(task_t *p)
1199{
1200 return list_entry(rcu_dereference(p->thread_group.next),
1201 task_t, thread_group);
1202}
1203
1199static inline int thread_group_empty(task_t *p) 1204static inline int thread_group_empty(task_t *p)
1200{ 1205{
1201 return list_empty(&p->pids[PIDTYPE_TGID].pid_list); 1206 return list_empty(&p->thread_group);
1202} 1207}
1203 1208
1204#define delay_group_leader(p) \ 1209#define delay_group_leader(p) \
diff --git a/kernel/exit.c b/kernel/exit.c
index aea23e713cf4..22399caf7574 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -51,7 +51,6 @@ static void __unhash_process(struct task_struct *p)
51{ 51{
52 nr_threads--; 52 nr_threads--;
53 detach_pid(p, PIDTYPE_PID); 53 detach_pid(p, PIDTYPE_PID);
54 detach_pid(p, PIDTYPE_TGID);
55 if (thread_group_leader(p)) { 54 if (thread_group_leader(p)) {
56 detach_pid(p, PIDTYPE_PGID); 55 detach_pid(p, PIDTYPE_PGID);
57 detach_pid(p, PIDTYPE_SID); 56 detach_pid(p, PIDTYPE_SID);
@@ -59,7 +58,7 @@ static void __unhash_process(struct task_struct *p)
59 list_del_init(&p->tasks); 58 list_del_init(&p->tasks);
60 __get_cpu_var(process_counts)--; 59 __get_cpu_var(process_counts)--;
61 } 60 }
62 61 list_del_rcu(&p->thread_group);
63 remove_parent(p); 62 remove_parent(p);
64} 63}
65 64
@@ -964,13 +963,6 @@ asmlinkage long sys_exit(int error_code)
964 do_exit((error_code&0xff)<<8); 963 do_exit((error_code&0xff)<<8);
965} 964}
966 965
967task_t fastcall *next_thread(const task_t *p)
968{
969 return pid_task(p->pids[PIDTYPE_TGID].pid_list.next, PIDTYPE_TGID);
970}
971
972EXPORT_SYMBOL(next_thread);
973
974/* 966/*
975 * Take down every thread in the group. This is called by fatal signals 967 * Take down every thread in the group. This is called by fatal signals
976 * as well as by sys_exit_group (below). 968 * as well as by sys_exit_group (below).
diff --git a/kernel/fork.c b/kernel/fork.c
index 12cdd9fc9d02..bc551efb5fd4 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1112,6 +1112,7 @@ static task_t *copy_process(unsigned long clone_flags,
1112 * We dont wake it up yet. 1112 * We dont wake it up yet.
1113 */ 1113 */
1114 p->group_leader = p; 1114 p->group_leader = p;
1115 INIT_LIST_HEAD(&p->thread_group);
1115 INIT_LIST_HEAD(&p->ptrace_children); 1116 INIT_LIST_HEAD(&p->ptrace_children);
1116 INIT_LIST_HEAD(&p->ptrace_list); 1117 INIT_LIST_HEAD(&p->ptrace_list);
1117 1118
@@ -1165,7 +1166,9 @@ static task_t *copy_process(unsigned long clone_flags,
1165 retval = -EAGAIN; 1166 retval = -EAGAIN;
1166 goto bad_fork_cleanup_namespace; 1167 goto bad_fork_cleanup_namespace;
1167 } 1168 }
1169
1168 p->group_leader = current->group_leader; 1170 p->group_leader = current->group_leader;
1171 list_add_tail_rcu(&p->thread_group, &p->group_leader->thread_group);
1169 1172
1170 if (current->signal->group_stop_count > 0) { 1173 if (current->signal->group_stop_count > 0) {
1171 /* 1174 /*
@@ -1213,7 +1216,6 @@ static task_t *copy_process(unsigned long clone_flags,
1213 list_add_tail(&p->tasks, &init_task.tasks); 1216 list_add_tail(&p->tasks, &init_task.tasks);
1214 __get_cpu_var(process_counts)++; 1217 __get_cpu_var(process_counts)++;
1215 } 1218 }
1216 attach_pid(p, PIDTYPE_TGID, p->tgid);
1217 attach_pid(p, PIDTYPE_PID, p->pid); 1219 attach_pid(p, PIDTYPE_PID, p->pid);
1218 nr_threads++; 1220 nr_threads++;
1219 } 1221 }