memory hotplug: make kmem_cache_node for SLUB on memory online avoid panic
Fix a panic due to access NULL pointer of kmem_cache_node at discard_slab()
after memory online.
When memory online is called, kmem_cache_nodes are created for all SLUBs
for new node whose memory are available.
slab_mem_going_online_callback() is called to make kmem_cache_node() in
callback of memory online event. If it (or other callbacks) fails, then
slab_mem_offline_callback() is called for rollback.
In memory offline, slab_mem_going_offline_callback() is called to shrink
all slub cache, then slab_mem_offline_callback() is called later.
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: locking fix]
[akpm@linux-foundation.org: build fix]
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/memory.h b/include/linux/memory.h
index ec376e4..33f0ff0 100644
--- a/include/linux/memory.h
+++ b/include/linux/memory.h
@@ -83,10 +83,14 @@
#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
+#ifdef CONFIG_MEMORY_HOTPLUG
#define hotplug_memory_notifier(fn, pri) { \
static struct notifier_block fn##_mem_nb = \
{ .notifier_call = fn, .priority = pri }; \
register_memory_notifier(&fn##_mem_nb); \
}
+#else
+#define hotplug_memory_notifier(fn, pri) do { } while (0)
+#endif
#endif /* _LINUX_MEMORY_H_ */