[PATCH] rcu: keep rcu callback event counter
This makes call_rcu() keep track of how many events there are on the RCU
list, and cause a reschedule event when the list gets too long.
This helps keep RCU event lists down.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index dd99415..2559d4b 100644
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -109,6 +109,10 @@
rdp = &__get_cpu_var(rcu_data);
*rdp->nxttail = head;
rdp->nxttail = &head->next;
+
+ if (unlikely(++rdp->count > 10000))
+ set_need_resched();
+
local_irq_restore(flags);
}
@@ -140,6 +144,12 @@
rdp = &__get_cpu_var(rcu_bh_data);
*rdp->nxttail = head;
rdp->nxttail = &head->next;
+ rdp->count++;
+/*
+ * Should we directly call rcu_do_batch() here ?
+ * if (unlikely(rdp->count > 10000))
+ * rcu_do_batch(rdp);
+ */
local_irq_restore(flags);
}
@@ -157,6 +167,7 @@
next = rdp->donelist = list->next;
list->func(list);
list = next;
+ rdp->count--;
if (++count >= maxbatch)
break;
}