/* * 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 1.128 1999/03/19 05:21:03 alc 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 #include #include #include #include #include #include #include #include #include static void vm_page_queue_init __P((void)); static vm_page_t vm_page_select_cache __P((vm_object_t, vm_pindex_t)); /* * Associated with page of user-allocatable memory is a * page structure. */ static struct vm_page **vm_page_buckets; /* Array of buckets */ static int vm_page_bucket_count; /* How big is array? */ static int vm_page_hash_mask; /* Mask for hash function */ static volatile int vm_page_bucket_generation; struct pglist vm_page_queue_free[PQ_L2_SIZE] = {{0}}; struct pglist vm_page_queue_active = {0}; struct pglist vm_page_queue_inactive = {0}; struct pglist vm_page_queue_cache[PQ_L2_SIZE] = {{0}}; static int no_queue=0; struct vpgqueues vm_page_queues[PQ_COUNT] = {{0}}; static int pqcnt[PQ_COUNT] = {0}; static void vm_page_queue_init(void) { int i; vm_page_queues[PQ_NONE].pl = NULL; vm_page_queues[PQ_NONE].cnt = &no_queue; for(i=0;i biggestsize) { biggestone = i; biggestsize = size; } ++nblocks; total += size; } start = phys_avail[biggestone]; /* * Initialize the queue headers for the free queue, the active queue * and the inactive queue. */ vm_page_queue_init(); /* * 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. * * We make the hash table approximately 2x the number of pages to * reduce the chain length. This is about the same size using the * singly-linked list as the 1x hash table we were using before * using TAILQ but the chain length will be smaller. * * Note: This computation can be tweaked if desired. */ vm_page_buckets = (struct vm_page **)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_bucket_count <<= 1; vm_page_hash_mask = vm_page_bucket_count - 1; /* * Validate these addresses. */ new_start = start + vm_page_bucket_count * sizeof(struct vm_page *); new_start = round_page(new_start); mapped = round_page(vaddr); vaddr = pmap_map(mapped, start, new_start, VM_PROT_READ | VM_PROT_WRITE); start = new_start; vaddr = round_page(vaddr); bzero((caddr_t) mapped, vaddr - mapped); for (i = 0; i < vm_page_bucket_count; i++) { *bucket = NULL; bucket++; } /* * Compute the number of pages of memory that will be available for * use (taking into account the overhead of a page structure per * page). */ first_page = phys_avail[0] / PAGE_SIZE; last_page = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE; page_range = last_page - (phys_avail[0] / PAGE_SIZE); npages = (total - (page_range * sizeof(struct vm_page)) - (start - phys_avail[biggestone])) / 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)); vm_page_array_size = page_range; /* * Construct the free queue(s) in descending order (by physical * address) so that the first 16MB of physical memory is allocated * last rather than first. On large-memory machines, this avoids * the exhaustion of low physical memory before isa_dmainit has run. */ 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->phys_addr = pa; m->flags = 0; m->pc = (pa >> PAGE_SHIFT) & PQ_L2_MASK; m->queue = m->pc + PQ_FREE; TAILQ_INSERT_HEAD(vm_page_queues[m->queue].pl, m, pageq); ++(*vm_page_queues[m->queue].lcnt); pa += PAGE_SIZE; } } 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. * This routine may not block. * * We try to randomize the hash based on the object to spread the pages * out in the hash table without it costing us too much. */ static __inline int vm_page_hash(object, pindex) vm_object_t object; vm_pindex_t pindex; { int i = ((uintptr_t)object + pindex) ^ object->hash_rand; return(i & vm_page_hash_mask); } /* * vm_page_insert: [ internal use only ] * * Inserts the given mem entry into the object and object list. * * The pagetables are not updated but will presumably fault the page * in if necessary, or if a kernel page the caller will at some point * enter the page into the kernel's pmap. We are not allowed to block * here so we *can't* do this anyway. * * The object and page must be locked, and must be splhigh. * This routine may not block. */ void vm_page_insert(m, object, pindex) register vm_page_t m; register vm_object_t object; register vm_pindex_t pindex; { register struct vm_page **bucket; if (m->object != NULL) panic("vm_page_insert: already inserted"); /* * Record the object/offset pair in this page */ m->object = object; m->pindex = pindex; /* * Insert it into the object_object/offset hash table */ bucket = &vm_page_buckets[vm_page_hash(object, pindex)]; m->hnext = *bucket; *bucket = m; vm_page_bucket_generation++; /* * Now link into the object's list of backed pages. */ TAILQ_INSERT_TAIL(&object->memq, m, listq); m->object->generation++; if (m->wire_count) object->wire_count++; if ((m->queue - m->pc) == PQ_CACHE) object->cache_count++; /* * show that the object has one more resident page. */ object->resident_page_count++; /* * Since we are inserting a new and possibly dirty page, * update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags. */ if (m->flags & PG_WRITEABLE) vm_object_set_flag(object, OBJ_WRITEABLE|OBJ_MIGHTBEDIRTY); } /* * vm_page_remove: * NOTE: used by device pager as well -wfj * * Removes the given mem entry from the object/offset-page * table and the object page list, but do not invalidate/terminate * the backing store. * * The object and page must be locked, and at splhigh. * The underlying pmap entry (if any) is NOT removed here. * This routine may not block. */ void vm_page_remove(m) vm_page_t m; { vm_object_t object; if (m->object == NULL) return; #if !defined(MAX_PERF) if ((m->flags & PG_BUSY) == 0) { panic("vm_page_remove: page not busy"); } #endif /* * Basically destroy the page. */ vm_page_wakeup(m); object = m->object; if (m->wire_count) object->wire_count--; if ((m->queue - m->pc) == PQ_CACHE) object->cache_count--; /* * Remove from the object_object/offset hash table. The object * must be on the hash queue, we will panic if it isn't * * Note: we must NULL-out m->hnext to prevent loops in detached * buffers with vm_page_lookup(). */ { struct vm_page **bucket; bucket = &vm_page_buckets[vm_page_hash(m->object, m->pindex)]; while (*bucket != m) { #if !defined(MAX_PERF) if (*bucket == NULL) panic("vm_page_remove(): page not found in hash"); #endif bucket = &(*bucket)->hnext; } *bucket = m->hnext; m->hnext = NULL; vm_page_bucket_generation++; } /* * Now remove from the object's list of backed pages. */ TAILQ_REMOVE(&object->memq, m, listq); /* * And show that the object has one fewer resident page. */ object->resident_page_count--; object->generation++; m->object = NULL; } /* * vm_page_lookup: * * Returns the page associated with the object/offset * pair specified; if none is found, NULL is returned. * * NOTE: the code below does not lock. It will operate properly if * an interrupt makes a change, but the generation algorithm will not * operate properly in an SMP environment where both cpu's are able to run * kernel code simultaniously. * * The object must be locked. No side effects. * This routine may not block. * This is a critical path routine */ vm_page_t vm_page_lookup(object, pindex) register vm_object_t object; register vm_pindex_t pindex; { register vm_page_t m; register struct vm_page **bucket; int generation; /* * Search the hash table for this object/offset pair */ retry: generation = vm_page_bucket_generation; bucket = &vm_page_buckets[vm_page_hash(object, pindex)]; for (m = *bucket; m != NULL; m = m->hnext) { if ((m->object == object) && (m->pindex == pindex)) { if (vm_page_bucket_generation != generation) goto retry; return (m); } } if (vm_page_bucket_generation != generation) goto retry; 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. * This routine may not block. * * Note: this routine will raise itself to splvm(), the caller need not. * * Note: swap associated with the page must be invalidated by the move. We * have to do this for several reasons: (1) we aren't freeing the * page, (2) we are dirtying the page, (3) the VM system is probably * moving the page from object A to B, and will then later move * the backing store from A to B and we can't have a conflict. * * Note: we *always* dirty the page. It is necessary both for the * fact that we moved it, and because we may be invalidating * swap. If the page is on the cache, we have to deactivate it * or vm_page_dirty() will panic. Dirty pages are not allowed * on the cache. */ void vm_page_rename(m, new_object, new_pindex) register vm_page_t m; register vm_object_t new_object; vm_pindex_t new_pindex; { int s; s = splvm(); vm_page_remove(m); vm_page_insert(m, new_object, new_pindex); if (m->queue - m->pc == PQ_CACHE) vm_page_deactivate(m); vm_page_dirty(m); splx(s); } /* * vm_page_unqueue_nowakeup: * * vm_page_unqueue() without any wakeup * * This routine must be called at splhigh(). * This routine may not block. */ void vm_page_unqueue_nowakeup(m) vm_page_t m; { int queue = m->queue; struct vpgqueues *pq; if (queue != PQ_NONE) { pq = &vm_page_queues[queue]; m->queue = PQ_NONE; TAILQ_REMOVE(pq->pl, m, pageq); (*pq->cnt)--; (*pq->lcnt)--; if ((queue - m->pc) == PQ_CACHE) { if (m->object) m->object->cache_count--; } } } /* * vm_page_unqueue: * * Remove a page from its queue. * * This routine must be called at splhigh(). * This routine may not block. */ void vm_page_unqueue(m) vm_page_t m; { int queue = m->queue; struct vpgqueues *pq; if (queue != PQ_NONE) { m->queue = PQ_NONE; pq = &vm_page_queues[queue]; TAILQ_REMOVE(pq->pl, m, pageq); (*pq->cnt)--; (*pq->lcnt)--; if ((queue - m->pc) == PQ_CACHE) { if ((cnt.v_cache_count + cnt.v_free_count) < (cnt.v_free_reserved + cnt.v_cache_min)) pagedaemon_wakeup(); if (m->object) m->object->cache_count--; } } } #if PQ_L2_SIZE > 1 /* * vm_page_list_find: * * Find a page on the specified queue with color optimization. * * The page coloring optimization attempts to locate a page * that does not overload other nearby pages in the object in * the cpu's L1 or L2 caches. We need this optmization because * cpu caches tend to be physical caches, while object spaces tend * to be virtual. * * This routine must be called at splvm(). * This routine may not block. * * This routine may only be called from the vm_page_list_find() macro * in vm_page.h */ vm_page_t _vm_page_list_find(basequeue, index) int basequeue, index; { int i; vm_page_t m = NULL; struct vpgqueues *pq; pq = &vm_page_queues[basequeue]; /* * Note that for the first loop, index+i and index-i wind up at the * same place. Even though this is not totally optimal, we've already * blown it by missing the cache case so we do not care. */ for(i = PQ_L2_SIZE / 2; i > 0; --i) { if ((m = TAILQ_FIRST(pq[(index + i) & PQ_L2_MASK].pl)) != NULL) break; if ((m = TAILQ_FIRST(pq[(index - i) & PQ_L2_MASK].pl)) != NULL) break; } return(m); } #endif /* * vm_page_select_cache: * * Find a page on the cache queue with color optimization. As pages * might be found, but not applicable, they are deactivated. This * keeps us from using potentially busy cached pages. * * This routine must be called at splvm(). * This routine may not block. */ vm_page_t vm_page_select_cache(object, pindex) vm_object_t object; vm_pindex_t pindex; { vm_page_t m; while (TRUE) { m = vm_page_list_find( PQ_CACHE, (pindex + object->pg_color) & PQ_L2_MASK, FALSE ); if (m && ((m->flags & PG_BUSY) || m->busy || m->hold_count || m->wire_count)) { vm_page_deactivate(m); continue; } return m; } } /* * vm_page_select_free: * * Find a free or zero page, with specified preference. We attempt to * inline the nominal case and fall back to _vm_page_select_free() * otherwise. * * This routine must be called at splvm(). * This routine may not block. */ static __inline vm_page_t vm_page_select_free(vm_object_t object, vm_pindex_t pindex, boolean_t prefer_zero) { vm_page_t m; m = vm_page_list_find( PQ_FREE, (pindex + object->pg_color) & PQ_L2_MASK, prefer_zero ); return(m); } /* * vm_page_alloc: * * Allocate and return a memory cell associated * with this VM object/offset pair. * * page_req classes: * VM_ALLOC_NORMAL normal process request * VM_ALLOC_SYSTEM system *really* needs a page * VM_ALLOC_INTERRUPT interrupt time request * VM_ALLOC_ZERO zero page * * Object must be locked. * This routine may not block. * * Additional special handling is required when called from an * interrupt (VM_ALLOC_INTERRUPT). We are not allowed to mess with * the page cache in this case. */ vm_page_t vm_page_alloc(object, pindex, page_req) vm_object_t object; vm_pindex_t pindex; int page_req; { register vm_page_t m = NULL; int s; KASSERT(!vm_page_lookup(object, pindex), ("vm_page_alloc: page already allocated")); /* * The pager is allowed to eat deeper into the free page list. */ if ((curproc == pageproc) && (page_req != VM_ALLOC_INTERRUPT)) { page_req = VM_ALLOC_SYSTEM; }; s = splvm(); loop: if (cnt.v_free_count > cnt.v_free_reserved) { /* * Allocate from the free queue if there are plenty of pages * in it. */ if (page_req == VM_ALLOC_ZERO) m = vm_page_select_free(object, pindex, TRUE); else m = vm_page_select_free(object, pindex, FALSE); } else if ( (page_req == VM_ALLOC_SYSTEM && cnt.v_cache_count == 0 && cnt.v_free_count > cnt.v_interrupt_free_min) || (page_req == VM_ALLOC_INTERRUPT && cnt.v_free_count > 0) ) { /* * Interrupt or system, dig deeper into the free list. */ m = vm_page_select_free(object, pindex, FALSE); } else if (page_req != VM_ALLOC_INTERRUPT) { /* * Allocateable from cache (non-interrupt only). On success, * we must free the page and try again, thus ensuring that * cnt.v_*_free_min counters are replenished. */ m = vm_page_select_cache(object, pindex); if (m == NULL) { splx(s); #if defined(DIAGNOSTIC) if (cnt.v_cache_count > 0) printf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", cnt.v_cache_count); #endif vm_pageout_deficit++; pagedaemon_wakeup(); return (NULL); } KASSERT(m->dirty == 0, ("Found dirty cache page %p", m)); vm_page_busy(m); vm_page_protect(m, VM_PROT_NONE); vm_page_free(m); goto loop; } else { /* * Not allocateable from cache from interrupt, give up. */ splx(s); vm_pageout_deficit++; pagedaemon_wakeup(); return (NULL); } /* * At this point we had better have found a good page. */ KASSERT( m != NULL, ("vm_page_alloc(): missing page on free queue\n") ); /* * Remove from free queue */ { struct vpgqueues *pq = &vm_page_queues[m->queue]; TAILQ_REMOVE(pq->pl, m, pageq); (*pq->cnt)--; (*pq->lcnt)--; } /* * Initialize structure. Only the PG_ZERO flag is inherited. */ if (m->flags & PG_ZERO) { vm_page_zero_count--; m->flags = PG_ZERO | PG_BUSY; } else { m->flags = PG_BUSY; } m->wire_count = 0; m->hold_count = 0; m->act_count = 0; m->busy = 0; m->valid = 0; m->dirty = 0; m->queue = PQ_NONE; /* * vm_page_insert() is safe prior to the splx(). Note also that * inserting a page here does not insert it into the pmap (which * could cause us to block allocating memory). We cannot block * anywhere. */ vm_page_insert(m, object, pindex); /* * Don't wakeup too often - wakeup the pageout daemon when * we would be nearly out of memory. */ if (((cnt.v_free_count + cnt.v_cache_count) < (cnt.v_free_reserved + cnt.v_cache_min)) || (cnt.v_free_count < cnt.v_pageout_free_min)) pagedaemon_wakeup(); splx(s); return (m); } /* * vm_wait: (also see VM_WAIT macro) * * Block until free pages are available for allocation */ void vm_wait() { int s; s = splvm(); if (curproc == pageproc) { vm_pageout_pages_needed = 1; tsleep(&vm_pageout_pages_needed, PSWP, "vmwait", 0); } else { if (!vm_pages_needed) { vm_pages_needed++; wakeup(&vm_pages_needed); } tsleep(&cnt.v_free_count, PVM, "vmwait", 0); } splx(s); } /* * vm_await: (also see VM_AWAIT macro) * * asleep on an event that will signal when free pages are available * for allocation. */ void vm_await() { int s; s = splvm(); if (curproc == pageproc) { vm_pageout_pages_needed = 1; asleep(&vm_pageout_pages_needed, PSWP, "vmwait", 0); } else { if (!vm_pages_needed) { vm_pages_needed++; wakeup(&vm_pages_needed); } asleep(&cnt.v_free_count, PVM, "vmwait", 0); } splx(s); } #if 0 /* * vm_page_sleep: * * Block until page is no longer busy. */ int vm_page_sleep(vm_page_t m, char *msg, char *busy) { int slept = 0; if ((busy && *busy) || (m->flags & PG_BUSY)) { int s; s = splvm(); if ((busy && *busy) || (m->flags & PG_BUSY)) { vm_page_flag_set(m, PG_WANTED); tsleep(m, PVM, msg, 0); slept = 1; } splx(s); } return slept; } #endif #if 0 /* * vm_page_asleep: * * Similar to vm_page_sleep(), but does not block. Returns 0 if * the page is not busy, or 1 if the page is busy. * * This routine has the side effect of calling asleep() if the page * was busy (1 returned). */ int vm_page_asleep(vm_page_t m, char *msg, char *busy) { int slept = 0; if ((busy && *busy) || (m->flags & PG_BUSY)) { int s; s = splvm(); if ((busy && *busy) || (m->flags & PG_BUSY)) { vm_page_flag_set(m, PG_WANTED); asleep(m, PVM, msg, 0); slept = 1; } splx(s); } return slept; } #endif /* * vm_page_activate: * * Put the specified page on the active list (if appropriate). * * The page queues must be locked. * This routine may not block. */ void vm_page_activate(m) register vm_page_t m; { int s; s = splvm(); if (m->queue != PQ_ACTIVE) { if ((m->queue - m->pc) == PQ_CACHE) cnt.v_reactivated++; vm_page_unqueue(m); if (m->wire_count == 0) { m->queue = PQ_ACTIVE; ++(*vm_page_queues[PQ_ACTIVE].lcnt); TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq); if (m->act_count < ACT_INIT) m->act_count = ACT_INIT; cnt.v_active_count++; } } else { if (m->act_count < ACT_INIT) m->act_count = ACT_INIT; } splx(s); } /* * vm_page_free_wakeup: * * Helper routine for vm_page_free_toq() and vm_page_cache(). This * routine is called when a page has been added to the cache or free * queues. * * This routine may not block. * This routine must be called at splvm() */ static __inline void vm_page_free_wakeup() { /* * if pageout daemon needs pages, then tell it that there are * some free. */ if (vm_pageout_pages_needed) { wakeup(&vm_pageout_pages_needed); vm_pageout_pages_needed = 0; } /* * wakeup processes that are waiting on memory if we hit a * high water mark. And wakeup scheduler process if we have * lots of memory. this process will swapin processes. */ if (vm_pages_needed && ((cnt.v_free_count + cnt.v_cache_count) >= cnt.v_free_min)) { wakeup(&cnt.v_free_count); vm_pages_needed = 0; } } /* * vm_page_free_toq: * * Returns the given page to the PQ_FREE or PQ_ZERO list, * disassociating it with any VM object. * * Object and page must be locked prior to entry. * This routine may not block. */ void vm_page_free_toq(vm_page_t m) { int s; struct vpgqueues *pq; vm_object_t object = m->object; s = splvm(); cnt.v_tfree++; #if !defined(MAX_PERF) if (m->busy || ((m->queue - m->pc) == PQ_FREE) || (m->hold_count != 0)) { printf( "vm_page_free: pindex(%lu), busy(%d), PG_BUSY(%d), hold(%d)\n", (u_long)m->pindex, m->busy, (m->flags & PG_BUSY) ? 1 : 0, m->hold_count); if ((m->queue - m->pc) == PQ_FREE) panic("vm_page_free: freeing free page"); else panic("vm_page_free: freeing busy page"); } #endif /* * unqueue, then remove page. Note that we cannot destroy * the page here because we do not want to call the pager's * callback routine until after we've put the page on the * appropriate free queue. */ vm_page_unqueue_nowakeup(m); vm_page_remove(m); /* * If fictitious remove object association and * return, otherwise delay object association removal. */ if ((m->flags & PG_FICTITIOUS) != 0) { splx(s); return; } m->valid = 0; if (m->wire_count != 0) { #if !defined(MAX_PERF) if (m->wire_count > 1) { panic("vm_page_free: invalid wire count (%d), pindex: 0x%x", m->wire_count, m->pindex); } #endif printf("vm_page_free: freeing wired page\n"); m->wire_count = 0; if (m->object) m->object->wire_count--; cnt.v_wire_count--; } /* * If we've exhausted the object's resident pages we want to free * it up. */ if (object && (object->type == OBJT_VNODE) && ((object->flags & OBJ_DEAD) == 0) ) { struct vnode *vp = (struct vnode *)object->handle; if (vp && VSHOULDFREE(vp)) { if ((vp->v_flag & (VTBFREE|VDOOMED|VFREE)) == 0) { TAILQ_INSERT_TAIL(&vnode_tobefree_list, vp, v_freelist); vp->v_flag |= VTBFREE; } } } #ifdef __alpha__ pmap_page_is_free(m); #endif m->queue = PQ_FREE + m->pc; pq = &vm_page_queues[m->queue]; ++(*pq->lcnt); ++(*pq->cnt); /* * Put zero'd pages on the end ( where we look for zero'd pages * first ) and non-zerod pages at the head. */ if (m->flags & PG_ZERO) { TAILQ_INSERT_TAIL(pq->pl, m, pageq); ++vm_page_zero_count; } else if (curproc == pageproc) { /* * If the pageout daemon is freeing pages, the pages are * likely to NOT be in the L1 or L2 caches due to their age. * For now we do not try to do anything special with this * info. */ TAILQ_INSERT_HEAD(pq->pl, m, pageq); } else { TAILQ_INSERT_HEAD(pq->pl, m, pageq); } vm_page_free_wakeup(); splx(s); } /* * 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. * This routine may not block. */ void vm_page_wire(m) register vm_page_t m; { int s; s = splvm(); if (m->wire_count == 0) { vm_page_unqueue(m); cnt.v_wire_count++; if (m->object) m->object->wire_count++; } m->wire_count++; splx(s); (*vm_page_queues[PQ_NONE].lcnt)++; vm_page_flag_set(m, PG_MAPPED); } /* * vm_page_unwire: * * Release one wiring of this page, potentially * enabling it to be paged again. * * Many pages placed on the inactive queue should actually go * into the cache, but it is difficult to figure out which. What * we do instead, if the inactive target is well met, is to put * clean pages at the head of the inactive queue instead of the tail. * This will cause them to be moved to the cache more quickly and * if not actively re-referenced, freed more quickly. If we just * stick these pages at the end of the inactive queue, heavy filesystem * meta-data accesses can cause an unnecessary paging load on memory bound * processes. This optimization causes one-time-use metadata to be * reused more quickly. * * A number of routines use vm_page_unwire() to guarentee that the page * will go into either the inactive or active queues, and will NEVER * be placed in the cache - for example, just after dirtying a page. * dirty pages in the cache are not allowed. * * The page queues must be locked. * This routine may not block. */ void vm_page_unwire(m, activate) register vm_page_t m; int activate; { int s; s = splvm(); if (m->wire_count > 0) { m->wire_count--; if (m->wire_count == 0) { if (m->object) m->object->wire_count--; cnt.v_wire_count--; if (activate) { TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq); m->queue = PQ_ACTIVE; (*vm_page_queues[PQ_ACTIVE].lcnt)++; cnt.v_active_count++; } else { TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq); m->queue = PQ_INACTIVE; (*vm_page_queues[PQ_INACTIVE].lcnt)++; cnt.v_inactive_count++; } } } else { #if !defined(MAX_PERF) panic("vm_page_unwire: invalid wire count: %d\n", m->wire_count); #endif } splx(s); } /* * Move the specified page to the inactive queue. If the page has * any associated swap, the swap is deallocated. * * This routine may not block. */ void vm_page_deactivate(m) register vm_page_t m; { int s; /* * Ignore if already inactive. */ if (m->queue == PQ_INACTIVE) return; s = splvm(); if (m->wire_count == 0) { if ((m->queue - m->pc) == PQ_CACHE) cnt.v_reactivated++; vm_page_unqueue(m); TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq); m->queue = PQ_INACTIVE; ++(*vm_page_queues[PQ_INACTIVE].lcnt); cnt.v_inactive_count++; } splx(s); } /* * vm_page_cache * * Put the specified page onto the page cache queue (if appropriate). * * This routine may not block. */ void vm_page_cache(m) register vm_page_t m; { int s; #if !defined(MAX_PERF) if ((m->flags & PG_BUSY) || m->busy || m->wire_count) { printf("vm_page_cache: attempting to cache busy page\n"); return; } #endif if ((m->queue - m->pc) == PQ_CACHE) return; /* * Remove all pmaps and indicate that the page is not * writeable or mapped. */ vm_page_protect(m, VM_PROT_NONE); #if !defined(MAX_PERF) if (m->dirty != 0) { panic("vm_page_cache: caching a dirty page, pindex: %d", m->pindex); } #endif s = splvm(); vm_page_unqueue_nowakeup(m); m->queue = PQ_CACHE + m->pc; (*vm_page_queues[m->queue].lcnt)++; TAILQ_INSERT_TAIL(vm_page_queues[m->queue].pl, m, pageq); cnt.v_cache_count++; m->object->cache_count++; vm_page_free_wakeup(); splx(s); } /* * Grab a page, waiting until we are waken up due to the page * changing state. We keep on waiting, if the page continues * to be in the object. If the page doesn't exist, allocate it. * * This routine may block. */ vm_page_t vm_page_grab(object, pindex, allocflags) vm_object_t object; vm_pindex_t pindex; int allocflags; { vm_page_t m; int s, generation; retrylookup: if ((m = vm_page_lookup(object, pindex)) != NULL) { if (m->busy || (m->flags & PG_BUSY)) { generation = object->generation; s = splvm(); while ((object->generation == generation) && (m->busy || (m->flags & PG_BUSY))) { vm_page_flag_set(m, PG_WANTED | PG_REFERENCED); tsleep(m, PVM, "pgrbwt", 0); if ((allocflags & VM_ALLOC_RETRY) == 0) { splx(s); return NULL; } } splx(s); goto retrylookup; } else { vm_page_busy(m); return m; } } m = vm_page_alloc(object, pindex, allocflags & ~VM_ALLOC_RETRY); if (m == NULL) { VM_WAIT; if ((allocflags & VM_ALLOC_RETRY) == 0) return NULL; goto retrylookup; } return m; } /* * Mapping function for valid bits or for dirty bits in * a page. May not block. * * Inputs are required to range within a page. */ __inline int vm_page_bits(int base, int size) { int first_bit; int last_bit; KASSERT( base + size <= PAGE_SIZE, ("vm_page_bits: illegal base/size %d/%d", base, size) ); if (size == 0) /* handle degenerate case */ return(0); first_bit = base >> DEV_BSHIFT; last_bit = (base + size - 1) >> DEV_BSHIFT; return ((2 << last_bit) - (1 << first_bit)); } /* * set a page valid and clean. May not block. * * In order to maintain consistancy due to the DEV_BSIZE granularity * of the valid bits, we have to zero non-DEV_BSIZE aligned portions of * the page at the beginning and end of the valid range when the * associated valid bits are not already set. * * (base + size) must be less then or equal to PAGE_SIZE. */ void vm_page_set_validclean(m, base, size) vm_page_t m; int base; int size; { int pagebits; int frag; int endoff; if (size == 0) /* handle degenerate case */ return; /* * If the base is not DEV_BSIZE aligned and the valid * bit is clear, we have to zero out a portion of the * first block. */ if ((frag = base & ~(DEV_BSIZE - 1)) != base && (m->valid & (1 << (base >> DEV_BSHIFT))) == 0 ) { pmap_zero_page_area( VM_PAGE_TO_PHYS(m), frag, base - frag ); } /* * If the ending offset is not DEV_BSIZE aligned and the * valid bit is clear, we have to zero out a portion of * the last block. */ endoff = base + size; if ((frag = endoff & ~(DEV_BSIZE - 1)) != endoff && (m->valid & (1 << (endoff >> DEV_BSHIFT))) == 0 ) { pmap_zero_page_area( VM_PAGE_TO_PHYS(m), endoff, DEV_BSIZE - (endoff & (DEV_BSIZE - 1)) ); } /* * Set valid, clear dirty bits. If validating the entire * page we can safely clear the pmap modify bit. */ pagebits = vm_page_bits(base, size); m->valid |= pagebits; m->dirty &= ~pagebits; if (base == 0 && size == PAGE_SIZE) pmap_clear_modify(VM_PAGE_TO_PHYS(m)); } /* * set a page (partially) invalid. May not block. */ void vm_page_set_invalid(m, base, size) vm_page_t m; int base; int size; { int bits; m->valid &= ~(bits = vm_page_bits(base, size)); if (m->valid == 0) m->dirty &= ~bits; m->object->generation++; } /* * vm_page_zero_invalid() * * The kernel assumes that the invalid portions of a page contain * garbage, but such pages can be mapped into memory by user code. * When this occurs, we must zero out the non-valid portions of the * page so user code sees what it expects. * * Pages are most often semi-valid when the end of a file is mapped * into memory and the file's size is not page aligned. */ void vm_page_zero_invalid(vm_page_t m, boolean_t setvalid) { int b; int i; /* * Scan the valid bits looking for invalid sections that * must be zerod. Invalid sub-DEV_BSIZE'd areas ( where the * valid bit may be set ) have already been zerod by * vm_page_set_validclean(). */ for (b = i = 0; i <= PAGE_SIZE / DEV_BSIZE; ++i) { if (i == (PAGE_SIZE / DEV_BSIZE) || (m->valid & (1 << i)) ) { if (i > b) { pmap_zero_page_area( VM_PAGE_TO_PHYS(m), b << DEV_BSHIFT, (i - b) << DEV_BSHIFT ); } b = i + 1; } } /* * setvalid is TRUE when we can safely set the zero'd areas * as being valid. We can do this if there are no cache consistancy * issues. e.g. it is ok to do with UFS, but not ok to do with NFS. */ if (setvalid) m->valid = VM_PAGE_BITS_ALL; } /* * vm_page_is_valid: * * Is (partial) page valid? Note that the case where size == 0 * will return FALSE in the degenerate case where the page is * entirely invalid, and TRUE otherwise. * * May not block. */ int vm_page_is_valid(m, base, size) vm_page_t m; int base; int size; { int bits = vm_page_bits(base, size); if (m->valid && ((m->valid & bits) == bits)) return 1; else return 0; } /* * update dirty bits from pmap/mmu. May not block. */ void vm_page_test_dirty(m) vm_page_t m; { if ((m->dirty != VM_PAGE_BITS_ALL) && pmap_is_modified(VM_PAGE_TO_PHYS(m))) { vm_page_dirty(m); } } /* * This interface is for merging with malloc() someday. * Even if we never implement compaction so that contiguous allocation * works after initialization time, malloc()'s data structures are good * for statistics and for allocations of less than a page. */ void * contigmalloc1(size, type, flags, low, high, alignment, boundary, map) unsigned long size; /* should be size_t here and for malloc() */ struct malloc_type *type; int flags; unsigned long low; unsigned long high; unsigned long alignment; unsigned long boundary; vm_map_t map; { int i, s, start; vm_offset_t addr, phys, tmp_addr; int pass; vm_page_t pga = vm_page_array; size = round_page(size); #if !defined(MAX_PERF) if (size == 0) panic("contigmalloc1: size must not be 0"); if ((alignment & (alignment - 1)) != 0) panic("contigmalloc1: alignment must be a power of 2"); if ((boundary & (boundary - 1)) != 0) panic("contigmalloc1: boundary must be a power of 2"); #endif start = 0; for (pass = 0; pass <= 1; pass++) { s = splvm(); again: /* * Find first page in array that is free, within range, aligned, and * such that the boundary won't be crossed. */ for (i = start; i < cnt.v_page_count; i++) { int pqtype; phys = VM_PAGE_TO_PHYS(&pga[i]); pqtype = pga[i].queue - pga[i].pc; if (((pqtype == PQ_FREE) || (pqtype == PQ_CACHE)) && (phys >= low) && (phys < high) && ((phys & (alignment - 1)) == 0) && (((phys ^ (phys + size - 1)) & ~(boundary - 1)) == 0)) break; } /* * If the above failed or we will exceed the upper bound, fail. */ if ((i == cnt.v_page_count) || ((VM_PAGE_TO_PHYS(&pga[i]) + size) > high)) { vm_page_t m, next; again1: for (m = TAILQ_FIRST(&vm_page_queue_inactive); m != NULL; m = next) { if (m->queue != PQ_INACTIVE) { break; } next = TAILQ_NEXT(m, pageq); if (vm_page_sleep_busy(m, TRUE, "vpctw0")) goto again1; vm_page_test_dirty(m); if (m->dirty) { if (m->object->type == OBJT_VNODE) { vn_lock(m->object->handle, LK_EXCLUSIVE | LK_RETRY, curproc); vm_object_page_clean(m->object, 0, 0, OBJPC_SYNC); VOP_UNLOCK(m->object->handle, 0, curproc); goto again1; } else if (m->object->type == OBJT_SWAP || m->object->type == OBJT_DEFAULT) { vm_pageout_flush(&m, 1, 0); goto again1; } } if ((m->dirty == 0) && (m->busy == 0) && (m->hold_count == 0)) vm_page_cache(m); } for (m = TAILQ_FIRST(&vm_page_queue_active); m != NULL; m = next) { if (m->queue != PQ_ACTIVE) { break; } next = TAILQ_NEXT(m, pageq); if (vm_page_sleep_busy(m, TRUE, "vpctw1")) goto again1; vm_page_test_dirty(m); if (m->dirty) { if (m->object->type == OBJT_VNODE) { vn_lock(m->object->handle, LK_EXCLUSIVE | LK_RETRY, curproc); vm_object_page_clean(m->object, 0, 0, OBJPC_SYNC); VOP_UNLOCK(m->object->handle, 0, curproc); goto again1; } else if (m->object->type == OBJT_SWAP || m->object->type == OBJT_DEFAULT) { vm_pageout_flush(&m, 1, 0); goto again1; } } if ((m->dirty == 0) && (m->busy == 0) && (m->hold_count == 0)) vm_page_cache(m); } splx(s); continue; } start = i; /* * Check successive pages for contiguous and free. */ for (i = start + 1; i < (start + size / PAGE_SIZE); i++) { int pqtype; pqtype = pga[i].queue - pga[i].pc; if ((VM_PAGE_TO_PHYS(&pga[i]) != (VM_PAGE_TO_PHYS(&pga[i - 1]) + PAGE_SIZE)) || ((pqtype != PQ_FREE) && (pqtype != PQ_CACHE))) { start++; goto again; } } for (i = start; i < (start + size / PAGE_SIZE); i++) { int pqtype; vm_page_t m = &pga[i]; pqtype = m->queue - m->pc; if (pqtype == PQ_CACHE) { vm_page_busy(m); vm_page_free(m); } TAILQ_REMOVE(vm_page_queues[m->queue].pl, m, pageq); (*vm_page_queues[m->queue].lcnt)--; cnt.v_free_count--; m->valid = VM_PAGE_BITS_ALL; m->flags = 0; m->dirty = 0; m->wire_count = 0; m->busy = 0; m->queue = PQ_NONE; m->object = NULL; vm_page_wire(m); } /* * We've found a contiguous chunk that meets are requirements. * Allocate kernel VM, unfree and assign the physical pages to it and * return kernel VM pointer. */ tmp_addr = addr = kmem_alloc_pageable(map, size); if (addr == 0) { /* * XXX We almost never run out of kernel virtual * space, so we don't make the allocated memory * above available. */ splx(s); return (NULL); } for (i = start; i < (start + size / PAGE_SIZE); i++) { vm_page_t m = &pga[i]; vm_page_insert(m, kernel_object, OFF_TO_IDX(tmp_addr - VM_MIN_KERNEL_ADDRESS)); pmap_kenter(tmp_addr, VM_PAGE_TO_PHYS(m)); tmp_addr += PAGE_SIZE; } splx(s); return ((void *)addr); } return NULL; } void * contigmalloc(size, type, flags, low, high, alignment, boundary) unsigned long size; /* should be size_t here and for malloc() */ struct malloc_type *type; int flags; unsigned long low; unsigned long high; unsigned long alignment; unsigned long boundary; { return contigmalloc1(size, type, flags, low, high, alignment, boundary, kernel_map); } vm_offset_t vm_page_alloc_contig(size, low, high, alignment) vm_offset_t size; vm_offset_t low; vm_offset_t high; vm_offset_t alignment; { return ((vm_offset_t)contigmalloc1(size, M_DEVBUF, M_NOWAIT, low, high, alignment, 0ul, kernel_map)); } #include "opt_ddb.h" #ifdef DDB #include #include DB_SHOW_COMMAND(page, vm_page_print_page_info) { db_printf("cnt.v_free_count: %d\n", cnt.v_free_count); db_printf("cnt.v_cache_count: %d\n", cnt.v_cache_count); db_printf("cnt.v_inactive_count: %d\n", cnt.v_inactive_count); db_printf("cnt.v_active_count: %d\n", cnt.v_active_count); db_printf("cnt.v_wire_count: %d\n", cnt.v_wire_count); db_printf("cnt.v_free_reserved: %d\n", cnt.v_free_reserved); db_printf("cnt.v_free_min: %d\n", cnt.v_free_min); db_printf("cnt.v_free_target: %d\n", cnt.v_free_target); db_printf("cnt.v_cache_min: %d\n", cnt.v_cache_min); db_printf("cnt.v_inactive_target: %d\n", cnt.v_inactive_target); } DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info) { int i; db_printf("PQ_FREE:"); for(i=0;i