Subject: + mm-memory_hotplugc-move-register_memory_resource-out-of-the-lock_memory_hotplug.patch added to -mm tree
To: nzimmer@xxxxxxx,hedi@xxxxxxx,isimatu.yasuaki@xxxxxxxxxxxxxx,kamezawa.hiroyu@xxxxxxxxxxxxxx,rafael.j.wysocki@xxxxxxxxx,tangchen@xxxxxxxxxxxxxx,travis@xxxxxxx,wency@xxxxxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Tue, 14 Jan 2014 15:13:51 -0800
The patch titled
Subject: mm/memory_hotplug.c: move register_memory_resource out of the lock_memory_hotplug
has been added to the -mm tree. Its filename is
mm-memory_hotplugc-move-register_memory_resource-out-of-the-lock_memory_hotplug.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-memory_hotplugc-move-register_memory_resource-out-of-the-lock_memory_hotplug.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-memory_hotplugc-move-register_memory_resource-out-of-the-lock_memory_hotplug.patch
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From: Nathan Zimmer <nzimmer@xxxxxxx>
Subject: mm/memory_hotplug.c: move register_memory_resource out of the lock_memory_hotplug
We don't need to do register_memory_resource() since it has its own lock
and doesn't make any callbacks.
Also register_memory_resource return NULL on failure so we don't have
anything to cleanup at this point.
The reason for this rfc is I was doing some experiments with hotplugging
of memory on some of our larger systems. While it seems to work, it can
be quite slow. With some preliminary digging I found that
lock_memory_hotplug is clearly ripe for breakup.
It could be broken up per nid or something but it also covers the
online_page_callback. The online_page_callback shouldn't be very hard to
break out.
Also there is the issue of various structures(wmarks come to mind) that are
only updated under the lock_memory_hotplug that would need to be dealt with.
Cc: Tang Chen <tangchen@xxxxxxxxxxxxxx>
Cc: Wen Congyang <wency@xxxxxxxxxxxxxx>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx>
Cc: Hedi <hedi@xxxxxxx>
Cc: Mike Travis <travis@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory_hotplug.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff -puN mm/memory_hotplug.c~mm-memory_hotplugc-move-register_memory_resource-out-of-the-lock_memory_hotplug mm/memory_hotplug.c
--- a/mm/memory_hotplug.c~mm-memory_hotplugc-move-register_memory_resource-out-of-the-lock_memory_hotplug
+++ a/mm/memory_hotplug.c
@@ -1107,17 +1107,18 @@ int __ref add_memory(int nid, u64 start,
if (ret)
return ret;
- lock_memory_hotplug();
-
res = register_memory_resource(start, size);
ret = -EEXIST;
if (!res)
- goto out;
+ return ret;
{ /* Stupid hack to suppress address-never-null warning */
void *p = NODE_DATA(nid);
new_pgdat = !p;
}
+
+ lock_memory_hotplug();
+
new_node = !node_online(nid);
if (new_node) {
pgdat = hotadd_new_pgdat(nid, start);
_
Patches currently in -mm which might be from nzimmer@xxxxxxx are
mm-memory_hotplugc-move-register_memory_resource-out-of-the-lock_memory_hotplug.patch
mm-memory_hotplugc-register_memory_resource-fixes.patch
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