Re: [lhcs-devel] Re: [RFC] don't create cpu/online sysfs file

Ashok Raj
2004-06-07T17:22:26Z

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On Mon, Jun 07, 2004 at 09:41:49AM -0700, Dave Hansen wrote:
> On Mon, 2004-06-07 at 07:08, Ashok Raj wrote:plugging.
> > + if (systemcfg->platform == PLATFORM_PSERIES_LPAR)
> > + cpu->no_control=1;
>
> That condition is also inverted. Should read:
>
> if (systemcfg->platform != PLATFORM_PSERIES_LPAR)
> cpu->no_control = 1;

Good catch...I knew i mentioned untested :-)

fixed patch attached...

Cheers,
ashok

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Signed-off-by: Ashok Raj <ashok.raj@intel.com>

D: This file provides ability for caller of register_cpu() to either create
D: a control file, or not. This can be handy if a particular platform decides
D: that certain CPU's are not removable. Hence would like to not create
D: a control file.

---

linux-2.6.7-rc2-root/arch/ppc64/kernel/sysfs.c | 10 ++++++++++
linux-2.6.7-rc2-root/drivers/base/cpu.c | 4 +++-
linux-2.6.7-rc2-root/include/linux/cpu.h | 1 +
3 files changed, 14 insertions(+), 1 deletion(-)

diff -puN include/linux/cpu.h~cpu_control_file include/linux/cpu.h
--- linux-2.6.7-rc2/include/linux/cpu.h~cpu_control_file 2004-06-06 12:54:02.319017387 -0700
+++ linux-2.6.7-rc2-root/include/linux/cpu.h 2004-06-07 06:25:44.667732023 -0700
@@ -27,6 +27,7 @@

struct cpu {
int node_id; /* The node which contains the CPU */
+ int no_control; /* Should the sysfs control file be created? */
struct sys_device sysdev;
};

diff -puN drivers/base/cpu.c~cpu_control_file drivers/base/cpu.c
--- linux-2.6.7-rc2/drivers/base/cpu.c~cpu_control_file 2004-06-06 12:56:47.349375320 -0700
+++ linux-2.6.7-rc2-root/drivers/base/cpu.c 2004-06-07 07:03:12.624937664 -0700
@@ -58,6 +58,8 @@ static inline void register_cpu_control(

/*
* register_cpu - Setup a driverfs device for a CPU.
+ * @cpu - Callers can set the cpu->no_control field to 1, to indicate not to
+ * generate a control file in sysfs for this CPU.
* @num - CPU number to use when creating the device.
*
* Initialize and register the CPU device.
@@ -75,7 +77,7 @@ int __init register_cpu(struct cpu *cpu,
error = sysfs_create_link(&root->sysdev.kobj,
&cpu->sysdev.kobj,
kobject_name(&cpu->sysdev.kobj));
- if (!error)
+ if (!error && !cpu->no_control)
register_cpu_control(cpu);
return error;
}
diff -puN arch/ppc64/kernel/sysfs.c~cpu_control_file arch/ppc64/kernel/sysfs.c
--- linux-2.6.7-rc2/arch/ppc64/kernel/sysfs.c~cpu_control_file 2004-06-06 13:12:06.467033408 -0700
+++ linux-2.6.7-rc2-root/arch/ppc64/kernel/sysfs.c 2004-06-07 10:12:45.999901454 -0700
@@ -325,6 +325,16 @@ static int __init topology_init(void)
#ifdef CONFIG_NUMA
parent = &node_devices[cpu_to_node(cpu)];
#endif
+ /*
+ * For now, we just see if the system supports making
+ * the RTAS calls for CPU hotplug. But, there may be a
+ * more comprehensive way to do this for an individual
+ * CPU. For instance, the boot cpu might never be valid
+ * for hotplugging.
+ */
+ if (systemcfg->platform != PLATFORM_PSERIES_LPAR)
+ cpu->no_control=1;
+
register_cpu(c, cpu, parent);

register_cpu_pmc(&c->sysdev);

_