This commit was manufactured by cvs2svn to create tag 'FreeBSD-release/1.1'.

[unix-history] / sys / i386 / i386 / vm_machdep.c

diff --git a/sys/i386/i386/vm_machdep.c b/sys/i386/i386/vm_machdep.c
index b926434..f99861a 100644 (file)
--- a/sys/i386/i386/vm_machdep.c
+++ b/sys/i386/i386/vm_machdep.c
@@ -37,7 +37,7 @@
  *
  *     from: @(#)vm_machdep.c  7.3 (Berkeley) 5/13/91
  *     Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
  *
  *     from: @(#)vm_machdep.c  7.3 (Berkeley) 5/13/91
  *     Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$

- *     $Id: vm_machdep.c,v 1.9 1994/01/14 16:23:42 davidg Exp $
+ *     $Id: vm_machdep.c,v 1.11 1994/02/08 09:26:04 davidg Exp $

  */
 
 #include "npx.h"
  */
 
 #include "npx.h"


@@ -338,3 +338,56 @@ cpu_reset() {
        /* NOTREACHED */
        while(1);
 }
        /* NOTREACHED */
        while(1);
 }

+
+/*
+ * Grow the user stack to allow for 'sp'. This version grows the stack in
+ *     chunks of SGROWSIZ.
+ */
+int
+grow(p, sp)
+       struct proc *p;
+       int sp;
+{
+       unsigned int nss;
+       caddr_t v;
+       struct vmspace *vm = p->p_vmspace;
+
+       if ((caddr_t)sp <= vm->vm_maxsaddr || (unsigned)sp >= (unsigned)USRSTACK)
+           return (1);
+
+       nss = roundup(USRSTACK - (unsigned)sp, PAGE_SIZE);
+
+       if (nss > p->p_rlimit[RLIMIT_STACK].rlim_cur)
+               return (0);
+
+       if (vm->vm_ssize && roundup(vm->vm_ssize << PAGE_SHIFT,
+           SGROWSIZ) < nss) {
+               int grow_amount;
+               /*
+                * If necessary, grow the VM that the stack occupies
+                * to allow for the rlimit. This allows us to not have
+                * to allocate all of the VM up-front in execve (which
+                * is expensive).
+                * Grow the VM by the amount requested rounded up to
+                * the nearest SGROWSIZ to provide for some hysteresis.
+                */
+               grow_amount = roundup((nss - (vm->vm_ssize << PAGE_SHIFT)), SGROWSIZ);
+               v = (char *)USRSTACK - roundup(vm->vm_ssize << PAGE_SHIFT,
+                   SGROWSIZ) - grow_amount;
+               /*
+                * If there isn't enough room to extend by SGROWSIZ, then
+                * just extend to the maximum size
+                */
+               if (v < vm->vm_maxsaddr) {
+                       v = vm->vm_maxsaddr;
+                       grow_amount = MAXSSIZ - (vm->vm_ssize << PAGE_SHIFT);
+               }
+               if (vm_allocate(&vm->vm_map, (vm_offset_t *)&v,
+                   grow_amount, FALSE) != KERN_SUCCESS) {
+                       return (0);
+               }
+               vm->vm_ssize += grow_amount >> PAGE_SHIFT;
+       }
+
+       return (1);
+}