Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753417AbZKSS4e (ORCPT ); Thu, 19 Nov 2009 13:56:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752432AbZKSS4e (ORCPT ); Thu, 19 Nov 2009 13:56:34 -0500 Received: from smtp1.linux-foundation.org ([140.211.169.13]:43777 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752005AbZKSS4d (ORCPT ); Thu, 19 Nov 2009 13:56:33 -0500 Date: Thu, 19 Nov 2009 10:54:42 -0800 (PST) From: Linus Torvalds X-X-Sender: torvalds@localhost.localdomain To: Andrew Haley cc: Richard Guenther , rostedt@goodmis.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , LKML , Andrew Morton , Heiko Carstens , feng.tang@intel.com, Fr??d??ric Weisbecker , Peter Zijlstra , jakub@redhat.com, gcc@gcc.gnu.org Subject: Re: BUG: GCC-4.4.x changes the function frame on some functions In-Reply-To: Message-ID: References: <20091119072040.GA23579@elte.hu> <1258653562.22249.682.camel@gandalf.stny.rr.com> <84fc9c000911191003t244eb864o3d5b355ab5485f@mail.gmail.com> <4B058CCD.8050605@redhat.com> User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1697 Lines: 51 On Thu, 19 Nov 2009, Linus Torvalds wrote: > > I bet other people than just the kernel use the mcount hook for subtler > things than just doing profiles. And even if they don't, the quoted code > generation is just crazy _crap_. For the kernel, if the only case is that timer_stat.c thing that Thomas pointed at, I guess we can at least work around it with something like the appended. The kernel code is certainly ugly too, no question about that. It's just that we'd like to be able to depend on mcount code generation not being insane even in the presense of ugly code.. The alternative would be to have some warning when this happens, so that we can at least see it. "mcount won't work reliably" Linus --- kernel/time/timer_stats.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/time/timer_stats.c b/kernel/time/timer_stats.c index ee5681f..488c7b8 100644 --- a/kernel/time/timer_stats.c +++ b/kernel/time/timer_stats.c @@ -76,7 +76,7 @@ struct entry { */ char comm[TASK_COMM_LEN + 1]; -} ____cacheline_aligned_in_smp; +}; /* * Spinlock protecting the tables - not taken during lookup: @@ -114,7 +114,7 @@ static ktime_t time_start, time_stop; #define MAX_ENTRIES (1UL << MAX_ENTRIES_BITS) static unsigned long nr_entries; -static struct entry entries[MAX_ENTRIES]; +static struct entry entries[MAX_ENTRIES] ____cacheline_aligned_in_smp; static atomic_t overflow_count; -- 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/