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authorIngo Molnar <mingo@elte.hu>2006-01-08 01:01:37 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2006-01-08 20:13:40 -0800
commite56d090310d7625ecb43a1eeebd479f04affb48b (patch)
tree2f479215dff4a2d8f3a9ed85200a5bc4f51534be /kernel/pid.c
parent4369ef3c3e9d3bd9b879580678778f558d481e90 (diff)
[PATCH] RCU signal handling
RCU tasklist_lock and RCU signal handling: send signals RCU-read-locked instead of tasklist_lock read-locked. This is a scalability improvement on SMP and a preemption-latency improvement under PREEMPT_RCU. Signed-off-by: Paul E. McKenney <paulmck@us.ibm.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Acked-by: William Irwin <wli@holomorphy.com> Cc: Roland McGrath <roland@redhat.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'kernel/pid.c')
-rw-r--r--kernel/pid.c22
1 files changed, 11 insertions, 11 deletions
diff --git a/kernel/pid.c b/kernel/pid.c
index edba31c681a..1acc0724699 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -136,7 +136,7 @@ struct pid * fastcall find_pid(enum pid_type type, int nr)
struct hlist_node *elem;
struct pid *pid;
- hlist_for_each_entry(pid, elem,
+ hlist_for_each_entry_rcu(pid, elem,
&pid_hash[type][pid_hashfn(nr)], pid_chain) {
if (pid->nr == nr)
return pid;
@@ -150,15 +150,15 @@ int fastcall attach_pid(task_t *task, enum pid_type type, int nr)
task_pid = &task->pids[type];
pid = find_pid(type, nr);
+ task_pid->nr = nr;
if (pid == NULL) {
- hlist_add_head(&task_pid->pid_chain,
- &pid_hash[type][pid_hashfn(nr)]);
INIT_LIST_HEAD(&task_pid->pid_list);
+ hlist_add_head_rcu(&task_pid->pid_chain,
+ &pid_hash[type][pid_hashfn(nr)]);
} else {
INIT_HLIST_NODE(&task_pid->pid_chain);
- list_add_tail(&task_pid->pid_list, &pid->pid_list);
+ list_add_tail_rcu(&task_pid->pid_list, &pid->pid_list);
}
- task_pid->nr = nr;
return 0;
}
@@ -170,20 +170,20 @@ static fastcall int __detach_pid(task_t *task, enum pid_type type)
pid = &task->pids[type];
if (!hlist_unhashed(&pid->pid_chain)) {
- hlist_del(&pid->pid_chain);
- if (list_empty(&pid->pid_list))
+ if (list_empty(&pid->pid_list)) {
nr = pid->nr;
- else {
+ hlist_del_rcu(&pid->pid_chain);
+ } else {
pid_next = list_entry(pid->pid_list.next,
struct pid, pid_list);
/* insert next pid from pid_list to hash */
- hlist_add_head(&pid_next->pid_chain,
- &pid_hash[type][pid_hashfn(pid_next->nr)]);
+ hlist_replace_rcu(&pid->pid_chain,
+ &pid_next->pid_chain);
}
}
- list_del(&pid->pid_list);
+ list_del_rcu(&pid->pid_list);
pid->nr = 0;
return nr;