lkml.org 
[lkml]   [2014]   [Jan]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC] hotplug, memory: move register_memory_resource out of the lock_memory_hotplug
Date
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: Andrew Morton <akpm@linux-foundation.org>
cc: Tang Chen <tangchen@cn.fujitsu.com>
cc: Wen Congyang <wency@cn.fujitsu.com>
cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
cc: Yasuaki Ishimatsu <isimatu.yasuaki@jp.fujitsu.com>
cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
cc: Hedi <hedi@sgi.com>
cc: Mike Travis <travis@sgi.com>
cc: linux-mm@kvack.org
cc: linux-kernel@vger.kernel.org


---
mm/memory_hotplug.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 1ad92b4..62a0cd1 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -1097,17 +1097,18 @@ int __ref add_memory(int nid, u64 start, u64 size)
struct resource *res;
int 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);
--
1.8.2.1


\
 
 \ /
  Last update: 2014-01-14 19:41    [W:0.053 / U:1.144 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site