uvm_page_array.c revision 1.5.2.2
1 1.5.2.2 martin /* $NetBSD: uvm_page_array.c,v 1.5.2.2 2020/04/08 14:09:04 martin Exp $ */ 2 1.5.2.2 martin 3 1.5.2.2 martin /*- 4 1.5.2.2 martin * Copyright (c)2011 YAMAMOTO Takashi, 5 1.5.2.2 martin * All rights reserved. 6 1.5.2.2 martin * 7 1.5.2.2 martin * Redistribution and use in source and binary forms, with or without 8 1.5.2.2 martin * modification, are permitted provided that the following conditions 9 1.5.2.2 martin * are met: 10 1.5.2.2 martin * 1. Redistributions of source code must retain the above copyright 11 1.5.2.2 martin * notice, this list of conditions and the following disclaimer. 12 1.5.2.2 martin * 2. Redistributions in binary form must reproduce the above copyright 13 1.5.2.2 martin * notice, this list of conditions and the following disclaimer in the 14 1.5.2.2 martin * documentation and/or other materials provided with the distribution. 15 1.5.2.2 martin * 16 1.5.2.2 martin * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 1.5.2.2 martin * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 1.5.2.2 martin * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 1.5.2.2 martin * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 1.5.2.2 martin * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 1.5.2.2 martin * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 1.5.2.2 martin * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 1.5.2.2 martin * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 1.5.2.2 martin * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 1.5.2.2 martin * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 1.5.2.2 martin * SUCH DAMAGE. 27 1.5.2.2 martin */ 28 1.5.2.2 martin 29 1.5.2.2 martin #include <sys/cdefs.h> 30 1.5.2.2 martin __KERNEL_RCSID(0, "$NetBSD: uvm_page_array.c,v 1.5.2.2 2020/04/08 14:09:04 martin Exp $"); 31 1.5.2.2 martin 32 1.5.2.2 martin #include <sys/param.h> 33 1.5.2.2 martin #include <sys/systm.h> 34 1.5.2.2 martin 35 1.5.2.2 martin #include <uvm/uvm_extern.h> 36 1.5.2.2 martin #include <uvm/uvm_object.h> 37 1.5.2.2 martin #include <uvm/uvm_page.h> 38 1.5.2.2 martin #include <uvm/uvm_page_array.h> 39 1.5.2.2 martin 40 1.5.2.2 martin /* 41 1.5.2.2 martin * uvm_page_array_init: initialize the array. 42 1.5.2.2 martin */ 43 1.5.2.2 martin 44 1.5.2.2 martin void 45 1.5.2.2 martin uvm_page_array_init(struct uvm_page_array *ar) 46 1.5.2.2 martin { 47 1.5.2.2 martin 48 1.5.2.2 martin ar->ar_idx = ar->ar_npages = 0; 49 1.5.2.2 martin } 50 1.5.2.2 martin 51 1.5.2.2 martin /* 52 1.5.2.2 martin * uvm_page_array_fini: clean up the array. 53 1.5.2.2 martin */ 54 1.5.2.2 martin 55 1.5.2.2 martin void 56 1.5.2.2 martin uvm_page_array_fini(struct uvm_page_array *ar) 57 1.5.2.2 martin { 58 1.5.2.2 martin 59 1.5.2.2 martin /* 60 1.5.2.2 martin * currently nothing to do. 61 1.5.2.2 martin */ 62 1.5.2.2 martin #if defined(DIAGNOSTIC) 63 1.5.2.2 martin /* 64 1.5.2.2 martin * poison to trigger assertion in uvm_page_array_peek to 65 1.5.2.2 martin * detect usage errors. 66 1.5.2.2 martin */ 67 1.5.2.2 martin ar->ar_npages = 1; 68 1.5.2.2 martin ar->ar_idx = 1000; 69 1.5.2.2 martin #endif /* defined(DIAGNOSTIC) */ 70 1.5.2.2 martin } 71 1.5.2.2 martin 72 1.5.2.2 martin /* 73 1.5.2.2 martin * uvm_page_array_clear: forget the cached pages and initialize the array. 74 1.5.2.2 martin */ 75 1.5.2.2 martin 76 1.5.2.2 martin void 77 1.5.2.2 martin uvm_page_array_clear(struct uvm_page_array *ar) 78 1.5.2.2 martin { 79 1.5.2.2 martin 80 1.5.2.2 martin KASSERT(ar->ar_idx <= ar->ar_npages); 81 1.5.2.2 martin uvm_page_array_init(ar); 82 1.5.2.2 martin } 83 1.5.2.2 martin 84 1.5.2.2 martin /* 85 1.5.2.2 martin * uvm_page_array_peek: return the next cached page. 86 1.5.2.2 martin */ 87 1.5.2.2 martin 88 1.5.2.2 martin struct vm_page * 89 1.5.2.2 martin uvm_page_array_peek(struct uvm_page_array *ar) 90 1.5.2.2 martin { 91 1.5.2.2 martin 92 1.5.2.2 martin KASSERT(ar->ar_idx <= ar->ar_npages); 93 1.5.2.2 martin if (ar->ar_idx == ar->ar_npages) { 94 1.5.2.2 martin return NULL; 95 1.5.2.2 martin } 96 1.5.2.2 martin return ar->ar_pages[ar->ar_idx]; 97 1.5.2.2 martin } 98 1.5.2.2 martin 99 1.5.2.2 martin /* 100 1.5.2.2 martin * uvm_page_array_advance: advance the array to the next cached page 101 1.5.2.2 martin */ 102 1.5.2.2 martin 103 1.5.2.2 martin void 104 1.5.2.2 martin uvm_page_array_advance(struct uvm_page_array *ar) 105 1.5.2.2 martin { 106 1.5.2.2 martin 107 1.5.2.2 martin KASSERT(ar->ar_idx <= ar->ar_npages); 108 1.5.2.2 martin ar->ar_idx++; 109 1.5.2.2 martin KASSERT(ar->ar_idx <= ar->ar_npages); 110 1.5.2.2 martin } 111 1.5.2.2 martin 112 1.5.2.2 martin /* 113 1.5.2.2 martin * uvm_page_array_fill: lookup pages and keep them cached. 114 1.5.2.2 martin * 115 1.5.2.2 martin * return 0 on success. in that case, cache the result in the array 116 1.5.2.2 martin * so that they will be picked by later uvm_page_array_peek. 117 1.5.2.2 martin * 118 1.5.2.2 martin * nwant is a number of pages to fetch. a caller should consider it a hint. 119 1.5.2.2 martin * nwant == 0 means a caller have no specific idea. 120 1.5.2.2 martin * 121 1.5.2.2 martin * return ENOENT if no pages are found. 122 1.5.2.2 martin * 123 1.5.2.2 martin * called with object lock held. 124 1.5.2.2 martin */ 125 1.5.2.2 martin 126 1.5.2.2 martin int 127 1.5.2.2 martin uvm_page_array_fill(struct uvm_page_array *ar, struct uvm_object *uobj, 128 1.5.2.2 martin voff_t off, unsigned int nwant, unsigned int flags) 129 1.5.2.2 martin { 130 1.5.2.2 martin unsigned int npages; 131 1.5.2.2 martin #if defined(DEBUG) 132 1.5.2.2 martin unsigned int i; 133 1.5.2.2 martin #endif /* defined(DEBUG) */ 134 1.5.2.2 martin unsigned int maxpages = __arraycount(ar->ar_pages); 135 1.5.2.2 martin const bool dense = (flags & UVM_PAGE_ARRAY_FILL_DENSE) != 0; 136 1.5.2.2 martin const bool backward = (flags & UVM_PAGE_ARRAY_FILL_BACKWARD) != 0; 137 1.5.2.2 martin 138 1.5.2.2 martin if (nwant != 0 && nwant < maxpages) { 139 1.5.2.2 martin maxpages = nwant; 140 1.5.2.2 martin } 141 1.5.2.2 martin #if 0 /* called from DDB for "show obj/f" without lock */ 142 1.5.2.2 martin KASSERT(rw_lock_held(uobj->vmobjlock)); 143 1.5.2.2 martin #endif 144 1.5.2.2 martin KASSERT(uvm_page_array_peek(ar) == NULL); 145 1.5.2.2 martin if ((flags & UVM_PAGE_ARRAY_FILL_DIRTY) != 0) { 146 1.5.2.2 martin unsigned int tagmask = UVM_PAGE_DIRTY_TAG; 147 1.5.2.2 martin 148 1.5.2.2 martin if ((flags & UVM_PAGE_ARRAY_FILL_WRITEBACK) != 0) { 149 1.5.2.2 martin tagmask |= UVM_PAGE_WRITEBACK_TAG; 150 1.5.2.2 martin } 151 1.5.2.2 martin npages = 152 1.5.2.2 martin (backward ? radix_tree_gang_lookup_tagged_node_reverse : 153 1.5.2.2 martin radix_tree_gang_lookup_tagged_node)( 154 1.5.2.2 martin &uobj->uo_pages, off >> PAGE_SHIFT, (void **)ar->ar_pages, 155 1.5.2.2 martin maxpages, dense, tagmask); 156 1.5.2.2 martin } else { 157 1.5.2.2 martin npages = 158 1.5.2.2 martin (backward ? radix_tree_gang_lookup_node_reverse : 159 1.5.2.2 martin radix_tree_gang_lookup_node)( 160 1.5.2.2 martin &uobj->uo_pages, off >> PAGE_SHIFT, (void **)ar->ar_pages, 161 1.5.2.2 martin maxpages, dense); 162 1.5.2.2 martin } 163 1.5.2.2 martin if (npages == 0) { 164 1.5.2.2 martin uvm_page_array_clear(ar); 165 1.5.2.2 martin return ENOENT; 166 1.5.2.2 martin } 167 1.5.2.2 martin KASSERT(npages <= maxpages); 168 1.5.2.2 martin ar->ar_npages = npages; 169 1.5.2.2 martin ar->ar_idx = 0; 170 1.5.2.2 martin #if defined(DEBUG) 171 1.5.2.2 martin for (i = 0; i < ar->ar_npages; i++) { 172 1.5.2.2 martin struct vm_page * const pg = ar->ar_pages[i]; 173 1.5.2.2 martin 174 1.5.2.2 martin KDASSERT(pg != NULL); 175 1.5.2.2 martin KDASSERT(pg->uobject == uobj); 176 1.5.2.2 martin if (backward) { 177 1.5.2.2 martin KDASSERT(pg->offset <= off); 178 1.5.2.2 martin KDASSERT(i == 0 || 179 1.5.2.2 martin pg->offset < ar->ar_pages[i - 1]->offset); 180 1.5.2.2 martin } else { 181 1.5.2.2 martin KDASSERT(pg->offset >= off); 182 1.5.2.2 martin KDASSERT(i == 0 || 183 1.5.2.2 martin pg->offset > ar->ar_pages[i - 1]->offset); 184 1.5.2.2 martin } 185 1.5.2.2 martin } 186 1.5.2.2 martin #endif /* defined(DEBUG) */ 187 1.5.2.2 martin return 0; 188 1.5.2.2 martin } 189 1.5.2.2 martin 190 1.5.2.2 martin /* 191 1.5.2.2 martin * uvm_page_array_fill_and_peek: 192 1.5.2.2 martin * same as uvm_page_array_peek except that, if the array is empty, try to fill 193 1.5.2.2 martin * it first. 194 1.5.2.2 martin */ 195 1.5.2.2 martin 196 1.5.2.2 martin struct vm_page * 197 1.5.2.2 martin uvm_page_array_fill_and_peek(struct uvm_page_array *a, struct uvm_object *uobj, 198 1.5.2.2 martin voff_t off, unsigned int nwant, unsigned int flags) 199 1.5.2.2 martin { 200 1.5.2.2 martin struct vm_page *pg; 201 1.5.2.2 martin int error; 202 1.5.2.2 martin 203 1.5.2.2 martin pg = uvm_page_array_peek(a); 204 1.5.2.2 martin if (pg != NULL) { 205 1.5.2.2 martin return pg; 206 1.5.2.2 martin } 207 1.5.2.2 martin error = uvm_page_array_fill(a, uobj, off, nwant, flags); 208 1.5.2.2 martin if (error != 0) { 209 1.5.2.2 martin return NULL; 210 1.5.2.2 martin } 211 1.5.2.2 martin pg = uvm_page_array_peek(a); 212 1.5.2.2 martin KASSERT(pg != NULL); 213 1.5.2.2 martin return pg; 214 1.5.2.2 martin } 215
Indexes created Thu Oct 02 10:09:58 GMT 2025