From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752932Ab3FIMbO (ORCPT ); Sun, 9 Jun 2013 08:31:14 -0400 Received: from intranet.asianux.com ([58.214.24.6]:6803 "EHLO intranet.asianux.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751495Ab3FIMbN (ORCPT ); Sun, 9 Jun 2013 08:31:13 -0400 X-Spam-Score: -100.8 Message-ID: <51B4755B.4020205@asianux.com> Date: Sun, 09 Jun 2013 20:30:19 +0800 From: Chen Gang User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130110 Thunderbird/17.0.2 MIME-Version: 1.0 To: Frederic Weisbecker , Thomas Gleixner , Sedat Dilek , Paul McKenney CC: Andrew Morton , Linus Torvalds , "linux-kernel@vger.kernel.org" Subject: [PATCH] kernel/softirq.c: delete 'while' looping to improve a little performance and beautify code Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org After finish the internal 'while', need not test TASKLET_STATE_SCHED again, so looping back to outside 'while' is only for set_bit(). When use 'if' and set_bit() instead of 'while', it will save at least one running conditional instruction, and also will be clearer for readers (although the binary size will be a little bigger). The related patch is "1da177e Linux-2.6.12-rc2" Signed-off-by: Chen Gang --- kernel/softirq.c | 3 ++- 1 files changed, 2 insertions(+), 1 deletions(-) diff --git a/kernel/softirq.c b/kernel/softirq.c index a5f8836..52da25f 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -540,10 +540,11 @@ void tasklet_kill(struct tasklet_struct *t) if (in_interrupt()) printk("Attempt to kill tasklet from interrupt\n"); - while (test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) { + if (test_and_set_bit(TASKLET_STATE_SCHED, &t->state)) { do { yield(); } while (test_bit(TASKLET_STATE_SCHED, &t->state)); + set_bit(TASKLET_STATE_SCHED, &t->state); } tasklet_unlock_wait(t); clear_bit(TASKLET_STATE_SCHED, &t->state); -- 1.7.7.6