From: Nathan Zimmer Date: Thu, 23 Jan 2014 23:53:26 +0000 (-0800) Subject: mm/memory_hotplug.c: move register_memory_resource out of the lock_memory_hotplug X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=ac13c4622bda2a9ff8f57bbbfeff48b2a42d0963;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git mm/memory_hotplug.c: move register_memory_resource out of the lock_memory_hotplug 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 Cc: Wen Congyang Cc: Kamezawa Hiroyuki Reviewed-by: Yasuaki Ishimatsu Cc: "Rafael J. Wysocki" Cc: Hedi Cc: Mike Travis Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index a512a47241a4..a650db29606f 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -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);