Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754587AbaJCVTh (ORCPT ); Fri, 3 Oct 2014 17:19:37 -0400 Received: from mx1.redhat.com ([209.132.183.28]:64566 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750939AbaJCVTg (ORCPT ); Fri, 3 Oct 2014 17:19:36 -0400 Date: Fri, 3 Oct 2014 23:16:10 +0200 From: Oleg Nesterov To: Sasha Levin Cc: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, luto@amacapital.net, dvlasenk@redhat.com, tglx@linutronix.de Subject: Re: [tip:x86/asm] x86: Speed up ___preempt_schedule*() by using THUNK helpers Message-ID: <20141003211610.GA28811@redhat.com> References: <20140921184153.GA23727@redhat.com> <542E2B05.5080607@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <542E2B05.5080607@oracle.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Sasha, On 10/03, Sasha Levin wrote: > > On 09/24/2014 11:02 AM, tip-bot for Oleg Nesterov wrote: > > Commit-ID: 0ad6e3c5199be12c9745da8f8b9e3c9f8066c235 > > Gitweb: http://git.kernel.org/tip/0ad6e3c5199be12c9745da8f8b9e3c9f8066c235 > > Author: Oleg Nesterov > > AuthorDate: Sun, 21 Sep 2014 20:41:53 +0200 > > Committer: Ingo Molnar > > CommitDate: Wed, 24 Sep 2014 15:15:38 +0200 > > > > x86: Speed up ___preempt_schedule*() by using THUNK helpers > > > > ___preempt_schedule() does SAVE_ALL/RESTORE_ALL but this is > > suboptimal, we do not need to save/restore the callee-saved > > register. And we already have arch/x86/lib/thunk_*.S which > > implements the similar asm wrappers, so it makes sense to > > redefine ___preempt_schedule() as "THUNK ..." and remove > > preempt.S altogether. > > > > Signed-off-by: Oleg Nesterov > > Reviewed-by: Andy Lutomirski > > Cc: Denys Vlasenko > > Cc: Peter Zijlstra > > Cc: Linus Torvalds > > Link: http://lkml.kernel.org/r/20140921184153.GA23727@redhat.com > > Signed-off-by: Ingo Molnar > > --- > > Hi Oleg, > > I *think* that this patch is causing the following trace (arch/x86/lib/thunk_64.S:44 > is new code introduced by this patch): Not sure, but I'm afraid your guess can be correct... > [ 921.908530] kernel BUG at kernel/sched/core.c:2702! OK, this is schedule_debug() -> BUG_ON(unlikely(task_stack_end_corrupted(prev))) in linux-next. But at first glance this doesn't match the disassembled code... Could you send me (privately) your kernel/sched/core.c just in case? And .config please. And, if possible, kernel/sched/core.s Oleg. -- 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/