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

deraadt@ dlg@.

1 files changed, 15 insertions, 144 deletions

diff --git a/sys/arch/i386/i386/machdep.c b/sys/arch/i386/i386/machdep.c
index 8202008a456..a6fb19dbb84 100644
--- a/sys/arch/i386/i386/machdep.c
+++ b/sys/arch/i386/i386/machdep.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: machdep.c,v 1.390 2007/05/25 15:55:26 art Exp $	*/
+/*	$OpenBSD: machdep.c,v 1.391 2007/05/26 20:26:50 pedro Exp $	*/
 /*	$NetBSD: machdep.c,v 1.214 1996/11/10 03:16:17 thorpej Exp $	*/
 
 /*-
@@ -174,17 +174,6 @@ extern struct proc *npxproc;
 #endif
 #endif /* NCOM > 0 || NPCCOM > 0 */
 
-/*
- * The following defines are for the code in setup_buffers that tries to
- * ensure that enough ISA DMAable memory is still left after the buffercache
- * has been allocated.
- */
-#define CHUNKSZ		(3 * 1024 * 1024)
-#define ISADMA_LIMIT	(16 * 1024 * 1024)	/* XXX wrong place */
-#define ALLOC_PGS(sz, limit, pgs) \
-    uvm_pglistalloc((sz), 0, (limit), PAGE_SIZE, 0, &(pgs), 1, 0)
-#define FREE_PGS(pgs) uvm_pglistfree(&(pgs))
-
 /* the following is used externally (sysctl_hw) */
 char machine[] = MACHINE;
 
@@ -199,14 +188,8 @@ int	cpu_apmhalt = 0;	/* sysctl'd to 1 for halt -p hack */
 int	user_ldt_enable = 0;	/* sysctl'd to 1 to enable */
 #endif
 
-#ifdef	NBUF
-int	nbuf = NBUF;
-#else
-int	nbuf = 0;
-#endif
-
 #ifndef BUFCACHEPERCENT
-#define BUFCACHEPERCENT 5
+#define BUFCACHEPERCENT 10
 #endif
 
 #ifdef	BUFPAGES
@@ -283,7 +266,7 @@ struct	extent *iomem_ex;
 static	int ioport_malloc_safe;
 
 caddr_t	allocsys(caddr_t);
-void	setup_buffers(vaddr_t *);
+void	setup_buffers(void);
 void	dumpsys(void);
 int	cpu_dump(void);
 void	init386(paddr_t);
@@ -444,7 +427,7 @@ cpu_startup()
 	 * Now allocate buffers proper.  They are different than the above
 	 * in that they usually occupy more virtual memory than physical.
 	 */
-	setup_buffers(&maxaddr);
+	setup_buffers();
 
 	/*
 	 * Allocate a submap for exec arguments.  This map effectively
@@ -462,8 +445,6 @@ cpu_startup()
 	printf("avail mem = %llu (%lluMB)\n",
 	    ptoa((unsigned long long)uvmexp.free),
 	    ptoa((unsigned long long)uvmexp.free)/1024U/1024U);
-	printf("using %d buffers containing %u bytes (%uK) of memory\n",
-	    nbuf, bufpages * PAGE_SIZE, bufpages * PAGE_SIZE / 1024);
 
 	/*
 	 * Set up buffers, so they can be used to read disk labels.
@@ -556,134 +537,24 @@ allocsys(caddr_t v)
 	valloc(msqids, struct msqid_ds, msginfo.msgmni);
 #endif
 
-	/*
-	 * Determine how many buffers to allocate.  We use 10% of the
-	 * first 2MB of memory, and 5% of the rest of below 4G memory,
-	 * with a minimum of 16 buffers.  We allocate 1/2 as many swap
-	 * buffer headers as file i/o buffers.
-	 */
-	if (bufpages == 0) {
-		bufpages = (btoc(2 * 1024 * 1024 + avail_end)) *
-		    bufcachepercent / 100;
-	}
-	if (nbuf == 0) {
-		nbuf = bufpages;
-		if (nbuf < 16)
-			nbuf = 16;
-	}
-
-	/* Restrict to at most 35% filled kvm */
-	/* XXX - This needs UBC... */
-	if (nbuf >
-	    (VM_MAX_KERNEL_ADDRESS-VM_MIN_KERNEL_ADDRESS) / MAXBSIZE * 35 / 100)
-		nbuf = (VM_MAX_KERNEL_ADDRESS-VM_MIN_KERNEL_ADDRESS) /
-		    MAXBSIZE * 35 / 100;
-
-	/* 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;
 }
 
 void
-setup_buffers(vaddr_t *maxaddr)
+setup_buffers()
 {
-	vsize_t size;
-	vaddr_t addr;
-	int base, residual, left, chunk, i;
-	struct pglist pgs, saved_pgs;
-	struct vm_page *pg;
-
-	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("cpu_startup: cannot allocate VM for buffers");
-	addr = (vaddr_t)buffers;
-
-	base = bufpages / nbuf;
-	residual = bufpages % nbuf;
-	if (base >= MAXBSIZE / PAGE_SIZE) {
-		/* don't want to alloc more physical mem than needed */
-		base = MAXBSIZE / PAGE_SIZE;
-		residual = 0;
-	}
-
 	/*
-	 * In case we might need DMA bouncing we have to make sure there
-	 * is some memory below 16MB available.  On machines with many
-	 * pages reserved for the buffer cache we risk filling all of that
-	 * area with buffer pages.  We still want much of the buffers
-	 * reside there as that lowers the probability of them needing to
-	 * bounce, but we have to set aside some space for DMA buffers too.
-	 *
-	 * The current strategy is to grab hold of one 3MB chunk below 16MB
-	 * first, which we are saving for DMA buffers, then try to get
-	 * one chunk at a time for fs buffers, until that is not possible
-	 * anymore, at which point we get the rest wherever we may find it.
-	 * After that we give our saved area back. That will guarantee at
-	 * least 3MB below 16MB left for drivers' attach routines, among
-	 * them isadma.  However we still have a potential problem of PCI
-	 * devices attached earlier snatching that memory.  This can be
-	 * solved by making the PCI DMA memory allocation routines go for
-	 * memory above 16MB first.
+	 * Determine how many buffers to allocate.  We use bufcachepercent%
+	 * of the memory below 4GB.
 	 */
-
-	left = bufpages;
-
-	/*
-	 * First, save ISA DMA bounce buffer area so we won't lose that
-	 * capability.
-	 */
-	TAILQ_INIT(&saved_pgs);
-	TAILQ_INIT(&pgs);
-	if (!ALLOC_PGS(CHUNKSZ, ISADMA_LIMIT, saved_pgs)) {
-		/*
-		 * Then, grab as much ISA DMAable memory as possible
-		 * for the buffer cache as it is nice to not need to
-		 * bounce all buffer I/O.
-		 */
-		for (left = bufpages; left > 0; left -= chunk) {
-			chunk = min(left, CHUNKSZ / PAGE_SIZE);
-			if (ALLOC_PGS(chunk * PAGE_SIZE, ISADMA_LIMIT, pgs))
-				break;
-		}
-	}
-
-	/*
-	 * If we need more pages for the buffer cache, get them from anywhere.
-	 */
-	if (left > 0 && ALLOC_PGS(left * PAGE_SIZE, avail_end, pgs))
-		panic("cannot get physical memory for buffer cache");
-
-	/*
-	 * Finally, give back the ISA DMA bounce buffer area, so it can be
-	 * allocated by the isadma driver later.
-	 */
-	if (!TAILQ_EMPTY(&saved_pgs))
-		FREE_PGS(saved_pgs);
-
-	pg = TAILQ_FIRST(&pgs);
-	for (i = 0; i < nbuf; i++) {
-		/*
-		 * First <residual> buffers get (base+1) physical pages
-		 * allocated for them.  The rest get (base) physical pages.
-		 *
-		 * The rest of each buffer occupies virtual space,
-		 * but has no physical memory allocated for it.
-		 */
-		addr = (vaddr_t)buffers + i * MAXBSIZE;
-		for (size = PAGE_SIZE * (i < residual ? base + 1 : base);
-		    size > 0; size -= PAGE_SIZE, addr += PAGE_SIZE) {
-			pmap_kenter_pa(addr, VM_PAGE_TO_PHYS(pg),
-			    VM_PROT_READ|VM_PROT_WRITE);
-			pg = TAILQ_NEXT(pg, pageq);
-		}
-	}
-	pmap_update(pmap_kernel());
+	if (bufpages == 0)
+		bufpages = btoc(avail_end) * bufcachepercent / 100;
+
+	/* 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;
 }
 
 /*