Any use of key->enabled (that is static_key_enabled and static_key_count)
outside jump_label_lock should handle its own serialization. In the case
of cpusets_enabled_key, the key is always incremented/decremented under
cpuset_mutex, and hence the same rule applies to nr_cpusets. The rule
*is* respected currently, but the mutex is static so nr_cpusets should
be static too.
Cc: Peter Zijlstra <pet...@infradead.org>
Cc: Zefan Li <lize...@huawei.com>
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
---
include/linux/cpuset.h | 6 ------
kernel/cgroup/cpuset.c | 7 +++++++
2 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index 119a3f9604b0..cedcc910b7a7 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -24,12 +24,6 @@ static inline bool cpusets_enabled(void)
return static_branch_unlikely(&cpusets_enabled_key);
}
-static inline int nr_cpusets(void)
-{
- /* jump label reference count + the top-level cpuset */
- return static_key_count(&cpusets_enabled_key.key) + 1;
-}
-
static inline void cpuset_inc(void)
{
static_branch_inc(&cpusets_enabled_key);
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index ae643412948a..f65db17e9e23 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -576,6 +576,13 @@ static void update_domain_attr_tree(struct
sched_domain_attr *dattr,
rcu_read_unlock();
}
+/* Must be called with cpuset_mutex held. */
+static inline int nr_cpusets(void)
+{
+ /* jump label reference count + the top-level cpuset */
+ return static_key_count(&cpusets_enabled_key.key) + 1;
+}
+
/*
* generate_sched_domains()
*
--
1.8.3.1
