From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760677AbYBHPtm (ORCPT ); Fri, 8 Feb 2008 10:49:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757265AbYBHPte (ORCPT ); Fri, 8 Feb 2008 10:49:34 -0500 Received: from mx1.redhat.com ([66.187.233.31]:49073 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757068AbYBHPtd (ORCPT ); Fri, 8 Feb 2008 10:49:33 -0500 Date: Fri, 8 Feb 2008 10:49:29 -0500 From: Jason Baron To: Stephen Hemminger Cc: linux-kernel@vger.kernel.org Subject: Re: [patch 3/4] make pr_debug() dynamic - sysctl support Message-ID: <20080208154929.GA13650@redhat.com> References: <20080207211229.GE14732@redhat.com> <20080207161052.6804a992@extreme> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080207161052.6804a992@extreme> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 07, 2008 at 04:10:52PM -0800, Stephen Hemminger wrote: > Jason Baron wrote: > > > > > -add /proc/sys/debug/pr_debug, to toggle pr_debug() on/off > > > > Signed-off-by: Jason Baron > > --- > > > > kernel/sysctl.c | 41 +++++++++++++++++++++++++++++++++++++++++ > > 1 files changed, 41 insertions(+), 0 deletions(-) > > > > > > diff --git a/kernel/sysctl.c b/kernel/sysctl.c > > index 7cb1ac3..73508d7 100644 > > --- a/kernel/sysctl.c > > +++ b/kernel/sysctl.c > > @@ -155,6 +155,11 @@ static int proc_do_cad_pid(struct ctl_table *table, int write, struct file *filp > > static int proc_dointvec_taint(struct ctl_table *table, int write, struct file *filp, > > void __user *buffer, size_t *lenp, loff_t *ppos); > > #endif > > +#ifdef CONFIG_PR_DEBUG_DYNAMIC > > +static int proc_pr_debug_handler(struct ctl_table *table, int write, > > + struct file *filp, void __user *buffer, > > + size_t *lenp, loff_t *ppos); > > +#endif > > > > static struct ctl_table root_table[]; > > static struct ctl_table_root sysctl_table_root; > > @@ -1312,6 +1317,16 @@ static struct ctl_table debug_table[] = { > > .proc_handler = proc_dointvec > > }, > > #endif > > +#ifdef CONFIG_PR_DEBUG_DYNAMIC > > + { > > + .ctl_name = CTL_UNNUMBERED, > > + .procname = "pr_debug", > > + .data = NULL, > > + .maxlen = sizeof(int), > > + .mode = 0644, > > + .proc_handler = &proc_pr_debug_handler > > + }, > > +#endif > > { .ctl_name = 0 } > > }; > > > > @@ -2499,6 +2514,32 @@ static int proc_do_cad_pid(struct ctl_table *table, int write, struct file *filp > > return 0; > > } > > > > +#ifdef CONFIG_PR_DEBUG_DYNAMIC > > + > > +static int proc_pr_debug_handler(struct ctl_table *table, int write, > > + struct file *filp, void __user *buffer, > > + size_t *lenp, loff_t *ppos) > > +{ > > + int tmp, r; > > + > > + if (!write) > > + tmp = imv_read(pr_debug_on); > > + r = __do_proc_dointvec(&tmp, table, write, filp, buffer, > > + lenp, ppos, NULL, NULL); > > + if (r) > > + return r; > > + > > + if (write) { > > + if (tmp) > > + imv_set(pr_debug_on, 1); > > + else > > + imv_set(pr_debug_on, 0); > > + } > > + return 0; > > +} > > + > > +#endif > > + > > #else /* CONFIG_PROC_FS */ > > > > int proc_dostring(struct ctl_table *table, int write, struct file *filp, > > Please no, there are many pr_debug calls that are only intended for debugging that > particular subsystem, not a global enable/disable. It also adds to kernel bloat. > Yes, but you are going to have to re-compile your kernel to get at them...the ability to turn on/off pr_debug() calls, at runtime, seems like a powerful runtime diagnostic tool...the CONFIG_PR_DEBUG_DYNAMIC can default to 'n', instead of being automactically set as I've proposed. In terms of bloat, the vmlinux file goes from 53649330 to 53985478, < %1 increase. thanks, -Jason