[src/trunk]: src/sys encapsulate knowledge of uarea allocation in some new fu...

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

details:   https://anonhg.NetBSD.org/src/rev/9ea54cef102a
branches:  trunk
changeset: 536799:9ea54cef102a
user:      chs <chs%NetBSD.org@localhost>
date:      Sun Sep 22 07:20:29 2002 +0000

description:
encapsulate knowledge of uarea allocation in some new functions.

diffstat:

 sys/kern/kern_fork.c |  12 +++-------
 sys/uvm/uvm_extern.h |   4 ++-
 sys/uvm/uvm_glue.c   |  53 +++++++++++++++++++++++++++++++++++++++++++++++++--
 3 files changed, 57 insertions(+), 12 deletions(-)

diffs (156 lines):

diff -r 9597f99f3e66 -r 9ea54cef102a sys/kern/kern_fork.c
--- a/sys/kern/kern_fork.c      Sun Sep 22 07:19:43 2002 +0000
+++ b/sys/kern/kern_fork.c      Sun Sep 22 07:20:29 2002 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: kern_fork.c,v 1.92 2002/08/28 07:16:37 gmcgarry Exp $  */
+/*     $NetBSD: kern_fork.c,v 1.93 2002/09/22 07:20:29 chs Exp $       */
 
 /*-
  * Copyright (c) 1999, 2001 The NetBSD Foundation, Inc.
@@ -78,7 +78,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_fork.c,v 1.92 2002/08/28 07:16:37 gmcgarry Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_fork.c,v 1.93 2002/09/22 07:20:29 chs Exp $");
 
 #include "opt_ktrace.h"
 #include "opt_systrace.h"
@@ -232,14 +232,10 @@
         * Allocate virtual address space for the U-area now, while it
         * is still easy to abort the fork operation if we're out of
         * kernel virtual address space.  The actual U-area pages will
-        * be allocated and wired in vm_fork().
+        * be allocated and wired in uvm_fork().
         */
 
-#ifndef USPACE_ALIGN
-#define        USPACE_ALIGN    0
-#endif
-
-       uaddr = uvm_km_valloc_align(kernel_map, USPACE, USPACE_ALIGN);
+       uaddr = uvm_uarea_alloc();
        if (__predict_false(uaddr == 0)) {
                (void)chgproccnt(uid, -1);
                nprocs--;
diff -r 9597f99f3e66 -r 9ea54cef102a sys/uvm/uvm_extern.h
--- a/sys/uvm/uvm_extern.h      Sun Sep 22 07:19:43 2002 +0000
+++ b/sys/uvm/uvm_extern.h      Sun Sep 22 07:20:29 2002 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_extern.h,v 1.72 2002/09/15 16:54:29 chs Exp $      */
+/*     $NetBSD: uvm_extern.h,v 1.73 2002/09/22 07:20:31 chs Exp $      */
 
 /*
  *
@@ -572,6 +572,8 @@
 boolean_t              uvm_kernacc __P((caddr_t, size_t, int));
 __dead void            uvm_scheduler __P((void)) __attribute__((noreturn));
 void                   uvm_swapin __P((struct proc *));
+vaddr_t                        uvm_uarea_alloc(void);
+void                   uvm_uarea_free(vaddr_t);
 boolean_t              uvm_useracc __P((caddr_t, size_t, int));
 int                    uvm_vslock __P((struct proc *, caddr_t, size_t,
                            vm_prot_t));
diff -r 9597f99f3e66 -r 9ea54cef102a sys/uvm/uvm_glue.c
--- a/sys/uvm/uvm_glue.c        Sun Sep 22 07:19:43 2002 +0000
+++ b/sys/uvm/uvm_glue.c        Sun Sep 22 07:20:29 2002 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_glue.c,v 1.59 2002/07/02 20:27:48 yamt Exp $       */
+/*     $NetBSD: uvm_glue.c,v 1.60 2002/09/22 07:20:32 chs Exp $        */
 
 /*
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -67,7 +67,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_glue.c,v 1.59 2002/07/02 20:27:48 yamt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_glue.c,v 1.60 2002/09/22 07:20:32 chs Exp $");
 
 #include "opt_kgdb.h"
 #include "opt_kstack.h"
@@ -98,6 +98,10 @@
 
 static void uvm_swapout __P((struct proc *));
 
+#define UVM_NUAREA_MAX 16
+void *uvm_uareas;
+int uvm_nuarea;
+
 /*
  * XXXCDC: do these really belong here?
  */
@@ -333,6 +337,7 @@
  * - we must run in a separate thread because freeing the vmspace
  *   of the dead process may block.
  */
+
 void
 uvm_exit(p)
        struct proc *p;
@@ -341,15 +346,56 @@
 
        uvmspace_free(p->p_vmspace);
        p->p_flag &= ~P_INMEM;
-       uvm_km_free(kernel_map, va, USPACE);
+       uvm_uarea_free(va);
        p->p_addr = NULL;
 }
 
 /*
+ * uvm_uarea_alloc: allocate a u-area
+ */
+
+vaddr_t
+uvm_uarea_alloc(void)
+{
+       vaddr_t uaddr;
+
+#ifndef USPACE_ALIGN
+#define USPACE_ALIGN    0
+#endif
+
+       uaddr = (vaddr_t)uvm_uareas;
+       if (uaddr) {
+               uvm_uareas = *(void **)uvm_uareas;
+               uvm_nuarea--;
+       } else {
+               uaddr = uvm_km_valloc_align(kernel_map, USPACE, USPACE_ALIGN);
+       }
+       return uaddr;
+}
+
+/*
+ * uvm_uarea_free: free a u-area
+ */
+
+void
+uvm_uarea_free(vaddr_t uaddr)
+{
+
+       if (uvm_nuarea < UVM_NUAREA_MAX) {
+               *(void **)uaddr = uvm_uareas;
+               uvm_uareas = (void *)uaddr;
+               uvm_nuarea++;
+       } else {
+               uvm_km_free(kernel_map, uaddr, USPACE);
+       }
+}
+
+/*
  * uvm_init_limit: init per-process VM limits
  *
  * - called for process 0 and then inherited by all others.
  */
+
 void
 uvm_init_limits(p)
        struct proc *p;
@@ -515,6 +561,7 @@
  *   are swapped... otherwise the longest-sleeping or stopped process
  *   is swapped, otherwise the longest resident process...
  */
+
 void
 uvm_swapout_threads()
 {