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proc: get_nr_threads() doesn't need ->siglock any longer

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Now that task->signal can't go away get_nr_threads() doesn't need
->siglock to read signal->count.

Also, make it inline, move into sched.h, and convert 2 other proc users of
signal->count to use this (now trivial) helper.

Henceforth get_nr_threads() is the only valid user of signal->count, we
are ready to turn it into "int nr_threads" or, perhaps, kill it.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Oleg Nesterov 2010-05-26 14:43:22 -07:00 committed by Linus Torvalds
parent 6e1be45aa6
commit 7e49827cc9
3 changed files with 7 additions and 14 deletions
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4
fs/proc/array.c
View File

@ -267,7 +267,7 @@ static inline void task_sig(struct seq_file *m, struct task_struct *p)
shpending = p->signal->shared_pending.signal;
blocked = p->blocked;
collect_sigign_sigcatch(p, &ignored, &caught);
num_threads = atomic_read(&p->signal->count);
num_threads = get_nr_threads(p);
rcu_read_lock(); /* FIXME: is this correct? */
qsize = atomic_read(&__task_cred(p)->user->sigpending);
rcu_read_unlock();
@ -410,7 +410,7 @@ static int do_task_stat(struct seq_file *m, struct pid_namespace *ns,
tty_nr = new_encode_dev(tty_devnum(sig->tty));
}
num_threads = atomic_read(&sig->count);
num_threads = get_nr_threads(task);
collect_sigign_sigcatch(task, &sigign, &sigcatch);
cmin_flt = sig->cmin_flt;

12
fs/proc/base.c
View File

@ -166,18 +166,6 @@ static int get_fs_path(struct task_struct *task, struct path *path, bool root)
return result;
}
static int get_nr_threads(struct task_struct *tsk)
{
unsigned long flags;
int count = 0;
if (lock_task_sighand(tsk, &flags)) {
count = atomic_read(&tsk->signal->count);
unlock_task_sighand(tsk, &flags);
}
return count;
}
static int proc_cwd_link(struct inode *inode, struct path *path)
{
struct task_struct *task = get_proc_task(inode);

5
include/linux/sched.h
View File

@ -2147,6 +2147,11 @@ extern bool current_is_single_threaded(void);
#define while_each_thread(g, t) \
while ((t = next_thread(t)) != g)
static inline int get_nr_threads(struct task_struct *tsk)
{
return atomic_read(&tsk->signal->count);
}
/* de_thread depends on thread_group_leader not being a pid based check */
#define thread_group_leader(p) (p == p->group_leader)