[PATCH] arch_topology: Clear LLC sibling when cacheinfo teardown

Song Shuai
2023-03-13T10:28:19Z

The teardown of CPUHP_AP_BASE_CACHEINFO_ONLINE now only invokes
free_cache_attributes() to clear share_cpu_map of cacheinfo list.
At the same time, clearing cpu_topology[].llc_sibling is
called quite late at the teardown code in hotplug STARTING section.

To avoid the incorrect LLC sibling masks generated, move its clearing
right after free_cache_attributes().

Fixes: 3fcbf1c77d08 ("arch_topology: Fix cache attributes detection in the CPU hotplug path")
Signed-off-by: Song Shuai <suagrfillet@gmail.com>
---
drivers/base/arch_topology.c | 16 ++++++++++++++--
drivers/base/cacheinfo.c | 2 ++
include/linux/arch_topology.h | 1 +
3 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index b1c1dd38ab01..8681654d6c07 100644
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -769,6 +769,20 @@ void update_siblings_masks(unsigned int cpuid)
}
}

+void clear_llc_topology(unsigned int cpu)
+{
+ int sib;
+
+ for_each_cpu(sib, topology_llc_cpumask(cpu)) {
+ if (sib == cpu)
+ continue;
+ if (last_level_cache_is_shared(cpu, sib)) {
+ cpumask_clear_cpu(cpu, topology_llc_cpumask(sib));
+ cpumask_clear_cpu(sib, topology_llc_cpumask(cpu));
+ }
+ }
+}
+
static void clear_cpu_topology(int cpu)
{
struct cpu_topology *cpu_topo = &cpu_topology[cpu];
@@ -811,8 +825,6 @@ void remove_cpu_topology(unsigned int cpu)
cpumask_clear_cpu(cpu, topology_sibling_cpumask(sibling));
for_each_cpu(sibling, topology_cluster_cpumask(cpu))
cpumask_clear_cpu(cpu, topology_cluster_cpumask(sibling));
- for_each_cpu(sibling, topology_llc_cpumask(cpu))
- cpumask_clear_cpu(cpu, topology_llc_cpumask(sibling));

clear_cpu_topology(cpu);
}
diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index f6573c335f4c..1c276b30fd5a 100644
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -19,6 +19,7 @@
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/sysfs.h>
+#include <linux/arch_topology.h>

/* pointer to per cpu cacheinfo */
static DEFINE_PER_CPU(struct cpu_cacheinfo, ci_cpu_cacheinfo);
@@ -814,6 +815,7 @@ static int cacheinfo_cpu_pre_down(unsigned int cpu)
cpu_cache_sysfs_exit(cpu);

free_cache_attributes(cpu);
+ clear_llc_topology(cpu);
return 0;
}

diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h
index a07b510e7dc5..1279ba2eb4a4 100644
--- a/include/linux/arch_topology.h
+++ b/include/linux/arch_topology.h
@@ -89,6 +89,7 @@ void store_cpu_topology(unsigned int cpuid);
const struct cpumask *cpu_coregroup_mask(int cpu);
const struct cpumask *cpu_clustergroup_mask(int cpu);
void update_siblings_masks(unsigned int cpu);
+void clear_llc_topology(unsigned int cpu);
void remove_cpu_topology(unsigned int cpuid);
void reset_cpu_topology(void);
int parse_acpi_topology(void);
--
2.20.1