/* * (MPSAFE) * * 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. * 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 * $FreeBSD: src/sys/vm/vm_page.c,v 1.147.2.18 2002/03/10 05:03:19 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. The module manipulates 'VM pages'. * A VM page is the core building block for memory management. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define VMACTION_HSIZE 256 #define VMACTION_HMASK (VMACTION_HSIZE - 1) static void vm_page_queue_init(void); static void vm_page_free_wakeup(void); static vm_page_t vm_page_select_cache(vm_object_t, vm_pindex_t); static vm_page_t _vm_page_list_find2(int basequeue, int index); struct vpgqueues vm_page_queues[PQ_COUNT]; /* Array of tailq lists */ LIST_HEAD(vm_page_action_list, vm_page_action); struct vm_page_action_list action_list[VMACTION_HSIZE]; static volatile int vm_pages_waiting; RB_GENERATE2(vm_page_rb_tree, vm_page, rb_entry, rb_vm_page_compare, vm_pindex_t, pindex); static void vm_page_queue_init(void) { int i; for (i = 0; i < PQ_L2_SIZE; i++) vm_page_queues[PQ_FREE+i].cnt = &vmstats.v_free_count; for (i = 0; i < PQ_L2_SIZE; i++) vm_page_queues[PQ_CACHE+i].cnt = &vmstats.v_cache_count; vm_page_queues[PQ_INACTIVE].cnt = &vmstats.v_inactive_count; vm_page_queues[PQ_ACTIVE].cnt = &vmstats.v_active_count; vm_page_queues[PQ_HOLD].cnt = &vmstats.v_active_count; /* PQ_NONE has no queue */ for (i = 0; i < PQ_COUNT; i++) TAILQ_INIT(&vm_page_queues[i].pl); for (i = 0; i < VMACTION_HSIZE; i++) LIST_INIT(&action_list[i]); } /* * note: place in initialized data section? Is this necessary? */ long first_page = 0; int vm_page_array_size = 0; int vm_page_zero_count = 0; vm_page_t vm_page_array = 0; /* * (low level boot) * * Sets the page size, perhaps based upon the memory size. * Must be called before any use of page-size dependent functions. */ void vm_set_page_size(void) { if (vmstats.v_page_size == 0) vmstats.v_page_size = PAGE_SIZE; if (((vmstats.v_page_size - 1) & vmstats.v_page_size) != 0) panic("vm_set_page_size: page size not a power of two"); } /* * (low level boot) * * Add a new page to the freelist for use by the system. New pages * are added to both the head and tail of the associated free page * queue in a bottom-up fashion, so both zero'd and non-zero'd page * requests pull 'recent' adds (higher physical addresses) first. * * Must be called in a critical section. */ static vm_page_t vm_add_new_page(vm_paddr_t pa) { struct vpgqueues *vpq; vm_page_t m; ++vmstats.v_page_count; ++vmstats.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; KKASSERT(m->dirty == 0); vpq = &vm_page_queues[m->queue]; if (vpq->flipflop) TAILQ_INSERT_TAIL(&vpq->pl, m, pageq); else TAILQ_INSERT_HEAD(&vpq->pl, m, pageq); vpq->flipflop = 1 - vpq->flipflop; vm_page_queues[m->queue].lcnt++; return (m); } /* * (low level boot) * * Initializes the resident memory module. * * Preallocates memory for critical VM structures and arrays prior to * kernel_map becoming available. * * Memory is allocated from (virtual2_start, virtual2_end) if available, * otherwise memory is allocated from (virtual_start, virtual_end). * * On x86-64 (virtual_start, virtual_end) is only 2GB and may not be * large enough to hold vm_page_array & other structures for machines with * large amounts of ram, so we want to use virtual2* when available. */ void vm_page_startup(void) { vm_offset_t vaddr = virtual2_start ? virtual2_start : virtual_start; vm_offset_t mapped; vm_size_t npages; vm_paddr_t page_range; vm_paddr_t new_end; int i; vm_paddr_t pa; int nblocks; vm_paddr_t last_pa; vm_paddr_t end; vm_paddr_t biggestone, biggestsize; vm_paddr_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_page64(phys_avail[i]); phys_avail[i + 1] = trunc_page64(phys_avail[i + 1]); } for (i = 0; phys_avail[i + 1]; i += 2) { vm_paddr_t size = phys_avail[i + 1] - phys_avail[i]; if (size > biggestsize) { biggestone = i; biggestsize = size; } ++nblocks; total += size; } end = phys_avail[biggestone+1]; end = trunc_page(end); /* * Initialize the queue headers for the free queue, the active queue * and the inactive queue. */ vm_page_queue_init(); /* VKERNELs don't support minidumps and as such don't need vm_page_dump */ #if !defined(_KERNEL_VIRTUAL) /* * Allocate a bitmap to indicate that a random physical page * needs to be included in a minidump. * * The amd64 port needs this to indicate which direct map pages * need to be dumped, via calls to dump_add_page()/dump_drop_page(). * * However, i386 still needs this workspace internally within the * minidump code. In theory, they are not needed on i386, but are * included should the sf_buf code decide to use them. */ page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE; vm_page_dump_size = round_page(roundup2(page_range, NBBY) / NBBY); end -= vm_page_dump_size; vm_page_dump = (void *)pmap_map(&vaddr, end, end + vm_page_dump_size, VM_PROT_READ | VM_PROT_WRITE); bzero((void *)vm_page_dump, vm_page_dump_size); #endif /* * 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; page_range = phys_avail[(nblocks - 1) * 2 + 1] / PAGE_SIZE - first_page; npages = (total - (page_range * sizeof(struct vm_page))) / PAGE_SIZE; /* * Initialize the mem entry structures now, and put them in the free * queue. */ new_end = trunc_page(end - page_range * sizeof(struct vm_page)); mapped = pmap_map(&vaddr, new_end, end, VM_PROT_READ | VM_PROT_WRITE); vm_page_array = (vm_page_t)mapped; #if defined(__x86_64__) && !defined(_KERNEL_VIRTUAL) /* * since pmap_map on amd64 returns stuff out of a direct-map region, * we have to manually add these pages to the minidump tracking so * that they can be dumped, including the vm_page_array. */ for (pa = new_end; pa < phys_avail[biggestone + 1]; pa += PAGE_SIZE) dump_add_page(pa); #endif /* * 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 ascending 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. */ vmstats.v_page_count = 0; vmstats.v_free_count = 0; for (i = 0; phys_avail[i + 1] && npages > 0; i += 2) { pa = phys_avail[i]; if (i == biggestone) last_pa = new_end; else last_pa = phys_avail[i + 1]; while (pa < last_pa && npages-- > 0) { vm_add_new_page(pa); pa += PAGE_SIZE; } } if (virtual2_start) virtual2_start = vaddr; else virtual_start = vaddr; } /* * Scan comparison function for Red-Black tree scans. An inclusive * (start,end) is expected. Other fields are not used. */ int rb_vm_page_scancmp(struct vm_page *p, void *data) { struct rb_vm_page_scan_info *info = data; if (p->pindex < info->start_pindex) return(-1); if (p->pindex > info->end_pindex) return(1); return(0); } int rb_vm_page_compare(struct vm_page *p1, struct vm_page *p2) { if (p1->pindex < p2->pindex) return(-1); if (p1->pindex > p2->pindex) return(1); return(0); } /* * Holding a page keeps it from being reused. Other parts of the system * can still disassociate the page from its current object and free it, or * perform read or write I/O on it and/or otherwise manipulate the page, * but if the page is held the VM system will leave the page and its data * intact and not reuse the page for other purposes until the last hold * reference is released. (see vm_page_wire() if you want to prevent the * page from being disassociated from its object too). * * The caller must hold vm_token. * * The caller must still validate the contents of the page and, if necessary, * wait for any pending I/O (e.g. vm_page_sleep_busy() loop) to complete * before manipulating the page. */ void vm_page_hold(vm_page_t m) { ASSERT_LWKT_TOKEN_HELD(&vm_token); ++m->hold_count; } /* * The opposite of vm_page_hold(). A page can be freed while being held, * which places it on the PQ_HOLD queue. We must call vm_page_free_toq() * in this case to actually free it once the hold count drops to 0. * * The caller must hold vm_token if non-blocking operation is desired, * but otherwise does not need to. */ void vm_page_unhold(vm_page_t m) { lwkt_gettoken(&vm_token); --m->hold_count; KASSERT(m->hold_count >= 0, ("vm_page_unhold: hold count < 0!!!")); if (m->hold_count == 0 && m->queue == PQ_HOLD) { vm_page_busy(m); vm_page_free_toq(m); } lwkt_reltoken(&vm_token); } /* * Inserts the given vm_page 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. * * This routine may not block. * This routine must be called with the vm_token held. * This routine must be called with the vm_object held. * This routine must be called with a critical section held. */ void vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex) { ASSERT_LWKT_TOKEN_HELD(&vm_token); 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. */ vm_page_rb_tree_RB_INSERT(&object->rb_memq, m); object->generation++; /* * show that the object has one more resident page. */ object->resident_page_count++; /* * Add the pv_list_cout of the page when its inserted in * the object */ object->agg_pv_list_count = object->agg_pv_list_count + m->md.pv_list_count; /* * Since we are inserting a new and possibly dirty page, * update the object's OBJ_WRITEABLE and OBJ_MIGHTBEDIRTY flags. */ if ((m->valid & m->dirty) || (m->flags & PG_WRITEABLE)) vm_object_set_writeable_dirty(object); /* * Checks for a swap assignment and sets PG_SWAPPED if appropriate. */ swap_pager_page_inserted(m); } /* * Removes the given vm_page_t from the global (object,index) hash table * and from the object's memq. * * The underlying pmap entry (if any) is NOT removed here. * This routine may not block. * * The page must be BUSY and will remain BUSY on return. * No other requirements. * * NOTE: FreeBSD side effect was to unbusy the page on return. We leave * it busy. */ void vm_page_remove(vm_page_t m) { vm_object_t object; lwkt_gettoken(&vm_token); if (m->object == NULL) { lwkt_reltoken(&vm_token); return; } if ((m->flags & PG_BUSY) == 0) panic("vm_page_remove: page not busy"); object = m->object; vm_object_hold(object); /* * Remove the page from the object and update the object. */ vm_page_rb_tree_RB_REMOVE(&object->rb_memq, m); object->resident_page_count--; object->agg_pv_list_count = object->agg_pv_list_count - m->md.pv_list_count; object->generation++; m->object = NULL; vm_object_drop(object); lwkt_reltoken(&vm_token); } /* * Locate and return the page at (object, pindex), or NULL if the * page could not be found. * * The caller must hold vm_token. */ vm_page_t vm_page_lookup(vm_object_t object, vm_pindex_t pindex) { vm_page_t m; /* * Search the hash table for this object/offset pair */ ASSERT_LWKT_TOKEN_HELD(&vm_token); m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); KKASSERT(m == NULL || (m->object == object && m->pindex == pindex)); return(m); } /* * 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(vm_page_t m, vm_object_t new_object, vm_pindex_t new_pindex) { lwkt_gettoken(&vm_token); vm_object_hold(new_object); 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); vm_page_wakeup(m); vm_object_drop(new_object); lwkt_reltoken(&vm_token); } /* * vm_page_unqueue() without any wakeup. This routine is used when a page * is being moved between queues or otherwise is to remain BUSYied by the * caller. * * The caller must hold vm_token * This routine may not block. */ void vm_page_unqueue_nowakeup(vm_page_t m) { int queue = m->queue; struct vpgqueues *pq; ASSERT_LWKT_TOKEN_HELD(&vm_token); if (queue != PQ_NONE) { pq = &vm_page_queues[queue]; m->queue = PQ_NONE; TAILQ_REMOVE(&pq->pl, m, pageq); (*pq->cnt)--; pq->lcnt--; } } /* * vm_page_unqueue() - Remove a page from its queue, wakeup the pagedemon * if necessary. * * The caller must hold vm_token * This routine may not block. */ void vm_page_unqueue(vm_page_t m) { int queue = m->queue; struct vpgqueues *pq; ASSERT_LWKT_TOKEN_HELD(&vm_token); 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 || (queue - m->pc) == PQ_FREE) pagedaemon_wakeup(); } } /* * 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 optimization because cpu caches tend to be * physical caches, while object spaces tend to be virtual. * * Must be called with vm_token held. * This routine may not block. * * Note that this routine is carefully inlined. A non-inlined version * is available for outside callers but the only critical path is * from within this source file. */ static __inline vm_page_t _vm_page_list_find(int basequeue, int index, boolean_t prefer_zero) { vm_page_t m; if (prefer_zero) m = TAILQ_LAST(&vm_page_queues[basequeue+index].pl, pglist); else m = TAILQ_FIRST(&vm_page_queues[basequeue+index].pl); if (m == NULL) m = _vm_page_list_find2(basequeue, index); return(m); } static vm_page_t _vm_page_list_find2(int basequeue, int 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); } /* * Must be called with vm_token held if the caller desired non-blocking * operation and a stable result. */ vm_page_t vm_page_list_find(int basequeue, int index, boolean_t prefer_zero) { return(_vm_page_list_find(basequeue, index, prefer_zero)); } /* * 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 may not block. * Must be called with vm_token held. */ vm_page_t vm_page_select_cache(vm_object_t object, vm_pindex_t pindex) { vm_page_t m; ASSERT_LWKT_TOKEN_HELD(&vm_token); while (TRUE) { m = _vm_page_list_find( PQ_CACHE, (pindex + object->pg_color) & PQ_L2_MASK, FALSE ); if (m && ((m->flags & (PG_BUSY|PG_UNMANAGED)) || m->busy || m->hold_count || m->wire_count)) { /* cache page found busy */ vm_page_deactivate(m); #ifdef INVARIANTS kprintf("Warning: busy page %p found in cache\n", m); #endif continue; } return m; } /* not reached */ } /* * 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 with a critical section held. * 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 allow use of cache pages, nominal free drain * VM_ALLOC_QUICK like normal but cannot use cache * VM_ALLOC_SYSTEM greater free drain * VM_ALLOC_INTERRUPT allow free list to be completely drained * VM_ALLOC_ZERO advisory request for pre-zero'd page * * The object must be locked. * This routine may not block. * The returned page will be marked PG_BUSY * * 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(vm_object_t object, vm_pindex_t pindex, int page_req) { vm_page_t m = NULL; lwkt_gettoken(&vm_token); KKASSERT(object != NULL); KASSERT(!vm_page_lookup(object, pindex), ("vm_page_alloc: page already allocated")); KKASSERT(page_req & (VM_ALLOC_NORMAL|VM_ALLOC_QUICK| VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM)); /* * Certain system threads (pageout daemon, buf_daemon's) are * allowed to eat deeper into the free page list. */ if (curthread->td_flags & TDF_SYSTHREAD) page_req |= VM_ALLOC_SYSTEM; loop: if (vmstats.v_free_count > vmstats.v_free_reserved || ((page_req & VM_ALLOC_INTERRUPT) && vmstats.v_free_count > 0) || ((page_req & VM_ALLOC_SYSTEM) && vmstats.v_cache_count == 0 && vmstats.v_free_count > vmstats.v_interrupt_free_min) ) { /* * The free queue has sufficient free pages to take one out. */ 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_NORMAL) { /* * Allocatable from the cache (non-interrupt only). On * success, we must free the page and try again, thus * ensuring that vmstats.v_*_free_min counters are replenished. */ #ifdef INVARIANTS if (curthread->td_preempted) { kprintf("vm_page_alloc(): warning, attempt to allocate" " cache page from preempting interrupt\n"); m = NULL; } else { m = vm_page_select_cache(object, pindex); } #else m = vm_page_select_cache(object, pindex); #endif /* * On success move the page into the free queue and loop. */ if (m != 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; } /* * On failure return NULL */ lwkt_reltoken(&vm_token); #if defined(DIAGNOSTIC) if (vmstats.v_cache_count > 0) kprintf("vm_page_alloc(NORMAL): missing pages on cache queue: %d\n", vmstats.v_cache_count); #endif vm_pageout_deficit++; pagedaemon_wakeup(); return (NULL); } else { /* * No pages available, wakeup the pageout daemon and give up. */ lwkt_reltoken(&vm_token); vm_pageout_deficit++; pagedaemon_wakeup(); return (NULL); } /* * Good page found. The page has not yet been busied. We are in * a critical section. */ KASSERT(m != NULL, ("vm_page_alloc(): missing page on free queue\n")); KASSERT(m->dirty == 0, ("vm_page_alloc: free/cache page %p was dirty", m)); /* * Remove from free queue */ vm_page_unqueue_nowakeup(m); /* * Initialize structure. Only the PG_ZERO flag is inherited. Set * the page PG_BUSY */ 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; /* * vm_page_insert() is safe while holding vm_token. 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. */ pagedaemon_wakeup(); lwkt_reltoken(&vm_token); /* * A PG_BUSY page is returned. */ return (m); } /* * Wait for sufficient free memory for nominal heavy memory use kernel * operations. */ void vm_wait_nominal(void) { while (vm_page_count_min(0)) vm_wait(0); } /* * Test if vm_wait_nominal() would block. */ int vm_test_nominal(void) { if (vm_page_count_min(0)) return(1); return(0); } /* * Block until free pages are available for allocation, called in various * places before memory allocations. * * The caller may loop if vm_page_count_min() == FALSE so we cannot be * more generous then that. */ void vm_wait(int timo) { /* * never wait forever */ if (timo == 0) timo = hz; lwkt_gettoken(&vm_token); if (curthread == pagethread) { /* * The pageout daemon itself needs pages, this is bad. */ if (vm_page_count_min(0)) { vm_pageout_pages_needed = 1; tsleep(&vm_pageout_pages_needed, 0, "VMWait", timo); } } else { /* * Wakeup the pageout daemon if necessary and wait. */ if (vm_page_count_target()) { if (vm_pages_needed == 0) { vm_pages_needed = 1; wakeup(&vm_pages_needed); } ++vm_pages_waiting; /* SMP race ok */ tsleep(&vmstats.v_free_count, 0, "vmwait", timo); } } lwkt_reltoken(&vm_token); } /* * Block until free pages are available for allocation * * Called only from vm_fault so that processes page faulting can be * easily tracked. */ void vm_waitpfault(void) { /* * Wakeup the pageout daemon if necessary and wait. */ if (vm_page_count_target()) { lwkt_gettoken(&vm_token); if (vm_page_count_target()) { if (vm_pages_needed == 0) { vm_pages_needed = 1; wakeup(&vm_pages_needed); } ++vm_pages_waiting; /* SMP race ok */ tsleep(&vmstats.v_free_count, 0, "pfault", hz); } lwkt_reltoken(&vm_token); } } /* * Put the specified page on the active list (if appropriate). Ensure * that act_count is at least ACT_INIT but do not otherwise mess with it. * * The page queues must be locked. * This routine may not block. */ void vm_page_activate(vm_page_t m) { lwkt_gettoken(&vm_token); if (m->queue != PQ_ACTIVE) { if ((m->queue - m->pc) == PQ_CACHE) mycpu->gd_cnt.v_reactivated++; vm_page_unqueue(m); if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { m->queue = PQ_ACTIVE; vm_page_queues[PQ_ACTIVE].lcnt++; TAILQ_INSERT_TAIL(&vm_page_queues[PQ_ACTIVE].pl, m, pageq); if (m->act_count < ACT_INIT) m->act_count = ACT_INIT; vmstats.v_active_count++; } } else { if (m->act_count < ACT_INIT) m->act_count = ACT_INIT; } lwkt_reltoken(&vm_token); } /* * 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(void) { /* * If the pageout daemon itself needs pages, then tell it that * there are some free. */ if (vm_pageout_pages_needed && vmstats.v_cache_count + vmstats.v_free_count >= vmstats.v_pageout_free_min ) { wakeup(&vm_pageout_pages_needed); vm_pageout_pages_needed = 0; } /* * Wakeup processes that are waiting on memory. * * NOTE: vm_paging_target() is the pageout daemon's target, while * vm_page_count_target() is somewhere inbetween. We want * to wake processes up prior to the pageout daemon reaching * its target to provide some hysteresis. */ if (vm_pages_waiting) { if (!vm_page_count_target()) { /* * Plenty of pages are free, wakeup everyone. */ vm_pages_waiting = 0; wakeup(&vmstats.v_free_count); ++mycpu->gd_cnt.v_ppwakeups; } else if (!vm_page_count_min(0)) { /* * Some pages are free, wakeup someone. */ int wcount = vm_pages_waiting; if (wcount > 0) --wcount; vm_pages_waiting = wcount; wakeup_one(&vmstats.v_free_count); ++mycpu->gd_cnt.v_ppwakeups; } } } /* * vm_page_free_toq: * * Returns the given page to the PQ_FREE list, disassociating it with * any VM object. * * The vm_page must be PG_BUSY on entry. PG_BUSY will be released on * return (the page will have been freed). No particular spl is required * on entry. * * This routine may not block. */ void vm_page_free_toq(vm_page_t m) { struct vpgqueues *pq; lwkt_gettoken(&vm_token); mycpu->gd_cnt.v_tfree++; KKASSERT((m->flags & PG_MAPPED) == 0); if (m->busy || ((m->queue - m->pc) == PQ_FREE)) { kprintf( "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"); } /* * 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); /* * No further management of fictitious pages occurs beyond object * and queue removal. */ if ((m->flags & PG_FICTITIOUS) != 0) { vm_page_wakeup(m); lwkt_reltoken(&vm_token); return; } m->valid = 0; vm_page_undirty(m); if (m->wire_count != 0) { if (m->wire_count > 1) { panic( "vm_page_free: invalid wire count (%d), pindex: 0x%lx", m->wire_count, (long)m->pindex); } panic("vm_page_free: freeing wired page"); } /* * Clear the UNMANAGED flag when freeing an unmanaged page. */ if (m->flags & PG_UNMANAGED) { vm_page_flag_clear(m, PG_UNMANAGED); } if (m->hold_count != 0) { vm_page_flag_clear(m, PG_ZERO); m->queue = PQ_HOLD; } else { 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 { TAILQ_INSERT_HEAD(&pq->pl, m, pageq); } vm_page_wakeup(m); vm_page_free_wakeup(); lwkt_reltoken(&vm_token); } /* * vm_page_free_fromq_fast() * * Remove a non-zero page from one of the free queues; the page is removed for * zeroing, so do not issue a wakeup. * * MPUNSAFE */ vm_page_t vm_page_free_fromq_fast(void) { static int qi; vm_page_t m; int i; lwkt_gettoken(&vm_token); for (i = 0; i < PQ_L2_SIZE; ++i) { m = vm_page_list_find(PQ_FREE, qi, FALSE); qi = (qi + PQ_PRIME2) & PQ_L2_MASK; if (m && (m->flags & PG_ZERO) == 0) { KKASSERT(m->busy == 0 && (m->flags & PG_BUSY) == 0); vm_page_unqueue_nowakeup(m); vm_page_busy(m); break; } m = NULL; } lwkt_reltoken(&vm_token); return (m); } /* * vm_page_unmanage() * * Prevent PV management from being done on the page. The page is * removed from the paging queues as if it were wired, and as a * consequence of no longer being managed the pageout daemon will not * touch it (since there is no way to locate the pte mappings for the * page). madvise() calls that mess with the pmap will also no longer * operate on the page. * * Beyond that the page is still reasonably 'normal'. Freeing the page * will clear the flag. * * This routine is used by OBJT_PHYS objects - objects using unswappable * physical memory as backing store rather then swap-backed memory and * will eventually be extended to support 4MB unmanaged physical * mappings. * * Must be called with a critical section held. * Must be called with vm_token held. */ void vm_page_unmanage(vm_page_t m) { ASSERT_LWKT_TOKEN_HELD(&vm_token); if ((m->flags & PG_UNMANAGED) == 0) { if (m->wire_count == 0) vm_page_unqueue(m); } vm_page_flag_set(m, PG_UNMANAGED); } /* * 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(vm_page_t m) { /* * Only bump the wire statistics if the page is not already wired, * and only unqueue the page if it is on some queue (if it is unmanaged * it is already off the queues). Don't do anything with fictitious * pages because they are always wired. */ lwkt_gettoken(&vm_token); if ((m->flags & PG_FICTITIOUS) == 0) { if (m->wire_count == 0) { if ((m->flags & PG_UNMANAGED) == 0) vm_page_unqueue(m); vmstats.v_wire_count++; } m->wire_count++; KASSERT(m->wire_count != 0, ("vm_page_wire: wire_count overflow m=%p", m)); } lwkt_reltoken(&vm_token); } /* * 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. * * BUT, if we are in a low-memory situation we have no choice but to * put clean pages on the cache queue. * * A number of routines use vm_page_unwire() to guarantee 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(vm_page_t m, int activate) { lwkt_gettoken(&vm_token); if (m->flags & PG_FICTITIOUS) { /* do nothing */ } else if (m->wire_count <= 0) { panic("vm_page_unwire: invalid wire count: %d", m->wire_count); } else { if (--m->wire_count == 0) { --vmstats.v_wire_count; if (m->flags & PG_UNMANAGED) { ; } else if (activate) { TAILQ_INSERT_TAIL( &vm_page_queues[PQ_ACTIVE].pl, m, pageq); m->queue = PQ_ACTIVE; vm_page_queues[PQ_ACTIVE].lcnt++; vmstats.v_active_count++; } else { vm_page_flag_clear(m, PG_WINATCFLS); TAILQ_INSERT_TAIL( &vm_page_queues[PQ_INACTIVE].pl, m, pageq); m->queue = PQ_INACTIVE; vm_page_queues[PQ_INACTIVE].lcnt++; vmstats.v_inactive_count++; ++vm_swapcache_inactive_heuristic; } } } lwkt_reltoken(&vm_token); } /* * Move the specified page to the inactive queue. If the page has * any associated swap, the swap is deallocated. * * Normally athead is 0 resulting in LRU operation. athead is set * to 1 if we want this page to be 'as if it were placed in the cache', * except without unmapping it from the process address space. * * This routine may not block. * The caller must hold vm_token. */ static __inline void _vm_page_deactivate(vm_page_t m, int athead) { /* * Ignore if already inactive. */ if (m->queue == PQ_INACTIVE) return; if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { if ((m->queue - m->pc) == PQ_CACHE) mycpu->gd_cnt.v_reactivated++; vm_page_flag_clear(m, PG_WINATCFLS); vm_page_unqueue(m); if (athead) { TAILQ_INSERT_HEAD(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); } else { TAILQ_INSERT_TAIL(&vm_page_queues[PQ_INACTIVE].pl, m, pageq); ++vm_swapcache_inactive_heuristic; } m->queue = PQ_INACTIVE; vm_page_queues[PQ_INACTIVE].lcnt++; vmstats.v_inactive_count++; } } /* * Attempt to deactivate a page. * * No requirements. */ void vm_page_deactivate(vm_page_t m) { lwkt_gettoken(&vm_token); _vm_page_deactivate(m, 0); lwkt_reltoken(&vm_token); } /* * Attempt to move a page to PQ_CACHE. * Returns 0 on failure, 1 on success * * No requirements. */ int vm_page_try_to_cache(vm_page_t m) { lwkt_gettoken(&vm_token); if (m->dirty || m->hold_count || m->busy || m->wire_count || (m->flags & (PG_BUSY|PG_UNMANAGED))) { lwkt_reltoken(&vm_token); return(0); } vm_page_busy(m); vm_page_test_dirty(m); if (m->dirty) { vm_page_wakeup(m); lwkt_reltoken(&vm_token); return(0); } vm_page_cache(m); lwkt_reltoken(&vm_token); return(1); } /* * Attempt to free the page. If we cannot free it, we do nothing. * 1 is returned on success, 0 on failure. * * No requirements. */ int vm_page_try_to_free(vm_page_t m) { lwkt_gettoken(&vm_token); if (m->dirty || m->hold_count || m->busy || m->wire_count || (m->flags & (PG_BUSY|PG_UNMANAGED))) { lwkt_reltoken(&vm_token); return(0); } vm_page_test_dirty(m); if (m->dirty) { lwkt_reltoken(&vm_token); return(0); } vm_page_busy(m); vm_page_protect(m, VM_PROT_NONE); vm_page_free(m); lwkt_reltoken(&vm_token); return(1); } /* * vm_page_cache * * Put the specified page onto the page cache queue (if appropriate). * * The caller must hold vm_token. * This routine may not block. * The page must be busy, and this routine will release the busy and * possibly even free the page. */ void vm_page_cache(vm_page_t m) { ASSERT_LWKT_TOKEN_HELD(&vm_token); if ((m->flags & PG_UNMANAGED) || m->busy || m->wire_count || m->hold_count) { kprintf("vm_page_cache: attempting to cache busy/held page\n"); vm_page_wakeup(m); return; } /* * Already in the cache (and thus not mapped) */ if ((m->queue - m->pc) == PQ_CACHE) { KKASSERT((m->flags & PG_MAPPED) == 0); vm_page_wakeup(m); return; } /* * Caller is required to test m->dirty, but note that the act of * removing the page from its maps can cause it to become dirty * on an SMP system due to another cpu running in usermode. */ if (m->dirty) { panic("vm_page_cache: caching a dirty page, pindex: %ld", (long)m->pindex); } /* * Remove all pmaps and indicate that the page is not * writeable or mapped. Our vm_page_protect() call may * have blocked (especially w/ VM_PROT_NONE), so recheck * everything. */ vm_page_protect(m, VM_PROT_NONE); if ((m->flags & (PG_UNMANAGED|PG_MAPPED)) || m->busy || m->wire_count || m->hold_count) { vm_page_wakeup(m); } else if (m->dirty) { vm_page_deactivate(m); vm_page_wakeup(m); } else { 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); vmstats.v_cache_count++; vm_page_wakeup(m); vm_page_free_wakeup(); } } /* * vm_page_dontneed() * * Cache, deactivate, or do nothing as appropriate. This routine * is typically used by madvise() MADV_DONTNEED. * * Generally speaking we want to move the page into the cache so * it gets reused quickly. However, this can result in a silly syndrome * due to the page recycling too quickly. Small objects will not be * fully cached. On the otherhand, if we move the page to the inactive * queue we wind up with a problem whereby very large objects * unnecessarily blow away our inactive and cache queues. * * The solution is to move the pages based on a fixed weighting. We * either leave them alone, deactivate them, or move them to the cache, * where moving them to the cache has the highest weighting. * By forcing some pages into other queues we eventually force the * system to balance the queues, potentially recovering other unrelated * space from active. The idea is to not force this to happen too * often. * * No requirements. */ void vm_page_dontneed(vm_page_t m) { static int dnweight; int dnw; int head; dnw = ++dnweight; /* * occassionally leave the page alone */ lwkt_gettoken(&vm_token); if ((dnw & 0x01F0) == 0 || m->queue == PQ_INACTIVE || m->queue - m->pc == PQ_CACHE ) { if (m->act_count >= ACT_INIT) --m->act_count; lwkt_reltoken(&vm_token); return; } /* * If vm_page_dontneed() is inactivating a page, it must clear * the referenced flag; otherwise the pagedaemon will see references * on the page in the inactive queue and reactivate it. Until the * page can move to the cache queue, madvise's job is not done. */ vm_page_flag_clear(m, PG_REFERENCED); pmap_clear_reference(m); if (m->dirty == 0) vm_page_test_dirty(m); if (m->dirty || (dnw & 0x0070) == 0) { /* * Deactivate the page 3 times out of 32. */ head = 0; } else { /* * Cache the page 28 times out of every 32. Note that * the page is deactivated instead of cached, but placed * at the head of the queue instead of the tail. */ head = 1; } _vm_page_deactivate(m, head); lwkt_reltoken(&vm_token); } /* * Grab a page, blocking if it is busy and allocating a page if necessary. * A busy page is returned or NULL. * * If VM_ALLOC_RETRY is specified VM_ALLOC_NORMAL must also be specified. * If VM_ALLOC_RETRY is not specified * * This routine may block, but if VM_ALLOC_RETRY is not set then NULL is * always returned if we had blocked. * This routine will never return NULL if VM_ALLOC_RETRY is set. * This routine may not be called from an interrupt. * The returned page may not be entirely valid. * * This routine may be called from mainline code without spl protection and * be guarenteed a busied page associated with the object at the specified * index. * * No requirements. */ vm_page_t vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags) { vm_page_t m; int generation; KKASSERT(allocflags & (VM_ALLOC_NORMAL|VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM)); lwkt_gettoken(&vm_token); vm_object_hold(object); retrylookup: if ((m = vm_page_lookup(object, pindex)) != NULL) { if (m->busy || (m->flags & PG_BUSY)) { generation = object->generation; while ((object->generation == generation) && (m->busy || (m->flags & PG_BUSY))) { vm_page_flag_set(m, PG_WANTED | PG_REFERENCED); tsleep(m, 0, "pgrbwt", 0); if ((allocflags & VM_ALLOC_RETRY) == 0) { m = NULL; goto done; } } goto retrylookup; } else { vm_page_busy(m); goto done; } } m = vm_page_alloc(object, pindex, allocflags & ~VM_ALLOC_RETRY); if (m == NULL) { vm_wait(0); if ((allocflags & VM_ALLOC_RETRY) == 0) goto done; goto retrylookup; } done: vm_object_drop(object); lwkt_reltoken(&vm_token); 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. * * No requirements. * Non blocking. */ 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)); } /* * Sets portions of a page valid and clean. The arguments are expected * to be DEV_BSIZE aligned but if they aren't the bitmap is inclusive * of any partial chunks touched by the range. The invalid portion of * such chunks will be zero'd. * * NOTE: When truncating a buffer vnode_pager_setsize() will automatically * align base to DEV_BSIZE so as not to mark clean a partially * truncated device block. Otherwise the dirty page status might be * lost. * * This routine may not block. * * (base + size) must be less then or equal to PAGE_SIZE. */ static void _vm_page_zero_valid(vm_page_t m, int base, int size) { 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. We also * use this opportunity to clear the PG_NOSYNC flag. If a process * takes a write fault on a MAP_NOSYNC memory area the flag will * be set again. * * We set valid bits inclusive of any overlap, but we can only * clear dirty bits for DEV_BSIZE chunks that are fully within * the range. * * Page must be busied? * No other requirements. */ void vm_page_set_valid(vm_page_t m, int base, int size) { _vm_page_zero_valid(m, base, size); m->valid |= vm_page_bits(base, size); } /* * Set valid bits and clear dirty bits. * * NOTE: This function does not clear the pmap modified bit. * Also note that e.g. NFS may use a byte-granular base * and size. * * WARNING: Page must be busied? But vfs_clean_one_page() will call * this without necessarily busying the page (via bdwrite()). * So for now vm_token must also be held. * * No other requirements. */ void vm_page_set_validclean(vm_page_t m, int base, int size) { int pagebits; _vm_page_zero_valid(m, base, size); pagebits = vm_page_bits(base, size); m->valid |= pagebits; m->dirty &= ~pagebits; if (base == 0 && size == PAGE_SIZE) { /*pmap_clear_modify(m);*/ vm_page_flag_clear(m, PG_NOSYNC); } } /* * Set valid & dirty. Used by buwrite() * * WARNING: Page must be busied? But vfs_dirty_one_page() will * call this function in buwrite() so for now vm_token must * be held. * * No other requirements. */ void vm_page_set_validdirty(vm_page_t m, int base, int size) { int pagebits; pagebits = vm_page_bits(base, size); m->valid |= pagebits; m->dirty |= pagebits; if (m->object) vm_object_set_writeable_dirty(m->object); } /* * Clear dirty bits. * * NOTE: This function does not clear the pmap modified bit. * Also note that e.g. NFS may use a byte-granular base * and size. * * Page must be busied? * No other requirements. */ void vm_page_clear_dirty(vm_page_t m, int base, int size) { m->dirty &= ~vm_page_bits(base, size); if (base == 0 && size == PAGE_SIZE) { /*pmap_clear_modify(m);*/ vm_page_flag_clear(m, PG_NOSYNC); } } /* * Make the page all-dirty. * * Also make sure the related object and vnode reflect the fact that the * object may now contain a dirty page. * * Page must be busied? * No other requirements. */ void vm_page_dirty(vm_page_t m) { #ifdef INVARIANTS int pqtype = m->queue - m->pc; #endif KASSERT(pqtype != PQ_CACHE && pqtype != PQ_FREE, ("vm_page_dirty: page in free/cache queue!")); if (m->dirty != VM_PAGE_BITS_ALL) { m->dirty = VM_PAGE_BITS_ALL; if (m->object) vm_object_set_writeable_dirty(m->object); } } /* * Invalidates DEV_BSIZE'd chunks within a page. Both the * valid and dirty bits for the effected areas are cleared. * * Page must be busied? * Does not block. * No other requirements. */ void vm_page_set_invalid(vm_page_t m, int base, int size) { int bits; bits = vm_page_bits(base, size); m->valid &= ~bits; m->dirty &= ~bits; m->object->generation++; } /* * 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. * * Page must be busied? * No other requirements. */ 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 consistency * 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; } /* * Is a (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. * * Does not block. * No other requirements. */ int vm_page_is_valid(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. * * Caller must hold vm_token if non-blocking operation desired. * No other requirements. */ void vm_page_test_dirty(vm_page_t m) { if ((m->dirty != VM_PAGE_BITS_ALL) && pmap_is_modified(m)) { vm_page_dirty(m); } } /* * Register an action, associating it with its vm_page */ void vm_page_register_action(vm_page_action_t action, vm_page_event_t event) { struct vm_page_action_list *list; int hv; hv = (int)((intptr_t)action->m >> 8) & VMACTION_HMASK; list = &action_list[hv]; lwkt_gettoken(&vm_token); vm_page_flag_set(action->m, PG_ACTIONLIST); action->event = event; LIST_INSERT_HEAD(list, action, entry); lwkt_reltoken(&vm_token); } /* * Unregister an action, disassociating it from its related vm_page */ void vm_page_unregister_action(vm_page_action_t action) { struct vm_page_action_list *list; int hv; lwkt_gettoken(&vm_token); if (action->event != VMEVENT_NONE) { action->event = VMEVENT_NONE; LIST_REMOVE(action, entry); hv = (int)((intptr_t)action->m >> 8) & VMACTION_HMASK; list = &action_list[hv]; if (LIST_EMPTY(list)) vm_page_flag_clear(action->m, PG_ACTIONLIST); } lwkt_reltoken(&vm_token); } /* * Issue an event on a VM page. Corresponding action structures are * removed from the page's list and called. * * If the vm_page has no more pending action events we clear its * PG_ACTIONLIST flag. */ void vm_page_event_internal(vm_page_t m, vm_page_event_t event) { struct vm_page_action_list *list; struct vm_page_action *scan; struct vm_page_action *next; int hv; int all; hv = (int)((intptr_t)m >> 8) & VMACTION_HMASK; list = &action_list[hv]; all = 1; lwkt_gettoken(&vm_token); LIST_FOREACH_MUTABLE(scan, list, entry, next) { if (scan->m == m) { if (scan->event == event) { scan->event = VMEVENT_NONE; LIST_REMOVE(scan, entry); scan->func(m, scan); /* XXX */ } else { all = 0; } } } if (all) vm_page_flag_clear(m, PG_ACTIONLIST); lwkt_reltoken(&vm_token); } #include "opt_ddb.h" #ifdef DDB #include #include DB_SHOW_COMMAND(page, vm_page_print_page_info) { db_printf("vmstats.v_free_count: %d\n", vmstats.v_free_count); db_printf("vmstats.v_cache_count: %d\n", vmstats.v_cache_count); db_printf("vmstats.v_inactive_count: %d\n", vmstats.v_inactive_count); db_printf("vmstats.v_active_count: %d\n", vmstats.v_active_count); db_printf("vmstats.v_wire_count: %d\n", vmstats.v_wire_count); db_printf("vmstats.v_free_reserved: %d\n", vmstats.v_free_reserved); db_printf("vmstats.v_free_min: %d\n", vmstats.v_free_min); db_printf("vmstats.v_free_target: %d\n", vmstats.v_free_target); db_printf("vmstats.v_cache_min: %d\n", vmstats.v_cache_min); db_printf("vmstats.v_inactive_target: %d\n", vmstats.v_inactive_target); } DB_SHOW_COMMAND(pageq, vm_page_print_pageq_info) { int i; db_printf("PQ_FREE:"); for(i=0;i