/* * 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. * * from: @(#)vm_page.c 7.4 (Berkeley) 5/7/91 * $Id: vm_page.c,v 1.4 1994/08/07 13:10:41 davidg Exp $ */ /* * 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 #include #include #include #include #include #include /* * Associated with page of user-allocatable memory is a * page structure. */ struct pglist *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 */ struct pglist vm_page_queue_free; struct pglist vm_page_queue_active; struct pglist vm_page_queue_inactive; simple_lock_data_t vm_page_queue_lock; simple_lock_data_t vm_page_queue_free_lock; /* has physical page allocation been initialized? */ boolean_t vm_page_startup_initialized; vm_page_t vm_page_array; long first_page; long last_page; vm_offset_t first_phys_addr; vm_offset_t last_phys_addr; vm_size_t page_mask; int page_shift; /* * 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 cnt.v_page_size. */ void vm_set_page_size() { if (cnt.v_page_size == 0) cnt.v_page_size = DEFAULT_PAGE_SIZE; page_mask = cnt.v_page_size - 1; if ((page_mask & cnt.v_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) == cnt.v_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(starta, enda, vaddr) register vm_offset_t starta; vm_offset_t enda; register vm_offset_t vaddr; { register vm_offset_t mapped; register vm_page_t m; register struct pglist *bucket; vm_size_t npages, page_range; register vm_offset_t new_start; int i; vm_offset_t pa; int nblocks; vm_offset_t first_managed_page; int size; extern vm_offset_t kentry_data; extern vm_size_t kentry_data_size; extern vm_offset_t phys_avail[]; /* the biggest memory array is the second group of pages */ vm_offset_t start; vm_offset_t biggestone, biggestsize; vm_offset_t total; total = 0; biggestsize = 0; biggestone = 0; nblocks = 0; vaddr = round_page(vaddr); for (i = 0; phys_avail[i + 1]; i += 2) { phys_avail[i] = round_page(phys_avail[i]); phys_avail[i+1] = trunc_page(phys_avail[i+1]); } for (i = 0; phys_avail[i + 1]; i += 2) { int size = phys_avail[i+1] - phys_avail[i]; if (size > biggestsize) { biggestone = i; biggestsize = size; } ++nblocks; total += size; } start = phys_avail[biggestone]; /* * 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. */ TAILQ_INIT(&vm_page_queue_free); TAILQ_INIT(&vm_page_queue_active); TAILQ_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 = (struct pglist *)vaddr; bucket = vm_page_buckets; if (vm_page_bucket_count == 0) { vm_page_bucket_count = 1; while (vm_page_bucket_count < atop(total)) vm_page_bucket_count <<= 1; } vm_page_hash_mask = vm_page_bucket_count - 1; /* * Validate these addresses. */ new_start = start + vm_page_bucket_count * sizeof(struct pglist); new_start = round_page(new_start); 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 = 0; i< vm_page_bucket_count; i++) { TAILQ_INIT(bucket); bucket++; } simple_lock_init(&bucket_lock); /* * round (or truncate) the addresses to our page size. */ /* * 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)); start = round_page(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). */ npages = (total - (start - phys_avail[biggestone])) / (PAGE_SIZE + sizeof(struct vm_page)); first_page = phys_avail[0] / PAGE_SIZE; page_range = (phys_avail[(nblocks-1)*2 + 1] - phys_avail[0]) / PAGE_SIZE; /* * Initialize the mem entry structures now, and * put them in the free queue. */ vm_page_array = (vm_page_t) vaddr; mapped = vaddr; /* * Validate these addresses. */ new_start = round_page(start + page_range * sizeof (struct vm_page)); mapped = pmap_map(mapped, start, new_start, VM_PROT_READ|VM_PROT_WRITE); start = new_start; first_managed_page = start / PAGE_SIZE; /* * Clear all of the page structures */ bzero((caddr_t)vm_page_array, page_range * sizeof(struct vm_page)); cnt.v_page_count = 0; cnt.v_free_count= 0; for (i = 0; phys_avail[i + 1] && npages > 0; i += 2) { if (i == biggestone) pa = ptoa(first_managed_page); else pa = phys_avail[i]; while (pa < phys_avail[i + 1] && npages-- > 0) { ++cnt.v_page_count; ++cnt.v_free_count; m = PHYS_TO_VM_PAGE(pa); m->flags = 0; m->object = 0; m->phys_addr = pa; m->hold_count = 0; TAILQ_INSERT_TAIL(&vm_page_queue_free, m, pageq); 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. */ inline const int vm_page_hash(object, offset) vm_object_t object; vm_offset_t offset; { return ((unsigned)object + offset/NBPG) & 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 struct pglist *bucket; int s; VM_PAGE_CHECK(mem); if (mem->flags & PG_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)]; s = splhigh(); simple_lock(&bucket_lock); TAILQ_INSERT_TAIL(bucket, mem, hashq); simple_unlock(&bucket_lock); (void) splx(s); /* * Now link into the object's list of backed pages. */ TAILQ_INSERT_TAIL(&object->memq, mem, listq); mem->flags |= PG_TABLED; /* * And show that the object has one more resident * page. */ object->resident_page_count++; } /* * vm_page_remove: [ internal use only ] * NOTE: used by device pager as well -wfj * * 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 struct pglist *bucket; int s; VM_PAGE_CHECK(mem); if (!(mem->flags & PG_TABLED)) return; /* * Remove from the object_object/offset hash table */ bucket = &vm_page_buckets[vm_page_hash(mem->object, mem->offset)]; s = splhigh(); simple_lock(&bucket_lock); TAILQ_REMOVE(bucket, mem, hashq); simple_unlock(&bucket_lock); (void) splx(s); /* * Now remove from the object's list of backed pages. */ TAILQ_REMOVE(&mem->object->memq, mem, listq); /* * And show that the object has one fewer resident * page. */ mem->object->resident_page_count--; mem->flags &= ~PG_TABLED; } /* * 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 struct pglist *bucket; int s; /* * Search the hash table for this object/offset pair */ bucket = &vm_page_buckets[vm_page_hash(object, offset)]; s = splhigh(); simple_lock(&bucket_lock); for (mem = bucket->tqh_first; mem != NULL; mem = mem->hashq.tqe_next) { VM_PAGE_CHECK(mem); if ((mem->object == object) && (mem->offset == offset)) { simple_unlock(&bucket_lock); splx(s); return(mem); } } simple_unlock(&bucket_lock); splx(s); 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(); } /* * 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 s; s = splhigh(); simple_lock(&vm_page_queue_free_lock); if ( object != kernel_object && object != kmem_object && curproc != pageproc && curproc != &proc0 && cnt.v_free_count < cnt.v_free_reserved) { simple_unlock(&vm_page_queue_free_lock); splx(s); /* * this wakeup seems unnecessary, but there is code that * might just check to see if there are free pages, and * punt if there aren't. VM_WAIT does this too, but * redundant wakeups aren't that bad... */ if (curproc != pageproc) wakeup((caddr_t) &vm_pages_needed); return(NULL); } if (( mem = vm_page_queue_free.tqh_first) == 0) { simple_unlock(&vm_page_queue_free_lock); printf("No pages???\n"); splx(s); /* * comment above re: wakeups applies here too... */ if (curproc != pageproc) wakeup((caddr_t) &vm_pages_needed); return(NULL); } TAILQ_REMOVE(&vm_page_queue_free, mem, pageq); cnt.v_free_count--; simple_unlock(&vm_page_queue_free_lock); VM_PAGE_INIT(mem, object, offset); splx(s); /* * don't wakeup too often, so we wakeup the pageout daemon when * we would be nearly out of memory. */ if (curproc != pageproc && (cnt.v_free_count < cnt.v_free_reserved)) wakeup((caddr_t) &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; { int s; s = splhigh(); vm_page_remove(mem); if (mem->flags & PG_ACTIVE) { TAILQ_REMOVE(&vm_page_queue_active, mem, pageq); mem->flags &= ~PG_ACTIVE; cnt.v_active_count--; } if (mem->flags & PG_INACTIVE) { TAILQ_REMOVE(&vm_page_queue_inactive, mem, pageq); mem->flags &= ~PG_INACTIVE; cnt.v_inactive_count--; } if (!(mem->flags & PG_FICTITIOUS)) { simple_lock(&vm_page_queue_free_lock); if (mem->wire_count) { cnt.v_wire_count--; mem->wire_count = 0; } TAILQ_INSERT_TAIL(&vm_page_queue_free, mem, pageq); cnt.v_free_count++; simple_unlock(&vm_page_queue_free_lock); splx(s); /* * if pageout daemon needs pages, then tell it that there * are some free. */ if (vm_pageout_pages_needed) wakeup((caddr_t)&vm_pageout_pages_needed); /* * wakeup processes that are waiting on memory if we * hit a high water mark. */ if (cnt.v_free_count == cnt.v_free_min) { wakeup((caddr_t)&cnt.v_free_count); } /* * wakeup scheduler process if we have lots of memory. * this process will swapin processes. */ if (cnt.v_free_count == cnt.v_free_target) { wakeup((caddr_t)&proc0); } } else { splx(s); } wakeup((caddr_t) mem); } /* * 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; { int s; VM_PAGE_CHECK(mem); if (mem->wire_count == 0) { s = splhigh(); if (mem->flags & PG_ACTIVE) { TAILQ_REMOVE(&vm_page_queue_active, mem, pageq); cnt.v_active_count--; mem->flags &= ~PG_ACTIVE; } if (mem->flags & PG_INACTIVE) { TAILQ_REMOVE(&vm_page_queue_inactive, mem, pageq); cnt.v_inactive_count--; mem->flags &= ~PG_INACTIVE; } splx(s); cnt.v_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; { int s; VM_PAGE_CHECK(mem); s = splhigh(); if( mem->wire_count) mem->wire_count--; if (mem->wire_count == 0) { TAILQ_INSERT_TAIL(&vm_page_queue_active, mem, pageq); cnt.v_active_count++; mem->flags |= PG_ACTIVE; cnt.v_wire_count--; } splx(s); } /* * 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; { int spl; VM_PAGE_CHECK(m); /* * Only move active pages -- ignore locked or already * inactive ones. * * XXX: sometimes we get pages which aren't wired down * or on any queue - we need to put them on the inactive * queue also, otherwise we lose track of them. * Paul Mackerras (paulus@cs.anu.edu.au) 9-Jan-93. */ spl = splhigh(); if (!(m->flags & PG_INACTIVE) && m->wire_count == 0 && m->hold_count == 0) { pmap_clear_reference(VM_PAGE_TO_PHYS(m)); if (m->flags & PG_ACTIVE) { TAILQ_REMOVE(&vm_page_queue_active, m, pageq); m->flags &= ~PG_ACTIVE; cnt.v_active_count--; } TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq); m->flags |= PG_INACTIVE; cnt.v_inactive_count++; #define NOT_DEACTIVATE_PROTECTS #ifndef NOT_DEACTIVATE_PROTECTS pmap_page_protect(VM_PAGE_TO_PHYS(m), VM_PROT_NONE); #else if ((m->flags & PG_CLEAN) && pmap_is_modified(VM_PAGE_TO_PHYS(m))) m->flags &= ~PG_CLEAN; #endif if ((m->flags & PG_CLEAN) == 0) m->flags |= PG_LAUNDRY; } splx(spl); } /* * 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; { int s; VM_PAGE_CHECK(m); s = splhigh(); if (m->flags & PG_INACTIVE) { TAILQ_REMOVE(&vm_page_queue_inactive, m, pageq); cnt.v_inactive_count--; m->flags &= ~PG_INACTIVE; } if (m->wire_count == 0) { if (m->flags & PG_ACTIVE) panic("vm_page_activate: already active"); TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq); m->flags |= PG_ACTIVE; TAILQ_REMOVE(&m->object->memq, m, listq); TAILQ_INSERT_TAIL(&m->object->memq, m, listq); m->act_count = 1; cnt.v_active_count++; } splx(s); } /* * 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)); }