From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755568AbaIKTSg (ORCPT ); Thu, 11 Sep 2014 15:18:36 -0400 Received: from mail-pd0-f177.google.com ([209.85.192.177]:50320 "EHLO mail-pd0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752896AbaIKTSe (ORCPT ); Thu, 11 Sep 2014 15:18:34 -0400 Date: Thu, 11 Sep 2014 12:18:30 -0700 From: Guenter Roeck To: roy.qing.li@gmail.com Cc: linux-kernel@vger.kernel.org, viro@zeniv.linux.org.uk, fabf@skynet.be, jkosina@suse.cz, paulmck@linux.vnet.ibm.com, richard@nod.at, oleg@redhat.com, akpm@linux-foundation.org Subject: Re: [RFC][PATCH] signal: replace !likely with unlikely! Message-ID: <20140911191830.GA31511@roeck-us.net> References: <1410396496-13845-1-git-send-email-roy.qing.li@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1410396496-13845-1-git-send-email-roy.qing.li@gmail.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Sep 11, 2014 at 08:48:16AM +0800, roy.qing.li@gmail.com wrote: > From: Li RongQing > > !likely() is hard to be understood, and I do not know if compiler can > optimise this condition, but unlikely(!()) is clear > > Signed-off-by: Li RongQing > --- > kernel/signal.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/signal.c b/kernel/signal.c > index 8f0876f..6156cfa 100644 > --- a/kernel/signal.c > +++ b/kernel/signal.c > @@ -1571,7 +1571,7 @@ int send_sigqueue(struct sigqueue *q, struct task_struct *t, int group) > BUG_ON(!(q->flags & SIGQUEUE_PREALLOC)); > > ret = -1; > - if (!likely(lock_task_sighand(t, &flags))) > + if (unlikely(!lock_task_sighand(t, &flags))) I wonder if you tested this code. Seems to be unlikely (punt not intended). Guenter > goto ret; > > ret = 1; /* the signal is ignored */ > -- > 1.7.10.4 > > -- > 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/ > >