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authorNadia Derbey <Nadia.Derbey@bull.net>2008-04-29 01:00:43 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-29 08:06:12 -0700
commit424450c1dbe72b6e2637e91108417d7d9580c4c3 (patch)
tree472fd07a519cdfd594a15da5d2167d8de937e95e /ipc/util.c
parentb6b337ad1c1d6fe11b09b35d75464b84b3e11f07 (diff)
downloadlinux-424450c1dbe72b6e2637e91108417d7d9580c4c3.tar.gz
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 <Nadia.Derbey@bull.net>
Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Matt Helsley <matthltc@us.ibm.com>
Cc: Mingming Cao <cmm@us.ibm.com>
Cc: Pierre Peiffer <pierre.peiffer@bull.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'ipc/util.c')
-rw-r--r--ipc/util.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/ipc/util.c b/ipc/util.c
index 2d545d7144a7..7a5d5e393c4b 100644
--- 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: