Line data Source code
1 : /* $OpenBSD: uvm_anon.c,v 1.48 2016/09/15 02:00:18 dlg Exp $ */
2 : /* $NetBSD: uvm_anon.c,v 1.10 2000/11/25 06:27:59 chs Exp $ */
3 :
4 : /*
5 : * Copyright (c) 1997 Charles D. Cranor and Washington University.
6 : * All rights reserved.
7 : *
8 : * Redistribution and use in source and binary forms, with or without
9 : * modification, are permitted provided that the following conditions
10 : * are met:
11 : * 1. Redistributions of source code must retain the above copyright
12 : * notice, this list of conditions and the following disclaimer.
13 : * 2. Redistributions in binary form must reproduce the above copyright
14 : * notice, this list of conditions and the following disclaimer in the
15 : * documentation and/or other materials provided with the distribution.
16 : *
17 : * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 : * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 : * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 : * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 : * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 : * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 : * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 : * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 : * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 : * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 : */
28 :
29 : /*
30 : * uvm_anon.c: uvm anon ops
31 : */
32 :
33 : #include <sys/param.h>
34 : #include <sys/systm.h>
35 : #include <sys/malloc.h>
36 : #include <sys/pool.h>
37 : #include <sys/kernel.h>
38 : #include <sys/atomic.h>
39 :
40 : #include <uvm/uvm.h>
41 : #include <uvm/uvm_swap.h>
42 :
43 : struct pool uvm_anon_pool;
44 :
45 : /*
46 : * allocate anons
47 : */
48 : void
49 0 : uvm_anon_init(void)
50 : {
51 0 : pool_init(&uvm_anon_pool, sizeof(struct vm_anon), 0, IPL_NONE,
52 : PR_WAITOK, "anonpl", NULL);
53 0 : pool_sethiwat(&uvm_anon_pool, uvmexp.free / 16);
54 0 : }
55 :
56 : /*
57 : * allocate an anon
58 : */
59 : struct vm_anon *
60 0 : uvm_analloc(void)
61 : {
62 : struct vm_anon *anon;
63 :
64 0 : anon = pool_get(&uvm_anon_pool, PR_NOWAIT);
65 0 : if (anon) {
66 0 : anon->an_ref = 1;
67 0 : anon->an_page = NULL;
68 0 : anon->an_swslot = 0;
69 0 : }
70 0 : return(anon);
71 : }
72 :
73 : /*
74 : * uvm_anfree: free a single anon structure
75 : *
76 : * => caller must remove anon from its amap before calling (if it was in
77 : * an amap).
78 : * => we may lock the pageq's.
79 : */
80 : void
81 0 : uvm_anfree(struct vm_anon *anon)
82 : {
83 : struct vm_page *pg;
84 :
85 : /* get page */
86 0 : pg = anon->an_page;
87 :
88 : /*
89 : * if we have a resident page, we must dispose of it before freeing
90 : * the anon.
91 : */
92 0 : if (pg) {
93 : /*
94 : * if page is busy then we just mark it as released (who ever
95 : * has it busy must check for this when they wake up). if the
96 : * page is not busy then we can free it now.
97 : */
98 0 : if ((pg->pg_flags & PG_BUSY) != 0) {
99 : /* tell them to dump it when done */
100 0 : atomic_setbits_int(&pg->pg_flags, PG_RELEASED);
101 0 : return;
102 : }
103 0 : pmap_page_protect(pg, PROT_NONE);
104 0 : uvm_lock_pageq(); /* lock out pagedaemon */
105 0 : uvm_pagefree(pg); /* bye bye */
106 0 : uvm_unlock_pageq(); /* free the daemon */
107 0 : }
108 0 : if (pg == NULL && anon->an_swslot != 0) {
109 : /* this page is no longer only in swap. */
110 0 : KASSERT(uvmexp.swpgonly > 0);
111 0 : uvmexp.swpgonly--;
112 0 : }
113 :
114 : /* free any swap resources. */
115 0 : uvm_anon_dropswap(anon);
116 :
117 : /*
118 : * now that we've stripped the data areas from the anon, free the anon
119 : * itself!
120 : */
121 0 : KASSERT(anon->an_page == NULL);
122 0 : KASSERT(anon->an_swslot == 0);
123 :
124 0 : pool_put(&uvm_anon_pool, anon);
125 0 : }
126 :
127 : /*
128 : * uvm_anwait: wait for memory to become available to allocate an anon.
129 : */
130 : void
131 0 : uvm_anwait(void)
132 : {
133 : struct vm_anon *anon;
134 :
135 : /* XXX: Want something like pool_wait()? */
136 0 : anon = pool_get(&uvm_anon_pool, PR_WAITOK);
137 0 : pool_put(&uvm_anon_pool, anon);
138 0 : }
139 :
140 : /*
141 : * uvm_anon_dropswap: release any swap resources from this anon.
142 : */
143 : void
144 0 : uvm_anon_dropswap(struct vm_anon *anon)
145 : {
146 :
147 0 : if (anon->an_swslot == 0)
148 : return;
149 :
150 0 : uvm_swap_free(anon->an_swslot, 1);
151 0 : anon->an_swslot = 0;
152 0 : }
153 :
154 : /*
155 : * fetch an anon's page.
156 : *
157 : * => returns TRUE if pagein was aborted due to lack of memory.
158 : */
159 :
160 : boolean_t
161 0 : uvm_anon_pagein(struct vm_anon *anon)
162 : {
163 : struct vm_page *pg;
164 : int rv;
165 :
166 0 : rv = uvmfault_anonget(NULL, NULL, anon);
167 :
168 0 : switch (rv) {
169 : case VM_PAGER_OK:
170 : break;
171 : case VM_PAGER_ERROR:
172 : case VM_PAGER_REFAULT:
173 : /*
174 : * nothing more to do on errors.
175 : * VM_PAGER_REFAULT can only mean that the anon was freed,
176 : * so again there's nothing to do.
177 : */
178 0 : return FALSE;
179 : default:
180 : #ifdef DIAGNOSTIC
181 0 : panic("anon_pagein: uvmfault_anonget -> %d", rv);
182 : #else
183 : return FALSE;
184 : #endif
185 : }
186 :
187 : /*
188 : * ok, we've got the page now.
189 : * mark it as dirty, clear its swslot and un-busy it.
190 : */
191 0 : pg = anon->an_page;
192 0 : uvm_swap_free(anon->an_swslot, 1);
193 0 : anon->an_swslot = 0;
194 0 : atomic_clearbits_int(&pg->pg_flags, PG_CLEAN);
195 :
196 : /* deactivate the page (to put it on a page queue) */
197 0 : pmap_clear_reference(pg);
198 0 : pmap_page_protect(pg, PROT_NONE);
199 0 : uvm_lock_pageq();
200 0 : uvm_pagedeactivate(pg);
201 0 : uvm_unlock_pageq();
202 :
203 0 : return FALSE;
204 0 : }
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