This set of commits to the VM system does the following, and contain

contributions or ideas from Stephen McKay <syssgm@devetir.qld.gov.au>,
Alan Cox <alc@cs.rice.edu>, David Greenman <davidg@freebsd.org> and me:

	More usage of the TAILQ macros.  Additional minor fix to queue.h.
	Performance enhancements to the pageout daemon.
		Addition of a wait in the case that the pageout daemon
		has to run immediately.
		Slightly modify the pageout algorithm.
	Significant revamp of the pmap/fork code:
		1) PTE's and UPAGES's are NO LONGER in the process's map.
		2) PTE's and UPAGES's reside in their own objects.
		3) TOTAL elimination of recursive page table pagefaults.
		4) The page directory now resides in the PTE object.
		5) Implemented pmap_copy, thereby speeding up fork time.
		6) Changed the pv entries so that the head is a pointer
		   and not an entire entry.
		7) Significant cleanup of pmap_protect, and pmap_remove.
		8) Removed significant amounts of machine dependent
		   fork code from vm_glue.  Pushed much of that code into
		   the machine dependent pmap module.
		9) Support more completely the reuse of already zeroed
		   pages (Page table pages and page directories) as being
		   already zeroed.
	Performance and code cleanups in vm_map:
		1) Improved and simplified allocation of map entries.
		2) Improved vm_map_copy code.
		3) Corrected some minor problems in the simplify code.
	Implemented splvm (combo of splbio and splimp.)  The VM code now
		seldom uses splhigh.
	Improved the speed of and simplified kmem_malloc.
	Minor mod to vm_fault to avoid using pre-zeroed pages in the case
		of objects with backing objects along with the already
		existant condition of having a vnode.  (If there is a backing
		object, there will likely be a COW...  With a COW, it isn't
		necessary to start with a pre-zeroed page.)
	Minor reorg of source to perhaps improve locality of ref.

3 files changed, 15 insertions, 32 deletions

diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c
index 50a5388..12dd958 100644
--- a/sys/kern/kern_exec.c
+++ b/sys/kern/kern_exec.c
@@ -23,7 +23,7 @@
  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  * SUCH DAMAGE.
  *
- *	$Id: kern_exec.c,v 1.39 1996/04/29 15:07:59 smpatel Exp $
+ *	$Id: kern_exec.c,v 1.40 1996/05/01 02:42:47 bde Exp $
  */
 
 #include <sys/param.h>
@@ -171,7 +171,7 @@ interpret:
 	 * Map the image header (first page) of the file into
 	 *	kernel address space
 	 */
-	error = vm_mmap(kernel_map,			/* map */
+	error = vm_mmap(exech_map,			/* map */
 			(vm_offset_t *)&imgp->image_header, /* address */
 			PAGE_SIZE,			/* size */
 			VM_PROT_READ, 			/* protection */
@@ -206,7 +206,7 @@ interpret:
 			/* free old vnode and name buffer */
 			vrele(ndp->ni_vp);
 			FREE(ndp->ni_cnd.cn_pnbuf, M_NAMEI);
-			if (vm_map_remove(kernel_map, (vm_offset_t)imgp->image_header,
+			if (vm_map_remove(exech_map, (vm_offset_t)imgp->image_header,
 			    (vm_offset_t)imgp->image_header + PAGE_SIZE))
 				panic("execve: header dealloc failed (1)");
 
@@ -319,7 +319,7 @@ interpret:
 	 * free various allocated resources
 	 */
 	kmem_free(exec_map, (vm_offset_t)imgp->stringbase, ARG_MAX);
-	if (vm_map_remove(kernel_map, (vm_offset_t)imgp->image_header,
+	if (vm_map_remove(exech_map, (vm_offset_t)imgp->image_header,
 	    (vm_offset_t)imgp->image_header + PAGE_SIZE))
 		panic("execve: header dealloc failed (2)");
 	vrele(ndp->ni_vp);
@@ -331,7 +331,7 @@ exec_fail_dealloc:
 	if (imgp->stringbase != NULL)
 		kmem_free(exec_map, (vm_offset_t)imgp->stringbase, ARG_MAX);
 	if (imgp->image_header && imgp->image_header != (char *)-1)
-		if (vm_map_remove(kernel_map, (vm_offset_t)imgp->image_header,
+		if (vm_map_remove(exech_map, (vm_offset_t)imgp->image_header,
 		    (vm_offset_t)imgp->image_header + PAGE_SIZE))
 			panic("execve: header dealloc failed (3)");
 	if (ndp->ni_vp)
diff --git a/sys/kern/subr_trap.c b/sys/kern/subr_trap.c
index c97e50a..b81cfc1 100644
--- a/sys/kern/subr_trap.c
+++ b/sys/kern/subr_trap.c
@@ -35,7 +35,7 @@
  * SUCH DAMAGE.
  *
  *	from: @(#)trap.c	7.4 (Berkeley) 5/13/91
- *	$Id: trap.c,v 1.74 1996/03/27 17:33:39 bde Exp $
+ *	$Id: trap.c,v 1.75 1996/03/28 05:40:57 dyson Exp $
  */
 
 /*
@@ -806,24 +806,10 @@ int trapwrite(addr)
 	v = trunc_page(vtopte(va));
 
 	/*
-	 * wire the pte page
-	 */
-	if (va < USRSTACK) {
-		vm_map_pageable(&vm->vm_map, v, round_page(v+1), FALSE);
-	}
-
-	/*
 	 * fault the data page
 	 */
 	rv = vm_fault(&vm->vm_map, va, VM_PROT_READ|VM_PROT_WRITE, FALSE);
 
-	/*
-	 * unwire the pte page
-	 */
-	if (va < USRSTACK) {
-		vm_map_pageable(&vm->vm_map, v, round_page(v+1), TRUE);
-	}
-
 	--p->p_lock;
 
 	if (rv != KERN_SUCCESS)
diff --git a/sys/kern/vfs_bio.c b/sys/kern/vfs_bio.c
index d449b94..cb76f05 100644
--- a/sys/kern/vfs_bio.c
+++ b/sys/kern/vfs_bio.c
@@ -18,7 +18,7 @@
  * 5. Modifications may be freely made to this file if the above conditions
  *    are met.
  *
- * $Id: vfs_bio.c,v 1.88 1996/03/09 06:46:51 dyson Exp $
+ * $Id: vfs_bio.c,v 1.89 1996/05/03 21:01:26 phk Exp $
  */
 
 /*
@@ -509,7 +509,7 @@ brelse(struct buf * bp)
 	/* buffers with no memory */
 	if (bp->b_bufsize == 0) {
 		bp->b_qindex = QUEUE_EMPTY;
-		TAILQ_INSERT_TAIL(&bufqueues[QUEUE_EMPTY], bp, b_freelist);
+		TAILQ_INSERT_HEAD(&bufqueues[QUEUE_EMPTY], bp, b_freelist);
 		LIST_REMOVE(bp, b_hash);
 		LIST_INSERT_HEAD(&invalhash, bp, b_hash);
 		bp->b_dev = NODEV;
@@ -742,7 +742,7 @@ start:
 		goto trytofreespace;
 
 	/* can we constitute a new buffer? */
-	if ((bp = bufqueues[QUEUE_EMPTY].tqh_first)) {
+	if ((bp = TAILQ_FIRST(&bufqueues[QUEUE_EMPTY]))) {
 		if (bp->b_qindex != QUEUE_EMPTY)
 			panic("getnewbuf: inconsistent EMPTY queue, qindex=%d",
 			    bp->b_qindex);
@@ -756,11 +756,11 @@ trytofreespace:
 	 * This is desirable because file data is cached in the
 	 * VM/Buffer cache even if a buffer is freed.
 	 */
-	if ((bp = bufqueues[QUEUE_AGE].tqh_first)) {
+	if ((bp = TAILQ_FIRST(&bufqueues[QUEUE_AGE]))) {
 		if (bp->b_qindex != QUEUE_AGE)
 			panic("getnewbuf: inconsistent AGE queue, qindex=%d",
 			    bp->b_qindex);
-	} else if ((bp = bufqueues[QUEUE_LRU].tqh_first)) {
+	} else if ((bp = TAILQ_FIRST(&bufqueues[QUEUE_LRU]))) {
 		if (bp->b_qindex != QUEUE_LRU)
 			panic("getnewbuf: inconsistent LRU queue, qindex=%d",
 			    bp->b_qindex);
@@ -783,7 +783,7 @@ trytofreespace:
 			(vmiospace < maxvmiobufspace)) {
 			--bp->b_usecount;
 			TAILQ_REMOVE(&bufqueues[QUEUE_LRU], bp, b_freelist);
-			if (bufqueues[QUEUE_LRU].tqh_first != NULL) {
+			if (TAILQ_FIRST(&bufqueues[QUEUE_LRU]) != NULL) {
 				TAILQ_INSERT_TAIL(&bufqueues[QUEUE_LRU], bp, b_freelist);
 				goto start;
 			}
@@ -1498,9 +1498,9 @@ count_lock_queue()
 	struct buf *bp;
 
 	count = 0;
-	for (bp = bufqueues[QUEUE_LOCKED].tqh_first;
+	for (bp = TAILQ_FIRST(&bufqueues[QUEUE_LOCKED]);
 	    bp != NULL;
-	    bp = bp->b_freelist.tqe_next)
+	    bp = TAILQ_NEXT(bp, b_freelist))
 		count++;
 	return (count);
 }
@@ -1663,7 +1663,6 @@ vfs_clean_pages(struct buf * bp)
 void
 vfs_bio_clrbuf(struct buf *bp) {
 	int i;
-	int remapbuffer = 0;
 	if( bp->b_flags & B_VMIO) {
 		if( (bp->b_npages == 1) && (bp->b_bufsize < PAGE_SIZE)) {
 			int mask;
@@ -1691,14 +1690,12 @@ vfs_bio_clrbuf(struct buf *bp) {
 						bzero(bp->b_data + (i << PAGE_SHIFT) + j * DEV_BSIZE, DEV_BSIZE);
 				}
 			}
-			bp->b_pages[i]->valid = VM_PAGE_BITS_ALL;
+			/* bp->b_pages[i]->valid = VM_PAGE_BITS_ALL; */
 		}
 		bp->b_resid = 0;
 	} else {
 		clrbuf(bp);
 	}
-	if (remapbuffer)
-			pmap_qenter(trunc_page(bp->b_data), bp->b_pages, bp->b_npages);
 }
 
 /*