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| author | Ingo Molnar <mingo@elte.hu> | 2006-01-08 01:01:37 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-01-08 20:13:40 -0800 |
| commit | e56d090310d7625ecb43a1eeebd479f04affb48b (patch) | |
| tree | 2f479215dff4a2d8f3a9ed85200a5bc4f51534be /kernel/pid.c | |
| parent | 4369ef3c3e9d3bd9b879580678778f558d481e90 (diff) | |
| download | lwn-e56d090310d7625ecb43a1eeebd479f04affb48b.tar.gz lwn-e56d090310d7625ecb43a1eeebd479f04affb48b.zip | |
[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.c | 22 |
1 files changed, 11 insertions, 11 deletions
diff --git a/kernel/pid.c b/kernel/pid.c index edba31c681ac..1acc07246991 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; |