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freebsd-dev/sys/vm/vm_page.h
Mark Johnston 1d3a1bcfac Dequeue wired pages lazily. 
Previously, wiring a page would cause it to be removed from its page
queue. In the common case, unwiring causes it to be enqueued at the tail
of that page queue. This change modifies vm_page_wire() to not dequeue
the page, thus avoiding the highly contended page queue locks. Instead,
vm_page_unwire() takes care of requeuing the page as a single operation,
and the page daemon dequeues wired pages as they are encountered during
a queue scan to avoid needlessly revisiting them later. For pages in
PQ_ACTIVE we do even better, since a requeue is unnecessary.

The change improves scalability for some common workloads. For instance,
threads wiring pages into the buffer cache no longer need to modify
global page queues, and unwiring is usually done by the bufspace thread,
so concurrency is not as much of an issue. As another example, many
sysctl handlers wire the output buffer to avoid faults on copyout, and
since the buffer is likely to be in PQ_ACTIVE, we now entirely avoid
modifying the page queue in this case.

The change also adds a block comment describing some properties of
struct vm_page's reference counters, and the busy lock.

Reviewed by:	jeff
Discussed with:	alc, kib
MFC after:	1 month
Differential Revision:	https://reviews.freebsd.org/D11943
2018-02-07 16:57:10 +00:00

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/*-
* SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU)
*
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* The Mach Operating System project at Carnegie-Mellon University.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. 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.h 8.2 (Berkeley) 12/13/93
*
*
* 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.
*
* $FreeBSD$
*/
/*
* Resident memory system definitions.
*/
#ifndef _VM_PAGE_
#define _VM_PAGE_
#include <vm/pmap.h>
/*
* Management of resident (logical) pages.
*
* A small structure is kept for each resident
* page, indexed by page number. Each structure
* is an element of several collections:
*
* A radix tree used to quickly
* perform object/offset lookups
*
* A list of all pages for a given object,
* so they can be quickly deactivated at
* time of deallocation.
*
* An ordered list of pages due for pageout.
*
* In addition, the structure contains the object
* and offset to which this page belongs (for pageout),
* and sundry status bits.
*
* In general, operations on this structure's mutable fields are
* synchronized using either one of or a combination of the lock on the
* object that the page belongs to (O), the pool lock for the page (P),
* or the lock for either the free or paging queue (Q). If a field is
* annotated below with two of these locks, then holding either lock is
* sufficient for read access, but both locks are required for write
* access. An annotation of (C) indicates that the field is immutable.
*
* In contrast, the synchronization of accesses to the page's
* dirty field is machine dependent (M). In the
* machine-independent layer, the lock on the object that the
* page belongs to must be held in order to operate on the field.
* However, the pmap layer is permitted to set all bits within
* the field without holding that lock. If the underlying
* architecture does not support atomic read-modify-write
* operations on the field's type, then the machine-independent
* layer uses a 32-bit atomic on the aligned 32-bit word that
* contains the dirty field. In the machine-independent layer,
* the implementation of read-modify-write operations on the
* field is encapsulated in vm_page_clear_dirty_mask().
*
* The page structure contains two counters which prevent page reuse.
* Both counters are protected by the page lock (P). The hold
* counter counts transient references obtained via a pmap lookup, and
* is also used to prevent page reclamation in situations where it is
* undesirable to block other accesses to the page. The wire counter
* is used to implement mlock(2) and is non-zero for pages containing
* kernel memory. Pages that are wired or held will not be reclaimed
* or laundered by the page daemon, but are treated differently during
* a page queue scan: held pages remain at their position in the queue,
* while wired pages are removed from the queue and must later be
* re-enqueued appropriately by the unwiring thread. It is legal to
* call vm_page_free() on a held page; doing so causes it to be removed
* from its object and page queue, and the page is released to the
* allocator once the last hold reference is dropped. In contrast,
* wired pages may not be freed.
*
* In some pmap implementations, the wire count of a page table page is
* used to track the number of populated entries.
*
* The busy lock is an embedded reader-writer lock which protects the
* page's contents and identity (i.e., its <object, pindex> tuple) and
* interlocks with the object lock (O). In particular, a page may be
* busied or unbusied only with the object write lock held. To avoid
* bloating the page structure, the busy lock lacks some of the
* features available to the kernel's general-purpose synchronization
* primitives. As a result, busy lock ordering rules are not verified,
* lock recursion is not detected, and an attempt to xbusy a busy page
* or sbusy an xbusy page results will trigger a panic rather than
* causing the thread to block. vm_page_sleep_if_busy() can be used to
* sleep until the page's busy state changes, after which the caller
* must re-lookup the page and re-evaluate its state.
*/
#if PAGE_SIZE == 4096
#define VM_PAGE_BITS_ALL 0xffu
typedef uint8_t vm_page_bits_t;
#elif PAGE_SIZE == 8192
#define VM_PAGE_BITS_ALL 0xffffu
typedef uint16_t vm_page_bits_t;
#elif PAGE_SIZE == 16384
#define VM_PAGE_BITS_ALL 0xffffffffu
typedef uint32_t vm_page_bits_t;
#elif PAGE_SIZE == 32768
#define VM_PAGE_BITS_ALL 0xfffffffffffffffflu
typedef uint64_t vm_page_bits_t;
#endif
struct vm_page {
union {
TAILQ_ENTRY(vm_page) q; /* page queue or free list (Q) */
struct {
SLIST_ENTRY(vm_page) ss; /* private slists */
void *pv;
} s;
struct {
u_long p;
u_long v;
} memguard;
} plinks;
TAILQ_ENTRY(vm_page) listq; /* pages in same object (O) */
vm_object_t object; /* which object am I in (O,P) */
vm_pindex_t pindex; /* offset into object (O,P) */
vm_paddr_t phys_addr; /* physical address of page */
struct md_page md; /* machine dependent stuff */
u_int wire_count; /* wired down maps refs (P) */
volatile u_int busy_lock; /* busy owners lock */
uint16_t hold_count; /* page hold count (P) */
uint16_t flags; /* page PG_* flags (P) */
uint8_t aflags; /* access is atomic */
uint8_t oflags; /* page VPO_* flags (O) */
uint8_t queue; /* page queue index (P,Q) */
int8_t psind; /* pagesizes[] index (O) */
int8_t segind; /* vm_phys segment index (C) */
uint8_t order; /* index of the buddy queue */
uint8_t pool; /* vm_phys freepool index (Q) */
u_char act_count; /* page usage count (P) */
/* NOTE that these must support one bit per DEV_BSIZE in a page */
/* so, on normal X86 kernels, they must be at least 8 bits wide */
vm_page_bits_t valid; /* map of valid DEV_BSIZE chunks (O) */
vm_page_bits_t dirty; /* map of dirty DEV_BSIZE chunks (M) */
};
/*
* Page flags stored in oflags:
*
* Access to these page flags is synchronized by the lock on the object
* containing the page (O).
*
* Note: VPO_UNMANAGED (used by OBJT_DEVICE, OBJT_PHYS and OBJT_SG)
* indicates that the page is not under PV management but
* otherwise should be treated as a normal page. Pages not
* under PV management cannot be paged out via the
* object/vm_page_t because there is no knowledge of their pte
* mappings, and such pages are also not on any PQ queue.
*
*/
#define VPO_UNUSED01 0x01 /* --available-- */
#define VPO_SWAPSLEEP 0x02 /* waiting for swap to finish */
#define VPO_UNMANAGED 0x04 /* no PV management for page */
#define VPO_SWAPINPROG 0x08 /* swap I/O in progress on page */
#define VPO_NOSYNC 0x10 /* do not collect for syncer */
/*
* Busy page implementation details.
* The algorithm is taken mostly by rwlock(9) and sx(9) locks implementation,
* even if the support for owner identity is removed because of size
* constraints. Checks on lock recursion are then not possible, while the
* lock assertions effectiveness is someway reduced.
*/
#define VPB_BIT_SHARED 0x01
#define VPB_BIT_EXCLUSIVE 0x02
#define VPB_BIT_WAITERS 0x04
#define VPB_BIT_FLAGMASK \
(VPB_BIT_SHARED | VPB_BIT_EXCLUSIVE | VPB_BIT_WAITERS)
#define VPB_SHARERS_SHIFT 3
#define VPB_SHARERS(x) \
(((x) & ~VPB_BIT_FLAGMASK) >> VPB_SHARERS_SHIFT)
#define VPB_SHARERS_WORD(x) ((x) << VPB_SHARERS_SHIFT | VPB_BIT_SHARED)
#define VPB_ONE_SHARER (1 << VPB_SHARERS_SHIFT)
#define VPB_SINGLE_EXCLUSIVER VPB_BIT_EXCLUSIVE
#define VPB_UNBUSIED VPB_SHARERS_WORD(0)
#define PQ_NONE 255
#define PQ_INACTIVE 0
#define PQ_ACTIVE 1
#define PQ_LAUNDRY 2
#define PQ_UNSWAPPABLE 3
#define PQ_COUNT 4
#ifndef VM_PAGE_HAVE_PGLIST
TAILQ_HEAD(pglist, vm_page);
#define VM_PAGE_HAVE_PGLIST
#endif
SLIST_HEAD(spglist, vm_page);
#ifdef _KERNEL
extern vm_page_t bogus_page;
#endif /* _KERNEL */
extern struct mtx_padalign pa_lock[];
#if defined(__arm__)
#define PDRSHIFT PDR_SHIFT
#elif !defined(PDRSHIFT)
#define PDRSHIFT 21
#endif
#define pa_index(pa) ((pa) >> PDRSHIFT)
#define PA_LOCKPTR(pa) ((struct mtx *)(&pa_lock[pa_index(pa) % PA_LOCK_COUNT]))
#define PA_LOCKOBJPTR(pa) ((struct lock_object *)PA_LOCKPTR((pa)))
#define PA_LOCK(pa) mtx_lock(PA_LOCKPTR(pa))
#define PA_TRYLOCK(pa) mtx_trylock(PA_LOCKPTR(pa))
#define PA_UNLOCK(pa) mtx_unlock(PA_LOCKPTR(pa))
#define PA_UNLOCK_COND(pa) \
do { \
if ((pa) != 0) { \
PA_UNLOCK((pa)); \
(pa) = 0; \
} \
} while (0)
#define PA_LOCK_ASSERT(pa, a) mtx_assert(PA_LOCKPTR(pa), (a))
#ifdef KLD_MODULE
#define vm_page_lock(m) vm_page_lock_KBI((m), LOCK_FILE, LOCK_LINE)
#define vm_page_unlock(m) vm_page_unlock_KBI((m), LOCK_FILE, LOCK_LINE)
#define vm_page_trylock(m) vm_page_trylock_KBI((m), LOCK_FILE, LOCK_LINE)
#else /* !KLD_MODULE */
#define vm_page_lockptr(m) (PA_LOCKPTR(VM_PAGE_TO_PHYS((m))))
#define vm_page_lock(m) mtx_lock(vm_page_lockptr((m)))
#define vm_page_unlock(m) mtx_unlock(vm_page_lockptr((m)))
#define vm_page_trylock(m) mtx_trylock(vm_page_lockptr((m)))
#endif
#if defined(INVARIANTS)
#define vm_page_assert_locked(m) \
vm_page_assert_locked_KBI((m), __FILE__, __LINE__)
#define vm_page_lock_assert(m, a) \
vm_page_lock_assert_KBI((m), (a), __FILE__, __LINE__)
#else
#define vm_page_assert_locked(m)
#define vm_page_lock_assert(m, a)
#endif
/*
* The vm_page's aflags are updated using atomic operations. To set or clear
* these flags, the functions vm_page_aflag_set() and vm_page_aflag_clear()
* must be used. Neither these flags nor these functions are part of the KBI.
*
* PGA_REFERENCED may be cleared only if the page is locked. It is set by
* both the MI and MD VM layers. However, kernel loadable modules should not
* directly set this flag. They should call vm_page_reference() instead.
*
* PGA_WRITEABLE is set exclusively on managed pages by pmap_enter().
* When it does so, the object must be locked, or the page must be
* exclusive busied. The MI VM layer must never access this flag
* directly. Instead, it should call pmap_page_is_write_mapped().
*
* PGA_EXECUTABLE may be set by pmap routines, and indicates that a page has
* at least one executable mapping. It is not consumed by the MI VM layer.
*/
#define PGA_WRITEABLE 0x01 /* page may be mapped writeable */
#define PGA_REFERENCED 0x02 /* page has been referenced */
#define PGA_EXECUTABLE 0x04 /* page may be mapped executable */
/*
* Page flags. If changed at any other time than page allocation or
* freeing, the modification must be protected by the vm_page lock.
*/
#define PG_FICTITIOUS 0x0004 /* physical page doesn't exist */
#define PG_ZERO 0x0008 /* page is zeroed */
#define PG_MARKER 0x0010 /* special queue marker page */
#define PG_NODUMP 0x0080 /* don't include this page in a dump */
#define PG_UNHOLDFREE 0x0100 /* delayed free of a held page */
/*
* Misc constants.
*/
#define ACT_DECLINE 1
#define ACT_ADVANCE 3
#define ACT_INIT 5
#define ACT_MAX 64
#ifdef _KERNEL
#include <sys/systm.h>
#include <machine/atomic.h>
/*
* Each pageable resident page falls into one of five lists:
*
* free
* Available for allocation now.
*
* inactive
* Low activity, candidates for reclamation.
* This list is approximately LRU ordered.
*
* laundry
* This is the list of pages that should be
* paged out next.
*
* unswappable
* Dirty anonymous pages that cannot be paged
* out because no swap device is configured.
*
* active
* Pages that are "active", i.e., they have been
* recently referenced.
*
*/
extern vm_page_t vm_page_array; /* First resident page in table */
extern long vm_page_array_size; /* number of vm_page_t's */
extern long first_page; /* first physical page number */
#define VM_PAGE_TO_PHYS(entry) ((entry)->phys_addr)
/*
* PHYS_TO_VM_PAGE() returns the vm_page_t object that represents a memory
* page to which the given physical address belongs. The correct vm_page_t
* object is returned for addresses that are not page-aligned.
*/
vm_page_t PHYS_TO_VM_PAGE(vm_paddr_t pa);
/*
* Page allocation parameters for vm_page for the functions
* vm_page_alloc(), vm_page_grab(), vm_page_alloc_contig() and
* vm_page_alloc_freelist(). Some functions support only a subset
* of the flags, and ignore others, see the flags legend.
*
* The meaning of VM_ALLOC_ZERO differs slightly between the vm_page_alloc*()
* and the vm_page_grab*() functions. See these functions for details.
*
* Bits 0 - 1 define class.
* Bits 2 - 15 dedicated for flags.
* Legend:
* (a) - vm_page_alloc() supports the flag.
* (c) - vm_page_alloc_contig() supports the flag.
* (f) - vm_page_alloc_freelist() supports the flag.
* (g) - vm_page_grab() supports the flag.
* (p) - vm_page_grab_pages() supports the flag.
* Bits above 15 define the count of additional pages that the caller
* intends to allocate.
*/
#define VM_ALLOC_NORMAL 0
#define VM_ALLOC_INTERRUPT 1
#define VM_ALLOC_SYSTEM 2
#define VM_ALLOC_CLASS_MASK 3
#define VM_ALLOC_WAITOK 0x0008 /* (acf) Sleep and retry */
#define VM_ALLOC_WAITFAIL 0x0010 /* (acf) Sleep and return error */
#define VM_ALLOC_WIRED 0x0020 /* (acfgp) Allocate a wired page */
#define VM_ALLOC_ZERO 0x0040 /* (acfgp) Allocate a prezeroed page */
#define VM_ALLOC_NOOBJ 0x0100 /* (acg) No associated object */
#define VM_ALLOC_NOBUSY 0x0200 /* (acgp) Do not excl busy the page */
#define VM_ALLOC_IGN_SBUSY 0x1000 /* (gp) Ignore shared busy flag */
#define VM_ALLOC_NODUMP 0x2000 /* (ag) don't include in dump */
#define VM_ALLOC_SBUSY 0x4000 /* (acgp) Shared busy the page */
#define VM_ALLOC_NOWAIT 0x8000 /* (acfgp) Do not sleep */
#define VM_ALLOC_COUNT_SHIFT 16
#define VM_ALLOC_COUNT(count) ((count) << VM_ALLOC_COUNT_SHIFT)
#ifdef M_NOWAIT
static inline int
malloc2vm_flags(int malloc_flags)
{
int pflags;
KASSERT((malloc_flags & M_USE_RESERVE) == 0 ||
(malloc_flags & M_NOWAIT) != 0,
("M_USE_RESERVE requires M_NOWAIT"));
pflags = (malloc_flags & M_USE_RESERVE) != 0 ? VM_ALLOC_INTERRUPT :
VM_ALLOC_SYSTEM;
if ((malloc_flags & M_ZERO) != 0)
pflags |= VM_ALLOC_ZERO;
if ((malloc_flags & M_NODUMP) != 0)
pflags |= VM_ALLOC_NODUMP;
if ((malloc_flags & M_NOWAIT))
pflags |= VM_ALLOC_NOWAIT;
if ((malloc_flags & M_WAITOK))
pflags |= VM_ALLOC_WAITOK;
return (pflags);
}
#endif
/*
* Predicates supported by vm_page_ps_test():
*
* PS_ALL_DIRTY is true only if the entire (super)page is dirty.
* However, it can be spuriously false when the (super)page has become
* dirty in the pmap but that information has not been propagated to the
* machine-independent layer.
*/
#define PS_ALL_DIRTY 0x1
#define PS_ALL_VALID 0x2
#define PS_NONE_BUSY 0x4
void vm_page_busy_downgrade(vm_page_t m);
void vm_page_busy_sleep(vm_page_t m, const char *msg, bool nonshared);
void vm_page_flash(vm_page_t m);
void vm_page_hold(vm_page_t mem);
void vm_page_unhold(vm_page_t mem);
void vm_page_free(vm_page_t m);
void vm_page_free_zero(vm_page_t m);
void vm_page_activate (vm_page_t);
void vm_page_advise(vm_page_t m, int advice);
vm_page_t vm_page_alloc(vm_object_t, vm_pindex_t, int);
vm_page_t vm_page_alloc_domain(vm_object_t, vm_pindex_t, int, int);
vm_page_t vm_page_alloc_after(vm_object_t, vm_pindex_t, int, vm_page_t);
vm_page_t vm_page_alloc_domain_after(vm_object_t, vm_pindex_t, int, int,
vm_page_t);
vm_page_t vm_page_alloc_contig(vm_object_t object, vm_pindex_t pindex, int req,
u_long npages, vm_paddr_t low, vm_paddr_t high, u_long alignment,
vm_paddr_t boundary, vm_memattr_t memattr);
vm_page_t vm_page_alloc_contig_domain(vm_object_t object,
vm_pindex_t pindex, int domain, int req, u_long npages, vm_paddr_t low,
vm_paddr_t high, u_long alignment, vm_paddr_t boundary,
vm_memattr_t memattr);
vm_page_t vm_page_alloc_freelist(int, int);
vm_page_t vm_page_alloc_freelist_domain(int, int, int);
void vm_page_change_lock(vm_page_t m, struct mtx **mtx);
vm_page_t vm_page_grab (vm_object_t, vm_pindex_t, int);
int vm_page_grab_pages(vm_object_t object, vm_pindex_t pindex, int allocflags,
vm_page_t *ma, int count);
void vm_page_deactivate(vm_page_t);
void vm_page_deactivate_noreuse(vm_page_t);
void vm_page_dequeue(vm_page_t m);
void vm_page_dequeue_locked(vm_page_t m);
vm_page_t vm_page_find_least(vm_object_t, vm_pindex_t);
void vm_page_free_phys_pglist(struct pglist *tq);
bool vm_page_free_prep(vm_page_t m, bool pagequeue_locked);
vm_page_t vm_page_getfake(vm_paddr_t paddr, vm_memattr_t memattr);
void vm_page_initfake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr);
int vm_page_insert (vm_page_t, vm_object_t, vm_pindex_t);
void vm_page_launder(vm_page_t m);
vm_page_t vm_page_lookup (vm_object_t, vm_pindex_t);
vm_page_t vm_page_next(vm_page_t m);
int vm_page_pa_tryrelock(pmap_t, vm_paddr_t, vm_paddr_t *);
struct vm_pagequeue *vm_page_pagequeue(vm_page_t m);
vm_page_t vm_page_prev(vm_page_t m);
bool vm_page_ps_test(vm_page_t m, int flags, vm_page_t skip_m);
void vm_page_putfake(vm_page_t m);
void vm_page_readahead_finish(vm_page_t m);
bool vm_page_reclaim_contig(int req, u_long npages, vm_paddr_t low,
vm_paddr_t high, u_long alignment, vm_paddr_t boundary);
bool vm_page_reclaim_contig_domain(int domain, int req, u_long npages,
vm_paddr_t low, vm_paddr_t high, u_long alignment, vm_paddr_t boundary);
void vm_page_reference(vm_page_t m);
void vm_page_remove (vm_page_t);
int vm_page_rename (vm_page_t, vm_object_t, vm_pindex_t);
vm_page_t vm_page_replace(vm_page_t mnew, vm_object_t object,
vm_pindex_t pindex);
void vm_page_requeue(vm_page_t m);
void vm_page_requeue_locked(vm_page_t m);
int vm_page_sbusied(vm_page_t m);
vm_page_t vm_page_scan_contig(u_long npages, vm_page_t m_start,
vm_page_t m_end, u_long alignment, vm_paddr_t boundary, int options);
void vm_page_set_valid_range(vm_page_t m, int base, int size);
int vm_page_sleep_if_busy(vm_page_t m, const char *msg);
vm_offset_t vm_page_startup(vm_offset_t vaddr);
void vm_page_sunbusy(vm_page_t m);
bool vm_page_try_to_free(vm_page_t m);
int vm_page_trysbusy(vm_page_t m);
void vm_page_unhold_pages(vm_page_t *ma, int count);
void vm_page_unswappable(vm_page_t m);
bool vm_page_unwire(vm_page_t m, uint8_t queue);
bool vm_page_unwire_noq(vm_page_t m);
void vm_page_updatefake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr);
void vm_page_wire (vm_page_t);
void vm_page_xunbusy_hard(vm_page_t m);
void vm_page_xunbusy_maybelocked(vm_page_t m);
void vm_page_set_validclean (vm_page_t, int, int);
void vm_page_clear_dirty (vm_page_t, int, int);
void vm_page_set_invalid (vm_page_t, int, int);
int vm_page_is_valid (vm_page_t, int, int);
void vm_page_test_dirty (vm_page_t);
vm_page_bits_t vm_page_bits(int base, int size);
void vm_page_zero_invalid(vm_page_t m, boolean_t setvalid);
void vm_page_free_toq(vm_page_t m);
void vm_page_dirty_KBI(vm_page_t m);
void vm_page_lock_KBI(vm_page_t m, const char *file, int line);
void vm_page_unlock_KBI(vm_page_t m, const char *file, int line);
int vm_page_trylock_KBI(vm_page_t m, const char *file, int line);
#if defined(INVARIANTS) || defined(INVARIANT_SUPPORT)
void vm_page_assert_locked_KBI(vm_page_t m, const char *file, int line);
void vm_page_lock_assert_KBI(vm_page_t m, int a, const char *file, int line);
#endif
#define vm_page_assert_sbusied(m) \
KASSERT(vm_page_sbusied(m), \
("vm_page_assert_sbusied: page %p not shared busy @ %s:%d", \
(m), __FILE__, __LINE__))
#define vm_page_assert_unbusied(m) \
KASSERT(!vm_page_busied(m), \
("vm_page_assert_unbusied: page %p busy @ %s:%d", \
(m), __FILE__, __LINE__))
#define vm_page_assert_xbusied(m) \
KASSERT(vm_page_xbusied(m), \
("vm_page_assert_xbusied: page %p not exclusive busy @ %s:%d", \
(m), __FILE__, __LINE__))
#define vm_page_busied(m) \
((m)->busy_lock != VPB_UNBUSIED)
#define vm_page_sbusy(m) do { \
if (!vm_page_trysbusy(m)) \
panic("%s: page %p failed shared busying", __func__, \
(m)); \
} while (0)
#define vm_page_tryxbusy(m) \
(atomic_cmpset_acq_int(&(m)->busy_lock, VPB_UNBUSIED, \
VPB_SINGLE_EXCLUSIVER))
#define vm_page_xbusied(m) \
(((m)->busy_lock & VPB_SINGLE_EXCLUSIVER) != 0)
#define vm_page_xbusy(m) do { \
if (!vm_page_tryxbusy(m)) \
panic("%s: page %p failed exclusive busying", __func__, \
(m)); \
} while (0)
/* Note: page m's lock must not be owned by the caller. */
#define vm_page_xunbusy(m) do { \
if (!atomic_cmpset_rel_int(&(m)->busy_lock, \
VPB_SINGLE_EXCLUSIVER, VPB_UNBUSIED)) \
vm_page_xunbusy_hard(m); \
} while (0)
#ifdef INVARIANTS
void vm_page_object_lock_assert(vm_page_t m);
#define VM_PAGE_OBJECT_LOCK_ASSERT(m) vm_page_object_lock_assert(m)
void vm_page_assert_pga_writeable(vm_page_t m, uint8_t bits);
#define VM_PAGE_ASSERT_PGA_WRITEABLE(m, bits) \
vm_page_assert_pga_writeable(m, bits)
#else
#define VM_PAGE_OBJECT_LOCK_ASSERT(m) (void)0
#define VM_PAGE_ASSERT_PGA_WRITEABLE(m, bits) (void)0
#endif
/*
* We want to use atomic updates for the aflags field, which is 8 bits wide.
* However, not all architectures support atomic operations on 8-bit
* destinations. In order that we can easily use a 32-bit operation, we
* require that the aflags field be 32-bit aligned.
*/
CTASSERT(offsetof(struct vm_page, aflags) % sizeof(uint32_t) == 0);
/*
* Clear the given bits in the specified page.
*/
static inline void
vm_page_aflag_clear(vm_page_t m, uint8_t bits)
{
uint32_t *addr, val;
/*
* The PGA_REFERENCED flag can only be cleared if the page is locked.
*/
if ((bits & PGA_REFERENCED) != 0)
vm_page_assert_locked(m);
/*
* Access the whole 32-bit word containing the aflags field with an
* atomic update. Parallel non-atomic updates to the other fields
* within this word are handled properly by the atomic update.
*/
addr = (void *)&m->aflags;
KASSERT(((uintptr_t)addr & (sizeof(uint32_t) - 1)) == 0,
("vm_page_aflag_clear: aflags is misaligned"));
val = bits;
#if BYTE_ORDER == BIG_ENDIAN
val <<= 24;
#endif
atomic_clear_32(addr, val);
}
/*
* Set the given bits in the specified page.
*/
static inline void
vm_page_aflag_set(vm_page_t m, uint8_t bits)
{
uint32_t *addr, val;
VM_PAGE_ASSERT_PGA_WRITEABLE(m, bits);
/*
* Access the whole 32-bit word containing the aflags field with an
* atomic update. Parallel non-atomic updates to the other fields
* within this word are handled properly by the atomic update.
*/
addr = (void *)&m->aflags;
KASSERT(((uintptr_t)addr & (sizeof(uint32_t) - 1)) == 0,
("vm_page_aflag_set: aflags is misaligned"));
val = bits;
#if BYTE_ORDER == BIG_ENDIAN
val <<= 24;
#endif
atomic_set_32(addr, val);
}
/*
* vm_page_dirty:
*
* Set all bits in the page's dirty field.
*
* The object containing the specified page must be locked if the
* call is made from the machine-independent layer.
*
* See vm_page_clear_dirty_mask().
*/
static __inline void
vm_page_dirty(vm_page_t m)
{
/* Use vm_page_dirty_KBI() under INVARIANTS to save memory. */
#if defined(KLD_MODULE) || defined(INVARIANTS)
vm_page_dirty_KBI(m);
#else
m->dirty = VM_PAGE_BITS_ALL;
#endif
}
/*
* vm_page_remque:
*
* If the given page is in a page queue, then remove it from that page
* queue.
*
* The page must be locked.
*/
static inline void
vm_page_remque(vm_page_t m)
{
if (m->queue != PQ_NONE)
vm_page_dequeue(m);
}
/*
* vm_page_undirty:
*
* Set page to not be dirty. Note: does not clear pmap modify bits
*/
static __inline void
vm_page_undirty(vm_page_t m)
{
VM_PAGE_OBJECT_LOCK_ASSERT(m);
m->dirty = 0;
}
static inline void
vm_page_replace_checked(vm_page_t mnew, vm_object_t object, vm_pindex_t pindex,
vm_page_t mold)
{
vm_page_t mret;
mret = vm_page_replace(mnew, object, pindex);
KASSERT(mret == mold,
("invalid page replacement, mold=%p, mret=%p", mold, mret));
/* Unused if !INVARIANTS. */
(void)mold;
(void)mret;
}
static inline bool
vm_page_active(vm_page_t m)
{
return (m->queue == PQ_ACTIVE);
}
static inline bool
vm_page_inactive(vm_page_t m)
{
return (m->queue == PQ_INACTIVE);
}
static inline bool
vm_page_in_laundry(vm_page_t m)
{
return (m->queue == PQ_LAUNDRY || m->queue == PQ_UNSWAPPABLE);
}
/*
* vm_page_held:
*
* Return true if a reference prevents the page from being reclaimable.
*/
static inline bool
vm_page_held(vm_page_t m)
{
return (m->hold_count > 0 || m->wire_count > 0);
}
#endif /* _KERNEL */
#endif /* !_VM_PAGE_ */
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