+atomic_t nr_ipc_ns = ATOMIC_INIT(1);
+
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+
+static void ipc_memory_notifier(struct work_struct *work)
+{
+ ipcns_notify(IPCNS_MEMCHANGED);
+}
+
+static DECLARE_WORK(ipc_memory_wq, ipc_memory_notifier);
+
+
+static int ipc_memory_callback(struct notifier_block *self,
+ unsigned long action, void *arg)
+{
+ switch (action) {
+ case MEM_ONLINE: /* memory successfully brought online */
+ case MEM_OFFLINE: /* or offline: it's time to recompute msgmni */
+ /*
+ * This is done by invoking the ipcns notifier chain with the
+ * IPC_MEMCHANGED event.
+ * In order not to keep the lock on the hotplug memory chain
+ * for too long, queue a work item that will, when waken up,
+ * activate the ipcns notification chain.
+ * No need to keep several ipc work items on the queue.
+ */
+ if (!work_pending(&ipc_memory_wq))
+ schedule_work(&ipc_memory_wq);
+ break;
+ case MEM_GOING_ONLINE:
+ case MEM_GOING_OFFLINE:
+ case MEM_CANCEL_ONLINE:
+ case MEM_CANCEL_OFFLINE:
+ default:
+ break;
+ }
+
+ return NOTIFY_OK;
+}
+
+#endif /* CONFIG_MEMORY_HOTPLUG */
+