arch/powerpc/kernel/rtas.c | 9 +++++++++
kernel/cpu.c | 4 ++--
2 files changed, 11 insertions(+), 2 deletions(-)
Index: linux-2.6.19-rc5/arch/powerpc/kernel/rtas.c
===================================================================
--- linux-2.6.19-rc5.orig/arch/powerpc/kernel/rtas.c 2006-11-08 07:54:20.000000000 +0530
+++ linux-2.6.19-rc5/arch/powerpc/kernel/rtas.c 2006-11-13 17:39:10.000000000 +0530
@@ -53,6 +53,9 @@
unsigned long rtas_rmo_buf;
+extern int cpu_hotplug_disabled;
+extern struct mutex cpu_add_remove_lock;
+
/*
* If non-NULL, this gets called when the kernel terminates.
* This is done like this so rtas_flash can be a module.
@@ -881,6 +884,12 @@
#ifdef CONFIG_HOTPLUG_CPU
rtas_stop_self_args.token = rtas_token("stop-self");
+ if(rtas_stop_self_args.token == RTAS_UNKNOWN_SERVICE) {
+ mutex_lock(&cpu_add_remove_lock);
+ cpu_hotplug_disabled = 1;
+ mutex_unlock(&cpu_add_remove_lock);
+ }
+
#endif /* CONFIG_HOTPLUG_CPU */
#ifdef CONFIG_RTAS_ERROR_LOGGING
rtas_last_error_token = rtas_token("rtas-last-error");
Index: linux-2.6.19-rc5/kernel/cpu.c
===================================================================
--- linux-2.6.19-rc5.orig/kernel/cpu.c 2006-11-08 07:54:20.000000000 +0530
+++ linux-2.6.19-rc5/kernel/cpu.c 2006-11-13 17:36:22.000000000 +0530
@@ -16,7 +16,7 @@
#include <linux/mutex.h>
/* This protects CPUs going up and down... */
-static DEFINE_MUTEX(cpu_add_remove_lock);
+DEFINE_MUTEX(cpu_add_remove_lock);
static DEFINE_MUTEX(cpu_bitmask_lock);
static __cpuinitdata RAW_NOTIFIER_HEAD(cpu_chain);
@@ -24,7 +24,7 @@
/* If set, cpu_up and cpu_down will return -EBUSY and do nothing.
* Should always be manipulated under cpu_add_remove_lock
*/
-static int cpu_hotplug_disabled;
+int cpu_hotplug_disabled;
#ifdef CONFIG_HOTPLUG_CPU
> Since we are not supported by hardware for cpu hotplug. I have developed
> the patch which will disable cpu hotplug on IBM bladecentre JS20. Please
> let me know your comments on this please.
> +extern int cpu_hotplug_disabled;
> +extern struct mutex cpu_add_remove_lock;
[...]
> + if(rtas_stop_self_args.token == RTAS_UNKNOWN_SERVICE) {
> + mutex_lock(&cpu_add_remove_lock);
> + cpu_hotplug_disabled = 1;
> + mutex_unlock(&cpu_add_remove_lock);
> + }
> +
> #endif /* CONFIG_HOTPLUG_CPU */
> #ifdef CONFIG_RTAS_ERROR_LOGGING
> rtas_last_error_token = rtas_token("rtas-last-error");
You should add a function to kernel/cpu.c which you can call in order to
disable cpu hotplug instead of exporting its private data structures.
On Mon, Nov 13, 2006 at 02:09:26PM +0100, Heiko Carstens wrote:
> > Since we are not supported by hardware for cpu hotplug. I have developed
> > the patch which will disable cpu hotplug on IBM bladecentre JS20. Please
> > let me know your comments on this please.
>
> > +extern int cpu_hotplug_disabled;
> > +extern struct mutex cpu_add_remove_lock;
> [...]
> > + if(rtas_stop_self_args.token == RTAS_UNKNOWN_SERVICE) {
> > + mutex_lock(&cpu_add_remove_lock);
> > + cpu_hotplug_disabled = 1;
> > + mutex_unlock(&cpu_add_remove_lock);
> > + }
> > +
> > #endif /* CONFIG_HOTPLUG_CPU */
> > #ifdef CONFIG_RTAS_ERROR_LOGGING
> > rtas_last_error_token = rtas_token("rtas-last-error");
>
> You should add a function to kernel/cpu.c which you can call in order to
> disable cpu hotplug instead of exporting its private data structures.
Yup. Also, considering the fact that enable_nonboot_cpus() can reset
the cpu_hotplug_disabled flag, I would suggest the following:
a) create one additional state for cpu_hotplug_disabled, something
like
#define PERMANENTLY_DISABLED -1
b) Define a function kernel/cpu.c
void disable_cpu_hotplug_perm()
{
cpu_hotplug_disabled = PERMANENTLY_DISABLED;
}
and call it in rtas.c
c) Check for status of cpu_hotplug_disabled in functions cpu_up,
cpu_down, enable_nonboot_cpus and disable_nonboot_cpus and
if cpu_hotplug_disabled == PERMANENTLY_DISABLED,
return bypassing further code.
Thoughts?
Regards,
gautham.
--
Gautham R Shenoy
Linux Technology Center
IBM India.
"Freedom comes with a price tag of responsibility, which is still a bargain,
because Freedom is priceless!"
On Mon, 2006-11-13 at 18:40 +0530, Srinivasa Ds wrote:
> Hi
> when I tried to hot plug a cpu on IBM bladecentre JS20 system,it dropped
> in to xmon. On analyzing the problem,I found out that "self-stop" token
> is not exported
> to the OS through rtas(Could be verified by looking in to
> /proc/device-tree/rtas file).
Please CC powerpc related patches to [email protected]
arch/powerpc/kernel/rtas.c | 3 +++
include/linux/cpu.h | 4 ++++
kernel/cpu.c | 24 ++++++++++++++++++++++--
3 files changed, 29 insertions(+), 2 deletions(-)
Index: linux-2.6.19-rc5/arch/powerpc/kernel/rtas.c
===================================================================
--- linux-2.6.19-rc5.orig/arch/powerpc/kernel/rtas.c 2006-11-08 07:54:20.000000000 +0530
+++ linux-2.6.19-rc5/arch/powerpc/kernel/rtas.c 2006-11-14 15:59:58.000000000 +0530
@@ -19,6 +19,7 @@
#include <linux/init.h>
#include <linux/capability.h>
#include <linux/delay.h>
+#include <linux/cpu.h>
#include <asm/prom.h>
#include <asm/rtas.h>
@@ -881,6 +882,8 @@
#ifdef CONFIG_HOTPLUG_CPU
rtas_stop_self_args.token = rtas_token("stop-self");
+ if(rtas_stop_self_args.token == RTAS_UNKNOWN_SERVICE)
+ disable_cpu_hotplug_perm();
#endif /* CONFIG_HOTPLUG_CPU */
#ifdef CONFIG_RTAS_ERROR_LOGGING
rtas_last_error_token = rtas_token("rtas-last-error");
Index: linux-2.6.19-rc5/kernel/cpu.c
===================================================================
--- linux-2.6.19-rc5.orig/kernel/cpu.c 2006-11-08 07:54:20.000000000 +0530
+++ linux-2.6.19-rc5/kernel/cpu.c 2006-11-14 16:06:17.000000000 +0530
@@ -63,6 +63,18 @@
}
EXPORT_SYMBOL_GPL(unlock_cpu_hotplug);
+void disable_cpu_hotplug_perm(void)
+{
+ mutex_lock(&cpu_add_remove_lock);
+ cpu_hotplug_disabled = PERM_DISABLED_CPU_HOTPLUG;
+ mutex_unlock(&cpu_add_remove_lock);
+}
+
+static int is_cpu_hotplug_perm_disabled()
+{
+ return cpu_hotplug_disabled == PERM_DISABLED_CPU_HOTPLUG;
+}
+
#endif /* CONFIG_HOTPLUG_CPU */
/* Need to know about CPUs going up/down? */
@@ -193,7 +205,7 @@
int err = 0;
mutex_lock(&cpu_add_remove_lock);
- if (cpu_hotplug_disabled)
+ if (cpu_hotplug_disabled || is_cpu_hotplug_perm_disabled())
err = -EBUSY;
else
err = _cpu_down(cpu);
@@ -244,7 +256,7 @@
int err = 0;
mutex_lock(&cpu_add_remove_lock);
- if (cpu_hotplug_disabled)
+ if (cpu_hotplug_disabled || is_cpu_hotplug_perm_disabled())
err = -EBUSY;
else
err = _cpu_up(cpu);
@@ -261,6 +273,10 @@
int cpu, first_cpu, error;
mutex_lock(&cpu_add_remove_lock);
+ if(is_cpu_hotplug_perm_disabled()) {
+ error = -EBUSY;
+ goto out;
+ }
first_cpu = first_cpu(cpu_present_map);
if (!cpu_online(first_cpu)) {
error = _cpu_up(first_cpu);
@@ -311,6 +327,10 @@
/* Allow everyone to use the CPU hotplug again */
mutex_lock(&cpu_add_remove_lock);
+ if(is_cpu_hotplug_perm_disabled()) {
+ mutex_unlock(&cpu_add_remove_lock);
+ return;
+ }
cpu_hotplug_disabled = 0;
mutex_unlock(&cpu_add_remove_lock);
Index: linux-2.6.19-rc5/include/linux/cpu.h
===================================================================
--- linux-2.6.19-rc5.orig/include/linux/cpu.h 2006-11-14 15:55:26.000000000 +0530
+++ linux-2.6.19-rc5/include/linux/cpu.h 2006-11-14 16:08:36.000000000 +0530
@@ -31,6 +31,8 @@
struct sys_device sysdev;
};
+#define PERM_DISABLED_CPU_HOTPLUG -1
+
extern int register_cpu(struct cpu *cpu, int num);
extern struct sys_device *get_cpu_sysdev(unsigned cpu);
#ifdef CONFIG_HOTPLUG_CPU
@@ -68,6 +70,7 @@
/* Stop CPUs going up and down. */
extern void lock_cpu_hotplug(void);
extern void unlock_cpu_hotplug(void);
+extern void disable_cpu_hotplug_perm(void);
#define hotcpu_notifier(fn, pri) { \
static struct notifier_block fn##_nb = \
{ .notifier_call = fn, .priority = pri }; \
@@ -80,6 +83,7 @@
#else
#define lock_cpu_hotplug() do { } while (0)
#define unlock_cpu_hotplug() do { } while (0)
+#define disable_cpu_hotplug_perm() do { } while (0)
#define lock_cpu_hotplug_interruptible() 0
#define hotcpu_notifier(fn, pri) do { } while (0)
#define register_hotcpu_notifier(nb) do { } while (0)
arch/powerpc/kernel/rtas.c | 3 +++
include/linux/cpu.h | 4 ++++
kernel/cpu.c | 24 ++++++++++++++++++++++--
3 files changed, 29 insertions(+), 2 deletions(-)
Index: linux-2.6.19-rc5/arch/powerpc/kernel/rtas.c
===================================================================
--- linux-2.6.19-rc5.orig/arch/powerpc/kernel/rtas.c
+++ linux-2.6.19-rc5/arch/powerpc/kernel/rtas.c
@@ -19,6 +19,7 @@
#include <linux/init.h>
#include <linux/capability.h>
#include <linux/delay.h>
+#include <linux/cpu.h>
#include <asm/prom.h>
#include <asm/rtas.h>
@@ -881,6 +882,8 @@ void __init rtas_initialize(void)
#ifdef CONFIG_HOTPLUG_CPU
rtas_stop_self_args.token = rtas_token("stop-self");
+ if(rtas_stop_self_args.token == RTAS_UNKNOWN_SERVICE)
+ disable_cpu_hotplug_perm();
#endif /* CONFIG_HOTPLUG_CPU */
#ifdef CONFIG_RTAS_ERROR_LOGGING
rtas_last_error_token = rtas_token("rtas-last-error");
Index: linux-2.6.19-rc5/kernel/cpu.c
===================================================================
--- linux-2.6.19-rc5.orig/kernel/cpu.c
+++ linux-2.6.19-rc5/kernel/cpu.c
@@ -63,8 +63,20 @@ void unlock_cpu_hotplug(void)
}
EXPORT_SYMBOL_GPL(unlock_cpu_hotplug);
+void disable_cpu_hotplug_perm(void)
+{
+ mutex_lock(&cpu_add_remove_lock);
+ cpu_hotplug_disabled = PERM_DISABLED_CPU_HOTPLUG;
+ mutex_unlock(&cpu_add_remove_lock);
+}
+
#endif /* CONFIG_HOTPLUG_CPU */
+static int is_cpu_hotplug_perm_disabled()
+{
+ return cpu_hotplug_disabled == PERM_DISABLED_CPU_HOTPLUG;
+}
+
/* Need to know about CPUs going up/down? */
int __cpuinit register_cpu_notifier(struct notifier_block *nb)
{
@@ -193,7 +205,7 @@ int cpu_down(unsigned int cpu)
int err = 0;
mutex_lock(&cpu_add_remove_lock);
- if (cpu_hotplug_disabled)
+ if (cpu_hotplug_disabled || is_cpu_hotplug_perm_disabled())
err = -EBUSY;
else
err = _cpu_down(cpu);
@@ -244,7 +256,7 @@ int __devinit cpu_up(unsigned int cpu)
int err = 0;
mutex_lock(&cpu_add_remove_lock);
- if (cpu_hotplug_disabled)
+ if (cpu_hotplug_disabled || is_cpu_hotplug_perm_disabled())
err = -EBUSY;
else
err = _cpu_up(cpu);
@@ -261,6 +273,10 @@ int disable_nonboot_cpus(void)
int cpu, first_cpu, error;
mutex_lock(&cpu_add_remove_lock);
+ if(is_cpu_hotplug_perm_disabled()) {
+ error = -EBUSY;
+ goto out;
+ }
first_cpu = first_cpu(cpu_present_map);
if (!cpu_online(first_cpu)) {
error = _cpu_up(first_cpu);
@@ -311,6 +327,10 @@ void enable_nonboot_cpus(void)
/* Allow everyone to use the CPU hotplug again */
mutex_lock(&cpu_add_remove_lock);
+ if(is_cpu_hotplug_perm_disabled()) {
+ mutex_unlock(&cpu_add_remove_lock);
+ return;
+ }
cpu_hotplug_disabled = 0;
mutex_unlock(&cpu_add_remove_lock);
Index: linux-2.6.19-rc5/include/linux/cpu.h
===================================================================
--- linux-2.6.19-rc5.orig/include/linux/cpu.h
+++ linux-2.6.19-rc5/include/linux/cpu.h
@@ -31,6 +31,8 @@ struct cpu {
struct sys_device sysdev;
};
+#define PERM_DISABLED_CPU_HOTPLUG -1
+
extern int register_cpu(struct cpu *cpu, int num);
extern struct sys_device *get_cpu_sysdev(unsigned cpu);
#ifdef CONFIG_HOTPLUG_CPU
@@ -68,6 +70,7 @@ extern struct sysdev_class cpu_sysdev_cl
/* Stop CPUs going up and down. */
extern void lock_cpu_hotplug(void);
extern void unlock_cpu_hotplug(void);
+extern void disable_cpu_hotplug_perm(void);
#define hotcpu_notifier(fn, pri) { \
static struct notifier_block fn##_nb = \
{ .notifier_call = fn, .priority = pri }; \
@@ -80,6 +83,7 @@ int cpu_down(unsigned int cpu);
#else
#define lock_cpu_hotplug() do { } while (0)
#define unlock_cpu_hotplug() do { } while (0)
+#define disable_cpu_hotplug_perm() do { } while (0)
#define lock_cpu_hotplug_interruptible() 0
#define hotcpu_notifier(fn, pri) do { } while (0)
#define register_hotcpu_notifier(nb) do { } while (0)
On Tue, 2006-11-14 at 19:07 +0530, Srinivasa Ds wrote:
> Hi
> when I tried to hot plug a cpu on IBM bladecentre JS20 system,it dropped
> in to xmon.
How did you try to hot plug a cpu? Through sysfs/hmc/somethingelse ?
cheers
--
Michael Ellerman
OzLabs, IBM Australia Development Lab
wwweb: http://michael.ellerman.id.au
phone: +61 2 6212 1183 (tie line 70 21183)
We do not inherit the earth from our ancestors,
we borrow it from our children. - S.M.A.R.T Person
Michael Ellerman wrote:
> On Tue, 2006-11-14 at 19:07 +0530, Srinivasa Ds wrote:
>
>> Hi
>> when I tried to hot plug a cpu on IBM bladecentre JS20 system,it dropped
>> in to xmon.
>>
>
> How did you try to hot plug a cpu? Through sysfs/hmc/somethingelse ?
>
echo 0 > /sys/devices/system/cpu/cpu1/online
> cheers
>
>