2006-12-16 20:23:22

by Oleg Nesterov

[permalink] [raw]
Subject: [PATCH] kill_pid_info: kill acquired_tasklist_lock

Kill acquired_tasklist_lock, sig_needs_tasklist() is very cheap nowadays.

Signed-off-by: Oleg Nesterov <[email protected]>

--- eric-mm1/kernel/signal.c~3_kpi 2006-12-16 22:22:48.000000000 +0300
+++ eric-mm1/kernel/signal.c 2006-12-16 23:14:05.000000000 +0300
@@ -1247,19 +1247,18 @@ int kill_pgrp_info(int sig, struct sigin
int kill_pid_info(int sig, struct siginfo *info, struct pid *pid)
{
int error;
- int acquired_tasklist_lock = 0;
struct task_struct *p;

rcu_read_lock();
- if (unlikely(sig_needs_tasklist(sig))) {
+ if (unlikely(sig_needs_tasklist(sig)))
read_lock(&tasklist_lock);
- acquired_tasklist_lock = 1;
- }
+
p = pid_task(pid, PIDTYPE_PID);
error = -ESRCH;
if (p)
error = group_send_sig_info(sig, info, p);
- if (unlikely(acquired_tasklist_lock))
+
+ if (unlikely(sig_needs_tasklist(sig)))
read_unlock(&tasklist_lock);
rcu_read_unlock();
return error;