Patchwork powerpc: Use ibm,chip-id property to compute cpu_core_mask if available

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Submitter Paul Mackerras
Date July 4, 2013, 3:05 a.m.
Message ID <20130704030506.GA2396@iris.ozlabs.ibm.com>
Download mbox | patch
Permalink /patch/256776/
State Superseded
Headers show

Comments

Paul Mackerras - July 4, 2013, 3:05 a.m.
Some systems have an ibm,chip-id property in the cpu nodes in the
device tree.  On these systems, we now use that to compute the
cpu_core_mask (i.e. the set of core siblings) rather than looking
at cache properties.

Signed-off-by: Paul Mackerras <paulus@samba.org>
---
Vasant Hegde - Aug. 9, 2013, 7:22 a.m.
On 07/04/2013 08:35 AM, Paul Mackerras wrote:
> Some systems have an ibm,chip-id property in the cpu nodes in the
> device tree.  On these systems, we now use that to compute the
> cpu_core_mask (i.e. the set of core siblings) rather than looking
> at cache properties.
>

Paul,

I wanted to test this patch but not able to apply this patch on top of Linux 
tree. Looks like I'm missing traverse_core_siblings() related patch. I searched 
in ppc mailing list and couldn't figure out.

Can you point me to related patch?

-Vasant


> Signed-off-by: Paul Mackerras <paulus@samba.org>
> ---
> diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
> index b72d8c9..3b7a118 100644
> --- a/arch/powerpc/kernel/smp.c
> +++ b/arch/powerpc/kernel/smp.c
> @@ -587,6 +587,32 @@ int cpu_first_thread_of_core(int core)
>   }
>   EXPORT_SYMBOL_GPL(cpu_first_thread_of_core);
>
> +static void traverse_siblings_chip_id(int cpu, int add, int chipid)
> +{
> +	const struct cpumask *mask;
> +	struct device_node *np;
> +	int i, plen;
> +	const int *prop;
> +
> +	mask = add ? cpu_online_mask : cpu_present_mask;
> +	for_each_cpu(i, mask) {
> +		np = of_get_cpu_node(i, NULL);
> +		if (!np)
> +			continue;
> +		prop = of_get_property(np, "ibm,chip-id", &plen);
> +		if (prop && plen == sizeof(int) && *prop == chipid) {
> +			if (add) {
> +				cpumask_set_cpu(cpu, cpu_core_mask(i));
> +				cpumask_set_cpu(i, cpu_core_mask(cpu));
> +			} else {
> +				cpumask_clear_cpu(cpu, cpu_core_mask(i));
> +				cpumask_clear_cpu(i, cpu_core_mask(cpu));
> +			}
> +		}
> +		of_node_put(np);
> +	}
> +}
> +
>   /* Must be called when no change can occur to cpu_present_mask,
>    * i.e. during cpu online or offline.
>    */
> @@ -611,14 +637,29 @@ static struct device_node *cpu_to_l2cache(int cpu)
>
>   static void traverse_core_siblings(int cpu, int add)
>   {
> -	struct device_node *l2_cache;
> +	struct device_node *l2_cache, *np;
>   	const struct cpumask *mask;
> -	int i;
> +	int i, chip, plen;
> +	const int *prop;
> +
> +	/* First see if we have ibm,chip-id properties in cpu nodes */
> +	np = of_get_cpu_node(cpu, NULL);
> +	if (np) {
> +		chip = -1;
> +		prop = of_get_property(np, "ibm,chip-id", &plen);
> +		if (prop && plen == sizeof(int))
> +			chip = *(int *)prop;
> +		of_node_put(np);
> +		if (chip >= 0) {
> +			traverse_siblings_chip_id(cpu, add, chip);
> +			return;
> +		}
> +	}
>
>   	l2_cache = cpu_to_l2cache(cpu);
>   	mask = add ? cpu_online_mask : cpu_present_mask;
>   	for_each_cpu(i, mask) {
> -		struct device_node *np = cpu_to_l2cache(i);
> +		np = cpu_to_l2cache(i);
>   		if (!np)
>   			continue;
>   		if (np == l2_cache) {
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@lists.ozlabs.org
> https://lists.ozlabs.org/listinfo/linuxppc-dev
>
Paul Mackerras - Aug. 10, 2013, 3:44 a.m.
On Fri, Aug 09, 2013 at 12:52:12PM +0530, Vasant Hegde wrote:
> Paul,
> 
> I wanted to test this patch but not able to apply this patch on top
> of Linux tree. Looks like I'm missing traverse_core_siblings()
> related patch. I searched in ppc mailing list and couldn't figure
> out.

Oops, my fault, there were actually 2 patches in that series but
somehow I only posted the second one.  I'll repost both patches.

Paul.

Patch

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index b72d8c9..3b7a118 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -587,6 +587,32 @@  int cpu_first_thread_of_core(int core)
 }
 EXPORT_SYMBOL_GPL(cpu_first_thread_of_core);
 
+static void traverse_siblings_chip_id(int cpu, int add, int chipid)
+{
+	const struct cpumask *mask;
+	struct device_node *np;
+	int i, plen;
+	const int *prop;
+
+	mask = add ? cpu_online_mask : cpu_present_mask;
+	for_each_cpu(i, mask) {
+		np = of_get_cpu_node(i, NULL);
+		if (!np)
+			continue;
+		prop = of_get_property(np, "ibm,chip-id", &plen);
+		if (prop && plen == sizeof(int) && *prop == chipid) {
+			if (add) {
+				cpumask_set_cpu(cpu, cpu_core_mask(i));
+				cpumask_set_cpu(i, cpu_core_mask(cpu));
+			} else {
+				cpumask_clear_cpu(cpu, cpu_core_mask(i));
+				cpumask_clear_cpu(i, cpu_core_mask(cpu));
+			}
+		}
+		of_node_put(np);
+	}
+}
+
 /* Must be called when no change can occur to cpu_present_mask,
  * i.e. during cpu online or offline.
  */
@@ -611,14 +637,29 @@  static struct device_node *cpu_to_l2cache(int cpu)
 
 static void traverse_core_siblings(int cpu, int add)
 {
-	struct device_node *l2_cache;
+	struct device_node *l2_cache, *np;
 	const struct cpumask *mask;
-	int i;
+	int i, chip, plen;
+	const int *prop;
+
+	/* First see if we have ibm,chip-id properties in cpu nodes */
+	np = of_get_cpu_node(cpu, NULL);
+	if (np) {
+		chip = -1;
+		prop = of_get_property(np, "ibm,chip-id", &plen);
+		if (prop && plen == sizeof(int))
+			chip = *(int *)prop;
+		of_node_put(np);
+		if (chip >= 0) {
+			traverse_siblings_chip_id(cpu, add, chip);
+			return;
+		}
+	}
 
 	l2_cache = cpu_to_l2cache(cpu);
 	mask = add ? cpu_online_mask : cpu_present_mask;
 	for_each_cpu(i, mask) {
-		struct device_node *np = cpu_to_l2cache(i);
+		np = cpu_to_l2cache(i);
 		if (!np)
 			continue;
 		if (np == l2_cache) {