staging/lustre/obdclass: limit lu_site hash table size

Allocating a big hash table using the formula for osd
does not really work for clients. We will create new
hash table for each mount on a single client which is
a lot of memory more than expected.

This patch limits the hash table up to 8M which has
524288 entries
Signed-off-by: Li Dongyang <dongyang.li@anu.edu.au>
Reviewed-on: http://review.whamcloud.com/18048
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-7689Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Signed-off-by: Oleg Drokin <green@linuxhacker.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/obdclass/lu_object.c

@@ -935,7 +935,7 @@ static void lu_dev_add_linkage(struct lu_site *s, struct lu_device *d)
  * Initialize site \a s, with \a d as the top level device.
  */
 #define LU_SITE_BITS_MIN    12
-#define LU_SITE_BITS_MAX    24
+#define LU_SITE_BITS_MAX    19
 /**
  * total 256 buckets, we don't want too many buckets because:
  * - consume too much memory