simple version of lazy tlb shootdown seems to be only a minor win

in terms of performance on real hardware.. need to think more.

simple version of lazy tlb shootdown seems to be only a minor win
9d95b81b · Nickolai Zeldovich · 1cba0fc0 · 9d95b81b
--- a/kernel/vm.cc
+++ b/kernel/vm.cc
@@ -18,7 +18,7 @@
 #include "kmtrace.hh"

 enum { vm_debug = 0 };
-enum { tlb_lazy = 1 };
+enum { tlb_lazy = 0 };

 /*
 * vmnode