uvm_vnode.c revision 1.93
1 /* $NetBSD: uvm_vnode.c,v 1.93 2010/01/08 11:35:12 pooka Exp $ */ 2 3 /* 4 * Copyright (c) 1997 Charles D. Cranor and Washington University. 5 * Copyright (c) 1991, 1993 6 * The Regents of the University of California. 7 * Copyright (c) 1990 University of Utah. 8 * 9 * All rights reserved. 10 * 11 * This code is derived from software contributed to Berkeley by 12 * the Systems Programming Group of the University of Utah Computer 13 * Science Department. 14 * 15 * Redistribution and use in source and binary forms, with or without 16 * modification, are permitted provided that the following conditions 17 * are met: 18 * 1. Redistributions of source code must retain the above copyright 19 * notice, this list of conditions and the following disclaimer. 20 * 2. Redistributions in binary form must reproduce the above copyright 21 * notice, this list of conditions and the following disclaimer in the 22 * documentation and/or other materials provided with the distribution. 23 * 3. All advertising materials mentioning features or use of this software 24 * must display the following acknowledgement: 25 * This product includes software developed by Charles D. Cranor, 26 * Washington University, the University of California, Berkeley and 27 * its contributors. 28 * 4. Neither the name of the University nor the names of its contributors 29 * may be used to endorse or promote products derived from this software 30 * without specific prior written permission. 31 * 32 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 33 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 34 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 35 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 36 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 37 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 38 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 39 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 40 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 41 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 42 * SUCH DAMAGE. 43 * 44 * @(#)vnode_pager.c 8.8 (Berkeley) 2/13/94 45 * from: Id: uvm_vnode.c,v 1.1.2.26 1998/02/02 20:38:07 chuck Exp 46 */ 47 48 /* 49 * uvm_vnode.c: the vnode pager. 50 */ 51 52 #include <sys/cdefs.h> 53 __KERNEL_RCSID(0, "$NetBSD: uvm_vnode.c,v 1.93 2010/01/08 11:35:12 pooka Exp $"); 54 55 #include "opt_uvmhist.h" 56 57 #include <sys/param.h> 58 #include <sys/systm.h> 59 #include <sys/kernel.h> 60 #include <sys/proc.h> 61 #include <sys/malloc.h> 62 #include <sys/vnode.h> 63 #include <sys/disklabel.h> 64 #include <sys/ioctl.h> 65 #include <sys/fcntl.h> 66 #include <sys/conf.h> 67 #include <sys/pool.h> 68 #include <sys/mount.h> 69 70 #include <miscfs/specfs/specdev.h> 71 72 #include <uvm/uvm.h> 73 #include <uvm/uvm_readahead.h> 74 75 /* 76 * functions 77 */ 78 79 static void uvn_detach(struct uvm_object *); 80 static int uvn_get(struct uvm_object *, voff_t, struct vm_page **, int *, 81 int, vm_prot_t, int, int); 82 static int uvn_put(struct uvm_object *, voff_t, voff_t, int); 83 static void uvn_reference(struct uvm_object *); 84 85 static int uvn_findpage(struct uvm_object *, voff_t, struct vm_page **, 86 int); 87 88 /* 89 * master pager structure 90 */ 91 92 const struct uvm_pagerops uvm_vnodeops = { 93 .pgo_reference = uvn_reference, 94 .pgo_detach = uvn_detach, 95 .pgo_get = uvn_get, 96 .pgo_put = uvn_put, 97 }; 98 99 /* 100 * the ops! 101 */ 102 103 /* 104 * uvn_reference 105 * 106 * duplicate a reference to a VM object. Note that the reference 107 * count must already be at least one (the passed in reference) so 108 * there is no chance of the uvn being killed or locked out here. 109 * 110 * => caller must call with object unlocked. 111 * => caller must be using the same accessprot as was used at attach time 112 */ 113 114 static void 115 uvn_reference(struct uvm_object *uobj) 116 { 117 vref((struct vnode *)uobj); 118 } 119 120 121 /* 122 * uvn_detach 123 * 124 * remove a reference to a VM object. 125 * 126 * => caller must call with object unlocked and map locked. 127 */ 128 129 static void 130 uvn_detach(struct uvm_object *uobj) 131 { 132 vrele((struct vnode *)uobj); 133 } 134 135 /* 136 * uvn_put: flush page data to backing store. 137 * 138 * => object must be locked on entry! VOP_PUTPAGES must unlock it. 139 * => flags: PGO_SYNCIO -- use sync. I/O 140 * => note: caller must set PG_CLEAN and pmap_clear_modify (if needed) 141 */ 142 143 static int 144 uvn_put(struct uvm_object *uobj, voff_t offlo, voff_t offhi, int flags) 145 { 146 struct vnode *vp = (struct vnode *)uobj; 147 int error; 148 149 KASSERT(mutex_owned(&vp->v_interlock)); 150 error = VOP_PUTPAGES(vp, offlo, offhi, flags); 151 152 return error; 153 } 154 155 156 /* 157 * uvn_get: get pages (synchronously) from backing store 158 * 159 * => prefer map unlocked (not required) 160 * => object must be locked! we will _unlock_ it before starting any I/O. 161 * => flags: PGO_ALLPAGES: get all of the pages 162 * PGO_LOCKED: fault data structures are locked 163 * => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx] 164 * => NOTE: caller must check for released pages!! 165 */ 166 167 static int 168 uvn_get(struct uvm_object *uobj, voff_t offset, 169 struct vm_page **pps /* IN/OUT */, 170 int *npagesp /* IN (OUT if PGO_LOCKED)*/, 171 int centeridx, vm_prot_t access_type, int advice, int flags) 172 { 173 struct vnode *vp = (struct vnode *)uobj; 174 int error; 175 176 UVMHIST_FUNC("uvn_get"); UVMHIST_CALLED(ubchist); 177 178 UVMHIST_LOG(ubchist, "vp %p off 0x%x", vp, (int)offset, 0,0); 179 180 if ((access_type & VM_PROT_WRITE) == 0 && (flags & PGO_LOCKED) == 0) { 181 vn_ra_allocctx(vp); 182 uvm_ra_request(vp->v_ractx, advice, uobj, offset, 183 *npagesp << PAGE_SHIFT); 184 } 185 186 error = VOP_GETPAGES(vp, offset, pps, npagesp, centeridx, 187 access_type, advice, flags); 188 189 KASSERT(((flags & PGO_LOCKED) != 0 && mutex_owned(&vp->v_interlock)) || 190 (flags & PGO_LOCKED) == 0); 191 return error; 192 } 193 194 195 /* 196 * uvn_findpages: 197 * return the page for the uobj and offset requested, allocating if needed. 198 * => uobj must be locked. 199 * => returned pages will be BUSY. 200 */ 201 202 int 203 uvn_findpages(struct uvm_object *uobj, voff_t offset, int *npagesp, 204 struct vm_page **pgs, int flags) 205 { 206 int i, count, found, npages, rv; 207 208 count = found = 0; 209 npages = *npagesp; 210 if (flags & UFP_BACKWARD) { 211 for (i = npages - 1; i >= 0; i--, offset -= PAGE_SIZE) { 212 rv = uvn_findpage(uobj, offset, &pgs[i], flags); 213 if (rv == 0) { 214 if (flags & UFP_DIRTYONLY) 215 break; 216 } else 217 found++; 218 count++; 219 } 220 } else { 221 for (i = 0; i < npages; i++, offset += PAGE_SIZE) { 222 rv = uvn_findpage(uobj, offset, &pgs[i], flags); 223 if (rv == 0) { 224 if (flags & UFP_DIRTYONLY) 225 break; 226 } else 227 found++; 228 count++; 229 } 230 } 231 *npagesp = count; 232 return (found); 233 } 234 235 static int 236 uvn_findpage(struct uvm_object *uobj, voff_t offset, struct vm_page **pgp, 237 int flags) 238 { 239 struct vm_page *pg; 240 bool dirty; 241 UVMHIST_FUNC("uvn_findpage"); UVMHIST_CALLED(ubchist); 242 UVMHIST_LOG(ubchist, "vp %p off 0x%lx", uobj, offset,0,0); 243 244 if (*pgp != NULL) { 245 UVMHIST_LOG(ubchist, "dontcare", 0,0,0,0); 246 return 0; 247 } 248 for (;;) { 249 /* look for an existing page */ 250 pg = uvm_pagelookup(uobj, offset); 251 252 /* nope? allocate one now */ 253 if (pg == NULL) { 254 if (flags & UFP_NOALLOC) { 255 UVMHIST_LOG(ubchist, "noalloc", 0,0,0,0); 256 return 0; 257 } 258 pg = uvm_pagealloc(uobj, offset, NULL, 0); 259 if (pg == NULL) { 260 if (flags & UFP_NOWAIT) { 261 UVMHIST_LOG(ubchist, "nowait",0,0,0,0); 262 return 0; 263 } 264 mutex_exit(&uobj->vmobjlock); 265 uvm_wait("uvn_fp1"); 266 mutex_enter(&uobj->vmobjlock); 267 continue; 268 } 269 UVMHIST_LOG(ubchist, "alloced %p", pg,0,0,0); 270 break; 271 } else if (flags & UFP_NOCACHE) { 272 UVMHIST_LOG(ubchist, "nocache",0,0,0,0); 273 return 0; 274 } 275 276 /* page is there, see if we need to wait on it */ 277 if ((pg->flags & PG_BUSY) != 0) { 278 if (flags & UFP_NOWAIT) { 279 UVMHIST_LOG(ubchist, "nowait",0,0,0,0); 280 return 0; 281 } 282 pg->flags |= PG_WANTED; 283 UVMHIST_LOG(ubchist, "wait %p", pg,0,0,0); 284 UVM_UNLOCK_AND_WAIT(pg, &uobj->vmobjlock, 0, 285 "uvn_fp2", 0); 286 mutex_enter(&uobj->vmobjlock); 287 continue; 288 } 289 290 /* skip PG_RDONLY pages if requested */ 291 if ((flags & UFP_NORDONLY) && (pg->flags & PG_RDONLY)) { 292 UVMHIST_LOG(ubchist, "nordonly",0,0,0,0); 293 return 0; 294 } 295 296 /* stop on clean pages if requested */ 297 if (flags & UFP_DIRTYONLY) { 298 dirty = pmap_clear_modify(pg) || 299 (pg->flags & PG_CLEAN) == 0; 300 pg->flags |= PG_CLEAN; 301 if (!dirty) { 302 UVMHIST_LOG(ubchist, "dirtonly", 0,0,0,0); 303 return 0; 304 } 305 } 306 307 /* mark the page BUSY and we're done. */ 308 pg->flags |= PG_BUSY; 309 UVM_PAGE_OWN(pg, "uvn_findpage"); 310 UVMHIST_LOG(ubchist, "found %p", pg,0,0,0); 311 break; 312 } 313 *pgp = pg; 314 return 1; 315 } 316 317 /* 318 * uvm_vnp_setsize: grow or shrink a vnode uobj 319 * 320 * grow => just update size value 321 * shrink => toss un-needed pages 322 * 323 * => we assume that the caller has a reference of some sort to the 324 * vnode in question so that it will not be yanked out from under 325 * us. 326 */ 327 328 void 329 uvm_vnp_setsize(struct vnode *vp, voff_t newsize) 330 { 331 struct uvm_object *uobj = &vp->v_uobj; 332 voff_t pgend = round_page(newsize); 333 voff_t oldsize; 334 UVMHIST_FUNC("uvm_vnp_setsize"); UVMHIST_CALLED(ubchist); 335 336 mutex_enter(&uobj->vmobjlock); 337 UVMHIST_LOG(ubchist, "vp %p old 0x%x new 0x%x", 338 vp, vp->v_size, newsize, 0); 339 340 /* 341 * now check if the size has changed: if we shrink we had better 342 * toss some pages... 343 */ 344 345 KASSERT(newsize != VSIZENOTSET); 346 KASSERT(vp->v_size <= vp->v_writesize); 347 KASSERT(vp->v_size == vp->v_writesize || 348 newsize == vp->v_writesize || newsize <= vp->v_size); 349 350 oldsize = vp->v_writesize; 351 KASSERT(oldsize != VSIZENOTSET || pgend > oldsize); 352 353 if (oldsize > pgend) { 354 (void) uvn_put(uobj, pgend, 0, PGO_FREE | PGO_SYNCIO); 355 mutex_enter(&uobj->vmobjlock); 356 } 357 vp->v_size = vp->v_writesize = newsize; 358 mutex_exit(&uobj->vmobjlock); 359 } 360 361 void 362 uvm_vnp_setwritesize(struct vnode *vp, voff_t newsize) 363 { 364 365 mutex_enter(&vp->v_interlock); 366 KASSERT(newsize != VSIZENOTSET); 367 KASSERT(vp->v_size != VSIZENOTSET); 368 KASSERT(vp->v_writesize != VSIZENOTSET); 369 KASSERT(vp->v_size <= vp->v_writesize); 370 KASSERT(vp->v_size <= newsize); 371 vp->v_writesize = newsize; 372 mutex_exit(&vp->v_interlock); 373 } 374 375 bool 376 uvn_text_p(struct uvm_object *uobj) 377 { 378 struct vnode *vp = (struct vnode *)uobj; 379 380 return (vp->v_iflag & VI_EXECMAP) != 0; 381 } 382 383 bool 384 uvn_clean_p(struct uvm_object *uobj) 385 { 386 struct vnode *vp = (struct vnode *)uobj; 387 388 return (vp->v_iflag & VI_ONWORKLST) == 0; 389 } 390 391 bool 392 uvn_needs_writefault_p(struct uvm_object *uobj) 393 { 394 struct vnode *vp = (struct vnode *)uobj; 395 396 return uvn_clean_p(uobj) || 397 (vp->v_iflag & (VI_WRMAP|VI_WRMAPDIRTY)) == VI_WRMAP; 398 } 399
Indexes created Sun Sep 21 15:09:59 GMT 2025