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mm/memory_hotplug.c: move register_memory_resource out of the lock_memory_hotplug

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We don't need to do register_memory_resource() under
lock_memory_hotplug() 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@cn.fujitsu.com>
Cc: Wen Congyang <wency@cn.fujitsu.com>
Cc: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: 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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Nathan Zimmer 2014-01-23 15:53:26 -08:00 committed by Linus Torvalds
parent 354f17e1e2
commit ac13c4622b
1 changed files with 4 additions and 3 deletions
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7
mm/memory_hotplug.c
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@ -1107,17 +1107,18 @@ int __ref add_memory(int nid, u64 start, u64 size)
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);