From: Zqiang qiang.zhang@windriver.com
[ Upstream commit 88451f2cd3cec2abc30debdf129422d2699d1eba ]
If a CPU is offlined the debug objects per CPU pool is not cleaned up. If the CPU is never onlined again then the objects in the pool are wasted.
Add a CPU hotplug callback which is invoked after the CPU is dead to free the pool.
[ tglx: Massaged changelog and added comment about remote access safety ]
Signed-off-by: Zqiang qiang.zhang@windriver.com Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: Waiman Long longman@redhat.com Link: https://lore.kernel.org/r/20200908062709.11441-1-qiang.zhang@windriver.com Stable-dep-of: eabb7f1ace53 ("lib/debugobjects: fix stat count and optimize debug_objects_mem_init") Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/cpuhotplug.h | 1 + lib/debugobjects.c | 25 +++++++++++++++++++++++++ 2 files changed, 26 insertions(+)
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h index 15835f37bd5f..970b47fcd6ff 100644 --- a/include/linux/cpuhotplug.h +++ b/include/linux/cpuhotplug.h @@ -36,6 +36,7 @@ enum cpuhp_state { CPUHP_X86_MCE_DEAD, CPUHP_VIRT_NET_DEAD, CPUHP_SLUB_DEAD, + CPUHP_DEBUG_OBJ_DEAD, CPUHP_MM_WRITEBACK_DEAD, CPUHP_MM_VMSTAT_DEAD, CPUHP_SOFTIRQ_DEAD, diff --git a/lib/debugobjects.c b/lib/debugobjects.c index 48054dbf1b51..746b632792b5 100644 --- a/lib/debugobjects.c +++ b/lib/debugobjects.c @@ -19,6 +19,7 @@ #include <linux/slab.h> #include <linux/hash.h> #include <linux/kmemleak.h> +#include <linux/cpu.h>
#define ODEBUG_HASH_BITS 14 #define ODEBUG_HASH_SIZE (1 << ODEBUG_HASH_BITS) @@ -433,6 +434,25 @@ static void free_object(struct debug_obj *obj) } }
+#ifdef CONFIG_HOTPLUG_CPU +static int object_cpu_offline(unsigned int cpu) +{ + struct debug_percpu_free *percpu_pool; + struct hlist_node *tmp; + struct debug_obj *obj; + + /* Remote access is safe as the CPU is dead already */ + percpu_pool = per_cpu_ptr(&percpu_obj_pool, cpu); + hlist_for_each_entry_safe(obj, tmp, &percpu_pool->free_objs, node) { + hlist_del(&obj->node); + kmem_cache_free(obj_cache, obj); + } + percpu_pool->obj_free = 0; + + return 0; +} +#endif + /* * We run out of memory. That means we probably have tons of objects * allocated. @@ -1378,6 +1398,11 @@ void __init debug_objects_mem_init(void) } else debug_objects_selftest();
+#ifdef CONFIG_HOTPLUG_CPU + cpuhp_setup_state_nocalls(CPUHP_DEBUG_OBJ_DEAD, "object:offline", NULL, + object_cpu_offline); +#endif + /* * Increase the thresholds for allocating and freeing objects * according to the number of possible CPUs available in the system.