FreeBSD/Linux Kernel Cross Reference
sys/vm/vm_page.h

     /*
      * 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. All advertising materials mentioning features or use of this software
     *    must display the following acknowledgement:
     *      This product includes software developed by the University of
     *      California, Berkeley and its contributors.
     * 4. Neither the name of the University nor the names of its contributors
     *    may be used to endorse or promote products derived from this software
     *    without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     * SUCH DAMAGE.
     *
     *      from: @(#)vm_page.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: src/sys/vm/vm_page.h,v 1.75.2.8 2002/03/06 01:07:09 dillon Exp $
     */
    
    /*
     *      Resident memory system definitions.
     */
    
    #ifndef _VM_VM_PAGE_H_
    #define _VM_VM_PAGE_H_
    
    #ifndef _SYS_TYPES_H_
    #include <sys/types.h>
    #endif
    #ifndef _SYS_TREE_H_
    #include <sys/tree.h>
    #endif
    #ifndef _MACHINE_PMAP_H_
    #include <machine/pmap.h>
    #endif
    #ifndef _VM_PMAP_H_
    #include <vm/pmap.h>
    #endif
    #include <machine/atomic.h>
    
    #ifdef _KERNEL
    
    #ifndef _SYS_SYSTM_H_
    #include <sys/systm.h>
    #endif
    #ifndef _SYS_THREAD2_H_
    #include <sys/thread2.h>
    #endif
    
    #ifdef __x86_64__
    #include <machine/vmparam.h>
    #endif
   
   #endif
   
   typedef enum vm_page_event { VMEVENT_NONE, VMEVENT_COW } vm_page_event_t;
   
   struct vm_page_action {
           LIST_ENTRY(vm_page_action) entry;
           struct vm_page          *m;
           vm_page_event_t         event;
           void                    (*func)(struct vm_page *,
                                           struct vm_page_action *);
           void                    *data;
   };
   
   typedef struct vm_page_action *vm_page_action_t;
   
   /*
    *      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 lists:
    *
    *              A hash table bucket 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.
    *
    *      Fields in this structure are locked either by the lock on the
    *      object that the page belongs to (O) or by the lock on the page
    *      queues (P).
    *
    *      The 'valid' and 'dirty' fields are distinct.  A page may have dirty
    *      bits set without having associated valid bits set.  This is used by
    *      NFS to implement piecemeal writes.
    */
   
   TAILQ_HEAD(pglist, vm_page);
   
   struct vm_object;
   
   int rb_vm_page_compare(struct vm_page *, struct vm_page *);
   
   struct vm_page_rb_tree;
   RB_PROTOTYPE2(vm_page_rb_tree, vm_page, rb_entry, rb_vm_page_compare, vm_pindex_t);
   
   struct vm_page {
           TAILQ_ENTRY(vm_page) pageq;     /* vm_page_queues[] list (P)    */
           RB_ENTRY(vm_page) rb_entry;     /* Red-Black tree based at object */
   
           struct vm_object *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 dependant stuff */
           u_short queue;                  /* page queue index */
           u_short pc;                     /* page color */
           u_char  act_count;              /* page usage count */
           u_char  busy;                   /* page busy count */
           u_char  pat_mode;               /* hardware page attribute */
           u_char  unused02;
           u_int32_t flags;                /* see below */
           u_int   wire_count;             /* wired down maps refs (P) */
           int     hold_count;             /* page hold count */
   
           /*
            * 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.
            */
           u_char  valid;                  /* map of valid DEV_BSIZE chunks */
           u_char  dirty;                  /* map of dirty DEV_BSIZE chunks */
   
           int     ku_pagecnt;             /* kmalloc helper */
   #ifdef VM_PAGE_DEBUG
           const char *busy_func;
           int     busy_line;
   #endif
   };
   
   #ifdef VM_PAGE_DEBUG
   #define VM_PAGE_DEBUG_EXT(name) name ## _debug
   #define VM_PAGE_DEBUG_ARGS      , const char *func, int lineno
   #else
   #define VM_PAGE_DEBUG_EXT(name) name
   #define VM_PAGE_DEBUG_ARGS
   #endif
   
   #ifndef __VM_PAGE_T_DEFINED__
   #define __VM_PAGE_T_DEFINED__
   typedef struct vm_page *vm_page_t;
   #endif
   
   /*
    * Page coloring parameters.  We use generous parameters designed to
    * statistically spread pages over available cpu cache space.  This has
    * become less important over time as cache associativity is higher
    * in modern times but we still use the core algorithm to help reduce
    * lock contention between cpus.
    *
    * Page coloring cannot be disabled.
    */
   
   #define PQ_PRIME1 31    /* Prime number somewhat less than PQ_HASH_SIZE */
   #define PQ_PRIME2 23    /* Prime number somewhat less than PQ_HASH_SIZE */
   #define PQ_L2_SIZE 256  /* A number of colors opt for 1M cache */
   
   #if 0
   #define PQ_PRIME1 31    /* Prime number somewhat less than PQ_HASH_SIZE */
   #define PQ_PRIME2 23    /* Prime number somewhat less than PQ_HASH_SIZE */
   #define PQ_L2_SIZE 128  /* A number of colors opt for 512K cache */
   
   #define PQ_PRIME1 13    /* Prime number somewhat less than PQ_HASH_SIZE */
   #define PQ_PRIME2 7     /* Prime number somewhat less than PQ_HASH_SIZE */
   #define PQ_L2_SIZE 64   /* A number of colors opt for 256K cache */
   
   #define PQ_PRIME1 9     /* Produces a good PQ_L2_SIZE/3 + PQ_PRIME1 */
   #define PQ_PRIME2 5     /* Prime number somewhat less than PQ_HASH_SIZE */
   #define PQ_L2_SIZE 32   /* A number of colors opt for 128k cache */
   
   #define PQ_PRIME1 5     /* Prime number somewhat less than PQ_HASH_SIZE */
   #define PQ_PRIME2 3     /* Prime number somewhat less than PQ_HASH_SIZE */
   #define PQ_L2_SIZE 16   /* A reasonable number of colors (opt for 64K cache) */
   #endif
   
   #define PQ_L2_MASK      (PQ_L2_SIZE - 1)
   
   #define PQ_NONE         0
   #define PQ_FREE         (1 + 0*PQ_L2_SIZE)
   #define PQ_INACTIVE     (1 + 1*PQ_L2_SIZE)
   #define PQ_ACTIVE       (1 + 2*PQ_L2_SIZE)
   #define PQ_CACHE        (1 + 3*PQ_L2_SIZE)
   #define PQ_HOLD         (1 + 4*PQ_L2_SIZE)
   #define PQ_COUNT        (1 + 5*PQ_L2_SIZE)
   
   /*
    * Scan support
    */
   struct vm_map;
   
   struct rb_vm_page_scan_info {
           vm_pindex_t     start_pindex;
           vm_pindex_t     end_pindex;
           int             limit;
           int             desired;
           int             error;
           int             pagerflags;
           vm_offset_t     addr;
           vm_pindex_t     backing_offset_index;
           struct vm_object *object;
           struct vm_object *backing_object;
           struct vm_page  *mpte;
           struct pmap     *pmap;
           struct vm_map   *map;
   };
   
   int rb_vm_page_scancmp(struct vm_page *, void *);
   
   struct vpgqueues {
           struct pglist pl;
           int     *cnt;
           int     lcnt;
           int     flipflop;       /* probably not the best place */
           struct spinlock spin;
           char    unused[64 - sizeof(struct pglist) -
                           sizeof(int *) - sizeof(int) * 2];
   };
   
   extern struct vpgqueues vm_page_queues[PQ_COUNT];
   
   /*
    * These are the flags defined for vm_page.
    *
    *  PG_UNMANAGED (used by OBJT_PHYS) 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, nor can they be removed from their objects via 
    *  the object, and such pages are also not on any PQ queue.  The
    *  PG_MAPPED and PG_WRITEABLE flags are not applicable.
    *
    *  PG_MAPPED only applies to managed pages, indicating whether the page
    *  is mapped onto one or more pmaps.  A page might still be mapped to
    *  special pmaps in an unmanaged fashion, for example when mapped into a
    *  buffer cache buffer, without setting PG_MAPPED.
    *
    *  PG_WRITEABLE indicates that there may be a writeable managed pmap entry
    *  somewhere, and that the page can be dirtied by hardware at any time
    *  and may have to be tested for that.  The modified bit in unmanaged
    *  mappings or in the special clean map is not tested.
    *
    *  PG_SWAPPED indicates that the page is backed by a swap block.  Any
    *  VM object type other than OBJT_DEFAULT can have swap-backed pages now.
    *
    *  PG_SBUSY is set when m->busy != 0.  PG_SBUSY and m->busy are only modified
    *  when the page is PG_BUSY.
    */
   #define PG_BUSY         0x00000001      /* page is in transit (O) */
   #define PG_WANTED       0x00000002      /* someone is waiting for page (O) */
   #define PG_WINATCFLS    0x00000004      /* flush dirty page on inactive q */
   #define PG_FICTITIOUS   0x00000008      /* physical page doesn't exist (O) */
   #define PG_WRITEABLE    0x00000010      /* page is writeable */
   #define PG_MAPPED       0x00000020      /* page is mapped (managed) */
   #define PG_ZERO         0x00000040      /* page is zeroed */
   #define PG_REFERENCED   0x00000080      /* page has been referenced */
   #define PG_CLEANCHK     0x00000100      /* page will be checked for cleaning */
   #define PG_SWAPINPROG   0x00000200      /* swap I/O in progress on page      */
   #define PG_NOSYNC       0x00000400      /* do not collect for syncer */
   #define PG_UNMANAGED    0x00000800      /* No PV management for page */
   #define PG_MARKER       0x00001000      /* special queue marker page */
   #define PG_RAM          0x00002000      /* read ahead mark */
   #define PG_SWAPPED      0x00004000      /* backed by swap */
   #define PG_NOTMETA      0x00008000      /* do not back with swap */
   #define PG_ACTIONLIST   0x00010000      /* lookaside action list present */
   #define PG_SBUSY        0x00020000      /* soft-busy also set */
   #define PG_NEED_COMMIT  0x00040000      /* clean page requires commit */
   
   /*
    * Misc constants.
    */
   
   #define ACT_DECLINE             1
   #define ACT_ADVANCE             3
   #define ACT_INIT                5
   #define ACT_MAX                 64
   
   #ifdef _KERNEL
   /*
    * Each pageable resident page falls into one of four lists:
    *
    *      free
    *              Available for allocation now.
    *
    * The following are all LRU sorted:
    *
    *      cache
    *              Almost available for allocation. Still in an
    *              object, but clean and immediately freeable at
    *              non-interrupt times.
    *
    *      inactive
    *              Low activity, candidates for reclamation.
    *              This is the list of pages that should be
    *              paged out next.
    *
    *      active
    *              Pages that are "active" i.e. they have been
    *              recently referenced.
    *
    *      zero
    *              Pages that are really free and have been pre-zeroed
    *
    */
   
   extern int vm_page_zero_count;
   extern struct vm_page *vm_page_array;   /* First resident page in table */
   extern int 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)
   
   #define PHYS_TO_VM_PAGE(pa)     \
                   (&vm_page_array[atop(pa) - first_page])
   
   
   #if PAGE_SIZE == 4096
   #define VM_PAGE_BITS_ALL 0xff
   #endif
   
   /*
    * Note: the code will always use nominally free pages from the free list
    * before trying other flag-specified sources. 
    *
    * At least one of VM_ALLOC_NORMAL|VM_ALLOC_SYSTEM|VM_ALLOC_INTERRUPT 
    * must be specified.  VM_ALLOC_RETRY may only be specified if VM_ALLOC_NORMAL
    * is also specified.
    */
   #define VM_ALLOC_NORMAL         0x0001  /* ok to use cache pages */
   #define VM_ALLOC_SYSTEM         0x0002  /* ok to exhaust most of free list */
   #define VM_ALLOC_INTERRUPT      0x0004  /* ok to exhaust entire free list */
   #define VM_ALLOC_ZERO           0x0008  /* req pre-zero'd memory if avail */
   #define VM_ALLOC_QUICK          0x0010  /* like NORMAL but do not use cache */
   #define VM_ALLOC_FORCE_ZERO     0x0020  /* zero page even if already valid */
   #define VM_ALLOC_NULL_OK        0x0040  /* ok to return NULL on collision */
   #define VM_ALLOC_RETRY          0x0080  /* indefinite block (vm_page_grab()) */
   #define VM_ALLOC_USE_GD         0x0100  /* use per-gd cache */
   
   void vm_page_queue_spin_lock(vm_page_t);
   void vm_page_queues_spin_lock(u_short);
   void vm_page_and_queue_spin_lock(vm_page_t);
   
   void vm_page_queue_spin_unlock(vm_page_t);
   void vm_page_queues_spin_unlock(u_short);
   void vm_page_and_queue_spin_unlock(vm_page_t m);
   
   void vm_page_init(vm_page_t m);
   void vm_page_io_finish(vm_page_t m);
   void vm_page_io_start(vm_page_t m);
   void vm_page_need_commit(vm_page_t m);
   void vm_page_clear_commit(vm_page_t m);
   void vm_page_wakeup(vm_page_t m);
   void vm_page_hold(vm_page_t);
   void vm_page_unhold(vm_page_t);
   void vm_page_activate (vm_page_t);
   void vm_page_pcpu_cache(void);
   vm_page_t vm_page_alloc (struct vm_object *, vm_pindex_t, int);
   vm_page_t vm_page_alloc_contig(vm_paddr_t low, vm_paddr_t high,
                        unsigned long alignment, unsigned long boundary,
                        unsigned long size, vm_memattr_t memattr);
   vm_page_t vm_page_grab (struct vm_object *, vm_pindex_t, int);
   void vm_page_cache (vm_page_t);
   int vm_page_try_to_cache (vm_page_t);
   int vm_page_try_to_free (vm_page_t);
   void vm_page_dontneed (vm_page_t);
   void vm_page_deactivate (vm_page_t);
   void vm_page_deactivate_locked (vm_page_t);
   void vm_page_initfake(vm_page_t m, vm_paddr_t paddr, vm_memattr_t memattr);
   int vm_page_insert (vm_page_t, struct vm_object *, vm_pindex_t);
   vm_page_t vm_page_lookup (struct vm_object *, vm_pindex_t);
   vm_page_t VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_wait)(
                   struct vm_object *, vm_pindex_t, int, const char *
                   VM_PAGE_DEBUG_ARGS);
   vm_page_t VM_PAGE_DEBUG_EXT(vm_page_lookup_busy_try)(
                   struct vm_object *, vm_pindex_t, int, int *
                   VM_PAGE_DEBUG_ARGS);
   void vm_page_remove (vm_page_t);
   void vm_page_rename (vm_page_t, struct vm_object *, vm_pindex_t);
   void vm_page_startup (void);
   void vm_page_unmanage (vm_page_t);
   void vm_page_unwire (vm_page_t, int);
   void vm_page_wire (vm_page_t);
   void vm_page_unqueue (vm_page_t);
   void vm_page_unqueue_nowakeup (vm_page_t);
   vm_page_t vm_page_next (vm_page_t);
   void vm_page_set_validclean (vm_page_t, int, int);
   void vm_page_set_validdirty (vm_page_t, int, int);
   void vm_page_set_valid (vm_page_t, int, int);
   void vm_page_set_dirty (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);
   int vm_page_bits (int, int);
   vm_page_t vm_page_list_find(int basequeue, int index, boolean_t prefer_zero);
   void vm_page_zero_invalid(vm_page_t m, boolean_t setvalid);
   void vm_page_free_toq(vm_page_t m);
   void vm_page_free_contig(vm_page_t m, unsigned long size);
   vm_page_t vm_page_free_fromq_fast(void);
   void vm_page_event_internal(vm_page_t, vm_page_event_t);
   void vm_page_dirty(vm_page_t m);
   void vm_page_register_action(vm_page_action_t action, vm_page_event_t event);
   void vm_page_unregister_action(vm_page_action_t action);
   void vm_page_sleep_busy(vm_page_t m, int also_m_busy, const char *msg);
   void VM_PAGE_DEBUG_EXT(vm_page_busy_wait)(vm_page_t m, int also_m_busy, const char *wmsg VM_PAGE_DEBUG_ARGS);
   int VM_PAGE_DEBUG_EXT(vm_page_busy_try)(vm_page_t m, int also_m_busy VM_PAGE_DEBUG_ARGS);
   
   #ifdef VM_PAGE_DEBUG
   
   #define vm_page_lookup_busy_wait(object, pindex, alsob, msg)            \
           vm_page_lookup_busy_wait_debug(object, pindex, alsob, msg,      \
                                           __func__, __LINE__)
   
   #define vm_page_lookup_busy_try(object, pindex, alsob, errorp)          \
           vm_page_lookup_busy_try_debug(object, pindex, alsob, errorp,    \
                                           __func__, __LINE__)
   
   #define vm_page_busy_wait(m, alsob, msg)                                \
           vm_page_busy_wait_debug(m, alsob, msg, __func__, __LINE__)
   
   #define vm_page_busy_try(m, alsob)                                      \
           vm_page_busy_try_debug(m, alsob, __func__, __LINE__)
   
   #endif
   
   #endif                          /* _KERNEL */
   #endif                          /* !_VM_VM_PAGE_H_ */

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