[PATCH] Honour "panic_on_oops" sysctl on mips arch

[PATCH] Honour "panic_on_oops" sysctl on mips arch

[Maxime Bizon]

Hello all,

The panic_on_oops sysctl has no effect on mips, the following patch
fixes it.


Signed-off-by: Maxime Bizon <mbizon@freebox.fr>

--- linux-2.6.17.6/arch/mips/kernel/traps.c.orig	2006-07-20 18:42:37.000000000 +0200
+++ linux-2.6.17.6/arch/mips/kernel/traps.c	2006-07-20 18:42:56.000000000 +0200
@@ -21,6 +21,7 @@
 #include <linux/spinlock.h>
 #include <linux/kallsyms.h>
 #include <linux/bootmem.h>
+#include <linux/interrupt.h>
 
 #include <asm/bootinfo.h>
 #include <asm/branch.h>
@@ -293,6 +294,16 @@
 	printk("%s[#%d]:\n", str, ++die_counter);
 	show_registers(regs);
 	spin_unlock_irq(&die_lock);
+
+	if (in_interrupt())
+		panic("Fatal exception in interrupt");
+
+	if (panic_on_oops) {
+		printk(KERN_EMERG "Fatal exception: panic in 5 seconds\n");
+		ssleep(5);
+		panic("Fatal exception");
+	}
+
 	do_exit(SIGSEGV);
 }
 


Regards,

-- 
Maxime

Re: [PATCH] Honour "panic_on_oops" sysctl on mips arch

[Ralf Baechle]

On Thu, Jul 20, 2006 at 06:52:02PM +0200, Maxime Bizon wrote:

> The panic_on_oops sysctl has no effect on mips, the following patch
> fixes it.

Applied. thanks,

  Ralf

reserved pages and zero pages question

[pulsar]

Hi,

In my kernel startup I see the memory usage printed as:

Memory: 125312k/131072k available (1977k kernel code, 5648k reserved, 287k
data, 1664k init, 0k highmem)

I wonder where the reserved pages are used for and how we can minimize it
for small memory systems.

In my search I see that in arcm/mips/mm/init.c there are zero-pages
allocated and put to reserved.

Where are the zero pages used for and can we do without ?

thanks in advance,

Niels Sterrenburg

Re: reserved pages and zero pages question

[Thiemo Seufer]

pulsar@kpsws.com wrote:
> Hi,
> 
> In my kernel startup I see the memory usage printed as:
> 
> Memory: 125312k/131072k available (1977k kernel code, 5648k reserved, 287k
> data, 1664k init, 0k highmem)
> 
> I wonder where the reserved pages are used for and how we can minimize it
> for small memory systems.

Most of that is the ramdisk you included. :-)  It normally given back
once the ramdisk is decompressed.

> In my search I see that in arcm/mips/mm/init.c there are zero-pages
> allocated and put to reserved.
> 
> Where are the zero pages used for and can we do without ?

They provide a clean zeroed page which gets mapped read-only (probably
for copy-on-write). You can't do without.


Thiemo