FreeBSD/Linux Kernel Cross Reference
sys/vm/vm_object.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.
     * 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_object.h   8.3 (Berkeley) 1/12/94
     *
     *
     * 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.
     *
     * $FreeBSD$
     */
    
    /*
     *      Virtual memory object module definitions.
     */
    
    #ifndef _VM_OBJECT_
    #define _VM_OBJECT_
    
    #include <sys/queue.h>
    #include <sys/_lock.h>
    #include <sys/_mutex.h>
    #include <sys/_rwlock.h>
    
    #include <vm/_vm_radix.h>
    
    /*
     *      Types defined:
     *
     *      vm_object_t             Virtual memory object.
     *
     *      The root of cached pages pool is protected by both the per-object lock
     *      and the free pages queue mutex.
     *      On insert in the cache radix trie, the per-object lock is expected
     *      to be already held and the free pages queue mutex will be
     *      acquired during the operation too.
     *      On remove and lookup from the cache radix trie, only the free
     *      pages queue mutex is expected to be locked.
     *      These rules allow for reliably checking for the presence of cached
     *      pages with only the per-object lock held, thereby reducing contention
     *      for the free pages queue mutex.
     *
     * List of locks
     *      (c)     const until freed
     *      (o)     per-object lock 
     *      (f)     free pages queue mutex
     *
     */
    
   struct vm_object {
           struct rwlock lock;
           TAILQ_ENTRY(vm_object) object_list; /* list of all objects */
           LIST_HEAD(, vm_object) shadow_head; /* objects that this is a shadow for */
           LIST_ENTRY(vm_object) shadow_list; /* chain of shadow objects */
           TAILQ_HEAD(respgs, vm_page) memq; /* list of resident pages */
           struct vm_radix rtree;          /* root of the resident page radix trie*/
           vm_pindex_t size;               /* Object size */
           int generation;                 /* generation ID */
           int ref_count;                  /* How many refs?? */
           int shadow_count;               /* how many objects that this is a shadow for */
           vm_memattr_t memattr;           /* default memory attribute for pages */
           objtype_t type;                 /* type of pager */
           u_short flags;                  /* see below */
           u_short pg_color;               /* (c) color of first page in obj */
           u_int paging_in_progress;       /* Paging (in or out) so don't collapse or destroy */
           int resident_page_count;        /* number of resident pages */
           struct vm_object *backing_object; /* object that I'm a shadow of */
           vm_ooffset_t backing_object_offset;/* Offset in backing object */
           TAILQ_ENTRY(vm_object) pager_object_list; /* list of all objects of this pager type */
           LIST_HEAD(, vm_reserv) rvq;     /* list of reservations */
           struct vm_radix cache;          /* (o + f) root of the cache page radix trie */
           void *handle;
           union {
                   /*
                    * VNode pager
                    *
                    *      vnp_size - current size of file
                    */
                   struct {
                           off_t vnp_size;
                           vm_ooffset_t writemappings;
                   } vnp;
   
                   /*
                    * Device pager
                    *
                    *      devp_pglist - list of allocated pages
                    */
                   struct {
                           TAILQ_HEAD(, vm_page) devp_pglist;
                           struct cdev_pager_ops *ops;
                           struct cdev *dev;
                   } devp;
   
                   /*
                    * SG pager
                    *
                    *      sgp_pglist - list of allocated pages
                    */
                   struct {
                           TAILQ_HEAD(, vm_page) sgp_pglist;
                   } sgp;
   
                   /*
                    * Swap pager
                    *
                    *      swp_tmpfs - back-pointer to the tmpfs vnode,
                    *                   if any, which uses the vm object
                    *                   as backing store.  The handle
                    *                   cannot be reused for linking,
                    *                   because the vnode can be
                    *                   reclaimed and recreated, making
                    *                   the handle changed and hash-chain
                    *                   invalid.
                    *
                    *      swp_bcount - number of swap 'swblock' metablocks, each
                    *                   contains up to 16 swapblk assignments.
                    *                   see vm/swap_pager.h
                    */
                   struct {
                           void *swp_tmpfs;
                           int swp_bcount;
                   } swp;
           } un_pager;
           struct ucred *cred;
           vm_ooffset_t charge;
   };
   
   /*
    * Flags
    */
   #define OBJ_FICTITIOUS  0x0001          /* (c) contains fictitious pages */
   #define OBJ_UNMANAGED   0x0002          /* (c) contains unmanaged pages */
   #define OBJ_DEAD        0x0008          /* dead objects (during rundown) */
   #define OBJ_NOSPLIT     0x0010          /* dont split this object */
   #define OBJ_PIPWNT      0x0040          /* paging in progress wanted */
   #define OBJ_MIGHTBEDIRTY 0x0100         /* object might be dirty, only for vnode */
   #define OBJ_TMPFS_NODE  0x0200          /* object belongs to tmpfs VREG node */
   #define OBJ_TMPFS_DIRTY 0x0400          /* dirty tmpfs obj */
   #define OBJ_COLORED     0x1000          /* pg_color is defined */
   #define OBJ_ONEMAPPING  0x2000          /* One USE (a single, non-forked) mapping flag */
   #define OBJ_DISCONNECTWNT 0x4000        /* disconnect from vnode wanted */
   #define OBJ_TMPFS       0x8000          /* has tmpfs vnode allocated */
   
   #define IDX_TO_OFF(idx) (((vm_ooffset_t)(idx)) << PAGE_SHIFT)
   #define OFF_TO_IDX(off) ((vm_pindex_t)(((vm_ooffset_t)(off)) >> PAGE_SHIFT))
   
   #ifdef  _KERNEL
   
   #define OBJPC_SYNC      0x1                     /* sync I/O */
   #define OBJPC_INVAL     0x2                     /* invalidate */
   #define OBJPC_NOSYNC    0x4                     /* skip if PG_NOSYNC */
   
   /*
    * The following options are supported by vm_object_page_remove().
    */
   #define OBJPR_CLEANONLY 0x1             /* Don't remove dirty pages. */
   #define OBJPR_NOTMAPPED 0x2             /* Don't unmap pages. */
   
   TAILQ_HEAD(object_q, vm_object);
   
   extern struct object_q vm_object_list;  /* list of allocated objects */
   extern struct mtx vm_object_list_mtx;   /* lock for object list and count */
   
   extern struct vm_object kernel_object_store;
   extern struct vm_object kmem_object_store;
   
   #define kernel_object   (&kernel_object_store)
   #define kmem_object     (&kmem_object_store)
   
   #define VM_OBJECT_ASSERT_LOCKED(object)                                 \
           rw_assert(&(object)->lock, RA_LOCKED)
   #define VM_OBJECT_ASSERT_RLOCKED(object)                                \
           rw_assert(&(object)->lock, RA_RLOCKED)
   #define VM_OBJECT_ASSERT_WLOCKED(object)                                \
           rw_assert(&(object)->lock, RA_WLOCKED)
   #define VM_OBJECT_ASSERT_UNLOCKED(object)                               \
           rw_assert(&(object)->lock, RA_UNLOCKED)
   #define VM_OBJECT_LOCK_DOWNGRADE(object)                                \
           rw_downgrade(&(object)->lock)
   #define VM_OBJECT_RLOCK(object)                                         \
           rw_rlock(&(object)->lock)
   #define VM_OBJECT_RUNLOCK(object)                                       \
           rw_runlock(&(object)->lock)
   #define VM_OBJECT_SLEEP(object, wchan, pri, wmesg, timo)                \
           rw_sleep((wchan), &(object)->lock, (pri), (wmesg), (timo))
   #define VM_OBJECT_TRYRLOCK(object)                                      \
           rw_try_rlock(&(object)->lock)
   #define VM_OBJECT_TRYWLOCK(object)                                      \
           rw_try_wlock(&(object)->lock)
   #define VM_OBJECT_TRYUPGRADE(object)                                    \
           rw_try_upgrade(&(object)->lock)
   #define VM_OBJECT_WLOCK(object)                                         \
           rw_wlock(&(object)->lock)
   #define VM_OBJECT_WUNLOCK(object)                                       \
           rw_wunlock(&(object)->lock)
   
   /*
    *      The object must be locked or thread private.
    */
   static __inline void
   vm_object_set_flag(vm_object_t object, u_short bits)
   {
   
           object->flags |= bits;
   }
   
   void vm_object_clear_flag(vm_object_t object, u_short bits);
   void vm_object_pip_add(vm_object_t object, short i);
   void vm_object_pip_subtract(vm_object_t object, short i);
   void vm_object_pip_wakeup(vm_object_t object);
   void vm_object_pip_wakeupn(vm_object_t object, short i);
   void vm_object_pip_wait(vm_object_t object, char *waitid);
   
   static __inline boolean_t
   vm_object_cache_is_empty(vm_object_t object)
   {
   
           return (vm_radix_is_empty(&object->cache));
   }
   
   vm_object_t vm_object_allocate (objtype_t, vm_pindex_t);
   boolean_t vm_object_coalesce(vm_object_t, vm_ooffset_t, vm_size_t, vm_size_t,
      boolean_t);
   void vm_object_collapse (vm_object_t);
   void vm_object_deallocate (vm_object_t);
   void vm_object_destroy (vm_object_t);
   void vm_object_terminate (vm_object_t);
   void vm_object_set_writeable_dirty (vm_object_t);
   void vm_object_init (void);
   void vm_object_madvise(vm_object_t, vm_pindex_t, vm_pindex_t, int);
   void vm_object_page_cache(vm_object_t object, vm_pindex_t start,
       vm_pindex_t end);
   boolean_t vm_object_page_clean(vm_object_t object, vm_ooffset_t start,
       vm_ooffset_t end, int flags);
   void vm_object_page_remove(vm_object_t object, vm_pindex_t start,
       vm_pindex_t end, int options);
   boolean_t vm_object_populate(vm_object_t, vm_pindex_t, vm_pindex_t);
   void vm_object_print(long addr, boolean_t have_addr, long count, char *modif);
   void vm_object_reference (vm_object_t);
   void vm_object_reference_locked(vm_object_t);
   int  vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr);
   void vm_object_shadow (vm_object_t *, vm_ooffset_t *, vm_size_t);
   void vm_object_split(vm_map_entry_t);
   boolean_t vm_object_sync(vm_object_t, vm_ooffset_t, vm_size_t, boolean_t,
       boolean_t);
   void vm_object_unwire(vm_object_t object, vm_ooffset_t offset,
       vm_size_t length, uint8_t queue);
   struct vnode *vm_object_vnode(vm_object_t object);
   #endif                          /* _KERNEL */
   
   #endif                          /* _VM_OBJECT_ */

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