2022-05-25 11:32:23

by Sudeep Holla

Subject: [PATCH v3 12/16] arch_topology: Avoid parsing through all the CPUs once a outlier CPU is found

There is no point in looping through all the CPU's physical package
identifier to check if it is valid or not once a CPU which is outside
the topology(i.e. outlier CPU) is found.

Let us just break out of the loop early in such case.

Signed-off-by: Sudeep Holla <[email protected]>
---
drivers/base/arch_topology.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index f73a5e669e42..6ae450ca68bb 100644
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -637,8 +637,10 @@ static int __init parse_dt_topology(void)
* only mark cores described in the DT as possible.
*/
for_each_possible_cpu(cpu)
- if (cpu_topology[cpu].package_id < 0)
+ if (cpu_topology[cpu].package_id < 0) {
ret = -EINVAL;
+ break;
+ }

out_map:
of_node_put(map);
--
2.36.1

2022-05-25 20:28:58

by Sudeep Holla

Subject: [PATCH v3 13/16] arch_topology: Don't set cluster identifier as physical package identifier

Currently as we parse the CPU topology from /cpu-map node from the
device tree, we assign generated cluster count as the physical package
identifier for each CPU which is wrong.

The device tree bindings for CPU topology supports sockets to infer
the socket or physical package identifier for a given CPU. Since it is
fairly new and not support on most of the old and existing systems, we
can assume all such systems have single socket/physical package.

Fix the physical package identifier to 0 by removing the assignment of
cluster identifier to the same.

Signed-off-by: Sudeep Holla <[email protected]>
---
drivers/base/arch_topology.c | 6 +-----
1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index 6ae450ca68bb..e7876a7a82ec 100644
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -544,7 +544,6 @@ static int __init parse_cluster(struct device_node *cluster, int depth)
bool leaf = true;
bool has_cores = false;
struct device_node *c;
- static int package_id __initdata;
int core_id = 0;
int i, ret;

@@ -583,7 +582,7 @@ static int __init parse_cluster(struct device_node *cluster, int depth)
}

if (leaf) {
- ret = parse_core(c, package_id, core_id++);
+ ret = parse_core(c, 0, core_id++);
} else {
pr_err("%pOF: Non-leaf cluster with core %s\n",
cluster, name);
@@ -600,9 +599,6 @@ static int __init parse_cluster(struct device_node *cluster, int depth)
if (leaf && !has_cores)
pr_warn("%pOF: empty cluster\n", cluster);

- if (leaf)
- package_id++;
-
return 0;
}

--
2.36.1

2022-06-01 21:02:07

by Gavin Shan

Subject: Re: [PATCH v3 12/16] arch_topology: Avoid parsing through all the CPUs once a outlier CPU is found

On 5/25/22 4:14 PM, Sudeep Holla wrote:
> There is no point in looping through all the CPU's physical package
> identifier to check if it is valid or not once a CPU which is outside
> the topology(i.e. outlier CPU) is found.
>
> Let us just break out of the loop early in such case.
>
> Signed-off-by: Sudeep Holla <[email protected]>
> ---
> drivers/base/arch_topology.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>

Reviewed-by: Gavin Shan <[email protected]>

> diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
> index f73a5e669e42..6ae450ca68bb 100644
> --- a/drivers/base/arch_topology.c
> +++ b/drivers/base/arch_topology.c
> @@ -637,8 +637,10 @@ static int __init parse_dt_topology(void)
> * only mark cores described in the DT as possible.
> */
> for_each_possible_cpu(cpu)
> - if (cpu_topology[cpu].package_id < 0)
> + if (cpu_topology[cpu].package_id < 0) {
> ret = -EINVAL;
> + break;
> + }
>
> out_map:
> of_node_put(map);
>