[PATCH] PKT_SCHED: Make rate estimator work for all platforms

[Thomas Graf <tgraf@xxxxxxx>]

Fixes the existing rate estimator to compile cleanly on all platforms
and avoids carrying on the variance on platforms with HZ%4 != 0.

Patch also applies to 2.4 with some fuzz.

Signed-off-by: Thomas Graf <tgraf@xxxxxxx>

--- linux-2.6.9-rc3-bk4.orig/net/sched/estimator.c      2004-10-04 
22:41:26.000000000 +0200
+++ linux-2.6.9-rc3-bk4/net/sched/estimator.c   2004-10-04 22:53:54.000000000 
+0200
@@ -66,15 +66,11 @@
 
    * Minimal interval is HZ/4=250msec (it is the greatest common divisor
      for HZ=100 and HZ=1024 8)), maximal interval
-     is (HZ/4)*2^EST_MAX_INTERVAL = 8sec. Shorter intervals
+     is (HZ*2^EST_MAX_INTERVAL)/4 = 8sec. Shorter intervals
      are too expensive, longer ones can be implemented
      at user level painlessly.
  */
 
-#if (HZ%4) != 0
-#error Bad HZ value.
-#endif
-
 #define EST_MAX_INTERVAL       5
 
 struct qdisc_estimator
@@ -128,7 +124,7 @@
                spin_unlock(e->stats_lock);
        }
 
-       mod_timer(&elist[idx].timer, jiffies + ((HZ/4)<<idx));
+       mod_timer(&elist[idx].timer, jiffies + ((HZ<<idx)/4));
        read_unlock(&est_lock);
 }
 
@@ -161,7 +157,7 @@
        if (est->next == NULL) {
                init_timer(&elist[est->interval].timer);
                elist[est->interval].timer.data = est->interval;
-               elist[est->interval].timer.expires = jiffies + 
((HZ/4)<<est->interval);
+               elist[est->interval].timer.expires = jiffies + 
((HZ<<est->interval)/4);
                elist[est->interval].timer.function = est_timer;
                add_timer(&elist[est->interval].timer);
        }