Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756739Ab0D1TWJ (ORCPT ); Wed, 28 Apr 2010 15:22:09 -0400 Received: from mail-fx0-f46.google.com ([209.85.161.46]:40007 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753827Ab0D1TWG convert rfc822-to-8bit (ORCPT ); Wed, 28 Apr 2010 15:22:06 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type :content-transfer-encoding; b=kzQRzJLDMSsy7JPUj8mrfhIjC5sXJQISadEUd3ws9a0IhwLxdDaQ0PVzLBao/aa7ZU YtU+hAZdagll0+Nlrdtc84FhqxP90XUn0/rfP7vl4JXKp/PAmHuvF8uETu36Vgpo9gQo d0qXlVOHWyV1BFeUSobUu3raWfuT/X1mFGk2s= MIME-Version: 1.0 In-Reply-To: References: <1272396342-12504-1-git-send-email-jkacur@redhat.com> Date: Wed, 28 Apr 2010 21:22:02 +0200 X-Google-Sender-Auth: 51cbe5430c47dd5a Message-ID: Subject: Re: [PATCH:resend] rt: Remove CONFIG_STACK_TRACER from DEBUG_COUNT, and fix reminder block From: John Kacur To: Thomas Gleixner Cc: Clark Williams , Steven Rostedt , lkml , rt-users Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2151 Lines: 59 On Tue, Apr 27, 2010 at 10:39 PM, Thomas Gleixner wrote: > On Tue, 27 Apr 2010, John Kacur wrote: > >> This fix does two things. > > This changelog does suck in more than two ways. > >> 1. It reverts commit 3e39399ef4a742d994570488994be93ef17d4ef5. >> - The above commit added back a warning about CONFIG_STACK_TRACER >> NOT because the warning was necessary but to fix-up a problem where you could >> get an empty REMINDER block in the demg. > > The CONFIG_STACK_TRACER printk has been there before and got dropped > for whatever reason, but the DEBUG_COUNT accounting of > CONFIG_STACK_TRACER still remained. > > So the conclusion that the printk needs to be added back is _NOT_ > completely unreasonable. > >> However, CONFIG_STACK_TRACER really should not be in the reminder block. >> Even when configured-in it is not enabled, and thus has neglible impact. > > That argument is bogus as it applies to most of the tracing related > config options. Not quite. Some of the tracing options are believed to have an impact even when not enabled. In particular irqsoff and preemptoff still call a function. Not sure how minimal the impact is, but it isn't zero. > >> 2. It removes CONFIG_STACK_TRACER from DEBUG_COUNT which is the proper fix >> for the empty REMINDER block problem. > > It's the proper fix if the warning is not justified, which is not > clear at all. At least not from your changelog. > > I do not mind the patch per se, but > > 1) the changelog should simply say: > > ? rt: Remove CONFIG_STACK_TRACER from REMINDER block > > ? Reason: It does not matter because .... > > 2) the patch should cover _all_ tracing options which have no > ? considerable latency impact when just compiled in and not default > ? enabled. > Okay, you make some good points, although I'm having a hard time finding other CONFIGS to safely cut. Respinning the patch. Thanks for your reply. -- 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/