+/*
+ * Copyright (c) 1991 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_page.c 7.4 (Berkeley) 5/7/91
+ *
+ *
+ * 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.
+ */
+
+/*
+ * Resident memory management module.
+ */
+
+#include "param.h"
+
+#include "vm.h"
+#include "vm_map.h"
+#include "vm_page.h"
+#include "vm_pageout.h"
+
+/*
+ * Associated with page of user-allocatable memory is a
+ * page structure.
+ */
+
+queue_head_t *vm_page_buckets; /* Array of buckets */
+int vm_page_bucket_count = 0; /* How big is array? */
+int vm_page_hash_mask; /* Mask for hash function */
+simple_lock_data_t bucket_lock; /* lock for all buckets XXX */
+
+vm_size_t page_size = 4096;
+vm_size_t page_mask = 4095;
+int page_shift = 12;
+
+queue_head_t vm_page_queue_free;
+queue_head_t vm_page_queue_active;
+queue_head_t vm_page_queue_inactive;
+simple_lock_data_t vm_page_queue_lock;
+simple_lock_data_t vm_page_queue_free_lock;
+
+vm_page_t vm_page_array;
+long first_page;
+long last_page;
+vm_offset_t first_phys_addr;
+vm_offset_t last_phys_addr;
+
+int vm_page_free_count;
+int vm_page_active_count;
+int vm_page_inactive_count;
+int vm_page_wire_count;
+int vm_page_laundry_count;
+
+int vm_page_free_target = 0;
+int vm_page_free_min = 0;
+int vm_page_inactive_target = 0;
+int vm_page_free_reserved = 0;
+
+/*
+ * vm_set_page_size:
+ *
+ * Sets the page size, perhaps based upon the memory
+ * size. Must be called before any use of page-size
+ * dependent functions.
+ *
+ * Sets page_shift and page_mask from page_size.
+ */
+void vm_set_page_size()
+{
+ page_mask = page_size - 1;
+
+ if ((page_mask & page_size) != 0)
+ panic("vm_set_page_size: page size not a power of two");
+
+ for (page_shift = 0; ; page_shift++)
+ if ((1 << page_shift) == page_size)
+ break;
+}
+
+
+/*
+ * vm_page_startup:
+ *
+ * Initializes the resident memory module.
+ *
+ * Allocates memory for the page cells, and
+ * for the object/offset-to-page hash table headers.
+ * Each page cell is initialized and placed on the free list.
+ */
+vm_offset_t vm_page_startup(start, end, vaddr)
+ register vm_offset_t start;
+ vm_offset_t end;
+ register vm_offset_t vaddr;
+{
+ register vm_offset_t mapped;
+ register vm_page_t m;
+ register queue_t bucket;
+ vm_size_t npages;
+ register vm_offset_t new_start;
+ int i;
+ vm_offset_t pa;
+
+ extern vm_offset_t kentry_data;
+ extern vm_size_t kentry_data_size;
+
+
+ /*
+ * Initialize the locks
+ */
+
+ simple_lock_init(&vm_page_queue_free_lock);
+ simple_lock_init(&vm_page_queue_lock);
+
+ /*
+ * Initialize the queue headers for the free queue,
+ * the active queue and the inactive queue.
+ */
+
+ queue_init(&vm_page_queue_free);
+ queue_init(&vm_page_queue_active);
+ queue_init(&vm_page_queue_inactive);
+
+ /*
+ * Allocate (and initialize) the hash table buckets.
+ *
+ * The number of buckets MUST BE a power of 2, and
+ * the actual value is the next power of 2 greater
+ * than the number of physical pages in the system.
+ *
+ * Note:
+ * This computation can be tweaked if desired.
+ */
+
+ vm_page_buckets = (queue_t) vaddr;
+ bucket = vm_page_buckets;
+ if (vm_page_bucket_count == 0) {
+ vm_page_bucket_count = 1;
+ while (vm_page_bucket_count < atop(end - start))
+ vm_page_bucket_count <<= 1;
+ }
+
+ vm_page_hash_mask = vm_page_bucket_count - 1;
+
+ /*
+ * Validate these addresses.
+ */
+
+ new_start = round_page(((queue_t)start) + vm_page_bucket_count);
+ mapped = vaddr;
+ vaddr = pmap_map(mapped, start, new_start,
+ VM_PROT_READ|VM_PROT_WRITE);
+ start = new_start;
+ bzero((caddr_t) mapped, vaddr - mapped);
+ mapped = vaddr;
+
+ for (i = vm_page_bucket_count; i--;) {
+ queue_init(bucket);
+ bucket++;
+ }
+
+ simple_lock_init(&bucket_lock);
+
+ /*
+ * round (or truncate) the addresses to our page size.
+ */
+
+ end = trunc_page(end);
+
+ /*
+ * Pre-allocate maps and map entries that cannot be dynamically
+ * allocated via malloc(). The maps include the kernel_map and
+ * kmem_map which must be initialized before malloc() will
+ * work (obviously). Also could include pager maps which would
+ * be allocated before kmeminit.
+ *
+ * Allow some kernel map entries... this should be plenty
+ * since people shouldn't be cluttering up the kernel
+ * map (they should use their own maps).
+ */
+
+ kentry_data_size = MAX_KMAP * sizeof(struct vm_map) +
+ MAX_KMAPENT * sizeof(struct vm_map_entry);
+ kentry_data_size = round_page(kentry_data_size);
+ kentry_data = (vm_offset_t) vaddr;
+ vaddr += kentry_data_size;
+
+ /*
+ * Validate these zone addresses.
+ */
+
+ new_start = start + (vaddr - mapped);
+ pmap_map(mapped, start, new_start, VM_PROT_READ|VM_PROT_WRITE);
+ bzero((caddr_t) mapped, (vaddr - mapped));
+ mapped = vaddr;
+ start = new_start;
+
+ /*
+ * Compute the number of pages of memory that will be
+ * available for use (taking into account the overhead
+ * of a page structure per page).
+ */
+
+ vm_page_free_count = npages =
+ (end - start)/(PAGE_SIZE + sizeof(struct vm_page));
+
+ /*
+ * Initialize the mem entry structures now, and
+ * put them in the free queue.
+ */
+
+ m = vm_page_array = (vm_page_t) vaddr;
+ first_page = start;
+ first_page += npages*sizeof(struct vm_page);
+ first_page = atop(round_page(first_page));
+ last_page = first_page + npages - 1;
+
+ first_phys_addr = ptoa(first_page);
+ last_phys_addr = ptoa(last_page) + page_mask;
+
+ /*
+ * Validate these addresses.
+ */
+
+ new_start = start + (round_page(m + npages) - mapped);
+ mapped = pmap_map(mapped, start, new_start,
+ VM_PROT_READ|VM_PROT_WRITE);
+ start = new_start;
+
+ /*
+ * Clear all of the page structures
+ */
+ bzero((caddr_t)m, npages * sizeof(*m));
+
+ pa = first_phys_addr;
+ while (npages--) {
+ m->copy_on_write = FALSE;
+ m->wanted = FALSE;
+ m->inactive = FALSE;
+ m->active = FALSE;
+ m->busy = FALSE;
+ m->object = NULL;
+ m->phys_addr = pa;
+ queue_enter(&vm_page_queue_free, m, vm_page_t, pageq);
+ m++;
+ pa += PAGE_SIZE;
+ }
+
+ /*
+ * Initialize vm_pages_needed lock here - don't wait for pageout
+ * daemon XXX
+ */
+ simple_lock_init(&vm_pages_needed_lock);
+
+ return(mapped);
+}
+
+/*
+ * vm_page_hash:
+ *
+ * Distributes the object/offset key pair among hash buckets.
+ *
+ * NOTE: This macro depends on vm_page_bucket_count being a power of 2.
+ */
+#define vm_page_hash(object, offset) \
+ (((unsigned)object+(unsigned)atop(offset))&vm_page_hash_mask)
+
+/*
+ * vm_page_insert: [ internal use only ]
+ *
+ * Inserts the given mem entry into the object/object-page
+ * table and object list.
+ *
+ * The object and page must be locked.
+ */
+
+void vm_page_insert(mem, object, offset)
+ register vm_page_t mem;
+ register vm_object_t object;
+ register vm_offset_t offset;
+{
+ register queue_t bucket;
+ int spl;
+
+ VM_PAGE_CHECK(mem);
+
+ if (mem->tabled)
+ panic("vm_page_insert: already inserted");
+
+ /*
+ * Record the object/offset pair in this page
+ */
+
+ mem->object = object;
+ mem->offset = offset;
+
+ /*
+ * Insert it into the object_object/offset hash table
+ */
+
+ bucket = &vm_page_buckets[vm_page_hash(object, offset)];
+ spl = splimp();
+ simple_lock(&bucket_lock);
+ queue_enter(bucket, mem, vm_page_t, hashq);
+ simple_unlock(&bucket_lock);
+ (void) splx(spl);
+
+ /*
+ * Now link into the object's list of backed pages.
+ */
+
+ queue_enter(&object->memq, mem, vm_page_t, listq);
+ mem->tabled = TRUE;
+
+ /*
+ * And show that the object has one more resident
+ * page.
+ */
+
+ object->resident_page_count++;
+}
+
+/*
+ * vm_page_remove: [ internal use only ]
+ *
+ * Removes the given mem entry from the object/offset-page
+ * table and the object page list.
+ *
+ * The object and page must be locked.
+ */
+
+void vm_page_remove(mem)
+ register vm_page_t mem;
+{
+ register queue_t bucket;
+ int spl;
+
+ VM_PAGE_CHECK(mem);
+
+ if (!mem->tabled)
+ return;
+
+ /*
+ * Remove from the object_object/offset hash table
+ */
+
+ bucket = &vm_page_buckets[vm_page_hash(mem->object, mem->offset)];
+ spl = splimp();
+ simple_lock(&bucket_lock);
+ queue_remove(bucket, mem, vm_page_t, hashq);
+ simple_unlock(&bucket_lock);
+ (void) splx(spl);
+
+ /*
+ * Now remove from the object's list of backed pages.
+ */
+
+ queue_remove(&mem->object->memq, mem, vm_page_t, listq);
+
+ /*
+ * And show that the object has one fewer resident
+ * page.
+ */
+
+ mem->object->resident_page_count--;
+
+ mem->tabled = FALSE;
+}
+
+/*
+ * vm_page_lookup:
+ *
+ * Returns the page associated with the object/offset
+ * pair specified; if none is found, NULL is returned.
+ *
+ * The object must be locked. No side effects.
+ */
+
+vm_page_t vm_page_lookup(object, offset)
+ register vm_object_t object;
+ register vm_offset_t offset;
+{
+ register vm_page_t mem;
+ register queue_t bucket;
+ int spl;
+
+ /*
+ * Search the hash table for this object/offset pair
+ */
+
+ bucket = &vm_page_buckets[vm_page_hash(object, offset)];
+
+ spl = splimp();
+ simple_lock(&bucket_lock);
+ mem = (vm_page_t) queue_first(bucket);
+ while (!queue_end(bucket, (queue_entry_t) mem)) {
+ VM_PAGE_CHECK(mem);
+ if ((mem->object == object) && (mem->offset == offset)) {
+ simple_unlock(&bucket_lock);
+ splx(spl);
+ return(mem);
+ }
+ mem = (vm_page_t) queue_next(&mem->hashq);
+ }
+
+ simple_unlock(&bucket_lock);
+ splx(spl);
+ return(NULL);
+}
+
+/*
+ * vm_page_rename:
+ *
+ * Move the given memory entry from its
+ * current object to the specified target object/offset.
+ *
+ * The object must be locked.
+ */
+void vm_page_rename(mem, new_object, new_offset)
+ register vm_page_t mem;
+ register vm_object_t new_object;
+ vm_offset_t new_offset;
+{
+ if (mem->object == new_object)
+ return;
+
+ vm_page_lock_queues(); /* keep page from moving out from
+ under pageout daemon */
+ vm_page_remove(mem);
+ vm_page_insert(mem, new_object, new_offset);
+ vm_page_unlock_queues();
+}
+
+void vm_page_init(mem, object, offset)
+ vm_page_t mem;
+ vm_object_t object;
+ vm_offset_t offset;
+{
+#ifdef DEBUG
+#define vm_page_init(mem, object, offset) {\
+ (mem)->busy = TRUE; \
+ (mem)->tabled = FALSE; \
+ vm_page_insert((mem), (object), (offset)); \
+ (mem)->absent = FALSE; \
+ (mem)->fictitious = FALSE; \
+ (mem)->page_lock = VM_PROT_NONE; \
+ (mem)->unlock_request = VM_PROT_NONE; \
+ (mem)->laundry = FALSE; \
+ (mem)->active = FALSE; \
+ (mem)->inactive = FALSE; \
+ (mem)->wire_count = 0; \
+ (mem)->clean = TRUE; \
+ (mem)->copy_on_write = FALSE; \
+ (mem)->fake = TRUE; \
+ (mem)->pagerowned = FALSE; \
+ (mem)->ptpage = FALSE; \
+ }
+#else
+#define vm_page_init(mem, object, offset) {\
+ (mem)->busy = TRUE; \
+ (mem)->tabled = FALSE; \
+ vm_page_insert((mem), (object), (offset)); \
+ (mem)->absent = FALSE; \
+ (mem)->fictitious = FALSE; \
+ (mem)->page_lock = VM_PROT_NONE; \
+ (mem)->unlock_request = VM_PROT_NONE; \
+ (mem)->laundry = FALSE; \
+ (mem)->active = FALSE; \
+ (mem)->inactive = FALSE; \
+ (mem)->wire_count = 0; \
+ (mem)->clean = TRUE; \
+ (mem)->copy_on_write = FALSE; \
+ (mem)->fake = TRUE; \
+ }
+#endif
+
+ vm_page_init(mem, object, offset);
+}
+
+/*
+ * vm_page_alloc:
+ *
+ * Allocate and return a memory cell associated
+ * with this VM object/offset pair.
+ *
+ * Object must be locked.
+ */
+vm_page_t vm_page_alloc(object, offset)
+ vm_object_t object;
+ vm_offset_t offset;
+{
+ register vm_page_t mem;
+ int spl;
+
+ spl = splimp(); /* XXX */
+ simple_lock(&vm_page_queue_free_lock);
+ if (queue_empty(&vm_page_queue_free)) {
+ simple_unlock(&vm_page_queue_free_lock);
+ splx(spl);
+ return(NULL);
+ }
+
+ queue_remove_first(&vm_page_queue_free, mem, vm_page_t, pageq);
+
+ vm_page_free_count--;
+ simple_unlock(&vm_page_queue_free_lock);
+ splx(spl);
+
+ vm_page_init(mem, object, offset);
+
+ /*
+ * Decide if we should poke the pageout daemon.
+ * We do this if the free count is less than the low
+ * water mark, or if the free count is less than the high
+ * water mark (but above the low water mark) and the inactive
+ * count is less than its target.
+ *
+ * We don't have the counts locked ... if they change a little,
+ * it doesn't really matter.
+ */
+
+ if ((vm_page_free_count < vm_page_free_min) ||
+ ((vm_page_free_count < vm_page_free_target) &&
+ (vm_page_inactive_count < vm_page_inactive_target)))
+ thread_wakeup(&vm_pages_needed);
+ return(mem);
+}
+
+/*
+ * vm_page_free:
+ *
+ * Returns the given page to the free list,
+ * disassociating it with any VM object.
+ *
+ * Object and page must be locked prior to entry.
+ */
+void vm_page_free(mem)
+ register vm_page_t mem;
+{
+ vm_page_remove(mem);
+ if (mem->active) {
+ queue_remove(&vm_page_queue_active, mem, vm_page_t, pageq);
+ mem->active = FALSE;
+ vm_page_active_count--;
+ }
+
+ if (mem->inactive) {
+ queue_remove(&vm_page_queue_inactive, mem, vm_page_t, pageq);
+ mem->inactive = FALSE;
+ vm_page_inactive_count--;
+ }
+
+ if (!mem->fictitious) {
+ int spl;
+
+ spl = splimp();
+ simple_lock(&vm_page_queue_free_lock);
+ queue_enter(&vm_page_queue_free, mem, vm_page_t, pageq);
+
+ vm_page_free_count++;
+ simple_unlock(&vm_page_queue_free_lock);
+ splx(spl);
+ }
+}
+
+/*
+ * vm_page_wire:
+ *
+ * Mark this page as wired down by yet
+ * another map, removing it from paging queues
+ * as necessary.
+ *
+ * The page queues must be locked.
+ */
+void vm_page_wire(mem)
+ register vm_page_t mem;
+{
+ VM_PAGE_CHECK(mem);
+
+ if (mem->wire_count == 0) {
+ if (mem->active) {
+ queue_remove(&vm_page_queue_active, mem, vm_page_t,
+ pageq);
+ vm_page_active_count--;
+ mem->active = FALSE;
+ }
+ if (mem->inactive) {
+ queue_remove(&vm_page_queue_inactive, mem, vm_page_t,
+ pageq);
+ vm_page_inactive_count--;
+ mem->inactive = FALSE;
+ }
+ vm_page_wire_count++;
+ }
+ mem->wire_count++;
+}
+
+/*
+ * vm_page_unwire:
+ *
+ * Release one wiring of this page, potentially
+ * enabling it to be paged again.
+ *
+ * The page queues must be locked.
+ */
+void vm_page_unwire(mem)
+ register vm_page_t mem;
+{
+ VM_PAGE_CHECK(mem);
+
+ mem->wire_count--;
+ if (mem->wire_count == 0) {
+ queue_enter(&vm_page_queue_active, mem, vm_page_t, pageq);
+ vm_page_active_count++;
+ mem->active = TRUE;
+ vm_page_wire_count--;
+ }
+}
+
+/*
+ * vm_page_deactivate:
+ *
+ * Returns the given page to the inactive list,
+ * indicating that no physical maps have access
+ * to this page. [Used by the physical mapping system.]
+ *
+ * The page queues must be locked.
+ */
+void vm_page_deactivate(m)
+ register vm_page_t m;
+{
+ VM_PAGE_CHECK(m);
+
+ /*
+ * Only move active pages -- ignore locked or already
+ * inactive ones.
+ */
+
+ if (m->active) {
+ pmap_clear_reference(VM_PAGE_TO_PHYS(m));
+ queue_remove(&vm_page_queue_active, m, vm_page_t, pageq);
+ queue_enter(&vm_page_queue_inactive, m, vm_page_t, pageq);
+ m->active = FALSE;
+ m->inactive = TRUE;
+ vm_page_active_count--;
+ vm_page_inactive_count++;
+ if (pmap_is_modified(VM_PAGE_TO_PHYS(m)))
+ m->clean = FALSE;
+ m->laundry = !m->clean;
+ }
+}
+
+/*
+ * vm_page_activate:
+ *
+ * Put the specified page on the active list (if appropriate).
+ *
+ * The page queues must be locked.
+ */
+
+void vm_page_activate(m)
+ register vm_page_t m;
+{
+ VM_PAGE_CHECK(m);
+
+ if (m->inactive) {
+ queue_remove(&vm_page_queue_inactive, m, vm_page_t,
+ pageq);
+ vm_page_inactive_count--;
+ m->inactive = FALSE;
+ }
+ if (m->wire_count == 0) {
+ if (m->active)
+ panic("vm_page_activate: already active");
+
+ queue_enter(&vm_page_queue_active, m, vm_page_t, pageq);
+ m->active = TRUE;
+ vm_page_active_count++;
+ }
+}
+
+/*
+ * vm_page_zero_fill:
+ *
+ * Zero-fill the specified page.
+ * Written as a standard pagein routine, to
+ * be used by the zero-fill object.
+ */
+
+boolean_t vm_page_zero_fill(m)
+ vm_page_t m;
+{
+ VM_PAGE_CHECK(m);
+
+ pmap_zero_page(VM_PAGE_TO_PHYS(m));
+ return(TRUE);
+}
+
+/*
+ * vm_page_copy:
+ *
+ * Copy one page to another
+ */
+
+void vm_page_copy(src_m, dest_m)
+ vm_page_t src_m;
+ vm_page_t dest_m;
+{
+ VM_PAGE_CHECK(src_m);
+ VM_PAGE_CHECK(dest_m);
+
+ pmap_copy_page(VM_PAGE_TO_PHYS(src_m), VM_PAGE_TO_PHYS(dest_m));
+}
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