Dynamic buffer cache. Initial diff from mickey@, okay art@ beck@ toby@

deraadt@ dlg@.

1 files changed, 10 insertions, 68 deletions

diff --git a/sys/arch/mac68k/mac68k/machdep.c b/sys/arch/mac68k/mac68k/machdep.c
index 46956d3b101..02e1ebc0128 100644
--- a/sys/arch/mac68k/mac68k/machdep.c
+++ b/sys/arch/mac68k/mac68k/machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: machdep.c,v 1.137 2007/05/23 20:33:46 pvalchev Exp $	*/
+/*	$OpenBSD: machdep.c,v 1.138 2007/05/26 20:26:50 pedro Exp $	*/
 /*	$NetBSD: machdep.c,v 1.207 1998/07/08 04:39:34 thorpej Exp $	*/
 
 /*
@@ -173,12 +173,6 @@ struct vm_map *phys_map = NULL;
 /*
  * Declare these as initialized data so we can patch them.
  */
-#ifdef	NBUF
-int	nbuf = NBUF;
-#else
-int	nbuf = 0;
-#endif
-
 #ifndef	BUFCACHEPERCENT
 #define	BUFCACHEPERCENT	5
 #endif
@@ -364,7 +358,6 @@ cpu_startup(void)
 	caddr_t v;
 	unsigned i;
 	int vers;
-	int base, residual;
 	vaddr_t minaddr, maxaddr;
 	vsize_t size = 0;	/* To avoid compiler warning */
 	int delay;
@@ -419,43 +412,17 @@ cpu_startup(void)
 		panic("startup: table size inconsistency");
 
 	/*
-	 * Now allocate buffers proper.  They are different than the above
-	 * in that they usually occupy more virtual memory than physical.
+	 * Determine how many buffers to allocate.
+	 * We allocate bufcachepercent% of memory for buffer space.
 	 */
-	size = MAXBSIZE * nbuf;
-	if (uvm_map(kernel_map, (vaddr_t *) &buffers, round_page(size),
-	    NULL, UVM_UNKNOWN_OFFSET, 0, UVM_MAPFLAG(UVM_PROT_NONE,
-	    UVM_PROT_NONE, UVM_INH_NONE, UVM_ADV_NORMAL, 0)))
-		panic("startup: cannot allocate VM for buffers");
-	minaddr = (vaddr_t)buffers;
-	base = bufpages / nbuf;
-	residual = bufpages % nbuf;
-	for (i = 0; i < nbuf; i++) {
-		vsize_t curbufsize;
-		vaddr_t curbuf;
-		struct vm_page *pg;
+	if (bufpages == 0)
+		bufpages = physmem * bufcachepercent / 100;
 
-		/*
-		 * Each buffer has MAXBSIZE bytes of VM space allocated.  Of
-		 * that MAXBSIZE space, we allocate and map (base+1) pages
-		 * for the first "residual" buffers, and then we allocate
-		 * "base" pages for the rest.
-		 */
-		curbuf = (vaddr_t) buffers + (i * MAXBSIZE);
-		curbufsize = PAGE_SIZE * ((i < residual) ? (base+1) : base);
-
-		while (curbufsize) {
-			pg = uvm_pagealloc(NULL, 0, NULL, 0);
-			if (pg == NULL) 
-				panic("cpu_startup: not enough memory for "
-				    "buffer cache");
-			pmap_kenter_pa(curbuf, VM_PAGE_TO_PHYS(pg),
-			    VM_PROT_READ|VM_PROT_WRITE);
-			curbuf += PAGE_SIZE;
-			curbufsize -= PAGE_SIZE;
-		}
-		pmap_update(pmap_kernel());
-	}
+	/* Restrict to at most 25% filled kvm */
+	if (bufpages >
+	    (VM_MAX_KERNEL_ADDRESS-VM_MIN_KERNEL_ADDRESS) / PAGE_SIZE / 4) 
+		bufpages = (VM_MAX_KERNEL_ADDRESS-VM_MIN_KERNEL_ADDRESS) /
+		    PAGE_SIZE / 4;
 
 	/*
 	 * Allocate a submap for exec arguments.  This map effectively
@@ -472,8 +439,6 @@ cpu_startup(void)
 
 	printf("avail mem = %lu (%luMB)\n", ptoa(uvmexp.free),
 	    ptoa(uvmexp.free) / 1024 / 1024);
-	printf("using %d buffers containing %u bytes (%uK) of memory\n",
-	    nbuf, bufpages * PAGE_SIZE, bufpages * PAGE_SIZE / 1024);
 
 	/*
 	 * Set up CPU-specific registers, cache, etc.
@@ -526,29 +491,6 @@ allocsys(v)
 	valloc(msqids, struct msqid_ds, msginfo.msgmni);
 #endif
 
-	/*
-	 * Determine how many buffers to allocate (enough to
-	 * hold 5% of total physical memory, but at least 16).
-	 * Allocate 1/2 as many swap buffer headers as file i/o buffers.
-	 */
-	if (bufpages == 0)
-		bufpages = physmem * bufcachepercent / 100;
-	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 / PAGE_SIZE)
-		bufpages = nbuf * MAXBSIZE / PAGE_SIZE;
-
-	valloc(buf, struct buf, nbuf);
 	return (v);
 }