LU-569: Make lu_object cache size adjustable

lu_object cache is specified to consume 20% of total memory. This
limits 200 clients at most can be mounted on one node. We should make
it adjustable so that customers have a chance to configure it by
their needs.

Change-Id: I8dcb993c88a3abd9fc8ba11ff1578aa3897c3933
Signed-off-by: Jinshan Xiong <jay@whamcloud.com>
Reviewed-on: http://review.whamcloud.com/1188
Tested-by: Hudson
Reviewed-by: Oleg Drokin <green@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>

diff --git a/lustre/obdclass/lu_object.c b/lustre/obdclass/lu_object.c
index e430eb1..8c49f8c 100644 (file)
--- a/lustre/obdclass/lu_object.c
+++ b/lustre/obdclass/lu_object.c
@@ -754,9 +754,14 @@ void lu_site_print(const struct lu_env *env, struct lu_site *s, void *cookie,
 EXPORT_SYMBOL(lu_site_print);
 
 enum {
 EXPORT_SYMBOL(lu_site_print);
 
 enum {

-        LU_CACHE_PERCENT   = 20,
+        LU_CACHE_PERCENT_MAX     = 50,
+        LU_CACHE_PERCENT_DEFAULT = 20

 };
 
 };
 

+static unsigned int lu_cache_percent = LU_CACHE_PERCENT_DEFAULT;
+CFS_MODULE_PARM(lu_cache_percent, "i", int, 0644,
+                "Percentage of memory to be used as lu_object cache");
+

 /**
  * Return desired hash table order.
  */
 /**
  * Return desired hash table order.
  */


@@ -780,7 +785,16 @@ static int lu_htable_order(void)
                 cache_size = 1 << (30 - CFS_PAGE_SHIFT) * 3 / 4;
 #endif
 
                 cache_size = 1 << (30 - CFS_PAGE_SHIFT) * 3 / 4;
 #endif
 

-        cache_size = cache_size / 100 * LU_CACHE_PERCENT *
+        /* clear off unreasonable cache setting. */
+        if (lu_cache_percent == 0 || lu_cache_percent > LU_CACHE_PERCENT_MAX) {
+                CWARN("obdclass: invalid lu_cache_percent: %u, it must be in"
+                      " the range of (0, %u]. Will use default value: %u.\n",
+                      lu_cache_percent, LU_CACHE_PERCENT_MAX,
+                      LU_CACHE_PERCENT_DEFAULT);
+
+                lu_cache_percent = LU_CACHE_PERCENT_DEFAULT;
+        }
+        cache_size = cache_size / 100 * lu_cache_percent *

                 (CFS_PAGE_SIZE / 1024);
 
         for (bits = 1; (1 << bits) < cache_size; ++bits) {
                 (CFS_PAGE_SIZE / 1024);
 
         for (bits = 1; (1 << bits) < cache_size; ++bits) {