Created attachment 22784 [details]
patch to decay_load

The reply_timeout counter is not cleared by 0 when the worker becomes force
recovery state.

In addition, the counter doesn't decay because the following codes are not executed when Busyness is specified to method directive.
Therefore, it is easy to become an error state.
-----jk_lb_worker.c
600:    if (p->lbmethod != JK_LB_METHOD_BUSYNESS) {
601:        for (i = 0; i < p->num_of_workers; i++) {
602:            lb_sub_worker_t *w = &p->lb_workers[i];
603:            ajp_worker_t *aw = (ajp_worker_t *)w->worker->worker_private;
604:            w->s->lb_value >>= exponent;
605:            if (w->s->lb_value > curmax) {
606:                curmax = w->s->lb_value;
607:            }
608:            aw->s->reply_timeouts >>= exponent;
609:        }
610:    }
---

I think that to decay the counter is nice idea for Busyness method as well as in the case of other methods. 
How about as follows?

Index: mod_jk-head/native/common/jk_lb_worker.c
===================================================================
--- mod_jk-head/native/common/jk_lb_worker.c	(revision 708408)
+++ mod_jk-head/native/common/jk_lb_worker.c	(working copy)
@@ -597,16 +597,16 @@
     jk_uint64_t curmax = 0;
 
     JK_TRACE_ENTER(l);
-    if (p->lbmethod != JK_LB_METHOD_BUSYNESS) {
-        for (i = 0; i < p->num_of_workers; i++) {
-            lb_sub_worker_t *w = &p->lb_workers[i];
-            ajp_worker_t *aw = (ajp_worker_t *)w->worker->worker_private;
+    for (i = 0; i < p->num_of_workers; i++) {
+        lb_sub_worker_t *w = &p->lb_workers[i];
+        ajp_worker_t *aw = (ajp_worker_t *)w->worker->worker_private;
+        if (p->lbmethod != JK_LB_METHOD_BUSYNESS) {
             w->s->lb_value >>= exponent;
             if (w->s->lb_value > curmax) {
                 curmax = w->s->lb_value;
             }
-            aw->s->reply_timeouts >>= exponent;
         }
+        aw->s->reply_timeouts >>= exponent;
     }
     JK_TRACE_EXIT(l);

regards.