1113 lines
27 KiB
C
1113 lines
27 KiB
C
/* $NetBSD: uvm_aobj.c,v 1.20 1999/05/25 00:09:00 thorpej Exp $ */
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/*
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* Copyright (c) 1998 Chuck Silvers, Charles D. Cranor and
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* Washington University.
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* All rights reserved.
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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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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by Charles D. Cranor and
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* Washington University.
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* 4. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* from: Id: uvm_aobj.c,v 1.1.2.5 1998/02/06 05:14:38 chs Exp
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*/
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/*
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* uvm_aobj.c: anonymous memory uvm_object pager
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*
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* author: Chuck Silvers <chuq@chuq.com>
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* started: Jan-1998
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*
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* - design mostly from Chuck Cranor
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*/
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#include "opt_uvmhist.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/proc.h>
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#include <sys/malloc.h>
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#include <sys/pool.h>
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#include <vm/vm.h>
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#include <vm/vm_page.h>
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#include <vm/vm_kern.h>
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#include <uvm/uvm.h>
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/*
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* an aobj manages anonymous-memory backed uvm_objects. in addition
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* to keeping the list of resident pages, it also keeps a list of
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* allocated swap blocks. depending on the size of the aobj this list
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* of allocated swap blocks is either stored in an array (small objects)
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* or in a hash table (large objects).
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*/
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/*
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* local structures
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*/
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/*
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* for hash tables, we break the address space of the aobj into blocks
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* of UAO_SWHASH_CLUSTER_SIZE pages. we require the cluster size to
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* be a power of two.
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*/
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#define UAO_SWHASH_CLUSTER_SHIFT 4
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#define UAO_SWHASH_CLUSTER_SIZE (1 << UAO_SWHASH_CLUSTER_SHIFT)
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/* get the "tag" for this page index */
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#define UAO_SWHASH_ELT_TAG(PAGEIDX) \
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((PAGEIDX) >> UAO_SWHASH_CLUSTER_SHIFT)
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/* given an ELT and a page index, find the swap slot */
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#define UAO_SWHASH_ELT_PAGESLOT(ELT, PAGEIDX) \
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((ELT)->slots[(PAGEIDX) & (UAO_SWHASH_CLUSTER_SIZE - 1)])
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/* given an ELT, return its pageidx base */
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#define UAO_SWHASH_ELT_PAGEIDX_BASE(ELT) \
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((ELT)->tag << UAO_SWHASH_CLUSTER_SHIFT)
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/*
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* the swhash hash function
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*/
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#define UAO_SWHASH_HASH(AOBJ, PAGEIDX) \
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(&(AOBJ)->u_swhash[(((PAGEIDX) >> UAO_SWHASH_CLUSTER_SHIFT) \
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& (AOBJ)->u_swhashmask)])
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/*
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* the swhash threshhold determines if we will use an array or a
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* hash table to store the list of allocated swap blocks.
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*/
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#define UAO_SWHASH_THRESHOLD (UAO_SWHASH_CLUSTER_SIZE * 4)
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#define UAO_USES_SWHASH(AOBJ) \
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((AOBJ)->u_pages > UAO_SWHASH_THRESHOLD) /* use hash? */
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/*
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* the number of buckets in a swhash, with an upper bound
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*/
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#define UAO_SWHASH_MAXBUCKETS 256
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#define UAO_SWHASH_BUCKETS(AOBJ) \
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(min((AOBJ)->u_pages >> UAO_SWHASH_CLUSTER_SHIFT, \
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UAO_SWHASH_MAXBUCKETS))
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/*
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* uao_swhash_elt: when a hash table is being used, this structure defines
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* the format of an entry in the bucket list.
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*/
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struct uao_swhash_elt {
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LIST_ENTRY(uao_swhash_elt) list; /* the hash list */
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vaddr_t tag; /* our 'tag' */
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int count; /* our number of active slots */
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int slots[UAO_SWHASH_CLUSTER_SIZE]; /* the slots */
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};
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/*
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* uao_swhash: the swap hash table structure
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*/
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LIST_HEAD(uao_swhash, uao_swhash_elt);
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/*
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* uao_swhash_elt_pool: pool of uao_swhash_elt structures
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*/
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struct pool uao_swhash_elt_pool;
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/*
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* uvm_aobj: the actual anon-backed uvm_object
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*
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* => the uvm_object is at the top of the structure, this allows
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* (struct uvm_device *) == (struct uvm_object *)
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* => only one of u_swslots and u_swhash is used in any given aobj
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*/
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struct uvm_aobj {
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struct uvm_object u_obj; /* has: lock, pgops, memq, #pages, #refs */
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int u_pages; /* number of pages in entire object */
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int u_flags; /* the flags (see uvm_aobj.h) */
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int *u_swslots; /* array of offset->swapslot mappings */
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/*
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* hashtable of offset->swapslot mappings
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* (u_swhash is an array of bucket heads)
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*/
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struct uao_swhash *u_swhash;
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u_long u_swhashmask; /* mask for hashtable */
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LIST_ENTRY(uvm_aobj) u_list; /* global list of aobjs */
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};
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/*
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* uvm_aobj_pool: pool of uvm_aobj structures
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*/
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struct pool uvm_aobj_pool;
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/*
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* local functions
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*/
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static void uao_init __P((void));
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static struct uao_swhash_elt *uao_find_swhash_elt __P((struct uvm_aobj *,
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int, boolean_t));
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static int uao_find_swslot __P((struct uvm_aobj *,
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int));
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static boolean_t uao_flush __P((struct uvm_object *,
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vaddr_t, vaddr_t,
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int));
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static void uao_free __P((struct uvm_aobj *));
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static int uao_get __P((struct uvm_object *, vaddr_t,
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vm_page_t *, int *, int,
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vm_prot_t, int, int));
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static boolean_t uao_releasepg __P((struct vm_page *,
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struct vm_page **));
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/*
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* aobj_pager
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*
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* note that some functions (e.g. put) are handled elsewhere
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*/
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struct uvm_pagerops aobj_pager = {
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uao_init, /* init */
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uao_reference, /* reference */
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uao_detach, /* detach */
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NULL, /* fault */
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uao_flush, /* flush */
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uao_get, /* get */
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NULL, /* asyncget */
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NULL, /* put (done by pagedaemon) */
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NULL, /* cluster */
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NULL, /* mk_pcluster */
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uvm_shareprot, /* shareprot */
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NULL, /* aiodone */
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uao_releasepg /* releasepg */
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};
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/*
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* uao_list: global list of active aobjs, locked by uao_list_lock
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*/
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static LIST_HEAD(aobjlist, uvm_aobj) uao_list;
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static simple_lock_data_t uao_list_lock;
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/*
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* functions
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*/
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/*
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* hash table/array related functions
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*/
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/*
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* uao_find_swhash_elt: find (or create) a hash table entry for a page
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* offset.
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*
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* => the object should be locked by the caller
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*/
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static struct uao_swhash_elt *
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uao_find_swhash_elt(aobj, pageidx, create)
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struct uvm_aobj *aobj;
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int pageidx;
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boolean_t create;
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{
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struct uao_swhash *swhash;
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struct uao_swhash_elt *elt;
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int page_tag;
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swhash = UAO_SWHASH_HASH(aobj, pageidx); /* first hash to get bucket */
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page_tag = UAO_SWHASH_ELT_TAG(pageidx); /* tag to search for */
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/*
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* now search the bucket for the requested tag
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*/
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for (elt = swhash->lh_first; elt != NULL; elt = elt->list.le_next) {
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if (elt->tag == page_tag)
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return(elt);
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}
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/* fail now if we are not allowed to create a new entry in the bucket */
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if (!create)
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return NULL;
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/*
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* allocate a new entry for the bucket and init/insert it in
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*/
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elt = pool_get(&uao_swhash_elt_pool, PR_WAITOK);
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LIST_INSERT_HEAD(swhash, elt, list);
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elt->tag = page_tag;
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elt->count = 0;
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memset(elt->slots, 0, sizeof(elt->slots));
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return(elt);
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}
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/*
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* uao_find_swslot: find the swap slot number for an aobj/pageidx
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*
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* => object must be locked by caller
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*/
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__inline static int
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uao_find_swslot(aobj, pageidx)
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struct uvm_aobj *aobj;
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int pageidx;
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{
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/*
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* if noswap flag is set, then we never return a slot
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*/
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if (aobj->u_flags & UAO_FLAG_NOSWAP)
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return(0);
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/*
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* if hashing, look in hash table.
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*/
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if (UAO_USES_SWHASH(aobj)) {
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struct uao_swhash_elt *elt =
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uao_find_swhash_elt(aobj, pageidx, FALSE);
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if (elt)
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return(UAO_SWHASH_ELT_PAGESLOT(elt, pageidx));
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else
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return(NULL);
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}
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/*
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* otherwise, look in the array
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*/
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return(aobj->u_swslots[pageidx]);
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}
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/*
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* uao_set_swslot: set the swap slot for a page in an aobj.
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*
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* => setting a slot to zero frees the slot
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* => object must be locked by caller
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*/
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int
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uao_set_swslot(uobj, pageidx, slot)
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struct uvm_object *uobj;
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int pageidx, slot;
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{
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struct uvm_aobj *aobj = (struct uvm_aobj *)uobj;
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int oldslot;
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UVMHIST_FUNC("uao_set_swslot"); UVMHIST_CALLED(pdhist);
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UVMHIST_LOG(pdhist, "aobj %p pageidx %d slot %d",
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aobj, pageidx, slot, 0);
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/*
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* if noswap flag is set, then we can't set a slot
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*/
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if (aobj->u_flags & UAO_FLAG_NOSWAP) {
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if (slot == 0)
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return(0); /* a clear is ok */
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/* but a set is not */
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printf("uao_set_swslot: uobj = %p\n", uobj);
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panic("uao_set_swslot: attempt to set a slot on a NOSWAP object");
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}
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/*
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* are we using a hash table? if so, add it in the hash.
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*/
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if (UAO_USES_SWHASH(aobj)) {
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/*
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* Avoid allocating an entry just to free it again if
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* the page had not swap slot in the first place, and
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* we are freeing.
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*/
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struct uao_swhash_elt *elt =
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uao_find_swhash_elt(aobj, pageidx, slot ? TRUE : FALSE);
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if (elt == NULL) {
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#ifdef DIAGNOSTIC
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if (slot)
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panic("uao_set_swslot: didn't create elt");
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#endif
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return (0);
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}
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oldslot = UAO_SWHASH_ELT_PAGESLOT(elt, pageidx);
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UAO_SWHASH_ELT_PAGESLOT(elt, pageidx) = slot;
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/*
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* now adjust the elt's reference counter and free it if we've
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* dropped it to zero.
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*/
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/* an allocation? */
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if (slot) {
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if (oldslot == 0)
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elt->count++;
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} else { /* freeing slot ... */
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if (oldslot) /* to be safe */
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elt->count--;
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if (elt->count == 0) {
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LIST_REMOVE(elt, list);
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pool_put(&uao_swhash_elt_pool, elt);
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}
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}
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} else {
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/* we are using an array */
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oldslot = aobj->u_swslots[pageidx];
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aobj->u_swslots[pageidx] = slot;
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}
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return (oldslot);
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}
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/*
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* end of hash/array functions
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*/
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/*
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* uao_free: free all resources held by an aobj, and then free the aobj
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*
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* => the aobj should be dead
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*/
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static void
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uao_free(aobj)
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struct uvm_aobj *aobj;
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{
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if (UAO_USES_SWHASH(aobj)) {
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int i, hashbuckets = aobj->u_swhashmask + 1;
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/*
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* free the swslots from each hash bucket,
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* then the hash bucket, and finally the hash table itself.
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*/
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for (i = 0; i < hashbuckets; i++) {
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struct uao_swhash_elt *elt, *next;
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for (elt = aobj->u_swhash[i].lh_first; elt != NULL;
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elt = next) {
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int j;
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for (j = 0; j < UAO_SWHASH_CLUSTER_SIZE; j++)
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{
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int slot = elt->slots[j];
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if (slot) {
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uvm_swap_free(slot, 1);
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/*
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* this page is no longer
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* only in swap.
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*/
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simple_lock(&uvm.swap_data_lock);
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uvmexp.swpgonly--;
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simple_unlock(&uvm.swap_data_lock);
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}
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}
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next = elt->list.le_next;
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pool_put(&uao_swhash_elt_pool, elt);
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}
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}
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FREE(aobj->u_swhash, M_UVMAOBJ);
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} else {
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int i;
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/*
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* free the array
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*/
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for (i = 0; i < aobj->u_pages; i++)
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{
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int slot = aobj->u_swslots[i];
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if (slot) {
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uvm_swap_free(slot, 1);
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/* this page is no longer only in swap. */
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simple_lock(&uvm.swap_data_lock);
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uvmexp.swpgonly--;
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simple_unlock(&uvm.swap_data_lock);
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}
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}
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FREE(aobj->u_swslots, M_UVMAOBJ);
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}
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/*
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* finally free the aobj itself
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*/
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pool_put(&uvm_aobj_pool, aobj);
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}
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/*
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* pager functions
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*/
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/*
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* uao_create: create an aobj of the given size and return its uvm_object.
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*
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* => for normal use, flags are always zero
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* => for the kernel object, the flags are:
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* UAO_FLAG_KERNOBJ - allocate the kernel object (can only happen once)
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* UAO_FLAG_KERNSWAP - enable swapping of kernel object (" ")
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*/
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struct uvm_object *
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uao_create(size, flags)
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vsize_t size;
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int flags;
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{
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static struct uvm_aobj kernel_object_store; /* home of kernel_object */
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static int kobj_alloced = 0; /* not allocated yet */
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int pages = round_page(size) >> PAGE_SHIFT;
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struct uvm_aobj *aobj;
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/*
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* malloc a new aobj unless we are asked for the kernel object
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*/
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if (flags & UAO_FLAG_KERNOBJ) { /* want kernel object? */
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if (kobj_alloced)
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panic("uao_create: kernel object already allocated");
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/*
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* XXXTHORPEJ: Need to call this now, so the pool gets
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* initialized!
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*/
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uao_init();
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aobj = &kernel_object_store;
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aobj->u_pages = pages;
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aobj->u_flags = UAO_FLAG_NOSWAP; /* no swap to start */
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/* we are special, we never die */
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aobj->u_obj.uo_refs = UVM_OBJ_KERN;
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kobj_alloced = UAO_FLAG_KERNOBJ;
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} else if (flags & UAO_FLAG_KERNSWAP) {
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aobj = &kernel_object_store;
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if (kobj_alloced != UAO_FLAG_KERNOBJ)
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panic("uao_create: asked to enable swap on kernel object");
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kobj_alloced = UAO_FLAG_KERNSWAP;
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} else { /* normal object */
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aobj = pool_get(&uvm_aobj_pool, PR_WAITOK);
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aobj->u_pages = pages;
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aobj->u_flags = 0; /* normal object */
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aobj->u_obj.uo_refs = 1; /* start with 1 reference */
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}
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/*
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* allocate hash/array if necessary
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|
*
|
|
* note: in the KERNSWAP case no need to worry about locking since
|
|
* we are still booting we should be the only thread around.
|
|
*/
|
|
if (flags == 0 || (flags & UAO_FLAG_KERNSWAP) != 0) {
|
|
int mflags = (flags & UAO_FLAG_KERNSWAP) != 0 ?
|
|
M_NOWAIT : M_WAITOK;
|
|
|
|
/* allocate hash table or array depending on object size */
|
|
if (UAO_USES_SWHASH(aobj)) {
|
|
aobj->u_swhash = hashinit(UAO_SWHASH_BUCKETS(aobj),
|
|
M_UVMAOBJ, mflags, &aobj->u_swhashmask);
|
|
if (aobj->u_swhash == NULL)
|
|
panic("uao_create: hashinit swhash failed");
|
|
} else {
|
|
MALLOC(aobj->u_swslots, int *, pages * sizeof(int),
|
|
M_UVMAOBJ, mflags);
|
|
if (aobj->u_swslots == NULL)
|
|
panic("uao_create: malloc swslots failed");
|
|
memset(aobj->u_swslots, 0, pages * sizeof(int));
|
|
}
|
|
|
|
if (flags) {
|
|
aobj->u_flags &= ~UAO_FLAG_NOSWAP; /* clear noswap */
|
|
return(&aobj->u_obj);
|
|
/* done! */
|
|
}
|
|
}
|
|
|
|
/*
|
|
* init aobj fields
|
|
*/
|
|
simple_lock_init(&aobj->u_obj.vmobjlock);
|
|
aobj->u_obj.pgops = &aobj_pager;
|
|
TAILQ_INIT(&aobj->u_obj.memq);
|
|
aobj->u_obj.uo_npages = 0;
|
|
|
|
/*
|
|
* now that aobj is ready, add it to the global list
|
|
* XXXCHS: uao_init hasn't been called'd in the KERNOBJ case,
|
|
* do we really need the kernel object on this list anyway?
|
|
*/
|
|
simple_lock(&uao_list_lock);
|
|
LIST_INSERT_HEAD(&uao_list, aobj, u_list);
|
|
simple_unlock(&uao_list_lock);
|
|
|
|
/*
|
|
* done!
|
|
*/
|
|
return(&aobj->u_obj);
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
* uao_init: set up aobj pager subsystem
|
|
*
|
|
* => called at boot time from uvm_pager_init()
|
|
*/
|
|
static void
|
|
uao_init()
|
|
{
|
|
static int uao_initialized;
|
|
|
|
if (uao_initialized)
|
|
return;
|
|
uao_initialized = TRUE;
|
|
|
|
LIST_INIT(&uao_list);
|
|
simple_lock_init(&uao_list_lock);
|
|
|
|
/*
|
|
* NOTE: Pages fror this pool must not come from a pageable
|
|
* kernel map!
|
|
*/
|
|
pool_init(&uao_swhash_elt_pool, sizeof(struct uao_swhash_elt),
|
|
0, 0, 0, "uaoeltpl", 0, NULL, NULL, M_UVMAOBJ);
|
|
|
|
pool_init(&uvm_aobj_pool, sizeof(struct uvm_aobj), 0, 0, 0,
|
|
"aobjpl", 0,
|
|
pool_page_alloc_nointr, pool_page_free_nointr, M_UVMAOBJ);
|
|
}
|
|
|
|
/*
|
|
* uao_reference: add a ref to an aobj
|
|
*
|
|
* => aobj must be unlocked (we will lock it)
|
|
*/
|
|
void
|
|
uao_reference(uobj)
|
|
struct uvm_object *uobj;
|
|
{
|
|
UVMHIST_FUNC("uao_reference"); UVMHIST_CALLED(maphist);
|
|
|
|
/*
|
|
* kernel_object already has plenty of references, leave it alone.
|
|
*/
|
|
|
|
if (UVM_OBJ_IS_KERN_OBJECT(uobj))
|
|
return;
|
|
|
|
simple_lock(&uobj->vmobjlock);
|
|
uobj->uo_refs++; /* bump! */
|
|
UVMHIST_LOG(maphist, "<- done (uobj=0x%x, ref = %d)",
|
|
uobj, uobj->uo_refs,0,0);
|
|
simple_unlock(&uobj->vmobjlock);
|
|
}
|
|
|
|
/*
|
|
* uao_detach: drop a reference to an aobj
|
|
*
|
|
* => aobj must be unlocked, we will lock it
|
|
*/
|
|
void
|
|
uao_detach(uobj)
|
|
struct uvm_object *uobj;
|
|
{
|
|
struct uvm_aobj *aobj = (struct uvm_aobj *)uobj;
|
|
struct vm_page *pg;
|
|
boolean_t busybody;
|
|
UVMHIST_FUNC("uao_detach"); UVMHIST_CALLED(maphist);
|
|
|
|
/*
|
|
* detaching from kernel_object is a noop.
|
|
*/
|
|
if (UVM_OBJ_IS_KERN_OBJECT(uobj))
|
|
return;
|
|
|
|
simple_lock(&uobj->vmobjlock);
|
|
|
|
UVMHIST_LOG(maphist," (uobj=0x%x) ref=%d", uobj,uobj->uo_refs,0,0);
|
|
uobj->uo_refs--; /* drop ref! */
|
|
if (uobj->uo_refs) { /* still more refs? */
|
|
simple_unlock(&uobj->vmobjlock);
|
|
UVMHIST_LOG(maphist, "<- done (rc>0)", 0,0,0,0);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* remove the aobj from the global list.
|
|
*/
|
|
simple_lock(&uao_list_lock);
|
|
LIST_REMOVE(aobj, u_list);
|
|
simple_unlock(&uao_list_lock);
|
|
|
|
/*
|
|
* free all the pages that aren't PG_BUSY, mark for release any that are.
|
|
*/
|
|
|
|
busybody = FALSE;
|
|
for (pg = uobj->memq.tqh_first ; pg != NULL ; pg = pg->listq.tqe_next) {
|
|
|
|
if (pg->flags & PG_BUSY) {
|
|
pg->flags |= PG_RELEASED;
|
|
busybody = TRUE;
|
|
continue;
|
|
}
|
|
|
|
/* zap the mappings, free the swap slot, free the page */
|
|
pmap_page_protect(PMAP_PGARG(pg), VM_PROT_NONE);
|
|
uao_dropswap(&aobj->u_obj, pg->offset >> PAGE_SHIFT);
|
|
uvm_lock_pageq();
|
|
uvm_pagefree(pg);
|
|
uvm_unlock_pageq();
|
|
}
|
|
|
|
/*
|
|
* if we found any busy pages, we're done for now.
|
|
* mark the aobj for death, releasepg will finish up for us.
|
|
*/
|
|
if (busybody) {
|
|
aobj->u_flags |= UAO_FLAG_KILLME;
|
|
simple_unlock(&aobj->u_obj.vmobjlock);
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* finally, free the rest.
|
|
*/
|
|
uao_free(aobj);
|
|
}
|
|
|
|
/*
|
|
* uao_flush: uh, yea, sure it's flushed. really!
|
|
*/
|
|
boolean_t
|
|
uao_flush(uobj, start, end, flags)
|
|
struct uvm_object *uobj;
|
|
vaddr_t start, end;
|
|
int flags;
|
|
{
|
|
|
|
/*
|
|
* anonymous memory doesn't "flush"
|
|
*/
|
|
/*
|
|
* XXX
|
|
* deal with PGO_DEACTIVATE (for madvise(MADV_SEQUENTIAL))
|
|
* and PGO_FREE (for msync(MSINVALIDATE))
|
|
*/
|
|
return TRUE;
|
|
}
|
|
|
|
/*
|
|
* uao_get: fetch me a page
|
|
*
|
|
* we have three cases:
|
|
* 1: page is resident -> just return the page.
|
|
* 2: page is zero-fill -> allocate a new page and zero it.
|
|
* 3: page is swapped out -> fetch the page from swap.
|
|
*
|
|
* cases 1 and 2 can be handled with PGO_LOCKED, case 3 cannot.
|
|
* so, if the "center" page hits case 3 (or any page, with PGO_ALLPAGES),
|
|
* then we will need to return VM_PAGER_UNLOCK.
|
|
*
|
|
* => prefer map unlocked (not required)
|
|
* => object must be locked! we will _unlock_ it before starting any I/O.
|
|
* => flags: PGO_ALLPAGES: get all of the pages
|
|
* PGO_LOCKED: fault data structures are locked
|
|
* => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx]
|
|
* => NOTE: caller must check for released pages!!
|
|
*/
|
|
static int
|
|
uao_get(uobj, offset, pps, npagesp, centeridx, access_type, advice, flags)
|
|
struct uvm_object *uobj;
|
|
vaddr_t offset;
|
|
struct vm_page **pps;
|
|
int *npagesp;
|
|
int centeridx, advice, flags;
|
|
vm_prot_t access_type;
|
|
{
|
|
struct uvm_aobj *aobj = (struct uvm_aobj *)uobj;
|
|
vaddr_t current_offset;
|
|
vm_page_t ptmp;
|
|
int lcv, gotpages, maxpages, swslot, rv;
|
|
boolean_t done;
|
|
UVMHIST_FUNC("uao_get"); UVMHIST_CALLED(pdhist);
|
|
|
|
UVMHIST_LOG(pdhist, "aobj=%p offset=%d, flags=%d", aobj, offset, flags,0);
|
|
|
|
/*
|
|
* get number of pages
|
|
*/
|
|
|
|
maxpages = *npagesp;
|
|
|
|
/*
|
|
* step 1: handled the case where fault data structures are locked.
|
|
*/
|
|
|
|
if (flags & PGO_LOCKED) {
|
|
|
|
/*
|
|
* step 1a: get pages that are already resident. only do
|
|
* this if the data structures are locked (i.e. the first
|
|
* time through).
|
|
*/
|
|
|
|
done = TRUE; /* be optimistic */
|
|
gotpages = 0; /* # of pages we got so far */
|
|
|
|
for (lcv = 0, current_offset = offset ; lcv < maxpages ;
|
|
lcv++, current_offset += PAGE_SIZE) {
|
|
/* do we care about this page? if not, skip it */
|
|
if (pps[lcv] == PGO_DONTCARE)
|
|
continue;
|
|
|
|
ptmp = uvm_pagelookup(uobj, current_offset);
|
|
|
|
/*
|
|
* if page is new, attempt to allocate the page, then
|
|
* zero-fill it.
|
|
*/
|
|
if (ptmp == NULL && uao_find_swslot(aobj,
|
|
current_offset >> PAGE_SHIFT) == 0) {
|
|
ptmp = uvm_pagealloc(uobj, current_offset,
|
|
NULL, 0);
|
|
if (ptmp) {
|
|
/* new page */
|
|
ptmp->flags &= ~(PG_BUSY|PG_FAKE);
|
|
ptmp->pqflags |= PQ_AOBJ;
|
|
UVM_PAGE_OWN(ptmp, NULL);
|
|
uvm_pagezero(ptmp);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* to be useful must get a non-busy, non-released page
|
|
*/
|
|
if (ptmp == NULL ||
|
|
(ptmp->flags & (PG_BUSY|PG_RELEASED)) != 0) {
|
|
if (lcv == centeridx ||
|
|
(flags & PGO_ALLPAGES) != 0)
|
|
/* need to do a wait or I/O! */
|
|
done = FALSE;
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* useful page: busy/lock it and plug it in our
|
|
* result array
|
|
*/
|
|
/* caller must un-busy this page */
|
|
ptmp->flags |= PG_BUSY;
|
|
UVM_PAGE_OWN(ptmp, "uao_get1");
|
|
pps[lcv] = ptmp;
|
|
gotpages++;
|
|
|
|
} /* "for" lcv loop */
|
|
|
|
/*
|
|
* step 1b: now we've either done everything needed or we
|
|
* to unlock and do some waiting or I/O.
|
|
*/
|
|
|
|
UVMHIST_LOG(pdhist, "<- done (done=%d)", done, 0,0,0);
|
|
|
|
*npagesp = gotpages;
|
|
if (done)
|
|
/* bingo! */
|
|
return(VM_PAGER_OK);
|
|
else
|
|
/* EEK! Need to unlock and I/O */
|
|
return(VM_PAGER_UNLOCK);
|
|
}
|
|
|
|
/*
|
|
* step 2: get non-resident or busy pages.
|
|
* object is locked. data structures are unlocked.
|
|
*/
|
|
|
|
for (lcv = 0, current_offset = offset ; lcv < maxpages ;
|
|
lcv++, current_offset += PAGE_SIZE) {
|
|
/*
|
|
* - skip over pages we've already gotten or don't want
|
|
* - skip over pages we don't _have_ to get
|
|
*/
|
|
if (pps[lcv] != NULL ||
|
|
(lcv != centeridx && (flags & PGO_ALLPAGES) == 0))
|
|
continue;
|
|
|
|
/*
|
|
* we have yet to locate the current page (pps[lcv]). we
|
|
* first look for a page that is already at the current offset.
|
|
* if we find a page, we check to see if it is busy or
|
|
* released. if that is the case, then we sleep on the page
|
|
* until it is no longer busy or released and repeat the lookup.
|
|
* if the page we found is neither busy nor released, then we
|
|
* busy it (so we own it) and plug it into pps[lcv]. this
|
|
* 'break's the following while loop and indicates we are
|
|
* ready to move on to the next page in the "lcv" loop above.
|
|
*
|
|
* if we exit the while loop with pps[lcv] still set to NULL,
|
|
* then it means that we allocated a new busy/fake/clean page
|
|
* ptmp in the object and we need to do I/O to fill in the data.
|
|
*/
|
|
|
|
/* top of "pps" while loop */
|
|
while (pps[lcv] == NULL) {
|
|
/* look for a resident page */
|
|
ptmp = uvm_pagelookup(uobj, current_offset);
|
|
|
|
/* not resident? allocate one now (if we can) */
|
|
if (ptmp == NULL) {
|
|
|
|
ptmp = uvm_pagealloc(uobj, current_offset,
|
|
NULL, 0);
|
|
|
|
/* out of RAM? */
|
|
if (ptmp == NULL) {
|
|
simple_unlock(&uobj->vmobjlock);
|
|
UVMHIST_LOG(pdhist,
|
|
"sleeping, ptmp == NULL\n",0,0,0,0);
|
|
uvm_wait("uao_getpage");
|
|
simple_lock(&uobj->vmobjlock);
|
|
/* goto top of pps while loop */
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* safe with PQ's unlocked: because we just
|
|
* alloc'd the page
|
|
*/
|
|
ptmp->pqflags |= PQ_AOBJ;
|
|
|
|
/*
|
|
* got new page ready for I/O. break pps while
|
|
* loop. pps[lcv] is still NULL.
|
|
*/
|
|
break;
|
|
}
|
|
|
|
/* page is there, see if we need to wait on it */
|
|
if ((ptmp->flags & (PG_BUSY|PG_RELEASED)) != 0) {
|
|
ptmp->flags |= PG_WANTED;
|
|
UVMHIST_LOG(pdhist,
|
|
"sleeping, ptmp->flags 0x%x\n",
|
|
ptmp->flags,0,0,0);
|
|
UVM_UNLOCK_AND_WAIT(ptmp, &uobj->vmobjlock, 0,
|
|
"uao_get", 0);
|
|
simple_lock(&uobj->vmobjlock);
|
|
continue; /* goto top of pps while loop */
|
|
}
|
|
|
|
/*
|
|
* if we get here then the page has become resident and
|
|
* unbusy between steps 1 and 2. we busy it now (so we
|
|
* own it) and set pps[lcv] (so that we exit the while
|
|
* loop).
|
|
*/
|
|
/* we own it, caller must un-busy */
|
|
ptmp->flags |= PG_BUSY;
|
|
UVM_PAGE_OWN(ptmp, "uao_get2");
|
|
pps[lcv] = ptmp;
|
|
}
|
|
|
|
/*
|
|
* if we own the valid page at the correct offset, pps[lcv] will
|
|
* point to it. nothing more to do except go to the next page.
|
|
*/
|
|
if (pps[lcv])
|
|
continue; /* next lcv */
|
|
|
|
/*
|
|
* we have a "fake/busy/clean" page that we just allocated.
|
|
* do the needed "i/o", either reading from swap or zeroing.
|
|
*/
|
|
swslot = uao_find_swslot(aobj, current_offset >> PAGE_SHIFT);
|
|
|
|
/*
|
|
* just zero the page if there's nothing in swap.
|
|
*/
|
|
if (swslot == 0)
|
|
{
|
|
/*
|
|
* page hasn't existed before, just zero it.
|
|
*/
|
|
uvm_pagezero(ptmp);
|
|
}
|
|
else
|
|
{
|
|
UVMHIST_LOG(pdhist, "pagein from swslot %d",
|
|
swslot, 0,0,0);
|
|
|
|
/*
|
|
* page in the swapped-out page.
|
|
* unlock object for i/o, relock when done.
|
|
*/
|
|
simple_unlock(&uobj->vmobjlock);
|
|
rv = uvm_swap_get(ptmp, swslot, PGO_SYNCIO);
|
|
simple_lock(&uobj->vmobjlock);
|
|
|
|
/*
|
|
* I/O done. check for errors.
|
|
*/
|
|
if (rv != VM_PAGER_OK)
|
|
{
|
|
UVMHIST_LOG(pdhist, "<- done (error=%d)",
|
|
rv,0,0,0);
|
|
if (ptmp->flags & PG_WANTED)
|
|
/* object lock still held */
|
|
thread_wakeup(ptmp);
|
|
ptmp->flags &= ~(PG_WANTED|PG_BUSY);
|
|
UVM_PAGE_OWN(ptmp, NULL);
|
|
uvm_lock_pageq();
|
|
uvm_pagefree(ptmp);
|
|
uvm_unlock_pageq();
|
|
simple_unlock(&uobj->vmobjlock);
|
|
return (rv);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* we got the page! clear the fake flag (indicates valid
|
|
* data now in page) and plug into our result array. note
|
|
* that page is still busy.
|
|
*
|
|
* it is the callers job to:
|
|
* => check if the page is released
|
|
* => unbusy the page
|
|
* => activate the page
|
|
*/
|
|
|
|
ptmp->flags &= ~PG_FAKE; /* data is valid ... */
|
|
pmap_clear_modify(PMAP_PGARG(ptmp)); /* ... and clean */
|
|
pps[lcv] = ptmp;
|
|
|
|
} /* lcv loop */
|
|
|
|
/*
|
|
* finally, unlock object and return.
|
|
*/
|
|
|
|
simple_unlock(&uobj->vmobjlock);
|
|
UVMHIST_LOG(pdhist, "<- done (OK)",0,0,0,0);
|
|
return(VM_PAGER_OK);
|
|
}
|
|
|
|
/*
|
|
* uao_releasepg: handle released page in an aobj
|
|
*
|
|
* => "pg" is a PG_BUSY [caller owns it], PG_RELEASED page that we need
|
|
* to dispose of.
|
|
* => caller must handle PG_WANTED case
|
|
* => called with page's object locked, pageq's unlocked
|
|
* => returns TRUE if page's object is still alive, FALSE if we
|
|
* killed the page's object. if we return TRUE, then we
|
|
* return with the object locked.
|
|
* => if (nextpgp != NULL) => we return pageq.tqe_next here, and return
|
|
* with the page queues locked [for pagedaemon]
|
|
* => if (nextpgp == NULL) => we return with page queues unlocked [normal case]
|
|
* => we kill the aobj if it is not referenced and we are suppose to
|
|
* kill it ("KILLME").
|
|
*/
|
|
static boolean_t uao_releasepg(pg, nextpgp)
|
|
struct vm_page *pg;
|
|
struct vm_page **nextpgp; /* OUT */
|
|
{
|
|
struct uvm_aobj *aobj = (struct uvm_aobj *) pg->uobject;
|
|
|
|
#ifdef DIAGNOSTIC
|
|
if ((pg->flags & PG_RELEASED) == 0)
|
|
panic("uao_releasepg: page not released!");
|
|
#endif
|
|
|
|
/*
|
|
* dispose of the page [caller handles PG_WANTED] and swap slot.
|
|
*/
|
|
pmap_page_protect(PMAP_PGARG(pg), VM_PROT_NONE);
|
|
uao_dropswap(&aobj->u_obj, pg->offset >> PAGE_SHIFT);
|
|
uvm_lock_pageq();
|
|
if (nextpgp)
|
|
*nextpgp = pg->pageq.tqe_next; /* next page for daemon */
|
|
uvm_pagefree(pg);
|
|
if (!nextpgp)
|
|
uvm_unlock_pageq(); /* keep locked for daemon */
|
|
|
|
/*
|
|
* if we're not killing the object, we're done.
|
|
*/
|
|
if ((aobj->u_flags & UAO_FLAG_KILLME) == 0)
|
|
return TRUE;
|
|
|
|
#ifdef DIAGNOSTIC
|
|
if (aobj->u_obj.uo_refs)
|
|
panic("uvm_km_releasepg: kill flag set on referenced object!");
|
|
#endif
|
|
|
|
/*
|
|
* if there are still pages in the object, we're done for now.
|
|
*/
|
|
if (aobj->u_obj.uo_npages != 0)
|
|
return TRUE;
|
|
|
|
#ifdef DIAGNOSTIC
|
|
if (aobj->u_obj.memq.tqh_first)
|
|
panic("uvn_releasepg: pages in object with npages == 0");
|
|
#endif
|
|
|
|
/*
|
|
* finally, free the rest.
|
|
*/
|
|
uao_free(aobj);
|
|
|
|
return FALSE;
|
|
}
|
|
|
|
/*
|
|
* uao_dropswap: release any swap resources from this aobj page.
|
|
*
|
|
* => aobj must be locked or have a reference count of 0.
|
|
*/
|
|
|
|
void
|
|
uao_dropswap(uobj, pageidx)
|
|
struct uvm_object *uobj;
|
|
int pageidx;
|
|
{
|
|
int slot;
|
|
|
|
slot = uao_set_swslot(uobj, pageidx, 0);
|
|
if (slot) {
|
|
uvm_swap_free(slot, 1);
|
|
}
|
|
}
|