uvm_vnode.c revision 1.85
1 /* $NetBSD: uvm_vnode.c,v 1.85 2007/08/04 09:42:58 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 1.85 2007/08/04 09:42:58 pooka Exp $"); 54 55 #include "fs_nfs.h" 56 #include "opt_uvmhist.h" 57 #include "opt_ddb.h" 58 59 #include <sys/param.h> 60 #include <sys/systm.h> 61 #include <sys/kernel.h> 62 #include <sys/proc.h> 63 #include <sys/malloc.h> 64 #include <sys/vnode.h> 65 #include <sys/disklabel.h> 66 #include <sys/ioctl.h> 67 #include <sys/fcntl.h> 68 #include <sys/conf.h> 69 #include <sys/pool.h> 70 #include <sys/mount.h> 71 72 #include <miscfs/specfs/specdev.h> 73 74 #include <uvm/uvm.h> 75 #include <uvm/uvm_readahead.h> 76 77 /* 78 * functions 79 */ 80 81 static void uvn_detach(struct uvm_object *); 82 static int uvn_get(struct uvm_object *, voff_t, struct vm_page **, int *, 83 int, vm_prot_t, int, int); 84 static int uvn_put(struct uvm_object *, voff_t, voff_t, int); 85 static void uvn_reference(struct uvm_object *); 86 87 static int uvn_findpage(struct uvm_object *, voff_t, struct vm_page **, 88 int); 89 90 /* 91 * master pager structure 92 */ 93 94 struct uvm_pagerops uvm_vnodeops = { 95 NULL, 96 uvn_reference, 97 uvn_detach, 98 NULL, 99 uvn_get, 100 uvn_put, 101 }; 102 103 /* 104 * the ops! 105 */ 106 107 /* 108 * uvn_reference 109 * 110 * duplicate a reference to a VM object. Note that the reference 111 * count must already be at least one (the passed in reference) so 112 * there is no chance of the uvn being killed or locked out here. 113 * 114 * => caller must call with object unlocked. 115 * => caller must be using the same accessprot as was used at attach time 116 */ 117 118 static void 119 uvn_reference(struct uvm_object *uobj) 120 { 121 VREF((struct vnode *)uobj); 122 } 123 124 125 /* 126 * uvn_detach 127 * 128 * remove a reference to a VM object. 129 * 130 * => caller must call with object unlocked and map locked. 131 */ 132 133 static void 134 uvn_detach(struct uvm_object *uobj) 135 { 136 vrele((struct vnode *)uobj); 137 } 138 139 /* 140 * uvn_put: flush page data to backing store. 141 * 142 * => object must be locked on entry! VOP_PUTPAGES must unlock it. 143 * => flags: PGO_SYNCIO -- use sync. I/O 144 * => note: caller must set PG_CLEAN and pmap_clear_modify (if needed) 145 */ 146 147 static int 148 uvn_put(struct uvm_object *uobj, voff_t offlo, voff_t offhi, int flags) 149 { 150 struct vnode *vp = (struct vnode *)uobj; 151 int error; 152 153 LOCK_ASSERT(simple_lock_held(&vp->v_interlock)); 154 error = VOP_PUTPAGES(vp, offlo, offhi, flags); 155 LOCK_ASSERT(!simple_lock_held(&vp->v_interlock)); 156 return error; 157 } 158 159 160 /* 161 * uvn_get: get pages (synchronously) from backing store 162 * 163 * => prefer map unlocked (not required) 164 * => object must be locked! we will _unlock_ it before starting any I/O. 165 * => flags: PGO_ALLPAGES: get all of the pages 166 * PGO_LOCKED: fault data structures are locked 167 * => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx] 168 * => NOTE: caller must check for released pages!! 169 */ 170 171 static int 172 uvn_get(struct uvm_object *uobj, voff_t offset, 173 struct vm_page **pps /* IN/OUT */, 174 int *npagesp /* IN (OUT if PGO_LOCKED)*/, 175 int centeridx, vm_prot_t access_type, int advice, int flags) 176 { 177 struct vnode *vp = (struct vnode *)uobj; 178 int error; 179 180 UVMHIST_FUNC("uvn_get"); UVMHIST_CALLED(ubchist); 181 182 UVMHIST_LOG(ubchist, "vp %p off 0x%x", vp, (int)offset, 0,0); 183 184 if ((access_type & VM_PROT_WRITE) == 0 && (flags & PGO_LOCKED) == 0) { 185 simple_unlock(&vp->v_interlock); 186 vn_ra_allocctx(vp); 187 uvm_ra_request(vp->v_ractx, advice, uobj, offset, 188 *npagesp << PAGE_SHIFT); 189 simple_lock(&vp->v_interlock); 190 } 191 192 error = VOP_GETPAGES(vp, offset, pps, npagesp, centeridx, 193 access_type, advice, flags); 194 195 LOCK_ASSERT(((flags & PGO_LOCKED) != 0 && 196 simple_lock_held(&vp->v_interlock)) || 197 ((flags & PGO_LOCKED) == 0 && 198 !simple_lock_held(&vp->v_interlock))); 199 return error; 200 } 201 202 203 /* 204 * uvn_findpages: 205 * return the page for the uobj and offset requested, allocating if needed. 206 * => uobj must be locked. 207 * => returned pages will be BUSY. 208 */ 209 210 int 211 uvn_findpages(struct uvm_object *uobj, voff_t offset, int *npagesp, 212 struct vm_page **pgs, int flags) 213 { 214 int i, count, found, npages, rv; 215 216 count = found = 0; 217 npages = *npagesp; 218 if (flags & UFP_BACKWARD) { 219 for (i = npages - 1; i >= 0; i--, offset -= PAGE_SIZE) { 220 rv = uvn_findpage(uobj, offset, &pgs[i], flags); 221 if (rv == 0) { 222 if (flags & UFP_DIRTYONLY) 223 break; 224 } else 225 found++; 226 count++; 227 } 228 } else { 229 for (i = 0; i < npages; i++, offset += PAGE_SIZE) { 230 rv = uvn_findpage(uobj, offset, &pgs[i], flags); 231 if (rv == 0) { 232 if (flags & UFP_DIRTYONLY) 233 break; 234 } else 235 found++; 236 count++; 237 } 238 } 239 *npagesp = count; 240 return (found); 241 } 242 243 static int 244 uvn_findpage(struct uvm_object *uobj, voff_t offset, struct vm_page **pgp, 245 int flags) 246 { 247 struct vm_page *pg; 248 bool dirty; 249 UVMHIST_FUNC("uvn_findpage"); UVMHIST_CALLED(ubchist); 250 UVMHIST_LOG(ubchist, "vp %p off 0x%lx", uobj, offset,0,0); 251 252 if (*pgp != NULL) { 253 UVMHIST_LOG(ubchist, "dontcare", 0,0,0,0); 254 return 0; 255 } 256 for (;;) { 257 /* look for an existing page */ 258 pg = uvm_pagelookup(uobj, offset); 259 260 /* nope? allocate one now */ 261 if (pg == NULL) { 262 if (flags & UFP_NOALLOC) { 263 UVMHIST_LOG(ubchist, "noalloc", 0,0,0,0); 264 return 0; 265 } 266 pg = uvm_pagealloc(uobj, offset, NULL, 0); 267 if (pg == NULL) { 268 if (flags & UFP_NOWAIT) { 269 UVMHIST_LOG(ubchist, "nowait",0,0,0,0); 270 return 0; 271 } 272 simple_unlock(&uobj->vmobjlock); 273 uvm_wait("uvn_fp1"); 274 simple_lock(&uobj->vmobjlock); 275 continue; 276 } 277 UVMHIST_LOG(ubchist, "alloced %p", pg,0,0,0); 278 break; 279 } else if (flags & UFP_NOCACHE) { 280 UVMHIST_LOG(ubchist, "nocache",0,0,0,0); 281 return 0; 282 } 283 284 /* page is there, see if we need to wait on it */ 285 if ((pg->flags & PG_BUSY) != 0) { 286 if (flags & UFP_NOWAIT) { 287 UVMHIST_LOG(ubchist, "nowait",0,0,0,0); 288 return 0; 289 } 290 pg->flags |= PG_WANTED; 291 UVMHIST_LOG(ubchist, "wait %p", pg,0,0,0); 292 UVM_UNLOCK_AND_WAIT(pg, &uobj->vmobjlock, 0, 293 "uvn_fp2", 0); 294 simple_lock(&uobj->vmobjlock); 295 continue; 296 } 297 298 /* skip PG_RDONLY pages if requested */ 299 if ((flags & UFP_NORDONLY) && (pg->flags & PG_RDONLY)) { 300 UVMHIST_LOG(ubchist, "nordonly",0,0,0,0); 301 return 0; 302 } 303 304 /* stop on clean pages if requested */ 305 if (flags & UFP_DIRTYONLY) { 306 dirty = pmap_clear_modify(pg) || 307 (pg->flags & PG_CLEAN) == 0; 308 pg->flags |= PG_CLEAN; 309 if (!dirty) { 310 UVMHIST_LOG(ubchist, "dirtonly", 0,0,0,0); 311 return 0; 312 } 313 } 314 315 /* mark the page BUSY and we're done. */ 316 pg->flags |= PG_BUSY; 317 UVM_PAGE_OWN(pg, "uvn_findpage"); 318 UVMHIST_LOG(ubchist, "found %p", pg,0,0,0); 319 break; 320 } 321 *pgp = pg; 322 return 1; 323 } 324 325 /* 326 * uvm_vnp_setsize: grow or shrink a vnode uobj 327 * 328 * grow => just update size value 329 * shrink => toss un-needed pages 330 * 331 * => we assume that the caller has a reference of some sort to the 332 * vnode in question so that it will not be yanked out from under 333 * us. 334 */ 335 336 void 337 uvm_vnp_setsize(struct vnode *vp, voff_t newsize) 338 { 339 struct uvm_object *uobj = &vp->v_uobj; 340 voff_t pgend = round_page(newsize); 341 voff_t oldsize; 342 UVMHIST_FUNC("uvm_vnp_setsize"); UVMHIST_CALLED(ubchist); 343 344 simple_lock(&uobj->vmobjlock); 345 UVMHIST_LOG(ubchist, "vp %p old 0x%x new 0x%x", 346 vp, vp->v_size, newsize, 0); 347 348 /* 349 * now check if the size has changed: if we shrink we had better 350 * toss some pages... 351 */ 352 353 KASSERT(newsize != VSIZENOTSET); 354 KASSERT(vp->v_size <= vp->v_writesize); 355 KASSERT(vp->v_size == vp->v_writesize || 356 newsize == vp->v_writesize || newsize <= vp->v_size); 357 358 oldsize = vp->v_writesize; 359 KASSERT(oldsize != VSIZENOTSET || pgend > oldsize); 360 361 if (oldsize > pgend) { 362 (void) uvn_put(uobj, pgend, 0, PGO_FREE | PGO_SYNCIO); 363 simple_lock(&uobj->vmobjlock); 364 } 365 vp->v_size = vp->v_writesize = newsize; 366 simple_unlock(&uobj->vmobjlock); 367 } 368 369 void 370 uvm_vnp_setwritesize(struct vnode *vp, voff_t newsize) 371 { 372 373 simple_lock(&vp->v_interlock); 374 KASSERT(newsize != VSIZENOTSET); 375 KASSERT(vp->v_size != VSIZENOTSET); 376 KASSERT(vp->v_writesize != VSIZENOTSET); 377 KASSERT(vp->v_size <= vp->v_writesize); 378 KASSERT(vp->v_size <= newsize); 379 vp->v_writesize = newsize; 380 simple_unlock(&vp->v_interlock); 381 } 382 383 /* 384 * uvm_vnp_zerorange: set a range of bytes in a file to zero. 385 */ 386 387 void 388 uvm_vnp_zerorange(struct vnode *vp, off_t off, size_t len) 389 { 390 void *win; 391 int flags; 392 393 /* 394 * XXXUBC invent kzero() and use it 395 */ 396 397 while (len) { 398 vsize_t bytelen = len; 399 400 win = ubc_alloc(&vp->v_uobj, off, &bytelen, UVM_ADV_NORMAL, 401 UBC_WRITE); 402 memset(win, 0, bytelen); 403 flags = UBC_WANT_UNMAP(vp) ? UBC_UNMAP : 0; 404 ubc_release(win, flags); 405 406 off += bytelen; 407 len -= bytelen; 408 } 409 } 410 411 bool 412 uvn_text_p(struct uvm_object *uobj) 413 { 414 struct vnode *vp = (struct vnode *)uobj; 415 416 return (vp->v_flag & VEXECMAP) != 0; 417 } 418 419 bool 420 uvn_clean_p(struct uvm_object *uobj) 421 { 422 struct vnode *vp = (struct vnode *)uobj; 423 424 return (vp->v_flag & VONWORKLST) == 0; 425 } 426 427 bool 428 uvn_needs_writefault_p(struct uvm_object *uobj) 429 { 430 struct vnode *vp = (struct vnode *)uobj; 431 432 return uvn_clean_p(uobj) || 433 (vp->v_flag & (VWRITEMAP|VWRITEMAPDIRTY)) == VWRITEMAP; 434 } 435
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