/* * (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 #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(u_short pg_color); static vm_page_t _vm_page_list_find2(int basequeue, int index); static void _vm_page_deactivate_locked(vm_page_t m, int athead); /* * Array of tailq lists */ __cachealign struct vpgqueues vm_page_queues[PQ_COUNT]; LIST_HEAD(vm_page_action_list, vm_page_action); struct vm_page_action_list action_list[VMACTION_HSIZE]; static volatile int vm_pages_waiting; static struct alist vm_contig_alist; static struct almeta vm_contig_ameta[ALIST_RECORDS_65536]; static struct spinlock vm_contig_spin = SPINLOCK_INITIALIZER(&vm_contig_spin); static u_long vm_dma_reserved = 0; TUNABLE_ULONG("vm.dma_reserved", &vm_dma_reserved); SYSCTL_ULONG(_vm, OID_AUTO, dma_reserved, CTLFLAG_RD, &vm_dma_reserved, 0, "Memory reserved for DMA"); SYSCTL_UINT(_vm, OID_AUTO, dma_free_pages, CTLFLAG_RD, &vm_contig_alist.bl_free, 0, "Memory reserved for DMA"); 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; for (i = 0; i < PQ_L2_SIZE; i++) vm_page_queues[PQ_INACTIVE+i].cnt = &vmstats.v_inactive_count; for (i = 0; i < PQ_L2_SIZE; i++) vm_page_queues[PQ_ACTIVE+i].cnt = &vmstats.v_active_count; for (i = 0; i < PQ_L2_SIZE; i++) vm_page_queues[PQ_HOLD+i].cnt = &vmstats.v_active_count; /* PQ_NONE has no queue */ for (i = 0; i < PQ_COUNT; i++) { TAILQ_INIT(&vm_page_queues[i].pl); spin_init(&vm_page_queues[i].spin); } 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 = NULL; vm_paddr_t vm_low_phys_reserved; /* * (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. * * Beware that the page zeroing daemon will also be running soon after * boot, moving pages from the head to the tail of the PQ_FREE queues. * * Must be called in a critical section. */ static void vm_add_new_page(vm_paddr_t pa) { struct vpgqueues *vpq; vm_page_t m; m = PHYS_TO_VM_PAGE(pa); m->phys_addr = pa; m->flags = 0; m->pc = (pa >> PAGE_SHIFT) & PQ_L2_MASK; #ifdef SMP /* * Twist for cpu localization in addition to page coloring, so * different cpus selecting by m->queue get different page colors. */ m->pc ^= ((pa >> PAGE_SHIFT) / PQ_L2_SIZE) & PQ_L2_MASK; m->pc ^= ((pa >> PAGE_SHIFT) / (PQ_L2_SIZE * PQ_L2_SIZE)) & PQ_L2_MASK; #endif /* * Reserve a certain number of contiguous low memory pages for * contigmalloc() to use. */ if (pa < vm_low_phys_reserved) { atomic_add_int(&vmstats.v_page_count, 1); atomic_add_int(&vmstats.v_dma_pages, 1); m->queue = PQ_NONE; m->wire_count = 1; atomic_add_int(&vmstats.v_wire_count, 1); alist_free(&vm_contig_alist, pa >> PAGE_SHIFT, 1); return; } /* * General page */ m->queue = m->pc + PQ_FREE; KKASSERT(m->dirty == 0); atomic_add_int(&vmstats.v_page_count, 1); atomic_add_int(&vmstats.v_free_count, 1); vpq = &vm_page_queues[m->queue]; if ((vpq->flipflop & 15) == 0) { pmap_zero_page(VM_PAGE_TO_PHYS(m)); m->flags |= PG_ZERO; TAILQ_INSERT_TAIL(&vpq->pl, m, pageq); atomic_add_int(&vm_page_zero_count, 1); } else { TAILQ_INSERT_HEAD(&vpq->pl, m, pageq); } ++vpq->flipflop; ++vpq->lcnt; } /* * (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(); #if !defined(_KERNEL_VIRTUAL) /* * VKERNELs don't support minidumps and as such don't need * vm_page_dump * * 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; #ifndef _KERNEL_VIRTUAL /* * (only applies to real kernels) * * Initialize the contiguous reserve map. We initially reserve up * to 1/4 available physical memory or 65536 pages (~256MB), whichever * is lower. * * Once device initialization is complete we return most of the * reserved memory back to the normal page queues but leave some * in reserve for things like usb attachments. */ vm_low_phys_reserved = (vm_paddr_t)65536 << PAGE_SHIFT; if (vm_low_phys_reserved > total / 4) vm_low_phys_reserved = total / 4; if (vm_dma_reserved == 0) { vm_dma_reserved = 16 * 1024 * 1024; /* 16MB */ if (vm_dma_reserved > total / 16) vm_dma_reserved = total / 16; } #endif alist_init(&vm_contig_alist, 65536, vm_contig_ameta, ALIST_RECORDS_65536); /* * 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; } /* * We tended to reserve a ton of memory for contigmalloc(). Now that most * drivers have initialized we want to return most the remaining free * reserve back to the VM page queues so they can be used for normal * allocations. * * We leave vm_dma_reserved bytes worth of free pages in the reserve pool. */ static void vm_page_startup_finish(void *dummy __unused) { alist_blk_t blk; alist_blk_t rblk; alist_blk_t count; alist_blk_t xcount; alist_blk_t bfree; vm_page_t m; spin_lock(&vm_contig_spin); for (;;) { bfree = alist_free_info(&vm_contig_alist, &blk, &count); if (bfree <= vm_dma_reserved / PAGE_SIZE) break; if (count == 0) break; /* * Figure out how much of the initial reserve we have to * free in order to reach our target. */ bfree -= vm_dma_reserved / PAGE_SIZE; if (count > bfree) { blk += count - bfree; count = bfree; } /* * Calculate the nearest power of 2 <= count. */ for (xcount = 1; xcount <= count; xcount <<= 1) ; xcount >>= 1; blk += count - xcount; count = xcount; /* * Allocate the pages from the alist, then free them to * the normal VM page queues. * * Pages allocated from the alist are wired. We have to * busy, unwire, and free them. We must also adjust * vm_low_phys_reserved before freeing any pages to prevent * confusion. */ rblk = alist_alloc(&vm_contig_alist, blk, count); if (rblk != blk) { kprintf("vm_page_startup_finish: Unable to return " "dma space @0x%08x/%d -> 0x%08x\n", blk, count, rblk); break; } atomic_add_int(&vmstats.v_dma_pages, -count); spin_unlock(&vm_contig_spin); m = PHYS_TO_VM_PAGE((vm_paddr_t)blk << PAGE_SHIFT); vm_low_phys_reserved = VM_PAGE_TO_PHYS(m); while (count) { vm_page_busy_wait(m, FALSE, "cpgfr"); vm_page_unwire(m, 0); vm_page_free(m); --count; ++m; } spin_lock(&vm_contig_spin); } spin_unlock(&vm_contig_spin); /* * Print out how much DMA space drivers have already allocated and * how much is left over. */ kprintf("DMA space used: %jdk, remaining available: %jdk\n", (intmax_t)(vmstats.v_dma_pages - vm_contig_alist.bl_free) * (PAGE_SIZE / 1024), (intmax_t)vm_contig_alist.bl_free * (PAGE_SIZE / 1024)); } SYSINIT(vm_pgend, SI_SUB_PROC0_POST, SI_ORDER_ANY, vm_page_startup_finish, NULL) /* * 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); } /* * Each page queue has its own spin lock, which is fairly optimal for * allocating and freeing pages at least. * * The caller must hold the vm_page_spin_lock() before locking a vm_page's * queue spinlock via this function. Also note that m->queue cannot change * unless both the page and queue are locked. */ static __inline void _vm_page_queue_spin_lock(vm_page_t m) { u_short queue; queue = m->queue; if (queue != PQ_NONE) { spin_lock(&vm_page_queues[queue].spin); KKASSERT(queue == m->queue); } } static __inline void _vm_page_queue_spin_unlock(vm_page_t m) { u_short queue; queue = m->queue; cpu_ccfence(); if (queue != PQ_NONE) spin_unlock(&vm_page_queues[queue].spin); } static __inline void _vm_page_queues_spin_lock(u_short queue) { cpu_ccfence(); if (queue != PQ_NONE) spin_lock(&vm_page_queues[queue].spin); } static __inline void _vm_page_queues_spin_unlock(u_short queue) { cpu_ccfence(); if (queue != PQ_NONE) spin_unlock(&vm_page_queues[queue].spin); } void vm_page_queue_spin_lock(vm_page_t m) { _vm_page_queue_spin_lock(m); } void vm_page_queues_spin_lock(u_short queue) { _vm_page_queues_spin_lock(queue); } void vm_page_queue_spin_unlock(vm_page_t m) { _vm_page_queue_spin_unlock(m); } void vm_page_queues_spin_unlock(u_short queue) { _vm_page_queues_spin_unlock(queue); } /* * This locks the specified vm_page and its queue in the proper order * (page first, then queue). The queue may change so the caller must * recheck on return. */ static __inline void _vm_page_and_queue_spin_lock(vm_page_t m) { vm_page_spin_lock(m); _vm_page_queue_spin_lock(m); } static __inline void _vm_page_and_queue_spin_unlock(vm_page_t m) { _vm_page_queues_spin_unlock(m->queue); vm_page_spin_unlock(m); } void vm_page_and_queue_spin_unlock(vm_page_t m) { _vm_page_and_queue_spin_unlock(m); } void vm_page_and_queue_spin_lock(vm_page_t m) { _vm_page_and_queue_spin_lock(m); } /* * Helper function removes vm_page from its current queue. * Returns the base queue the page used to be on. * * The vm_page and the queue must be spinlocked. * This function will unlock the queue but leave the page spinlocked. */ static __inline u_short _vm_page_rem_queue_spinlocked(vm_page_t m) { struct vpgqueues *pq; u_short queue; queue = m->queue; if (queue != PQ_NONE) { pq = &vm_page_queues[queue]; TAILQ_REMOVE(&pq->pl, m, pageq); atomic_add_int(pq->cnt, -1); pq->lcnt--; m->queue = PQ_NONE; vm_page_queues_spin_unlock(queue); if ((queue - m->pc) == PQ_FREE && (m->flags & PG_ZERO)) atomic_subtract_int(&vm_page_zero_count, 1); if ((queue - m->pc) == PQ_CACHE || (queue - m->pc) == PQ_FREE) return (queue - m->pc); } return queue; } /* * Helper function places the vm_page on the specified queue. * * The vm_page must be spinlocked. * This function will return with both the page and the queue locked. */ static __inline void _vm_page_add_queue_spinlocked(vm_page_t m, u_short queue, int athead) { struct vpgqueues *pq; KKASSERT(m->queue == PQ_NONE); if (queue != PQ_NONE) { vm_page_queues_spin_lock(queue); pq = &vm_page_queues[queue]; ++pq->lcnt; atomic_add_int(pq->cnt, 1); m->queue = queue; /* * Put zero'd pages on the end ( where we look for zero'd pages * first ) and non-zerod pages at the head. */ if (queue - m->pc == PQ_FREE) { if (m->flags & PG_ZERO) { TAILQ_INSERT_TAIL(&pq->pl, m, pageq); atomic_add_int(&vm_page_zero_count, 1); } else { TAILQ_INSERT_HEAD(&pq->pl, m, pageq); } } else if (athead) { TAILQ_INSERT_HEAD(&pq->pl, m, pageq); } else { TAILQ_INSERT_TAIL(&pq->pl, m, pageq); } /* leave the queue spinlocked */ } } /* * Wait until page is no longer PG_BUSY or (if also_m_busy is TRUE) * m->busy is zero. Returns TRUE if it had to sleep, FALSE if we * did not. Only one sleep call will be made before returning. * * This function does NOT busy the page and on return the page is not * guaranteed to be available. */ void vm_page_sleep_busy(vm_page_t m, int also_m_busy, const char *msg) { u_int32_t flags; for (;;) { flags = m->flags; cpu_ccfence(); if ((flags & PG_BUSY) == 0 && (also_m_busy == 0 || (flags & PG_SBUSY) == 0)) { break; } tsleep_interlock(m, 0); if (atomic_cmpset_int(&m->flags, flags, flags | PG_WANTED | PG_REFERENCED)) { tsleep(m, PINTERLOCKED, msg, 0); break; } } } /* * Wait until PG_BUSY can be set, then set it. If also_m_busy is TRUE we * also wait for m->busy to become 0 before setting PG_BUSY. */ void VM_PAGE_DEBUG_EXT(vm_page_busy_wait)(vm_page_t m, int also_m_busy, const char *msg VM_PAGE_DEBUG_ARGS) { u_int32_t flags; for (;;) { flags = m->flags; cpu_ccfence(); if (flags & PG_BUSY) { tsleep_interlock(m, 0); if (atomic_cmpset_int(&m->flags, flags, flags | PG_WANTED | PG_REFERENCED)) { tsleep(m, PINTERLOCKED, msg, 0); } } else if (also_m_busy && (flags & PG_SBUSY)) { tsleep_interlock(m, 0); if (atomic_cmpset_int(&m->flags, flags, flags | PG_WANTED | PG_REFERENCED)) { tsleep(m, PINTERLOCKED, msg, 0); } } else { if (atomic_cmpset_int(&m->flags, flags, flags | PG_BUSY)) { #ifdef VM_PAGE_DEBUG m->busy_func = func; m->busy_line = lineno; #endif break; } } } } /* * Attempt to set PG_BUSY. If also_m_busy is TRUE we only succeed if m->busy * is also 0. * * Returns non-zero on failure. */ int VM_PAGE_DEBUG_EXT(vm_page_busy_try)(vm_page_t m, int also_m_busy VM_PAGE_DEBUG_ARGS) { u_int32_t flags; for (;;) { flags = m->flags; cpu_ccfence(); if (flags & PG_BUSY) return TRUE; if (also_m_busy && (flags & PG_SBUSY)) return TRUE; if (atomic_cmpset_int(&m->flags, flags, flags | PG_BUSY)) { #ifdef VM_PAGE_DEBUG m->busy_func = func; m->busy_line = lineno; #endif return FALSE; } } } /* * Clear the PG_BUSY flag and return non-zero to indicate to the caller * that a wakeup() should be performed. * * The vm_page must be spinlocked and will remain spinlocked on return. * The related queue must NOT be spinlocked (which could deadlock us). * * (inline version) */ static __inline int _vm_page_wakeup(vm_page_t m) { u_int32_t flags; for (;;) { flags = m->flags; cpu_ccfence(); if (atomic_cmpset_int(&m->flags, flags, flags & ~(PG_BUSY | PG_WANTED))) { break; } } return(flags & PG_WANTED); } /* * Clear the PG_BUSY flag and wakeup anyone waiting for the page. This * is typically the last call you make on a page before moving onto * other things. */ void vm_page_wakeup(vm_page_t m) { KASSERT(m->flags & PG_BUSY, ("vm_page_wakeup: page not busy!!!")); vm_page_spin_lock(m); if (_vm_page_wakeup(m)) { vm_page_spin_unlock(m); wakeup(m); } else { vm_page_spin_unlock(m); } } /* * 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 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. * * XXX get vm_page_spin_lock() here and move FREE->HOLD if necessary */ void vm_page_hold(vm_page_t m) { vm_page_spin_lock(m); atomic_add_int(&m->hold_count, 1); if (m->queue - m->pc == PQ_FREE) { _vm_page_queue_spin_lock(m); _vm_page_rem_queue_spinlocked(m); _vm_page_add_queue_spinlocked(m, PQ_HOLD + m->pc, 0); _vm_page_queue_spin_unlock(m); } vm_page_spin_unlock(m); } /* * The opposite of vm_page_hold(). A page can be freed while being held, * which places it on the PQ_HOLD queue. If we are able to busy the page * after the hold count drops to zero we will move the page to the * appropriate PQ_FREE queue by calling vm_page_free_toq(). */ void vm_page_unhold(vm_page_t m) { vm_page_spin_lock(m); atomic_add_int(&m->hold_count, -1); if (m->hold_count == 0 && m->queue - m->pc == PQ_HOLD) { _vm_page_queue_spin_lock(m); _vm_page_rem_queue_spinlocked(m); _vm_page_add_queue_spinlocked(m, PQ_FREE + m->pc, 0); _vm_page_queue_spin_unlock(m); } vm_page_spin_unlock(m); } /* * 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_object held. * This routine must be called with a critical section held. * * This routine returns TRUE if the page was inserted into the object * successfully, and FALSE if the page already exists in the object. */ int vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex) { ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); if (m->object != NULL) panic("vm_page_insert: already inserted"); object->generation++; /* * Record the object/offset pair in this page and add the * pv_list_count of the page to the object. * * The vm_page spin lock is required for interactions with the pmap. */ vm_page_spin_lock(m); m->object = object; m->pindex = pindex; if (vm_page_rb_tree_RB_INSERT(&object->rb_memq, m)) { m->object = NULL; m->pindex = 0; vm_page_spin_unlock(m); return FALSE; } object->resident_page_count++; /* atomic_add_int(&object->agg_pv_list_count, m->md.pv_list_count); */ vm_page_spin_unlock(m); /* * 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); return TRUE; } /* * Removes the given vm_page_t from the (object,index) table * * 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; if (m->object == NULL) { 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. * * The vm_page spin lock is required for interactions with the pmap. */ vm_page_spin_lock(m); vm_page_rb_tree_RB_REMOVE(&object->rb_memq, m); object->resident_page_count--; /* atomic_add_int(&object->agg_pv_list_count, -m->md.pv_list_count); */ m->object = NULL; vm_page_spin_unlock(m); object->generation++; vm_object_drop(object); } /* * Locate and return the page at (object, pindex), or NULL if the * page could not be found. * * The caller must hold the vm_object 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_object_token(object)); m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); KKASSERT(m == NULL || (m->object == object && m->pindex == pindex)); return(m); } vm_page_t VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_wait)(struct vm_object *object, vm_pindex_t pindex, int also_m_busy, const char *msg VM_PAGE_DEBUG_ARGS) { u_int32_t flags; vm_page_t m; ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); while (m) { KKASSERT(m->object == object && m->pindex == pindex); flags = m->flags; cpu_ccfence(); if (flags & PG_BUSY) { tsleep_interlock(m, 0); if (atomic_cmpset_int(&m->flags, flags, flags | PG_WANTED | PG_REFERENCED)) { tsleep(m, PINTERLOCKED, msg, 0); m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); } } else if (also_m_busy && (flags & PG_SBUSY)) { tsleep_interlock(m, 0); if (atomic_cmpset_int(&m->flags, flags, flags | PG_WANTED | PG_REFERENCED)) { tsleep(m, PINTERLOCKED, msg, 0); m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); } } else if (atomic_cmpset_int(&m->flags, flags, flags | PG_BUSY)) { #ifdef VM_PAGE_DEBUG m->busy_func = func; m->busy_line = lineno; #endif break; } } return m; } /* * Attempt to lookup and busy a page. * * Returns NULL if the page could not be found * * Returns a vm_page and error == TRUE if the page exists but could not * be busied. * * Returns a vm_page and error == FALSE on success. */ vm_page_t VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_try)(struct vm_object *object, vm_pindex_t pindex, int also_m_busy, int *errorp VM_PAGE_DEBUG_ARGS) { u_int32_t flags; vm_page_t m; ASSERT_LWKT_TOKEN_HELD(vm_object_token(object)); m = vm_page_rb_tree_RB_LOOKUP(&object->rb_memq, pindex); *errorp = FALSE; while (m) { KKASSERT(m->object == object && m->pindex == pindex); flags = m->flags; cpu_ccfence(); if (flags & PG_BUSY) { *errorp = TRUE; break; } if (also_m_busy && (flags & PG_SBUSY)) { *errorp = TRUE; break; } if (atomic_cmpset_int(&m->flags, flags, flags | PG_BUSY)) { #ifdef VM_PAGE_DEBUG m->busy_func = func; m->busy_line = lineno; #endif break; } } return m; } /* * Caller must hold the related vm_object */ vm_page_t vm_page_next(vm_page_t m) { vm_page_t next; next = vm_page_rb_tree_RB_NEXT(m); if (next && next->pindex != m->pindex + 1) next = NULL; return (next); } /* * vm_page_rename() * * Move the given vm_page from its current object to the specified * target object/offset. The page must be busy and will remain so * on return. * * new_object must be held. * This routine might block. XXX ? * * 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) { KKASSERT(m->flags & PG_BUSY); ASSERT_LWKT_TOKEN_HELD(vm_object_token(new_object)); if (m->object) { ASSERT_LWKT_TOKEN_HELD(vm_object_token(m->object)); vm_page_remove(m); } if (vm_page_insert(m, new_object, new_pindex) == FALSE) { panic("vm_page_rename: target exists (%p,%"PRIu64")", new_object, new_pindex); } if (m->queue - m->pc == PQ_CACHE) vm_page_deactivate(m); vm_page_dirty(m); } /* * 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. * * This routine may not block. */ void vm_page_unqueue_nowakeup(vm_page_t m) { vm_page_and_queue_spin_lock(m); (void)_vm_page_rem_queue_spinlocked(m); vm_page_spin_unlock(m); } /* * vm_page_unqueue() - Remove a page from its queue, wakeup the pagedemon * if necessary. * * This routine may not block. */ void vm_page_unqueue(vm_page_t m) { u_short queue; vm_page_and_queue_spin_lock(m); queue = _vm_page_rem_queue_spinlocked(m); if (queue == PQ_FREE || queue == PQ_CACHE) { vm_page_spin_unlock(m); pagedaemon_wakeup(); } else { vm_page_spin_unlock(m); } } /* * 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. * * On MP systems each PQ_FREE and PQ_CACHE color queue has its own spinlock * and the algorithm is adjusted to localize allocations on a per-core basis. * This is done by 'twisting' the colors. * * The page is returned spinlocked and removed from its queue (it will * be on PQ_NONE), or NULL. The page is not PG_BUSY'd. The caller * is responsible for dealing with the busy-page case (usually by * deactivating the page and looping). * * NOTE: 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. * * NOTE: This routine assumes that the vm_pages found in PQ_CACHE and PQ_FREE * represent stable storage, allowing us to order our locks vm_page * first, then queue. */ static __inline vm_page_t _vm_page_list_find(int basequeue, int index, boolean_t prefer_zero) { vm_page_t m; for (;;) { 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); } vm_page_and_queue_spin_lock(m); if (m->queue == basequeue + index) { _vm_page_rem_queue_spinlocked(m); /* vm_page_t spin held, no queue spin */ break; } vm_page_and_queue_spin_unlock(m); } 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) { for (;;) { m = TAILQ_FIRST(&pq[(index + i) & PQ_L2_MASK].pl); if (m) { _vm_page_and_queue_spin_lock(m); if (m->queue == basequeue + ((index + i) & PQ_L2_MASK)) { _vm_page_rem_queue_spinlocked(m); return(m); } _vm_page_and_queue_spin_unlock(m); continue; } m = TAILQ_FIRST(&pq[(index - i) & PQ_L2_MASK].pl); if (m) { _vm_page_and_queue_spin_lock(m); if (m->queue == basequeue + ((index - i) & PQ_L2_MASK)) { _vm_page_rem_queue_spinlocked(m); return(m); } _vm_page_and_queue_spin_unlock(m); continue; } break; /* next i */ } } return(m); } /* * Returns a vm_page candidate for allocation. The page is not busied so * it can move around. The caller must busy the page (and typically * deactivate it if it cannot be busied!) * * Returns a spinlocked vm_page that has been removed from its queue. */ 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, remove it * from the queue, and busy it. The returned page will not be spinlocked. * * A candidate failure will be deactivated. Candidates can fail due to * being busied by someone else, in which case they will be deactivated. * * This routine may not block. * */ static vm_page_t vm_page_select_cache(u_short pg_color) { vm_page_t m; for (;;) { m = _vm_page_list_find(PQ_CACHE, pg_color & PQ_L2_MASK, FALSE); if (m == NULL) break; /* * (m) has been removed from its queue and spinlocked */ if (vm_page_busy_try(m, TRUE)) { _vm_page_deactivate_locked(m, 0); vm_page_spin_unlock(m); #ifdef INVARIANTS kprintf("Warning: busy page %p found in cache\n", m); #endif } else { /* * We successfully busied the page */ if ((m->flags & PG_UNMANAGED) == 0 && m->hold_count == 0 && m->wire_count == 0) { vm_page_spin_unlock(m); pagedaemon_wakeup(); return(m); } _vm_page_deactivate_locked(m, 0); if (_vm_page_wakeup(m)) { vm_page_spin_unlock(m); wakeup(m); } else { vm_page_spin_unlock(m); } } } return (m); } /* * 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. A busied page is removed from the queue and returned. * * This routine may not block. */ static __inline vm_page_t vm_page_select_free(u_short pg_color, boolean_t prefer_zero) { vm_page_t m; for (;;) { m = _vm_page_list_find(PQ_FREE, pg_color & PQ_L2_MASK, prefer_zero); if (m == NULL) break; if (vm_page_busy_try(m, TRUE)) { /* * Various mechanisms such as a pmap_collect can * result in a busy page on the free queue. We * have to move the page out of the way so we can * retry the allocation. If the other thread is not * allocating the page then m->valid will remain 0 and * the pageout daemon will free the page later on. * * Since we could not busy the page, however, we * cannot make assumptions as to whether the page * will be allocated by the other thread or not, * so all we can do is deactivate it to move it out * of the way. In particular, if the other thread * wires the page it may wind up on the inactive * queue and the pageout daemon will have to deal * with that case too. */ _vm_page_deactivate_locked(m, 0); vm_page_spin_unlock(m); #ifdef INVARIANTS kprintf("Warning: busy page %p found in cache\n", m); #endif } else { /* * Theoretically if we are able to busy the page * atomic with the queue removal (using the vm_page * lock) nobody else should be able to mess with the * page before us. */ KKASSERT((m->flags & PG_UNMANAGED) == 0); KKASSERT(m->hold_count == 0); KKASSERT(m->wire_count == 0); vm_page_spin_unlock(m); pagedaemon_wakeup(); /* return busied and removed page */ return(m); } } return(m); } /* * This implements a per-cpu cache of free, zero'd, ready-to-go pages. * The idea is to populate this cache prior to acquiring any locks so * we don't wind up potentially zeroing VM pages (under heavy loads) while * holding potentialy contending locks. * * Note that we allocate the page uninserted into anything and use a pindex * of 0, the vm_page_alloc() will effectively add gd_cpuid so these * allocations should wind up being uncontended. However, we still want * to rove across PQ_L2_SIZE. */ void vm_page_pcpu_cache(void) { #if 0 globaldata_t gd = mycpu; vm_page_t m; if (gd->gd_vmpg_count < GD_MINVMPG) { crit_enter_gd(gd); while (gd->gd_vmpg_count < GD_MAXVMPG) { m = vm_page_alloc(NULL, ticks & ~ncpus2_mask, VM_ALLOC_NULL_OK | VM_ALLOC_NORMAL | VM_ALLOC_NULL_OK | VM_ALLOC_ZERO); if (gd->gd_vmpg_count < GD_MAXVMPG) { if ((m->flags & PG_ZERO) == 0) { pmap_zero_page(VM_PAGE_TO_PHYS(m)); vm_page_flag_set(m, PG_ZERO); } gd->gd_vmpg_array[gd->gd_vmpg_count++] = m; } else { vm_page_free(m); } } crit_exit_gd(gd); } #endif } /* * vm_page_alloc() * * Allocate and return a memory cell associated with this VM object/offset * pair. If object is NULL an unassociated page will be allocated. * * The returned page will be busied and removed from its queues. This * routine can block and may return NULL if a race occurs and the page * is found to already exist at the specified (object, pindex). * * 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 only * VM_ALLOC_FORCE_ZERO advisory request for pre-zero'd page only * VM_ALLOC_NULL_OK ok to return NULL on insertion collision * (see vm_page_grab()) * VM_ALLOC_USE_GD ok to use per-gd cache * * The object must be held if not NULL * 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(vm_object_t object, vm_pindex_t pindex, int page_req) { #ifdef SMP globaldata_t gd = mycpu; #endif vm_object_t obj; vm_page_t m; u_short pg_color; #if 0 /* * Special per-cpu free VM page cache. The pages are pre-busied * and pre-zerod for us. */ if (gd->gd_vmpg_count && (page_req & VM_ALLOC_USE_GD)) { crit_enter_gd(gd); if (gd->gd_vmpg_count) { m = gd->gd_vmpg_array[--gd->gd_vmpg_count]; crit_exit_gd(gd); goto done; } crit_exit_gd(gd); } #endif m = NULL; #ifdef SMP /* * Cpu twist - cpu localization algorithm */ if (object) { pg_color = gd->gd_cpuid + (pindex & ~ncpus_fit_mask) + (object->pg_color & ~ncpus_fit_mask); } else { pg_color = gd->gd_cpuid + (pindex & ~ncpus_fit_mask); } #else /* * Normal page coloring algorithm */ if (object) { pg_color = object->pg_color + pindex; } else { pg_color = pindex; } #endif 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 | VM_ALLOC_FORCE_ZERO)) m = vm_page_select_free(pg_color, TRUE); else m = vm_page_select_free(pg_color, 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(pg_color); } #else m = vm_page_select_cache(pg_color); #endif /* * On success move the page into the free queue and loop. * * Only do this if we can safely acquire the vm_object lock, * because this is effectively a random page and the caller * might be holding the lock shared, we don't want to * deadlock. */ if (m != NULL) { KASSERT(m->dirty == 0, ("Found dirty cache page %p", m)); if ((obj = m->object) != NULL) { if (vm_object_hold_try(obj)) { vm_page_protect(m, VM_PROT_NONE); vm_page_free(m); /* m->object NULL here */ vm_object_drop(obj); } else { vm_page_deactivate(m); vm_page_wakeup(m); } } else { vm_page_protect(m, VM_PROT_NONE); vm_page_free(m); } goto loop; } /* * On failure return NULL */ #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. */ vm_pageout_deficit++; pagedaemon_wakeup(); return (NULL); } /* * v_free_count can race so loop if we don't find the expected * page. */ if (m == NULL) goto loop; /* * Good page found. The page has already been busied for us and * removed from its queues. */ KASSERT(m->dirty == 0, ("vm_page_alloc: free/cache page %p was dirty", m)); KKASSERT(m->queue == PQ_NONE); #if 0 done: #endif /* * Initialize the structure, inheriting some flags but clearing * all the rest. The page has already been busied for us. */ vm_page_flag_clear(m, ~(PG_ZERO | PG_BUSY | PG_SBUSY)); KKASSERT(m->wire_count == 0); KKASSERT(m->busy == 0); m->act_count = 0; m->valid = 0; /* * Caller must be holding the object lock (asserted by * vm_page_insert()). * * NOTE: Inserting a page here does not insert it into any pmaps * (which could cause us to block allocating memory). * * NOTE: If no object an unassociated page is allocated, m->pindex * can be used by the caller for any purpose. */ if (object) { if (vm_page_insert(m, object, pindex) == FALSE) { kprintf("PAGE RACE (%p:%d,%"PRIu64")\n", object, object->type, pindex); vm_page_free(m); m = NULL; if ((page_req & VM_ALLOC_NULL_OK) == 0) panic("PAGE RACE"); } } else { m->pindex = pindex; } /* * Don't wakeup too often - wakeup the pageout daemon when * we would be nearly out of memory. */ pagedaemon_wakeup(); /* * A PG_BUSY page is returned. */ return (m); } /* * Attempt to allocate contiguous physical memory with the specified * requirements. */ vm_page_t vm_page_alloc_contig(vm_paddr_t low, vm_paddr_t high, unsigned long alignment, unsigned long boundary, unsigned long size) { alist_blk_t blk; alignment >>= PAGE_SHIFT; if (alignment == 0) alignment = 1; boundary >>= PAGE_SHIFT; if (boundary == 0) boundary = 1; size = (size + PAGE_MASK) >> PAGE_SHIFT; spin_lock(&vm_contig_spin); blk = alist_alloc(&vm_contig_alist, 0, size); if (blk == ALIST_BLOCK_NONE) { spin_unlock(&vm_contig_spin); if (bootverbose) { kprintf("vm_page_alloc_contig: %ldk nospace\n", (size + PAGE_MASK) * (PAGE_SIZE / 1024)); } return(NULL); } if (high && ((vm_paddr_t)(blk + size) << PAGE_SHIFT) > high) { alist_free(&vm_contig_alist, blk, size); spin_unlock(&vm_contig_spin); if (bootverbose) { kprintf("vm_page_alloc_contig: %ldk high " "%016jx failed\n", (size + PAGE_MASK) * (PAGE_SIZE / 1024), (intmax_t)high); } return(NULL); } spin_unlock(&vm_contig_spin); if (bootverbose) { kprintf("vm_page_alloc_contig: %016jx/%ldk\n", (intmax_t)(vm_paddr_t)blk << PAGE_SHIFT, (size + PAGE_MASK) * (PAGE_SIZE / 1024)); } return (PHYS_TO_VM_PAGE((vm_paddr_t)blk << PAGE_SHIFT)); } /* * Free contiguously allocated pages. The pages will be wired but not busy. * When freeing to the alist we leave them wired and not busy. */ void vm_page_free_contig(vm_page_t m, unsigned long size) { vm_paddr_t pa = VM_PAGE_TO_PHYS(m); vm_pindex_t start = pa >> PAGE_SHIFT; vm_pindex_t pages = (size + PAGE_MASK) >> PAGE_SHIFT; if (bootverbose) { kprintf("vm_page_free_contig: %016jx/%ldk\n", (intmax_t)pa, size / 1024); } if (pa < vm_low_phys_reserved) { KKASSERT(pa + size <= vm_low_phys_reserved); spin_lock(&vm_contig_spin); alist_free(&vm_contig_alist, start, pages); spin_unlock(&vm_contig_spin); } else { while (pages) { vm_page_busy_wait(m, FALSE, "cpgfr"); vm_page_unwire(m, 0); vm_page_free(m); --pages; ++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 caller should be holding the page busied ? XXX * This routine may not block. */ void vm_page_activate(vm_page_t m) { u_short oqueue; vm_page_spin_lock(m); if (m->queue - m->pc != PQ_ACTIVE) { _vm_page_queue_spin_lock(m); oqueue = _vm_page_rem_queue_spinlocked(m); /* page is left spinlocked, queue is unlocked */ if (oqueue == PQ_CACHE) mycpu->gd_cnt.v_reactivated++; if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { if (m->act_count < ACT_INIT) m->act_count = ACT_INIT; _vm_page_add_queue_spinlocked(m, PQ_ACTIVE + m->pc, 0); } _vm_page_and_queue_spin_unlock(m); if (oqueue == PQ_CACHE || oqueue == PQ_FREE) pagedaemon_wakeup(); } else { if (m->act_count < ACT_INIT) m->act_count = ACT_INIT; vm_page_spin_unlock(m); } } /* * 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. */ 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; } } } /* * Returns the given page to the PQ_FREE or PQ_HOLD list and disassociates * it from its VM object. * * The vm_page must be PG_BUSY on entry. PG_BUSY will be released on * return (the page will have been freed). */ void vm_page_free_toq(vm_page_t m) { mycpu->gd_cnt.v_tfree++; KKASSERT((m->flags & PG_MAPPED) == 0); KKASSERT(m->flags & PG_BUSY); 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"); } /* * Remove from object, spinlock the page and its queues and * remove from any queue. No queue spinlock will be held * after this section (because the page was removed from any * queue). */ vm_page_remove(m); vm_page_and_queue_spin_lock(m); _vm_page_rem_queue_spinlocked(m); /* * No further management of fictitious pages occurs beyond object * and queue removal. */ if ((m->flags & PG_FICTITIOUS) != 0) { vm_page_spin_unlock(m); vm_page_wakeup(m); 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); _vm_page_add_queue_spinlocked(m, PQ_HOLD + m->pc, 0); } else { _vm_page_add_queue_spinlocked(m, PQ_FREE + m->pc, 0); } /* * This sequence allows us to clear PG_BUSY while still holding * its spin lock, which reduces contention vs allocators. We * must not leave the queue locked or _vm_page_wakeup() may * deadlock. */ _vm_page_queue_spin_unlock(m); if (_vm_page_wakeup(m)) { vm_page_spin_unlock(m); wakeup(m); } else { vm_page_spin_unlock(m); } vm_page_free_wakeup(); } /* * 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. */ vm_page_t vm_page_free_fromq_fast(void) { static int qi; vm_page_t m; int i; for (i = 0; i < PQ_L2_SIZE; ++i) { m = vm_page_list_find(PQ_FREE, qi, FALSE); /* page is returned spinlocked and removed from its queue */ if (m) { if (vm_page_busy_try(m, TRUE)) { /* * We were unable to busy the page, deactivate * it and loop. */ _vm_page_deactivate_locked(m, 0); vm_page_spin_unlock(m); } else if (m->flags & PG_ZERO) { /* * The page is PG_ZERO, requeue it and loop */ _vm_page_add_queue_spinlocked(m, PQ_FREE + m->pc, 0); vm_page_queue_spin_unlock(m); if (_vm_page_wakeup(m)) { vm_page_spin_unlock(m); wakeup(m); } else { vm_page_spin_unlock(m); } } else { /* * The page is not PG_ZERO'd so return it. */ vm_page_spin_unlock(m); KKASSERT((m->flags & PG_UNMANAGED) == 0); KKASSERT(m->hold_count == 0); KKASSERT(m->wire_count == 0); break; } m = NULL; } qi = (qi + PQ_PRIME2) & PQ_L2_MASK; } 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. * * Caller must be holding the page busy. */ void vm_page_unmanage(vm_page_t m) { KKASSERT(m->flags & PG_BUSY); 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. * * Caller must be holding the page busy. */ 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. */ KKASSERT(m->flags & PG_BUSY); if ((m->flags & PG_FICTITIOUS) == 0) { if (atomic_fetchadd_int(&m->wire_count, 1) == 0) { if ((m->flags & PG_UNMANAGED) == 0) vm_page_unqueue(m); atomic_add_int(&vmstats.v_wire_count, 1); } KASSERT(m->wire_count != 0, ("vm_page_wire: wire_count overflow m=%p", m)); } } /* * 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) { KKASSERT(m->flags & PG_BUSY); 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 (atomic_fetchadd_int(&m->wire_count, -1) == 1) { atomic_add_int(&vmstats.v_wire_count, -1); if (m->flags & PG_UNMANAGED) { ; } else if (activate) { vm_page_spin_lock(m); _vm_page_add_queue_spinlocked(m, PQ_ACTIVE + m->pc, 0); _vm_page_and_queue_spin_unlock(m); } else { vm_page_spin_lock(m); vm_page_flag_clear(m, PG_WINATCFLS); _vm_page_add_queue_spinlocked(m, PQ_INACTIVE + m->pc, 0); ++vm_swapcache_inactive_heuristic; _vm_page_and_queue_spin_unlock(m); } } } } /* * 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. * * vm_page's spinlock must be held on entry and will remain held on return. * This routine may not block. */ static void _vm_page_deactivate_locked(vm_page_t m, int athead) { u_short oqueue; /* * Ignore if already inactive. */ if (m->queue - m->pc == PQ_INACTIVE) return; _vm_page_queue_spin_lock(m); oqueue = _vm_page_rem_queue_spinlocked(m); if (m->wire_count == 0 && (m->flags & PG_UNMANAGED) == 0) { if (oqueue == PQ_CACHE) mycpu->gd_cnt.v_reactivated++; vm_page_flag_clear(m, PG_WINATCFLS); _vm_page_add_queue_spinlocked(m, PQ_INACTIVE + m->pc, athead); if (athead == 0) ++vm_swapcache_inactive_heuristic; } _vm_page_queue_spin_unlock(m); /* leaves vm_page spinlocked */ } /* * Attempt to deactivate a page. * * No requirements. */ void vm_page_deactivate(vm_page_t m) { vm_page_spin_lock(m); _vm_page_deactivate_locked(m, 0); vm_page_spin_unlock(m); } void vm_page_deactivate_locked(vm_page_t m) { _vm_page_deactivate_locked(m, 0); } /* * Attempt to move a page to PQ_CACHE. * * Returns 0 on failure, 1 on success * * The page should NOT be busied by the caller. This function will validate * whether the page can be safely moved to the cache. */ int vm_page_try_to_cache(vm_page_t m) { vm_page_spin_lock(m); if (vm_page_busy_try(m, TRUE)) { vm_page_spin_unlock(m); return(0); } if (m->dirty || m->hold_count || m->wire_count || (m->flags & PG_UNMANAGED)) { if (_vm_page_wakeup(m)) { vm_page_spin_unlock(m); wakeup(m); } else { vm_page_spin_unlock(m); } return(0); } vm_page_spin_unlock(m); /* * Page busied by us and no longer spinlocked. Dirty pages cannot * be moved to the cache. */ vm_page_test_dirty(m); if (m->dirty) { vm_page_wakeup(m); return(0); } vm_page_cache(m); 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) { vm_page_spin_lock(m); if (vm_page_busy_try(m, TRUE)) { vm_page_spin_unlock(m); return(0); } if (m->dirty || m->hold_count || m->wire_count || (m->flags & PG_UNMANAGED)) { if (_vm_page_wakeup(m)) { vm_page_spin_unlock(m); wakeup(m); } else { vm_page_spin_unlock(m); } return(0); } vm_page_spin_unlock(m); /* * Page busied by us and no longer spinlocked. Dirty pages will * not be freed by this function. We have to re-test the * dirty bit after cleaning out the pmaps. */ vm_page_test_dirty(m); if (m->dirty) { vm_page_wakeup(m); return(0); } vm_page_protect(m, VM_PROT_NONE); if (m->dirty) { vm_page_wakeup(m); return(0); } vm_page_free(m); return(1); } /* * vm_page_cache * * Put the specified page onto the page cache queue (if appropriate). * * 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) { 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_and_queue_spin_lock(m); _vm_page_rem_queue_spinlocked(m); _vm_page_add_queue_spinlocked(m, PQ_CACHE + m->pc, 0); _vm_page_queue_spin_unlock(m); if (_vm_page_wakeup(m)) { vm_page_spin_unlock(m); wakeup(m); } else { vm_page_spin_unlock(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. * * The page must be busied. */ void vm_page_dontneed(vm_page_t m) { static int dnweight; int dnw; int head; dnw = ++dnweight; /* * occassionally leave the page alone */ if ((dnw & 0x01F0) == 0 || m->queue - m->pc == PQ_INACTIVE || m->queue - m->pc == PQ_CACHE ) { if (m->act_count >= ACT_INIT) --m->act_count; 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_spin_lock(m); _vm_page_deactivate_locked(m, head); vm_page_spin_unlock(m); } /* * These routines manipulate the 'soft busy' count for a page. A soft busy * is almost like PG_BUSY except that it allows certain compatible operations * to occur on the page while it is busy. For example, a page undergoing a * write can still be mapped read-only. * * Because vm_pages can overlap buffers m->busy can be > 1. m->busy is only * adjusted while the vm_page is PG_BUSY so the flash will occur when the * busy bit is cleared. */ void vm_page_io_start(vm_page_t m) { KASSERT(m->flags & PG_BUSY, ("vm_page_io_start: page not busy!!!")); atomic_add_char(&m->busy, 1); vm_page_flag_set(m, PG_SBUSY); } void vm_page_io_finish(vm_page_t m) { KASSERT(m->flags & PG_BUSY, ("vm_page_io_finish: page not busy!!!")); atomic_subtract_char(&m->busy, 1); if (m->busy == 0) vm_page_flag_clear(m, PG_SBUSY); } /* * Grab a page, blocking if it is busy and allocating a page if necessary. * A busy page is returned or NULL. The page may or may not be valid and * might not be on a queue (the caller is responsible for the disposition of * the page). * * If VM_ALLOC_ZERO is specified and the grab must allocate a new page, the * page will be zero'd and marked valid. * * If VM_ALLOC_FORCE_ZERO is specified the page will be zero'd and marked * valid even if it already exists. * * If VM_ALLOC_RETRY is specified this routine will never return NULL. Also * note that VM_ALLOC_NORMAL must be specified if VM_ALLOC_RETRY is specified. * VM_ALLOC_NULL_OK is implied when VM_ALLOC_RETRY is specified. * * This routine may block, but if VM_ALLOC_RETRY is not set then NULL is * always returned if we had blocked. * * This routine may not be called from an interrupt. * * PG_ZERO is *ALWAYS* cleared by this routine. * * No other requirements. */ vm_page_t vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags) { vm_page_t m; int error; KKASSERT(allocflags & (VM_ALLOC_NORMAL|VM_ALLOC_INTERRUPT|VM_ALLOC_SYSTEM)); vm_object_hold(object); for (;;) { m = vm_page_lookup_busy_try(object, pindex, TRUE, &error); if (error) { vm_page_sleep_busy(m, TRUE, "pgrbwt"); if ((allocflags & VM_ALLOC_RETRY) == 0) { m = NULL; break; } /* retry */ } else if (m == NULL) { if (allocflags & VM_ALLOC_RETRY) allocflags |= VM_ALLOC_NULL_OK; m = vm_page_alloc(object, pindex, allocflags & ~VM_ALLOC_RETRY); if (m) break; vm_wait(0); if ((allocflags & VM_ALLOC_RETRY) == 0) goto failed; } else { /* m found */ break; } } /* * If VM_ALLOC_ZERO an invalid page will be zero'd and set valid. * * If VM_ALLOC_FORCE_ZERO the page is unconditionally zero'd and set * valid even if already valid. */ if (m->valid == 0) { if (allocflags & (VM_ALLOC_ZERO | VM_ALLOC_FORCE_ZERO)) { if ((m->flags & PG_ZERO) == 0) pmap_zero_page(VM_PAGE_TO_PHYS(m)); m->valid = VM_PAGE_BITS_ALL; } } else if (allocflags & VM_ALLOC_FORCE_ZERO) { pmap_zero_page(VM_PAGE_TO_PHYS(m)); m->valid = VM_PAGE_BITS_ALL; } vm_page_flag_clear(m, PG_ZERO); failed: vm_object_drop(object); 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 the page busy */ 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