From bb0fe7e7e79dff4b526b8ca71014f542705518b9 Mon Sep 17 00:00:00 2001
From: deraadt <deraadt@openbsd.org>
Date: Sat, 1 Feb 1997 11:02:41 +0000
Subject: [PATCH] Implement BUFCACHEPERCENT. Allow bufpages/nbuf larger than 1
 (still max out at all buffers be MAXBSIZE).  Remove faulty limit test of
 buffer pages allocation.  The check is now done at the bufpages+nbuf
 calculations.

---
 sys/arch/arc/arc/machdep.c | 34 ++++++++++++++++++++++++++++++----
 1 file changed, 30 insertions(+), 4 deletions(-)

diff --git a/sys/arch/arc/arc/machdep.c b/sys/arch/arc/arc/machdep.c
index 755fd0f1954..36aba12888a 100644
--- a/sys/arch/arc/arc/machdep.c
+++ b/sys/arch/arc/arc/machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: machdep.c,v 1.17 1997/01/28 03:54:52 deraadt Exp $	*/
+/*	$OpenBSD: machdep.c,v 1.18 1997/02/01 11:02:41 deraadt Exp $	*/
 /*
  * Copyright (c) 1988 University of Utah.
  * Copyright (c) 1992, 1993
@@ -38,7 +38,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)machdep.c	8.3 (Berkeley) 1/12/94
- *      $Id: machdep.c,v 1.17 1997/01/28 03:54:52 deraadt Exp $
+ *      $Id: machdep.c,v 1.18 1997/02/01 11:02:41 deraadt Exp $
  */
 
 /* from: Utah Hdr: machdep.c 1.63 91/04/24 */
@@ -406,6 +406,10 @@ mips_init(argc, argv, code)
 	valloc(msqids, struct msqid_ds, msginfo.msgmni);
 #endif
 
+#ifndef BUFCACHEPERCENT
+#define BUFCACHEPERCENT 5
+#endif
+
 	/*
 	 * Determine how many buffers to allocate.
 	 * We allocate more buffer space than the BSD standard of
@@ -413,13 +417,29 @@ mips_init(argc, argv, code)
 	 * We just allocate a flat 10%. Ensure a minimum of 16 buffers.
 	 * We allocate 1/2 as many swap buffer headers as file i/o buffers.
 	 */
-	if (bufpages == 0)
-		bufpages = physmem / 10 / CLSIZE;
+	if (bufpages == 0) {
+		if (physmem < btoc(2 * 1024 * 1024))
+			bufpages = physmem / (10 * CLSIZE);
+		else
+			bufpages = (btoc(2 * 1024 * 1024) + physmem) /
+			    ((100/BUFCACHEPERCENT) * CLSIZE);
+	}
 	if (nbuf == 0) {
 		nbuf = bufpages;
 		if (nbuf < 16)
 			nbuf = 16;
 	}
+
+	/* Restrict to at most 70% filled kvm */
+	if (nbuf * MAXBSIZE >
+	    (VM_MAX_KERNEL_ADDRESS-VM_MIN_KERNEL_ADDRESS) * 7 / 10)
+		nbuf = (VM_MAX_KERNEL_ADDRESS-VM_MIN_KERNEL_ADDRESS) /
+		    MAXBSIZE * 7 / 10;
+
+	/* More buffer pages than fits into the buffers is senseless.  */
+	if (bufpages > nbuf * MAXBSIZE / CLBYTES)
+		bufpages = nbuf * MAXBSIZE / CLBYTES;
+
 	if (nswbuf == 0) {
 		nswbuf = (nbuf / 2) &~ 1;	/* force even */
 		if (nswbuf > 256)
@@ -561,6 +581,12 @@ cpu_startup()
 		panic("startup: cannot allocate buffers");
 	base = bufpages / nbuf;
 	residual = bufpages % nbuf;
+	if (base >= MAXBSIZE / CLBYTES) {
+		/* don't want to alloc more physical mem than needed */
+		base = MAXBSIZE / CLBYTES;
+		residual = 0;
+	}
+
 	for (i = 0; i < nbuf; i++) {
 		vm_size_t curbufsize;
 		vm_offset_t curbuf;
-- 
2.20.1