012f4aa201
an ordering dependence: A pmap operation that clears PG_WRITEABLE and calls vm_page_dirty() must perform the call first. Otherwise, pmap_is_modified() could return FALSE without acquiring the page queues lock because the page is not (currently) writeable, and the caller to pmap_is_modified() might believe that the page's dirty field is clear because it has not seen the effect of the vm_page_dirty() call. When I pushed down the page queues lock into pmap_is_modified(), I overlooked one place where this ordering dependence is violated: pmap_enter(). In a rare situation pmap_enter() can be called to replace a dirty mapping to one page with a mapping to another page. (I say rare because replacements generally occur as a result of a copy-on-write fault, and so the old page is not dirty.) This change delays clearing PG_WRITEABLE until after vm_page_dirty() has been called. Fixing the ordering dependency also makes it easy to introduce a small optimization: When pmap_enter() used to replace a mapping to one page with a mapping to another page, it freed the pv entry for the first mapping and later called the pv entry allocator for the new mapping. Now, pmap_enter() attempts to recycle the old pv entry, saving two calls to the pv entry allocator. There is no point in setting PG_WRITEABLE on unmanaged pages, so don't. Update a comment to reflect this. Tidy up the variable declarations at the start of pmap_enter().
416 lines
14 KiB
C
416 lines
14 KiB
C
/*-
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* The Mach Operating System project at Carnegie-Mellon University.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* from: @(#)vm_page.h 8.2 (Berkeley) 12/13/93
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*
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*
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* Copyright (c) 1987, 1990 Carnegie-Mellon University.
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* All rights reserved.
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*
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* Authors: Avadis Tevanian, Jr., Michael Wayne Young
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*
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* Permission to use, copy, modify and distribute this software and
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* its documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
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* FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie the
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* rights to redistribute these changes.
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*
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* $FreeBSD$
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*/
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/*
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* Resident memory system definitions.
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*/
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#ifndef _VM_PAGE_
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#define _VM_PAGE_
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#include <vm/pmap.h>
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/*
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* Management of resident (logical) pages.
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*
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* A small structure is kept for each resident
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* page, indexed by page number. Each structure
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* is an element of several lists:
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*
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* A hash table bucket used to quickly
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* perform object/offset lookups
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*
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* A list of all pages for a given object,
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* so they can be quickly deactivated at
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* time of deallocation.
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*
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* An ordered list of pages due for pageout.
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*
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* In addition, the structure contains the object
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* and offset to which this page belongs (for pageout),
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* and sundry status bits.
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*
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* Fields in this structure are locked either by the lock on the
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* object that the page belongs to (O), its corresponding page lock (P),
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* or by the lock on the page queues (Q).
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*
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*/
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TAILQ_HEAD(pglist, vm_page);
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struct vm_page {
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TAILQ_ENTRY(vm_page) pageq; /* queue info for FIFO queue or free list (Q) */
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TAILQ_ENTRY(vm_page) listq; /* pages in same object (O) */
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struct vm_page *left; /* splay tree link (O) */
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struct vm_page *right; /* splay tree link (O) */
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vm_object_t object; /* which object am I in (O,P)*/
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vm_pindex_t pindex; /* offset into object (O,Q) */
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vm_paddr_t phys_addr; /* physical address of page */
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struct md_page md; /* machine dependant stuff */
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uint8_t queue; /* page queue index (P,Q) */
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int8_t segind;
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u_short flags; /* see below */
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uint8_t order; /* index of the buddy queue */
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uint8_t pool;
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u_short cow; /* page cow mapping count (P) */
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u_int wire_count; /* wired down maps refs (P) */
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short hold_count; /* page hold count (P) */
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u_short oflags; /* page flags (O) */
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u_char act_count; /* page usage count (P) */
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u_char busy; /* page busy count (O) */
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/* NOTE that these must support one bit per DEV_BSIZE in a page!!! */
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/* so, on normal X86 kernels, they must be at least 8 bits wide */
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#if PAGE_SIZE == 4096
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u_char valid; /* map of valid DEV_BSIZE chunks (O) */
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u_char dirty; /* map of dirty DEV_BSIZE chunks (O) */
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#elif PAGE_SIZE == 8192
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u_short valid; /* map of valid DEV_BSIZE chunks (O) */
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u_short dirty; /* map of dirty DEV_BSIZE chunks (O) */
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#elif PAGE_SIZE == 16384
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u_int valid; /* map of valid DEV_BSIZE chunks (O) */
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u_int dirty; /* map of dirty DEV_BSIZE chunks (O) */
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#elif PAGE_SIZE == 32768
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u_long valid; /* map of valid DEV_BSIZE chunks (O) */
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u_long dirty; /* map of dirty DEV_BSIZE chunks (O) */
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#endif
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};
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/*
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* Page flags stored in oflags:
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*
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* Access to these page flags is synchronized by the lock on the object
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* containing the page (O).
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*/
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#define VPO_BUSY 0x0001 /* page is in transit */
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#define VPO_WANTED 0x0002 /* someone is waiting for page */
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#define VPO_CLEANCHK 0x0100 /* page will be checked for cleaning */
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#define VPO_SWAPINPROG 0x0200 /* swap I/O in progress on page */
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#define VPO_NOSYNC 0x0400 /* do not collect for syncer */
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#define PQ_NONE 0
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#define PQ_INACTIVE 1
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#define PQ_ACTIVE 2
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#define PQ_HOLD 3
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#define PQ_COUNT 4
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/* Returns the real queue a page is on. */
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#define VM_PAGE_GETQUEUE(m) ((m)->queue)
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/* Returns the well known queue a page is on. */
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#define VM_PAGE_GETKNOWNQUEUE2(m) VM_PAGE_GETQUEUE(m)
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/* Returns true if the page is in the named well known queue. */
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#define VM_PAGE_INQUEUE2(m, q) (VM_PAGE_GETKNOWNQUEUE2(m) == (q))
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/* Sets the queue a page is on. */
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#define VM_PAGE_SETQUEUE2(m, q) (VM_PAGE_GETQUEUE(m) = (q))
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struct vpgqueues {
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struct pglist pl;
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int *cnt;
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};
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extern struct vpgqueues vm_page_queues[PQ_COUNT];
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struct vpglocks {
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struct mtx data;
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char pad[CACHE_LINE_SIZE - sizeof(struct mtx)];
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} __aligned(CACHE_LINE_SIZE);
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extern struct vpglocks vm_page_queue_free_lock;
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extern struct vpglocks pa_lock[];
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#if defined(__arm__)
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#define PDRSHIFT PDR_SHIFT
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#elif !defined(PDRSHIFT)
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#define PDRSHIFT 21
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#endif
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#define pa_index(pa) ((pa) >> PDRSHIFT)
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#define PA_LOCKPTR(pa) &pa_lock[pa_index((pa)) % PA_LOCK_COUNT].data
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#define PA_LOCKOBJPTR(pa) ((struct lock_object *)PA_LOCKPTR((pa)))
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#define PA_LOCK(pa) mtx_lock(PA_LOCKPTR(pa))
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#define PA_TRYLOCK(pa) mtx_trylock(PA_LOCKPTR(pa))
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#define PA_UNLOCK(pa) mtx_unlock(PA_LOCKPTR(pa))
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#define PA_UNLOCK_COND(pa) \
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do { \
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if ((pa) != 0) { \
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PA_UNLOCK((pa)); \
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(pa) = 0; \
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} \
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} while (0)
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#define PA_LOCK_ASSERT(pa, a) mtx_assert(PA_LOCKPTR(pa), (a))
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#define vm_page_lockptr(m) (PA_LOCKPTR(VM_PAGE_TO_PHYS((m))))
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#define vm_page_lock(m) mtx_lock(vm_page_lockptr((m)))
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#define vm_page_unlock(m) mtx_unlock(vm_page_lockptr((m)))
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#define vm_page_trylock(m) mtx_trylock(vm_page_lockptr((m)))
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#define vm_page_lock_assert(m, a) mtx_assert(vm_page_lockptr((m)), (a))
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#define vm_page_queue_free_mtx vm_page_queue_free_lock.data
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/*
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* These are the flags defined for vm_page.
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*
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* Note: PG_UNMANAGED (used by OBJT_PHYS) indicates that the page is
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* not under PV management but otherwise should be treated as a
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* normal page. Pages not under PV management cannot be paged out
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* via the object/vm_page_t because there is no knowledge of their
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* pte mappings, nor can they be removed from their objects via
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* the object, and such pages are also not on any PQ queue.
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*
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* PG_WRITEABLE is set exclusively on managed pages by pmap_enter(). When it
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* does so, the page must be VPO_BUSY.
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*/
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#define PG_CACHED 0x0001 /* page is cached */
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#define PG_FREE 0x0002 /* page is free */
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#define PG_WINATCFLS 0x0004 /* flush dirty page on inactive q */
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#define PG_FICTITIOUS 0x0008 /* physical page doesn't exist (O) */
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#define PG_WRITEABLE 0x0010 /* page is mapped writeable */
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#define PG_ZERO 0x0040 /* page is zeroed */
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#define PG_REFERENCED 0x0080 /* page has been referenced */
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#define PG_UNMANAGED 0x0800 /* No PV management for page */
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#define PG_MARKER 0x1000 /* special queue marker page */
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#define PG_SLAB 0x2000 /* object pointer is actually a slab */
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/*
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* Misc constants.
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*/
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#define ACT_DECLINE 1
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#define ACT_ADVANCE 3
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#define ACT_INIT 5
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#define ACT_MAX 64
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#ifdef _KERNEL
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#include <vm/vm_param.h>
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/*
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* Each pageable resident page falls into one of five lists:
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*
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* free
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* Available for allocation now.
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*
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* cache
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* Almost available for allocation. Still associated with
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* an object, but clean and immediately freeable.
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*
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* hold
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* Will become free after a pending I/O operation
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* completes.
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*
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* The following lists are LRU sorted:
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*
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* inactive
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* Low activity, candidates for reclamation.
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* This is the list of pages that should be
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* paged out next.
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*
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* active
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* Pages that are "active" i.e. they have been
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* recently referenced.
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*
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*/
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extern int vm_page_zero_count;
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extern vm_page_t vm_page_array; /* First resident page in table */
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extern int vm_page_array_size; /* number of vm_page_t's */
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extern long first_page; /* first physical page number */
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#define VM_PAGE_IS_FREE(m) (((m)->flags & PG_FREE) != 0)
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#define VM_PAGE_TO_PHYS(entry) ((entry)->phys_addr)
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vm_page_t vm_phys_paddr_to_vm_page(vm_paddr_t pa);
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static __inline vm_page_t PHYS_TO_VM_PAGE(vm_paddr_t pa);
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static __inline vm_page_t
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PHYS_TO_VM_PAGE(vm_paddr_t pa)
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{
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#ifdef VM_PHYSSEG_SPARSE
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return (vm_phys_paddr_to_vm_page(pa));
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#elif defined(VM_PHYSSEG_DENSE)
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return (&vm_page_array[atop(pa) - first_page]);
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#else
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#error "Either VM_PHYSSEG_DENSE or VM_PHYSSEG_SPARSE must be defined."
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#endif
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}
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extern struct vpglocks vm_page_queue_lock;
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#define vm_page_queue_mtx vm_page_queue_lock.data
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#define vm_page_lock_queues() mtx_lock(&vm_page_queue_mtx)
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#define vm_page_unlock_queues() mtx_unlock(&vm_page_queue_mtx)
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#if PAGE_SIZE == 4096
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#define VM_PAGE_BITS_ALL 0xffu
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#elif PAGE_SIZE == 8192
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#define VM_PAGE_BITS_ALL 0xffffu
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#elif PAGE_SIZE == 16384
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#define VM_PAGE_BITS_ALL 0xffffffffu
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#elif PAGE_SIZE == 32768
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#define VM_PAGE_BITS_ALL 0xfffffffffffffffflu
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#endif
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/* page allocation classes: */
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#define VM_ALLOC_NORMAL 0
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#define VM_ALLOC_INTERRUPT 1
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#define VM_ALLOC_SYSTEM 2
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#define VM_ALLOC_CLASS_MASK 3
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/* page allocation flags: */
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#define VM_ALLOC_WIRED 0x0020 /* non pageable */
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#define VM_ALLOC_ZERO 0x0040 /* Try to obtain a zeroed page */
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#define VM_ALLOC_RETRY 0x0080 /* vm_page_grab() only */
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#define VM_ALLOC_NOOBJ 0x0100 /* No associated object */
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#define VM_ALLOC_NOBUSY 0x0200 /* Do not busy the page */
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#define VM_ALLOC_IFCACHED 0x0400 /* Fail if the page is not cached */
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#define VM_ALLOC_IFNOTCACHED 0x0800 /* Fail if the page is cached */
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void vm_page_flag_set(vm_page_t m, unsigned short bits);
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void vm_page_flag_clear(vm_page_t m, unsigned short bits);
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void vm_page_busy(vm_page_t m);
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void vm_page_flash(vm_page_t m);
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void vm_page_io_start(vm_page_t m);
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void vm_page_io_finish(vm_page_t m);
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void vm_page_hold(vm_page_t mem);
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void vm_page_unhold(vm_page_t mem);
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void vm_page_free(vm_page_t m);
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void vm_page_free_zero(vm_page_t m);
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void vm_page_dirty(vm_page_t m);
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void vm_page_wakeup(vm_page_t m);
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void vm_pageq_remove(vm_page_t m);
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void vm_page_activate (vm_page_t);
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vm_page_t vm_page_alloc (vm_object_t, vm_pindex_t, int);
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vm_page_t vm_page_grab (vm_object_t, vm_pindex_t, int);
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void vm_page_cache(vm_page_t);
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void vm_page_cache_free(vm_object_t, vm_pindex_t, vm_pindex_t);
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void vm_page_cache_remove(vm_page_t);
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void vm_page_cache_transfer(vm_object_t, vm_pindex_t, vm_object_t);
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int vm_page_try_to_cache (vm_page_t);
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int vm_page_try_to_free (vm_page_t);
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void vm_page_dontneed(vm_page_t);
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void vm_page_deactivate (vm_page_t);
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void vm_page_insert (vm_page_t, vm_object_t, vm_pindex_t);
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vm_page_t vm_page_lookup (vm_object_t, vm_pindex_t);
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int vm_page_pa_tryrelock(pmap_t, vm_paddr_t, vm_paddr_t *);
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void vm_page_remove (vm_page_t);
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void vm_page_rename (vm_page_t, vm_object_t, vm_pindex_t);
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void vm_page_requeue(vm_page_t m);
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void vm_page_set_valid(vm_page_t m, int base, int size);
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void vm_page_sleep(vm_page_t m, const char *msg);
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vm_page_t vm_page_splay(vm_pindex_t, vm_page_t);
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vm_offset_t vm_page_startup(vm_offset_t vaddr);
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void vm_page_unwire (vm_page_t, int);
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void vm_page_wire (vm_page_t);
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void vm_page_set_validclean (vm_page_t, int, int);
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void vm_page_clear_dirty (vm_page_t, int, int);
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void vm_page_set_invalid (vm_page_t, int, int);
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int vm_page_is_valid (vm_page_t, int, int);
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void vm_page_test_dirty (vm_page_t);
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int vm_page_bits (int, int);
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void vm_page_zero_invalid(vm_page_t m, boolean_t setvalid);
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void vm_page_free_toq(vm_page_t m);
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void vm_page_zero_idle_wakeup(void);
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void vm_page_cowfault (vm_page_t);
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int vm_page_cowsetup(vm_page_t);
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void vm_page_cowclear (vm_page_t);
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/*
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* vm_page_sleep_if_busy:
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*
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* Sleep and release the page queues lock if VPO_BUSY is set or,
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* if also_m_busy is TRUE, busy is non-zero. Returns TRUE if the
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* thread slept and the page queues lock was released.
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* Otherwise, retains the page queues lock and returns FALSE.
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*
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* The object containing the given page must be locked.
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*/
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static __inline int
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vm_page_sleep_if_busy(vm_page_t m, int also_m_busy, const char *msg)
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{
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if ((m->oflags & VPO_BUSY) || (also_m_busy && m->busy)) {
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vm_page_sleep(m, msg);
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return (TRUE);
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}
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return (FALSE);
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}
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/*
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* vm_page_undirty:
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*
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* Set page to not be dirty. Note: does not clear pmap modify bits
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*/
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static __inline void
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vm_page_undirty(vm_page_t m)
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{
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m->dirty = 0;
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}
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#endif /* _KERNEL */
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#endif /* !_VM_PAGE_ */
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