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uvm_object.c revision 1.5 
      1 /*	$NetBSD: uvm_object.c,v 1.5 2008/01/04 21:18:18 ad Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 2006 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Mindaugas Rasiukevicius.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *      This product includes software developed by the NetBSD
     21  *      Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 /*
     40  * uvm_object.c: operate with memory objects
     41  *
     42  * TODO:
     43  *  1. Support PG_RELEASED-using objects
     44  *
     45  */
     46 
     47 #include <sys/cdefs.h>
     48 __KERNEL_RCSID(0, "$NetBSD: uvm_object.c,v 1.5 2008/01/04 21:18:18 ad Exp $");
     49 
     50 #include "opt_uvmhist.h"
     51 
     52 #include <sys/param.h>
     53 
     54 #include <uvm/uvm.h>
     55 
     56 /* We will fetch this page count per step */
     57 #define	FETCH_PAGECOUNT	16
     58 
     59 /*
     60  * uobj_wirepages: wire the pages of entire uobj
     61  *
     62  * => NOTE: this function should only be used for types of objects
     63  *  where PG_RELEASED flag is never set (aobj objects)
     64  * => caller must pass page-aligned start and end values
     65  */
     66 
     67 int
     68 uobj_wirepages(struct uvm_object *uobj, off_t start, off_t end)
     69 {
     70 	int i, npages, error;
     71 	struct vm_page *pgs[FETCH_PAGECOUNT], *pg = NULL;
     72 	off_t offset = start, left;
     73 
     74 	left = (end - start) >> PAGE_SHIFT;
     75 
     76 	mutex_enter(&uobj->vmobjlock);
     77 	while (left) {
     78 
     79 		npages = MIN(FETCH_PAGECOUNT, left);
     80 
     81 		/* Get the pages */
     82 		memset(pgs, 0, sizeof(pgs));
     83 		error = (*uobj->pgops->pgo_get)(uobj, offset, pgs, &npages, 0,
     84 			VM_PROT_READ | VM_PROT_WRITE, UVM_ADV_SEQUENTIAL,
     85 			PGO_ALLPAGES | PGO_SYNCIO);
     86 
     87 		if (error)
     88 			goto error;
     89 
     90 		mutex_enter(&uobj->vmobjlock);
     91 		for (i = 0; i < npages; i++) {
     92 
     93 			KASSERT(pgs[i] != NULL);
     94 			KASSERT(!(pgs[i]->flags & PG_RELEASED));
     95 
     96 			/*
     97 			 * Loan break
     98 			 */
     99 			if (pgs[i]->loan_count) {
    100 				while (pgs[i]->loan_count) {
    101 					pg = uvm_loanbreak(pgs[i]);
    102 					if (!pg) {
    103 						mutex_exit(&uobj->vmobjlock);
    104 						uvm_wait("uobjwirepg");
    105 						mutex_enter(&uobj->vmobjlock);
    106 						continue;
    107 					}
    108 				}
    109 				pgs[i] = pg;
    110 			}
    111 
    112 			if (pgs[i]->pqflags & PQ_AOBJ) {
    113 				pgs[i]->flags &= ~(PG_CLEAN);
    114 				uao_dropswap(uobj, i);
    115 			}
    116 		}
    117 
    118 		/* Wire the pages */
    119 		mutex_enter(&uvm_pageqlock);
    120 		for (i = 0; i < npages; i++) {
    121 			uvm_pagewire(pgs[i]);
    122 		}
    123 		mutex_exit(&uvm_pageqlock);
    124 
    125 		/* Unbusy the pages */
    126 		uvm_page_unbusy(pgs, npages);
    127 
    128 		left -= npages;
    129 		offset += npages << PAGE_SHIFT;
    130 	}
    131 	mutex_exit(&uobj->vmobjlock);
    132 
    133 	return 0;
    134 
    135 error:
    136 	/* Unwire the pages which has been wired */
    137 	uobj_unwirepages(uobj, start, offset);
    138 
    139 	return error;
    140 }
    141 
    142 /*
    143  * uobj_unwirepages: unwire the pages of entire uobj
    144  *
    145  * => NOTE: this function should only be used for types of objects
    146  *  where PG_RELEASED flag is never set
    147  * => caller must pass page-aligned start and end values
    148  */
    149 
    150 void
    151 uobj_unwirepages(struct uvm_object *uobj, off_t start, off_t end)
    152 {
    153 	struct vm_page *pg;
    154 	off_t offset;
    155 
    156 	mutex_enter(&uobj->vmobjlock);
    157 	mutex_enter(&uvm_pageqlock);
    158 	for (offset = start; offset < end; offset += PAGE_SIZE) {
    159 		pg = uvm_pagelookup(uobj, offset);
    160 
    161 		KASSERT(pg != NULL);
    162 		KASSERT(!(pg->flags & PG_RELEASED));
    163 
    164 		uvm_pageunwire(pg);
    165 	}
    166 	mutex_exit(&uvm_pageqlock);
    167 	mutex_exit(&uobj->vmobjlock);
    168 }
    169