uvm_vnode.c revision 1.93.4.3
1 /* $NetBSD: uvm_vnode.c,v 1.93.4.3 2011/03/05 20:56:38 rmind 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. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 * 39 * @(#)vnode_pager.c 8.8 (Berkeley) 2/13/94 40 * from: Id: uvm_vnode.c,v 1.1.2.26 1998/02/02 20:38:07 chuck Exp 41 */ 42 43 /* 44 * uvm_vnode.c: the vnode pager. 45 */ 46 47 #include <sys/cdefs.h> 48 __KERNEL_RCSID(0, "$NetBSD: uvm_vnode.c,v 1.93.4.3 2011/03/05 20:56:38 rmind Exp $"); 49 50 #include "opt_uvmhist.h" 51 52 #include <sys/param.h> 53 #include <sys/systm.h> 54 #include <sys/kernel.h> 55 #include <sys/proc.h> 56 #include <sys/malloc.h> 57 #include <sys/vnode.h> 58 #include <sys/disklabel.h> 59 #include <sys/ioctl.h> 60 #include <sys/fcntl.h> 61 #include <sys/conf.h> 62 #include <sys/pool.h> 63 #include <sys/mount.h> 64 65 #include <miscfs/specfs/specdev.h> 66 67 #include <uvm/uvm.h> 68 #include <uvm/uvm_readahead.h> 69 70 /* 71 * functions 72 */ 73 74 static void uvn_detach(struct uvm_object *); 75 static int uvn_get(struct uvm_object *, voff_t, struct vm_page **, int *, 76 int, vm_prot_t, int, int); 77 static int uvn_put(struct uvm_object *, voff_t, voff_t, int); 78 static void uvn_reference(struct uvm_object *); 79 80 static int uvn_findpage(struct uvm_object *, voff_t, struct vm_page **, 81 int); 82 83 /* 84 * master pager structure 85 */ 86 87 const struct uvm_pagerops uvm_vnodeops = { 88 .pgo_reference = uvn_reference, 89 .pgo_detach = uvn_detach, 90 .pgo_get = uvn_get, 91 .pgo_put = uvn_put, 92 }; 93 94 /* 95 * the ops! 96 */ 97 98 /* 99 * uvn_reference 100 * 101 * duplicate a reference to a VM object. Note that the reference 102 * count must already be at least one (the passed in reference) so 103 * there is no chance of the uvn being killed or locked out here. 104 * 105 * => caller must call with object unlocked. 106 * => caller must be using the same accessprot as was used at attach time 107 */ 108 109 static void 110 uvn_reference(struct uvm_object *uobj) 111 { 112 vref((struct vnode *)uobj); 113 } 114 115 116 /* 117 * uvn_detach 118 * 119 * remove a reference to a VM object. 120 * 121 * => caller must call with object unlocked and map locked. 122 */ 123 124 static void 125 uvn_detach(struct uvm_object *uobj) 126 { 127 vrele((struct vnode *)uobj); 128 } 129 130 /* 131 * uvn_put: flush page data to backing store. 132 * 133 * => object must be locked on entry! VOP_PUTPAGES must unlock it. 134 * => flags: PGO_SYNCIO -- use sync. I/O 135 * => note: caller must set PG_CLEAN and pmap_clear_modify (if needed) 136 */ 137 138 static int 139 uvn_put(struct uvm_object *uobj, voff_t offlo, voff_t offhi, int flags) 140 { 141 struct vnode *vp = (struct vnode *)uobj; 142 int error; 143 144 KASSERT(mutex_owned(vp->v_interlock)); 145 error = VOP_PUTPAGES(vp, offlo, offhi, flags); 146 147 return error; 148 } 149 150 151 /* 152 * uvn_get: get pages (synchronously) from backing store 153 * 154 * => prefer map unlocked (not required) 155 * => object must be locked! we will _unlock_ it before starting any I/O. 156 * => flags: PGO_ALLPAGES: get all of the pages 157 * PGO_LOCKED: fault data structures are locked 158 * => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx] 159 * => NOTE: caller must check for released pages!! 160 */ 161 162 static int 163 uvn_get(struct uvm_object *uobj, voff_t offset, 164 struct vm_page **pps /* IN/OUT */, 165 int *npagesp /* IN (OUT if PGO_LOCKED)*/, 166 int centeridx, vm_prot_t access_type, int advice, int flags) 167 { 168 struct vnode *vp = (struct vnode *)uobj; 169 int error; 170 171 UVMHIST_FUNC("uvn_get"); UVMHIST_CALLED(ubchist); 172 173 UVMHIST_LOG(ubchist, "vp %p off 0x%x", vp, (int)offset, 0,0); 174 175 if ((access_type & VM_PROT_WRITE) == 0 && (flags & PGO_LOCKED) == 0) { 176 vn_ra_allocctx(vp); 177 uvm_ra_request(vp->v_ractx, advice, uobj, offset, 178 *npagesp << PAGE_SHIFT); 179 } 180 181 error = VOP_GETPAGES(vp, offset, pps, npagesp, centeridx, 182 access_type, advice, flags); 183 184 KASSERT(((flags & PGO_LOCKED) != 0 && mutex_owned(vp->v_interlock)) || 185 (flags & PGO_LOCKED) == 0); 186 return error; 187 } 188 189 190 /* 191 * uvn_findpages: 192 * return the page for the uobj and offset requested, allocating if needed. 193 * => uobj must be locked. 194 * => returned pages will be BUSY. 195 */ 196 197 int 198 uvn_findpages(struct uvm_object *uobj, voff_t offset, int *npagesp, 199 struct vm_page **pgs, int flags) 200 { 201 int i, count, found, npages, rv; 202 203 count = found = 0; 204 npages = *npagesp; 205 if (flags & UFP_BACKWARD) { 206 for (i = npages - 1; i >= 0; i--, offset -= PAGE_SIZE) { 207 rv = uvn_findpage(uobj, offset, &pgs[i], flags); 208 if (rv == 0) { 209 if (flags & UFP_DIRTYONLY) 210 break; 211 } else 212 found++; 213 count++; 214 } 215 } else { 216 for (i = 0; i < npages; i++, offset += PAGE_SIZE) { 217 rv = uvn_findpage(uobj, offset, &pgs[i], flags); 218 if (rv == 0) { 219 if (flags & UFP_DIRTYONLY) 220 break; 221 } else 222 found++; 223 count++; 224 } 225 } 226 *npagesp = count; 227 return (found); 228 } 229 230 static int 231 uvn_findpage(struct uvm_object *uobj, voff_t offset, struct vm_page **pgp, 232 int flags) 233 { 234 struct vm_page *pg; 235 bool dirty; 236 UVMHIST_FUNC("uvn_findpage"); UVMHIST_CALLED(ubchist); 237 UVMHIST_LOG(ubchist, "vp %p off 0x%lx", uobj, offset,0,0); 238 239 KASSERT(mutex_owned(uobj->vmobjlock)); 240 241 if (*pgp != NULL) { 242 UVMHIST_LOG(ubchist, "dontcare", 0,0,0,0); 243 return 0; 244 } 245 for (;;) { 246 /* look for an existing page */ 247 pg = uvm_pagelookup(uobj, offset); 248 249 /* nope? allocate one now */ 250 if (pg == NULL) { 251 if (flags & UFP_NOALLOC) { 252 UVMHIST_LOG(ubchist, "noalloc", 0,0,0,0); 253 return 0; 254 } 255 pg = uvm_pagealloc(uobj, offset, NULL, 0); 256 if (pg == NULL) { 257 if (flags & UFP_NOWAIT) { 258 UVMHIST_LOG(ubchist, "nowait",0,0,0,0); 259 return 0; 260 } 261 mutex_exit(uobj->vmobjlock); 262 uvm_wait("uvn_fp1"); 263 mutex_enter(uobj->vmobjlock); 264 continue; 265 } 266 UVMHIST_LOG(ubchist, "alloced %p", pg,0,0,0); 267 break; 268 } else if (flags & UFP_NOCACHE) { 269 UVMHIST_LOG(ubchist, "nocache",0,0,0,0); 270 return 0; 271 } 272 273 /* page is there, see if we need to wait on it */ 274 if ((pg->flags & PG_BUSY) != 0) { 275 if (flags & UFP_NOWAIT) { 276 UVMHIST_LOG(ubchist, "nowait",0,0,0,0); 277 return 0; 278 } 279 pg->flags |= PG_WANTED; 280 UVMHIST_LOG(ubchist, "wait %p", pg,0,0,0); 281 UVM_UNLOCK_AND_WAIT(pg, uobj->vmobjlock, 0, 282 "uvn_fp2", 0); 283 mutex_enter(uobj->vmobjlock); 284 continue; 285 } 286 287 /* skip PG_RDONLY pages if requested */ 288 if ((flags & UFP_NORDONLY) && (pg->flags & PG_RDONLY)) { 289 UVMHIST_LOG(ubchist, "nordonly",0,0,0,0); 290 return 0; 291 } 292 293 /* stop on clean pages if requested */ 294 if (flags & UFP_DIRTYONLY) { 295 dirty = pmap_clear_modify(pg) || 296 (pg->flags & PG_CLEAN) == 0; 297 pg->flags |= PG_CLEAN; 298 if (!dirty) { 299 UVMHIST_LOG(ubchist, "dirtonly", 0,0,0,0); 300 return 0; 301 } 302 } 303 304 /* mark the page BUSY and we're done. */ 305 pg->flags |= PG_BUSY; 306 UVM_PAGE_OWN(pg, "uvn_findpage"); 307 UVMHIST_LOG(ubchist, "found %p", pg,0,0,0); 308 break; 309 } 310 *pgp = pg; 311 return 1; 312 } 313 314 /* 315 * uvm_vnp_setsize: grow or shrink a vnode uobj 316 * 317 * grow => just update size value 318 * shrink => toss un-needed pages 319 * 320 * => we assume that the caller has a reference of some sort to the 321 * vnode in question so that it will not be yanked out from under 322 * us. 323 */ 324 325 void 326 uvm_vnp_setsize(struct vnode *vp, voff_t newsize) 327 { 328 struct uvm_object *uobj = &vp->v_uobj; 329 voff_t pgend = round_page(newsize); 330 voff_t oldsize; 331 UVMHIST_FUNC("uvm_vnp_setsize"); UVMHIST_CALLED(ubchist); 332 333 mutex_enter(uobj->vmobjlock); 334 UVMHIST_LOG(ubchist, "vp %p old 0x%x new 0x%x", 335 vp, vp->v_size, newsize, 0); 336 337 /* 338 * now check if the size has changed: if we shrink we had better 339 * toss some pages... 340 */ 341 342 KASSERT(newsize != VSIZENOTSET); 343 KASSERT(vp->v_size <= vp->v_writesize); 344 KASSERT(vp->v_size == vp->v_writesize || 345 newsize == vp->v_writesize || newsize <= vp->v_size); 346 347 oldsize = vp->v_writesize; 348 KASSERT(oldsize != VSIZENOTSET || pgend > oldsize); 349 350 if (oldsize > pgend) { 351 (void) uvn_put(uobj, pgend, 0, PGO_FREE | PGO_SYNCIO); 352 mutex_enter(uobj->vmobjlock); 353 } 354 vp->v_size = vp->v_writesize = newsize; 355 mutex_exit(uobj->vmobjlock); 356 } 357 358 void 359 uvm_vnp_setwritesize(struct vnode *vp, voff_t newsize) 360 { 361 362 mutex_enter(vp->v_interlock); 363 KASSERT(newsize != VSIZENOTSET); 364 KASSERT(vp->v_size != VSIZENOTSET); 365 KASSERT(vp->v_writesize != VSIZENOTSET); 366 KASSERT(vp->v_size <= vp->v_writesize); 367 KASSERT(vp->v_size <= newsize); 368 vp->v_writesize = newsize; 369 mutex_exit(vp->v_interlock); 370 } 371 372 bool 373 uvn_text_p(struct uvm_object *uobj) 374 { 375 struct vnode *vp = (struct vnode *)uobj; 376 377 return (vp->v_iflag & VI_EXECMAP) != 0; 378 } 379 380 bool 381 uvn_clean_p(struct uvm_object *uobj) 382 { 383 struct vnode *vp = (struct vnode *)uobj; 384 385 return (vp->v_iflag & VI_ONWORKLST) == 0; 386 } 387 388 bool 389 uvn_needs_writefault_p(struct uvm_object *uobj) 390 { 391 struct vnode *vp = (struct vnode *)uobj; 392 393 return uvn_clean_p(uobj) || 394 (vp->v_iflag & (VI_WRMAP|VI_WRMAPDIRTY)) == VI_WRMAP; 395 } 396
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