Home | History | Annotate | Line # | Download | only in uvm
uvm_object.c revision 1.5.8.1 
      1 /*	$NetBSD: uvm_object.c,v 1.5.8.1 2008/05/18 12:35:56 yamt 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  *
     19  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29  * POSSIBILITY OF SUCH DAMAGE.
     30  */
     31 
     32 /*
     33  * uvm_object.c: operate with memory objects
     34  *
     35  * TODO:
     36  *  1. Support PG_RELEASED-using objects
     37  *
     38  */
     39 
     40 #include <sys/cdefs.h>
     41 __KERNEL_RCSID(0, "$NetBSD: uvm_object.c,v 1.5.8.1 2008/05/18 12:35:56 yamt Exp $");
     42 
     43 #include "opt_uvmhist.h"
     44 
     45 #include <sys/param.h>
     46 
     47 #include <uvm/uvm.h>
     48 
     49 /* We will fetch this page count per step */
     50 #define	FETCH_PAGECOUNT	16
     51 
     52 /*
     53  * uobj_wirepages: wire the pages of entire uobj
     54  *
     55  * => NOTE: this function should only be used for types of objects
     56  *  where PG_RELEASED flag is never set (aobj objects)
     57  * => caller must pass page-aligned start and end values
     58  */
     59 
     60 int
     61 uobj_wirepages(struct uvm_object *uobj, off_t start, off_t end)
     62 {
     63 	int i, npages, error;
     64 	struct vm_page *pgs[FETCH_PAGECOUNT], *pg = NULL;
     65 	off_t offset = start, left;
     66 
     67 	left = (end - start) >> PAGE_SHIFT;
     68 
     69 	mutex_enter(&uobj->vmobjlock);
     70 	while (left) {
     71 
     72 		npages = MIN(FETCH_PAGECOUNT, left);
     73 
     74 		/* Get the pages */
     75 		memset(pgs, 0, sizeof(pgs));
     76 		error = (*uobj->pgops->pgo_get)(uobj, offset, pgs, &npages, 0,
     77 			VM_PROT_READ | VM_PROT_WRITE, UVM_ADV_SEQUENTIAL,
     78 			PGO_ALLPAGES | PGO_SYNCIO);
     79 
     80 		if (error)
     81 			goto error;
     82 
     83 		mutex_enter(&uobj->vmobjlock);
     84 		for (i = 0; i < npages; i++) {
     85 
     86 			KASSERT(pgs[i] != NULL);
     87 			KASSERT(!(pgs[i]->flags & PG_RELEASED));
     88 
     89 			/*
     90 			 * Loan break
     91 			 */
     92 			if (pgs[i]->loan_count) {
     93 				while (pgs[i]->loan_count) {
     94 					pg = uvm_loanbreak(pgs[i]);
     95 					if (!pg) {
     96 						mutex_exit(&uobj->vmobjlock);
     97 						uvm_wait("uobjwirepg");
     98 						mutex_enter(&uobj->vmobjlock);
     99 						continue;
    100 					}
    101 				}
    102 				pgs[i] = pg;
    103 			}
    104 
    105 			if (pgs[i]->pqflags & PQ_AOBJ) {
    106 				pgs[i]->flags &= ~(PG_CLEAN);
    107 				uao_dropswap(uobj, i);
    108 			}
    109 		}
    110 
    111 		/* Wire the pages */
    112 		mutex_enter(&uvm_pageqlock);
    113 		for (i = 0; i < npages; i++) {
    114 			uvm_pagewire(pgs[i]);
    115 		}
    116 		mutex_exit(&uvm_pageqlock);
    117 
    118 		/* Unbusy the pages */
    119 		uvm_page_unbusy(pgs, npages);
    120 
    121 		left -= npages;
    122 		offset += npages << PAGE_SHIFT;
    123 	}
    124 	mutex_exit(&uobj->vmobjlock);
    125 
    126 	return 0;
    127 
    128 error:
    129 	/* Unwire the pages which has been wired */
    130 	uobj_unwirepages(uobj, start, offset);
    131 
    132 	return error;
    133 }
    134 
    135 /*
    136  * uobj_unwirepages: unwire the pages of entire uobj
    137  *
    138  * => NOTE: this function should only be used for types of objects
    139  *  where PG_RELEASED flag is never set
    140  * => caller must pass page-aligned start and end values
    141  */
    142 
    143 void
    144 uobj_unwirepages(struct uvm_object *uobj, off_t start, off_t end)
    145 {
    146 	struct vm_page *pg;
    147 	off_t offset;
    148 
    149 	mutex_enter(&uobj->vmobjlock);
    150 	mutex_enter(&uvm_pageqlock);
    151 	for (offset = start; offset < end; offset += PAGE_SIZE) {
    152 		pg = uvm_pagelookup(uobj, offset);
    153 
    154 		KASSERT(pg != NULL);
    155 		KASSERT(!(pg->flags & PG_RELEASED));
    156 
    157 		uvm_pageunwire(pg);
    158 	}
    159 	mutex_exit(&uvm_pageqlock);
    160 	mutex_exit(&uobj->vmobjlock);
    161 }
    162