1 files changed, 15 insertions, 8 deletions

diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 213071859030..2cef8f34b2cb 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -26,6 +26,7 @@
  *              and many others. thanks.
  */
 #include <linux/module.h>
+#include <linux/moduleparam.h>
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/string.h>
@@ -51,13 +52,17 @@
 */
 
 #define HTB_HSIZE 16            /* classid hash size */
-#define HTB_HYSTERESIS 1        /* whether to use mode hysteresis for speedup */
+static int htb_hysteresis __read_mostly = 0; /* whether to use mode hysteresis for speedup */
 #define HTB_VER 0x30011         /* major must be matched with number suplied by TC as version */
 
 #if HTB_VER >> 16 != TC_HTB_PROTOVER
 #error "Mismatched sch_htb.c and pkt_sch.h"
 #endif
 
+/* Module parameter and sysfs export */
+module_param    (htb_hysteresis, int, 0640);
+MODULE_PARM_DESC(htb_hysteresis, "Hysteresis mode, less CPU load, less accurate");
+
 /* used internaly to keep status of single class */
 enum htb_cmode {
         HTB_CANT_SEND,          /* class can't send and can't borrow */
@@ -460,19 +465,21 @@ static void htb_deactivate_prios(struct htb_sched *q, struct htb_class *cl)
                 htb_remove_class_from_row(q, cl, mask);
 }
 
-#if HTB_HYSTERESIS
 static inline long htb_lowater(const struct htb_class *cl)
 {
-        return cl->cmode != HTB_CANT_SEND ? -cl->cbuffer : 0;
+        if (htb_hysteresis)
+                return cl->cmode != HTB_CANT_SEND ? -cl->cbuffer : 0;
+        else
+                return 0;
 }
 static inline long htb_hiwater(const struct htb_class *cl)
 {
-        return cl->cmode == HTB_CAN_SEND ? -cl->buffer : 0;
+        if (htb_hysteresis)
+                return cl->cmode == HTB_CAN_SEND ? -cl->buffer : 0;
+        else
+                return 0;
 }
-#else
-#define htb_lowater(cl) (0)
-#define htb_hiwater(cl) (0)
-#endif
+
 
 /**
  * htb_class_mode - computes and returns current class mode