don't drop the kernel lock everytime. on a busy system, this results in

the reaper spending more than half its time in uvm_pause. we want the
system to be interactive, but we want throughput too. this seems like a
decent balance.

diff --git a/sys/uvm/uvm_glue.c b/sys/uvm/uvm_glue.c
index 7a9618a..9eff05e 100644 (file)
--- a/sys/uvm/uvm_glue.c
+++ b/sys/uvm/uvm_glue.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: uvm_glue.c,v 1.68 2014/12/05 04:12:48 uebayasi Exp $  */
+/*     $OpenBSD: uvm_glue.c,v 1.69 2014/12/15 20:38:22 tedu Exp $      */
 /*     $NetBSD: uvm_glue.c,v 1.44 2001/02/06 19:54:44 eeh Exp $        */
 
 /* 
@@ -467,8 +467,12 @@ uvm_atopg(vaddr_t kva)
 void
 uvm_pause(void)
 {
-       KERNEL_UNLOCK();
-       KERNEL_LOCK();
+       static unsigned int toggle;
+       if (toggle++ > 128) {
+               toggle = 0;
+               KERNEL_UNLOCK();
+               KERNEL_LOCK();
+       }
        if (curcpu()->ci_schedstate.spc_schedflags & SPCF_SHOULDYIELD)
                preempt(NULL);
 }