uvm_vnode.c revision 1.87
1 /* $NetBSD: uvm_vnode.c,v 1.87 2007/10/11 19:53:43 ad 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 1.87 2007/10/11 19:53:43 ad 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 return error; 156 } 157 158 159 /* 160 * uvn_get: get pages (synchronously) from backing store 161 * 162 * => prefer map unlocked (not required) 163 * => object must be locked! we will _unlock_ it before starting any I/O. 164 * => flags: PGO_ALLPAGES: get all of the pages 165 * PGO_LOCKED: fault data structures are locked 166 * => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx] 167 * => NOTE: caller must check for released pages!! 168 */ 169 170 static int 171 uvn_get(struct uvm_object *uobj, voff_t offset, 172 struct vm_page **pps /* IN/OUT */, 173 int *npagesp /* IN (OUT if PGO_LOCKED)*/, 174 int centeridx, vm_prot_t access_type, int advice, int flags) 175 { 176 struct vnode *vp = (struct vnode *)uobj; 177 int error; 178 179 UVMHIST_FUNC("uvn_get"); UVMHIST_CALLED(ubchist); 180 181 UVMHIST_LOG(ubchist, "vp %p off 0x%x", vp, (int)offset, 0,0); 182 183 if ((access_type & VM_PROT_WRITE) == 0 && (flags & PGO_LOCKED) == 0) { 184 simple_unlock(&vp->v_interlock); 185 vn_ra_allocctx(vp); 186 uvm_ra_request(vp->v_ractx, advice, uobj, offset, 187 *npagesp << PAGE_SHIFT); 188 simple_lock(&vp->v_interlock); 189 } 190 191 error = VOP_GETPAGES(vp, offset, pps, npagesp, centeridx, 192 access_type, advice, flags); 193 194 LOCK_ASSERT(((flags & PGO_LOCKED) != 0 && 195 simple_lock_held(&vp->v_interlock)) || 196 (flags & PGO_LOCKED) == 0); 197 return error; 198 } 199 200 201 /* 202 * uvn_findpages: 203 * return the page for the uobj and offset requested, allocating if needed. 204 * => uobj must be locked. 205 * => returned pages will be BUSY. 206 */ 207 208 int 209 uvn_findpages(struct uvm_object *uobj, voff_t offset, int *npagesp, 210 struct vm_page **pgs, int flags) 211 { 212 int i, count, found, npages, rv; 213 214 count = found = 0; 215 npages = *npagesp; 216 if (flags & UFP_BACKWARD) { 217 for (i = npages - 1; i >= 0; i--, offset -= PAGE_SIZE) { 218 rv = uvn_findpage(uobj, offset, &pgs[i], flags); 219 if (rv == 0) { 220 if (flags & UFP_DIRTYONLY) 221 break; 222 } else 223 found++; 224 count++; 225 } 226 } else { 227 for (i = 0; i < npages; i++, offset += PAGE_SIZE) { 228 rv = uvn_findpage(uobj, offset, &pgs[i], flags); 229 if (rv == 0) { 230 if (flags & UFP_DIRTYONLY) 231 break; 232 } else 233 found++; 234 count++; 235 } 236 } 237 *npagesp = count; 238 return (found); 239 } 240 241 static int 242 uvn_findpage(struct uvm_object *uobj, voff_t offset, struct vm_page **pgp, 243 int flags) 244 { 245 struct vm_page *pg; 246 bool dirty; 247 UVMHIST_FUNC("uvn_findpage"); UVMHIST_CALLED(ubchist); 248 UVMHIST_LOG(ubchist, "vp %p off 0x%lx", uobj, offset,0,0); 249 250 if (*pgp != NULL) { 251 UVMHIST_LOG(ubchist, "dontcare", 0,0,0,0); 252 return 0; 253 } 254 for (;;) { 255 /* look for an existing page */ 256 pg = uvm_pagelookup(uobj, offset); 257 258 /* nope? allocate one now */ 259 if (pg == NULL) { 260 if (flags & UFP_NOALLOC) { 261 UVMHIST_LOG(ubchist, "noalloc", 0,0,0,0); 262 return 0; 263 } 264 pg = uvm_pagealloc(uobj, offset, NULL, 0); 265 if (pg == NULL) { 266 if (flags & UFP_NOWAIT) { 267 UVMHIST_LOG(ubchist, "nowait",0,0,0,0); 268 return 0; 269 } 270 simple_unlock(&uobj->vmobjlock); 271 uvm_wait("uvn_fp1"); 272 simple_lock(&uobj->vmobjlock); 273 continue; 274 } 275 UVMHIST_LOG(ubchist, "alloced %p", pg,0,0,0); 276 break; 277 } else if (flags & UFP_NOCACHE) { 278 UVMHIST_LOG(ubchist, "nocache",0,0,0,0); 279 return 0; 280 } 281 282 /* page is there, see if we need to wait on it */ 283 if ((pg->flags & PG_BUSY) != 0) { 284 if (flags & UFP_NOWAIT) { 285 UVMHIST_LOG(ubchist, "nowait",0,0,0,0); 286 return 0; 287 } 288 pg->flags |= PG_WANTED; 289 UVMHIST_LOG(ubchist, "wait %p", pg,0,0,0); 290 UVM_UNLOCK_AND_WAIT(pg, &uobj->vmobjlock, 0, 291 "uvn_fp2", 0); 292 simple_lock(&uobj->vmobjlock); 293 continue; 294 } 295 296 /* skip PG_RDONLY pages if requested */ 297 if ((flags & UFP_NORDONLY) && (pg->flags & PG_RDONLY)) { 298 UVMHIST_LOG(ubchist, "nordonly",0,0,0,0); 299 return 0; 300 } 301 302 /* stop on clean pages if requested */ 303 if (flags & UFP_DIRTYONLY) { 304 dirty = pmap_clear_modify(pg) || 305 (pg->flags & PG_CLEAN) == 0; 306 pg->flags |= PG_CLEAN; 307 if (!dirty) { 308 UVMHIST_LOG(ubchist, "dirtonly", 0,0,0,0); 309 return 0; 310 } 311 } 312 313 /* mark the page BUSY and we're done. */ 314 pg->flags |= PG_BUSY; 315 UVM_PAGE_OWN(pg, "uvn_findpage"); 316 UVMHIST_LOG(ubchist, "found %p", pg,0,0,0); 317 break; 318 } 319 *pgp = pg; 320 return 1; 321 } 322 323 /* 324 * uvm_vnp_setsize: grow or shrink a vnode uobj 325 * 326 * grow => just update size value 327 * shrink => toss un-needed pages 328 * 329 * => we assume that the caller has a reference of some sort to the 330 * vnode in question so that it will not be yanked out from under 331 * us. 332 */ 333 334 void 335 uvm_vnp_setsize(struct vnode *vp, voff_t newsize) 336 { 337 struct uvm_object *uobj = &vp->v_uobj; 338 voff_t pgend = round_page(newsize); 339 voff_t oldsize; 340 UVMHIST_FUNC("uvm_vnp_setsize"); UVMHIST_CALLED(ubchist); 341 342 simple_lock(&uobj->vmobjlock); 343 UVMHIST_LOG(ubchist, "vp %p old 0x%x new 0x%x", 344 vp, vp->v_size, newsize, 0); 345 346 /* 347 * now check if the size has changed: if we shrink we had better 348 * toss some pages... 349 */ 350 351 KASSERT(newsize != VSIZENOTSET); 352 KASSERT(vp->v_size <= vp->v_writesize); 353 KASSERT(vp->v_size == vp->v_writesize || 354 newsize == vp->v_writesize || newsize <= vp->v_size); 355 356 oldsize = vp->v_writesize; 357 KASSERT(oldsize != VSIZENOTSET || pgend > oldsize); 358 359 if (oldsize > pgend) { 360 (void) uvn_put(uobj, pgend, 0, PGO_FREE | PGO_SYNCIO); 361 simple_lock(&uobj->vmobjlock); 362 } 363 vp->v_size = vp->v_writesize = newsize; 364 simple_unlock(&uobj->vmobjlock); 365 } 366 367 void 368 uvm_vnp_setwritesize(struct vnode *vp, voff_t newsize) 369 { 370 371 simple_lock(&vp->v_interlock); 372 KASSERT(newsize != VSIZENOTSET); 373 KASSERT(vp->v_size != VSIZENOTSET); 374 KASSERT(vp->v_writesize != VSIZENOTSET); 375 KASSERT(vp->v_size <= vp->v_writesize); 376 KASSERT(vp->v_size <= newsize); 377 vp->v_writesize = newsize; 378 simple_unlock(&vp->v_interlock); 379 } 380 381 /* 382 * uvm_vnp_zerorange: set a range of bytes in a file to zero. 383 */ 384 385 void 386 uvm_vnp_zerorange(struct vnode *vp, off_t off, size_t len) 387 { 388 void *win; 389 int flags; 390 391 /* 392 * XXXUBC invent kzero() and use it 393 */ 394 395 while (len) { 396 vsize_t bytelen = len; 397 398 win = ubc_alloc(&vp->v_uobj, off, &bytelen, UVM_ADV_NORMAL, 399 UBC_WRITE); 400 memset(win, 0, bytelen); 401 flags = UBC_WANT_UNMAP(vp) ? UBC_UNMAP : 0; 402 ubc_release(win, flags); 403 404 off += bytelen; 405 len -= bytelen; 406 } 407 } 408 409 bool 410 uvn_text_p(struct uvm_object *uobj) 411 { 412 struct vnode *vp = (struct vnode *)uobj; 413 414 return (vp->v_iflag & VI_EXECMAP) != 0; 415 } 416 417 bool 418 uvn_clean_p(struct uvm_object *uobj) 419 { 420 struct vnode *vp = (struct vnode *)uobj; 421 422 return (vp->v_iflag & VI_ONWORKLST) == 0; 423 } 424 425 bool 426 uvn_needs_writefault_p(struct uvm_object *uobj) 427 { 428 struct vnode *vp = (struct vnode *)uobj; 429 430 return uvn_clean_p(uobj) || 431 (vp->v_iflag & (VI_WRMAP|VI_WRMAPDIRTY)) == VI_WRMAP; 432 } 433
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