[XFRM]: Dynamic xfrm_state hash table sizing.

The grow algorithm is simple, we grow if:

1) we see a hash chain collision at insert, and
2) we haven't hit the hash size limit (currently 1*1024*1024 slots), and
3) the number of xfrm_state objects is > the current hash mask

All of this needs some tweaking.

Remove __initdata from "hashdist" so we can use it safely at run time.
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/bootmem.h

@@ -114,7 +114,7 @@ extern void *__init alloc_large_system_hash(const char *tablename,
 #else
 #define HASHDIST_DEFAULT 0
 #endif
-extern int __initdata hashdist;		/* Distribute hashes across NUMA nodes? */
+extern int hashdist;		/* Distribute hashes across NUMA nodes? */
 
 
 #endif /* _LINUX_BOOTMEM_H */

mm/page_alloc.c

@@ -2363,7 +2363,7 @@ int percpu_pagelist_fraction_sysctl_handler(ctl_table *table, int write,
 	return 0;
 }
 
-__initdata int hashdist = HASHDIST_DEFAULT;
+int hashdist = HASHDIST_DEFAULT;
 
 #ifdef CONFIG_NUMA
 static int __init set_hashdist(char *str)