Messages in this thread Patch in this message | | | Date | Thu, 23 Feb 2006 02:04:16 +0300 | From | Oleg Nesterov <> | Subject | [PATCH 1/6] sys_times: don't take tasklist_lock |
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sys_times: dont' take tasklist_lock
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
--- 2.6.16-rc3/kernel/sys.c~ Thu Feb 23 00:27:27 2006 +++ 2.6.16-rc3/kernel/sys.c Thu Feb 23 00:28:24 2006 @@ -1018,7 +1018,7 @@ asmlinkage long sys_times(struct tms __u struct task_struct *t; cputime_t utime, stime, cutime, cstime; - read_lock(&tasklist_lock); + spin_lock_irq(&tsk->sighand->siglock); utime = tsk->signal->utime; stime = tsk->signal->stime; t = tsk; @@ -1028,20 +1028,9 @@ asmlinkage long sys_times(struct tms __u t = next_thread(t); } while (t != tsk); - /* - * While we have tasklist_lock read-locked, no dying thread - * can be updating current->signal->[us]time. Instead, - * we got their counts included in the live thread loop. - * However, another thread can come in right now and - * do a wait call that updates current->signal->c[us]time. - * To make sure we always see that pair updated atomically, - * we take the siglock around fetching them. - */ - spin_lock_irq(&tsk->sighand->siglock); cutime = tsk->signal->cutime; cstime = tsk->signal->cstime; spin_unlock_irq(&tsk->sighand->siglock); - read_unlock(&tasklist_lock); tmp.tms_utime = cputime_to_clock_t(utime); tmp.tms_stime = cputime_to_clock_t(stime); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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