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| author | Lai Jiangshan <laijs@cn.fujitsu.com> | 2008-10-05 00:51:15 +0400 |
|---|---|---|
| committer | Alexey Dobriyan <adobriyan@gmail.com> | 2008-10-10 04:18:57 +0400 |
| commit | a6bebbc87a8c16eabb6bd5c6fd2d994be0236fba (patch) | |
| tree | 3e617ca49063f3a12c982da5d6c687882a1b4070 /kernel/sched_debug.c | |
| parent | 53167a3ef23df561d898dee636f3393e9fba937c (diff) | |
| download | blackbird-op-linux-a6bebbc87a8c16eabb6bd5c6fd2d994be0236fba.tar.gz blackbird-op-linux-a6bebbc87a8c16eabb6bd5c6fd2d994be0236fba.zip | |
[PATCH] signal, procfs: some lock_task_sighand() users do not need rcu_read_lock()
lock_task_sighand() make sure task->sighand is being protected,
so we do not need rcu_read_lock().
[ exec() will get task->sighand->siglock before change task->sighand! ]
But code using rcu_read_lock() _just_ to protect lock_task_sighand()
only appear in procfs. (and some code in procfs use lock_task_sighand()
without such redundant protection.)
Other subsystem may put lock_task_sighand() into rcu_read_lock()
critical region, but these rcu_read_lock() are used for protecting
"for_each_process()", "find_task_by_vpid()" etc. , not for protecting
lock_task_sighand().
Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
[ok from Oleg]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Diffstat (limited to 'kernel/sched_debug.c')
| -rw-r--r-- | kernel/sched_debug.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c index bbe6b31c3c56..ad958c1ec708 100644 --- a/kernel/sched_debug.c +++ b/kernel/sched_debug.c @@ -333,12 +333,10 @@ void proc_sched_show_task(struct task_struct *p, struct seq_file *m) unsigned long flags; int num_threads = 1; - rcu_read_lock(); if (lock_task_sighand(p, &flags)) { num_threads = atomic_read(&p->signal->count); unlock_task_sighand(p, &flags); } - rcu_read_unlock(); SEQ_printf(m, "%s (%d, #threads: %d)\n", p->comm, p->pid, num_threads); SEQ_printf(m, |
