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-rw-r--r--drivers/base/cacheinfo.c11
-rw-r--r--include/linux/sched/topology.h4
-rw-r--r--kernel/sched/topology.c22
3 files changed, 21 insertions, 16 deletions
diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index 9f9c72727a05..7a47a392568a 100644
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -1040,9 +1040,10 @@ static int cacheinfo_cpu_online(unsigned int cpu)
rc = cache_add_dev(cpu);
if (rc)
goto err;
- if (cpu_map_shared_cache(true, cpu, &cpu_map))
+ if (cpu_map_shared_cache(true, cpu, &cpu_map)) {
update_per_cpu_data_slice_size(true, cpu, cpu_map);
- sched_update_llc_bytes(cpu);
+ sched_update_llc_bytes(cpu_map);
+ }
return 0;
err:
free_cache_attributes(cpu);
@@ -1059,10 +1060,10 @@ static int cacheinfo_cpu_pre_down(unsigned int cpu)
cpu_cache_sysfs_exit(cpu);
free_cache_attributes(cpu);
- if (nr_shared > 1)
+ if (nr_shared > 1) {
update_per_cpu_data_slice_size(false, cpu, cpu_map);
-
- sched_update_llc_bytes(cpu);
+ sched_update_llc_bytes(cpu_map);
+ }
return 0;
}
diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
index b5d9d7c2b8ad..f96812d71c51 100644
--- a/include/linux/sched/topology.h
+++ b/include/linux/sched/topology.h
@@ -281,9 +281,9 @@ static inline int task_node(const struct task_struct *p)
}
#ifdef CONFIG_SCHED_CACHE
-extern void sched_update_llc_bytes(unsigned int cpu);
+extern void sched_update_llc_bytes(const struct cpumask *cpus);
#else
-static inline void sched_update_llc_bytes(unsigned int cpu) { }
+static inline void sched_update_llc_bytes(const struct cpumask *cpus) { }
#endif
#endif /* _LINUX_SCHED_TOPOLOGY_H */
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 0248227d983a..3dab0253976f 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -985,8 +985,8 @@ void sched_cache_active_set(void)
}
/*
- * Update the bottom sched_domain's llc_bytes for @cpu and all its
- * LLC siblings. Called from cacheinfo_cpu_online() or
+ * Update the bottom sched_domain's llc_bytes for @cpus sharing a physical
+ * LLC. Called from cacheinfo_cpu_online() or
* cacheinfo_cpu_pre_down() with cpu hotplug lock held.
*
* Note: get_effective_llc_bytes() returns 0 on PowerPC.
@@ -996,17 +996,13 @@ void sched_cache_active_set(void)
* and does not populates the per-CPU struct cpu_cacheinfo array
* that get_cpu_cacheinfo_llc() reads.
*/
-void sched_update_llc_bytes(unsigned int cpu)
+void sched_update_llc_bytes(const struct cpumask *cpus)
{
struct sched_domain *sd, *sdp;
unsigned int i;
sched_domains_mutex_lock();
- sdp = rcu_dereference_sched_domain(per_cpu(sd_llc, cpu));
- if (!sdp)
- goto unlock;
-
/*
* ci->shared_cpu_map is built incrementally as CPUs come
* online, so the first CPU in an LLC initially sees
@@ -1014,14 +1010,22 @@ void sched_update_llc_bytes(unsigned int cpu)
* get_effective_llc_bytes(). Re-evaluating every LLC
* sibling on each online event corrects this once the full
* shared_cpu_map is known.
+ *
+ * The departing CPU's domains have already been detached when
+ * cacheinfo removes it. Use the surviving cache siblings instead.
+ * They may belong to different cpuset partitions, so use each CPU's
+ * own LLC domain to scale its share of the physical cache.
*/
- for_each_cpu(i, sched_domain_span(sdp)) {
+ for_each_cpu(i, cpus) {
+ sdp = rcu_dereference_sched_domain(per_cpu(sd_llc, i));
+ if (!sdp)
+ continue;
+
sd = rcu_dereference_sched_domain(cpu_rq(i)->sd);
if (sd)
sd->llc_bytes = get_effective_llc_bytes(i, sdp);
}
-unlock:
sched_domains_mutex_unlock();
}