The patch titled
ipc: invoke the ipcns notifier chain as a work item
has been added to the -mm tree. Its filename is
ipc-invoke-the-ipcns-notifier-chain-as-a-work-item.patch
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The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: ipc: invoke the ipcns notifier chain as a work item
From: Nadia Derbey <Nadia.Derbey@xxxxxxxx>
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@xxxxxxxx>
Cc: Yasunori Goto <y-goto@xxxxxxxxxxxxxx>
Cc: Matt Helsley <matthltc@xxxxxxxxxx>
Cc: Mingming Cao <cmm@xxxxxxxxxx>
Cc: Pierre Peiffer <pierre.peiffer@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
ipc/util.c | 15 ++++++++++++++-
1 file changed, 14 insertions(+), 1 deletion(-)
diff -puN ipc/util.c~ipc-invoke-the-ipcns-notifier-chain-as-a-work-item ipc/util.c
--- a/ipc/util.c~ipc-invoke-the-ipcns-notifier-chain-as-a-work-item
+++ a/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 no
/*
* 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:
_
Patches currently in -mm which might be from Nadia.Derbey@xxxxxxxx are
origin.patch
ipc-use-ipc_buildid-directly-from-ipc_addid.patch
ipc-use-ipc_buildid-directly-from-ipc_addid-cleanup.patch
ipc-scale-msgmni-to-the-amount-of-lowmem.patch
ipc-scale-msgmni-to-the-number-of-ipc-namespaces.patch
ipc-define-the-slab_memory_callback-priority-as-a-constant.patch
ipc-recompute-msgmni-on-memory-add--remove.patch
ipc-invoke-the-ipcns-notifier-chain-as-a-work-item.patch
ipc-recompute-msgmni-on-ipc-namespace-creation-removal.patch
ipc-do-not-recompute-msgmni-anymore-if-explicitly-set-by-user.patch
ipc-re-enable-msgmni-automatic-recomputing-msgmni-if-set-to-negative.patch
-
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