[src/trunk]: src/sys comment

[yamt <yamt%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/39916f74dd7a
branches:  trunk
changeset: 763957:39916f74dd7a
user:      yamt <yamt%NetBSD.org@localhost>
date:      Fri Apr 08 10:36:58 2011 +0000

description:
comment

diffstat:

 sys/sys/userret.h |   9 ++++++++-
 sys/uvm/uvm_map.c |  13 +++++++------
 2 files changed, 15 insertions(+), 7 deletions(-)

diffs (58 lines):

diff -r 81908181ff55 -r 39916f74dd7a sys/sys/userret.h
--- a/sys/sys/userret.h Fri Apr 08 10:36:09 2011 +0000
+++ b/sys/sys/userret.h Fri Apr 08 10:36:58 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: userret.h,v 1.22 2011/02/25 22:37:12 yamt Exp $        */
+/*     $NetBSD: userret.h,v 1.23 2011/04/08 10:36:58 yamt Exp $        */
 
 /*-
  * Copyright (c) 1998, 2000, 2003, 2006, 2008 The NetBSD Foundation, Inc.
@@ -94,6 +94,13 @@
        if (__predict_false(((l->l_flag & LW_USERRET) | p->p_timerpend) != 0))
                lwp_userret(l);
        l->l_kpriority = false;
+       /*
+        * cpu_set_curpri(prio) is a MD optimized version of:
+        *
+        *      kpreempt_disable();
+        *      curcpu()->ci_schedstate.spc_curpriority = prio;
+        *      kpreempt_enable();
+        */
        cpu_set_curpri(l->l_priority);  /* XXX this needs to die */
 #else
        ci = l->l_cpu;
diff -r 81908181ff55 -r 39916f74dd7a sys/uvm/uvm_map.c
--- a/sys/uvm/uvm_map.c Fri Apr 08 10:36:09 2011 +0000
+++ b/sys/uvm/uvm_map.c Fri Apr 08 10:36:58 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_map.c,v 1.295 2011/02/02 15:25:27 chuck Exp $      */
+/*     $NetBSD: uvm_map.c,v 1.296 2011/04/08 10:38:36 yamt Exp $       */
 
 /*
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -66,7 +66,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_map.c,v 1.295 2011/02/02 15:25:27 chuck Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_map.c,v 1.296 2011/04/08 10:38:36 yamt Exp $");
 
 #include "opt_ddb.h"
 #include "opt_uvmhist.h"
@@ -3398,11 +3398,12 @@
                KASSERT(entry != &map->header);
                KASSERT(start < entry->end);
                /*
-                * XXX IMPLEMENT ME.
-                * Should invent a "weak" mode for uvm_fault()
-                * which would only do the PGO_LOCKED pgo_get().
+                * For now, we handle only the easy but commonly-requested case.
+                * ie. start prefetching of backing uobj pages.
                 *
-                * for now, we handle only the easy but common case.
+                * XXX It might be useful to pmap_enter() the already-in-core
+                * pages by inventing a "weak" mode for uvm_fault() which would
+                * only do the PGO_LOCKED pgo_get().
                 */
                if (UVM_ET_ISOBJ(entry) && amap == NULL && uobj != NULL) {
                        off_t offset;