ipc: invoke the ipcns notifier chain as a work item

Make the memory hotplug chain's mutex held for a shorter time: when memory is offlined or onlined a work item is added to the global workqueue. When the work item is run, it notifies the ipcns notifier chain with the IPCNS_MEMCHANGED event. Signed-off-by: Nadia Derbey <[email protected]> Cc: Yasunori Goto <[email protected]> Cc: Matt Helsley <[email protected]> Cc: Mingming Cao <[email protected]> Cc: Pierre Peiffer <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
rtvt123 · Apr 29, 2008 · 424450c · 424450c
1 parent b6b337a
commit 424450c
Showing 1 changed file with 14 additions and 1 deletion.
diff --git a/ipc/util.c b/ipc/util.c
@@ -58,6 +58,14 @@ 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)
 {
@@ -67,8 +75,13 @@ static int ipc_memory_callback(struct notifier_block *self,
 		/*
 		 * 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.
 		 */
-		ipcns_notify(IPCNS_MEMCHANGED);
+		if (!work_pending(&ipc_memory_wq))
+			schedule_work(&ipc_memory_wq);
 		break;
 	case MEM_GOING_ONLINE:
 	case MEM_GOING_OFFLINE: