Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751516AbWBVXHW (ORCPT ); Wed, 22 Feb 2006 18:07:22 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751513AbWBVXHW (ORCPT ); Wed, 22 Feb 2006 18:07:22 -0500 Received: from mail.tv-sign.ru ([213.234.233.51]:35560 "EHLO several.ru") by vger.kernel.org with ESMTP id S1751512AbWBVXHO (ORCPT ); Wed, 22 Feb 2006 18:07:14 -0500 Message-ID: <43FCEDF0.15D70D0D@tv-sign.ru> Date: Thu, 23 Feb 2006 02:04:16 +0300 From: Oleg Nesterov X-Mailer: Mozilla 4.76 [en] (X11; U; Linux 2.2.20 i686) X-Accept-Language: en MIME-Version: 1.0 To: Andrew Morton Cc: linux-kernel@vger.kernel.org, Ingo Molnar , "Paul E. McKenney" , "Eric W. Biederman" , David Howells , Christoph Lameter Subject: [PATCH 1/6] sys_times: don't take tasklist_lock Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1531 Lines: 41 sys_times: dont' take tasklist_lock Signed-off-by: Oleg Nesterov --- 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/