BSD 4.4 Lite Kernel Sources

1 files changed, 381 insertions, 0 deletions

diff --git a/sys/vm/vm_pager.c b/sys/vm/vm_pager.c
new file mode 100644
index 0000000..7123abb
--- /dev/null
+++ b/sys/vm/vm_pager.c
@@ -0,0 +1,381 @@
+/* 
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * The Mach Operating System project at Carnegie-Mellon University.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 4. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ *	@(#)vm_pager.c	8.6 (Berkeley) 1/12/94
+ *
+ *
+ * Copyright (c) 1987, 1990 Carnegie-Mellon University.
+ * All rights reserved.
+ *
+ * Authors: Avadis Tevanian, Jr., Michael Wayne Young
+ * 
+ * Permission to use, copy, modify and distribute this software and
+ * its documentation is hereby granted, provided that both the copyright
+ * notice and this permission notice appear in all copies of the
+ * software, derivative works or modified versions, and any portions
+ * thereof, and that both notices appear in supporting documentation.
+ * 
+ * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 
+ * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 
+ * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
+ * 
+ * Carnegie Mellon requests users of this software to return to
+ *
+ *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
+ *  School of Computer Science
+ *  Carnegie Mellon University
+ *  Pittsburgh PA 15213-3890
+ *
+ * any improvements or extensions that they make and grant Carnegie the
+ * rights to redistribute these changes.
+ */
+
+/*
+ *	Paging space routine stubs.  Emulates a matchmaker-like interface
+ *	for builtin pagers.
+ */
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/malloc.h>
+
+#include <vm/vm.h>
+#include <vm/vm_page.h>
+#include <vm/vm_kern.h>
+
+#ifdef SWAPPAGER
+extern struct pagerops swappagerops;
+#endif
+
+#ifdef VNODEPAGER
+extern struct pagerops vnodepagerops;
+#endif
+
+#ifdef DEVPAGER
+extern struct pagerops devicepagerops;
+#endif
+
+struct pagerops *pagertab[] = {
+#ifdef SWAPPAGER
+	&swappagerops,		/* PG_SWAP */
+#else
+	NULL,
+#endif
+#ifdef VNODEPAGER
+	&vnodepagerops,		/* PG_VNODE */
+#else
+	NULL,
+#endif
+#ifdef DEVPAGER
+	&devicepagerops,	/* PG_DEV */
+#else
+	NULL,
+#endif
+};
+int npagers = sizeof (pagertab) / sizeof (pagertab[0]);
+
+struct pagerops *dfltpagerops = NULL;	/* default pager */
+
+/*
+ * Kernel address space for mapping pages.
+ * Used by pagers where KVAs are needed for IO.
+ *
+ * XXX needs to be large enough to support the number of pending async
+ * cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size
+ * (MAXPHYS == 64k) if you want to get the most efficiency.
+ */
+#define PAGER_MAP_SIZE	(4 * 1024 * 1024)
+
+vm_map_t pager_map;
+boolean_t pager_map_wanted;
+vm_offset_t pager_sva, pager_eva;
+
+void
+vm_pager_init()
+{
+	struct pagerops **pgops;
+
+	/*
+	 * Allocate a kernel submap for tracking get/put page mappings
+	 */
+	pager_map = kmem_suballoc(kernel_map, &pager_sva, &pager_eva,
+				  PAGER_MAP_SIZE, FALSE);
+	/*
+	 * Initialize known pagers
+	 */
+	for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++)
+		if (pgops)
+			(*(*pgops)->pgo_init)();
+	if (dfltpagerops == NULL)
+		panic("no default pager");
+}
+
+/*
+ * Allocate an instance of a pager of the given type.
+ * Size, protection and offset parameters are passed in for pagers that
+ * need to perform page-level validation (e.g. the device pager).
+ */
+vm_pager_t
+vm_pager_allocate(type, handle, size, prot, off)
+	int type;
+	caddr_t handle;
+	vm_size_t size;
+	vm_prot_t prot;
+	vm_offset_t off;
+{
+	struct pagerops *ops;
+
+	ops = (type == PG_DFLT) ? dfltpagerops : pagertab[type];
+	if (ops)
+		return ((*ops->pgo_alloc)(handle, size, prot, off));
+	return (NULL);
+}
+
+void
+vm_pager_deallocate(pager)
+	vm_pager_t	pager;
+{
+	if (pager == NULL)
+		panic("vm_pager_deallocate: null pager");
+
+	(*pager->pg_ops->pgo_dealloc)(pager);
+}
+
+int
+vm_pager_get_pages(pager, mlist, npages, sync)
+	vm_pager_t	pager;
+	vm_page_t	*mlist;
+	int		npages;
+	boolean_t	sync;
+{
+	int rv;
+
+	if (pager == NULL) {
+		rv = VM_PAGER_OK;
+		while (npages--)
+			if (!vm_page_zero_fill(*mlist)) {
+				rv = VM_PAGER_FAIL;
+				break;
+			} else
+				mlist++;
+		return (rv);
+	}
+	return ((*pager->pg_ops->pgo_getpages)(pager, mlist, npages, sync));
+}
+
+int
+vm_pager_put_pages(pager, mlist, npages, sync)
+	vm_pager_t	pager;
+	vm_page_t	*mlist;
+	int		npages;
+	boolean_t	sync;
+{
+	if (pager == NULL)
+		panic("vm_pager_put_pages: null pager");
+	return ((*pager->pg_ops->pgo_putpages)(pager, mlist, npages, sync));
+}
+
+boolean_t
+vm_pager_has_page(pager, offset)
+	vm_pager_t	pager;
+	vm_offset_t	offset;
+{
+	if (pager == NULL)
+		panic("vm_pager_has_page: null pager");
+	return ((*pager->pg_ops->pgo_haspage)(pager, offset));
+}
+
+/*
+ * Called by pageout daemon before going back to sleep.
+ * Gives pagers a chance to clean up any completed async pageing operations.
+ */
+void
+vm_pager_sync()
+{
+	struct pagerops **pgops;
+
+	for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++)
+		if (pgops)
+			(*(*pgops)->pgo_putpages)(NULL, NULL, 0, FALSE);
+}
+
+void
+vm_pager_cluster(pager, offset, loff, hoff)
+	vm_pager_t	pager;
+	vm_offset_t	offset;
+	vm_offset_t	*loff;
+	vm_offset_t	*hoff;
+{
+	if (pager == NULL)
+		panic("vm_pager_cluster: null pager");
+	return ((*pager->pg_ops->pgo_cluster)(pager, offset, loff, hoff));
+}
+
+void
+vm_pager_clusternull(pager, offset, loff, hoff)
+	vm_pager_t	pager;
+	vm_offset_t	offset;
+	vm_offset_t	*loff;
+	vm_offset_t	*hoff;
+{
+	panic("vm_pager_nullcluster called");
+}
+
+vm_offset_t
+vm_pager_map_pages(mlist, npages, canwait)
+	vm_page_t	*mlist;
+	int		npages;
+	boolean_t	canwait;
+{
+	vm_offset_t kva, va;
+	vm_size_t size;
+	vm_page_t m;
+
+	/*
+	 * Allocate space in the pager map, if none available return 0.
+	 * This is basically an expansion of kmem_alloc_wait with optional
+	 * blocking on no space.
+	 */
+	size = npages * PAGE_SIZE;
+	vm_map_lock(pager_map);
+	while (vm_map_findspace(pager_map, 0, size, &kva)) {
+		if (!canwait) {
+			vm_map_unlock(pager_map);
+			return (0);
+		}
+		pager_map_wanted = TRUE;
+		vm_map_unlock(pager_map);
+		(void) tsleep(pager_map, PVM, "pager_map", 0);
+		vm_map_lock(pager_map);
+	}
+	vm_map_insert(pager_map, NULL, 0, kva, kva + size);
+	vm_map_unlock(pager_map);
+
+	for (va = kva; npages--; va += PAGE_SIZE) {
+		m = *mlist++;
+#ifdef DEBUG
+		if ((m->flags & PG_BUSY) == 0)
+			panic("vm_pager_map_pages: page not busy");
+		if (m->flags & PG_PAGEROWNED)
+			panic("vm_pager_map_pages: page already in pager");
+#endif
+#ifdef DEBUG
+		m->flags |= PG_PAGEROWNED;
+#endif
+		pmap_enter(vm_map_pmap(pager_map), va, VM_PAGE_TO_PHYS(m),
+			   VM_PROT_DEFAULT, TRUE);
+	}
+	return (kva);
+}
+
+void
+vm_pager_unmap_pages(kva, npages)
+	vm_offset_t	kva;
+	int		npages;
+{
+	vm_size_t size = npages * PAGE_SIZE;
+
+#ifdef DEBUG
+	vm_offset_t va;
+	vm_page_t m;
+	int np = npages;
+
+	for (va = kva; np--; va += PAGE_SIZE) {
+		m = vm_pager_atop(va);
+		if (m->flags & PG_PAGEROWNED)
+			m->flags &= ~PG_PAGEROWNED;
+		else
+			printf("vm_pager_unmap_pages: %x(%x/%x) not owned\n",
+			       m, va, VM_PAGE_TO_PHYS(m));
+	}
+#endif
+	pmap_remove(vm_map_pmap(pager_map), kva, kva + size);
+	vm_map_lock(pager_map);
+	(void) vm_map_delete(pager_map, kva, kva + size);
+	if (pager_map_wanted)
+		wakeup(pager_map);
+	vm_map_unlock(pager_map);
+}
+
+vm_page_t
+vm_pager_atop(kva)
+	vm_offset_t	kva;
+{
+	vm_offset_t pa;
+
+	pa = pmap_extract(vm_map_pmap(pager_map), kva);
+	if (pa == 0)
+		panic("vm_pager_atop");
+	return (PHYS_TO_VM_PAGE(pa));
+}
+
+vm_pager_t
+vm_pager_lookup(pglist, handle)
+	register struct pagerlst *pglist;
+	caddr_t handle;
+{
+	register vm_pager_t pager;
+
+	for (pager = pglist->tqh_first; pager; pager = pager->pg_list.tqe_next)
+		if (pager->pg_handle == handle)
+			return (pager);
+	return (NULL);
+}
+
+/*
+ * This routine gains a reference to the object.
+ * Explicit deallocation is necessary.
+ */
+int
+pager_cache(object, should_cache)
+	vm_object_t	object;
+	boolean_t	should_cache;
+{
+	if (object == NULL)
+		return (KERN_INVALID_ARGUMENT);
+
+	vm_object_cache_lock();
+	vm_object_lock(object);
+	if (should_cache)
+		object->flags |= OBJ_CANPERSIST;
+	else
+		object->flags &= ~OBJ_CANPERSIST;
+	vm_object_unlock(object);
+	vm_object_cache_unlock();
+
+	vm_object_deallocate(object);
+
+	return (KERN_SUCCESS);
+}