On Tue, May 06, 2008 at 01:55:24PM +0200, Ingo Molnar wrote:
quoted text
> 
> * Venki Pallipadi <venkatesh.pallipadi@intel.com> wrote:
> 
> > Below is the patch to enable debug messages by a boot option 
> > "debugpat".
> 
> ok, i have applied the patch with some modifications - see below.
> 
> Since we build in this code unconditionally also make the flag 
> switchable from a sysctl, so that users do not have to reboot to see PAT 
> debug messages ...
> 

Below patch adds the sysctl interface.

Thanks,
Venki


Add sysctl interface to runtime change debugpat setting.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>

---
 arch/x86/mm/pat.c      |    6 +++---
 include/linux/kernel.h |    1 +
 kernel/sysctl.c        |    8 ++++++++
 3 files changed, 12 insertions(+), 3 deletions(-)

Index: linux-2.6/arch/x86/mm/pat.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/pat.c	2008-05-06 10:52:51.000000000 -0700
+++ linux-2.6/arch/x86/mm/pat.c	2008-05-06 15:27:59.000000000 -0700
@@ -39,16 +39,16 @@ static int nopat(char *str)
 early_param("nopat", nopat);
 
 
-static int debug_enable;
+int pat_debug_enable = 0;
 static int __init pat_debug_setup(char *str)
 {
-	debug_enable = 1;
+	pat_debug_enable = 1;
 	return 0;
 }
 __setup("debugpat", pat_debug_setup);
 
 #define dprintk(fmt, arg...) \
-	do { if (debug_enable) printk(KERN_INFO fmt, ##arg); } while (0)
+	do { if (pat_debug_enable) printk(KERN_INFO fmt, ##arg); } while (0)
 
 
 static int pat_known_cpu(void)
Index: linux-2.6/include/linux/kernel.h
===================================================================
--- linux-2.6.orig/include/linux/kernel.h	2008-05-02 09:45:26.000000000 -0700
+++ linux-2.6/include/linux/kernel.h	2008-05-06 10:54:06.000000000 -0700
@@ -239,6 +239,7 @@ extern int tainted;
 extern const char *print_tainted(void);
 extern void add_taint(unsigned);
 extern int root_mountflags;
+extern int pat_debug_enable;
 
 /* Values used for system_state */
 extern enum system_states {
Index: linux-2.6/kernel/sysctl.c
===================================================================
--- linux-2.6.orig/kernel/sysctl.c	2008-05-02 09:45:26.000000000 -0700
+++ linux-2.6/kernel/sysctl.c	2008-05-06 10:55:08.000000000 -0700
@@ -685,6 +685,14 @@ static struct ctl_table kern_table[] = {
 		.mode		= 0644,
 		.proc_handler	= &proc_dointvec,
 	},
+	{
+		.ctl_name	= CTL_UNNUMBERED,
+		.procname	= "debugpat",
+		.data		= &pat_debug_enable,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec,
+	},
 #endif
 #if defined(CONFIG_MMU)
 	{
--
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