Messages in this thread Patch in this message | | | From | Nathan Zimmer <> | Subject | [RFC] hotplug, memory: move register_memory_resource out of the lock_memory_hotplug | Date | Tue, 14 Jan 2014 12:24:34 -0600 |
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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
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