[PATCH] hotplug CPU: clean up hotcpu_notifier() use

There was lots of #ifdef noise in the kernel due to hotcpu_notifier(fn,
prio) not correctly marking 'fn' as used in the !HOTPLUG_CPU case, and thus
generating compiler warnings of unused symbols, hence forcing people to add
#ifdefs.

the compiler can skip truly unused functions just fine:

    text    data     bss     dec     hex filename
 1624412  728710 3674856 6027978  5bfaca vmlinux.before
 1624412  728710 3674856 6027978  5bfaca vmlinux.after

[akpm@osdl.org: topology.c fix]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 2 insertions, 6 deletions

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 2273952300d4..27ec7a1b8022 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -701,7 +701,6 @@ void drain_node_pages(int nodeid)
 }
 #endif
 
-#if defined(CONFIG_PM) || defined(CONFIG_HOTPLUG_CPU)
 static void __drain_pages(unsigned int cpu)
 {
         unsigned long flags;
@@ -723,7 +722,6 @@ static void __drain_pages(unsigned int cpu)
                 }
         }
 }
-#endif /* CONFIG_PM || CONFIG_HOTPLUG_CPU */
 
 #ifdef CONFIG_PM
 
@@ -2907,7 +2905,6 @@ void __init free_area_init(unsigned long *zones_size)
                         __pa(PAGE_OFFSET) >> PAGE_SHIFT, NULL);
 }
 
-#ifdef CONFIG_HOTPLUG_CPU
 static int page_alloc_cpu_notify(struct notifier_block *self,
                                  unsigned long action, void *hcpu)
 {
@@ -2922,7 +2919,6 @@ static int page_alloc_cpu_notify(struct notifier_block *self,
         }
         return NOTIFY_OK;
 }
-#endif /* CONFIG_HOTPLUG_CPU */
 
 void __init page_alloc_init(void)
 {
diff --git a/mm/swap.c b/mm/swap.c
index 017e72ca9bbb..2ed7be39795e 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -514,5 +514,7 @@ void __init swap_setup(void)
          * Right now other parts of the system means that we
          * _really_ don't want to cluster much more
          */
+#ifdef CONFIG_HOTPLUG_CPU
         hotcpu_notifier(cpu_swap_callback, 0);
+#endif
 }
diff --git a/mm/vmscan.c b/mm/vmscan.c
index f6616e81fac7..093f5fe6dd77 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1513,7 +1513,6 @@ out:
 }
 #endif
 
-#ifdef CONFIG_HOTPLUG_CPU
 /* It's optimal to keep kswapds on the same CPUs as their memory, but
    not required for correctness.  So if the last cpu in a node goes
    away, we get changed to run anywhere: as the first one comes back,
@@ -1534,7 +1533,6 @@ static int __devinit cpu_callback(struct notifier_block *nfb,
         }
         return NOTIFY_OK;
 }
-#endif /* CONFIG_HOTPLUG_CPU */
 
 /*
  * This kswapd start function will be called by init and node-hot-add.