1 /* $NetBSD: uvm_vnode.c,v 1.99 2012/07/30 23:56:48 matt 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 1.99 2012/07/30 23:56:48 matt 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/vnode.h> 56 #include <sys/disklabel.h> 57 #include <sys/ioctl.h> 58 #include <sys/fcntl.h> 59 #include <sys/conf.h> 60 #include <sys/pool.h> 61 #include <sys/mount.h> 62 63 #include <miscfs/specfs/specdev.h> 64 65 #include <uvm/uvm.h> 66 #include <uvm/uvm_readahead.h> 67 68 #ifdef UVMHIST 69 UVMHIST_DEFINE(ubchist); 70 #endif 71 72 /* 73 * functions 74 */ 75 76 static void uvn_detach(struct uvm_object *); 77 static int uvn_get(struct uvm_object *, voff_t, struct vm_page **, int *, 78 int, vm_prot_t, int, int); 79 static int uvn_put(struct uvm_object *, voff_t, voff_t, int); 80 static void uvn_reference(struct uvm_object *); 81 82 static int uvn_findpage(struct uvm_object *, voff_t, struct vm_page **, 83 int); 84 85 /* 86 * master pager structure 87 */ 88 89 const struct uvm_pagerops uvm_vnodeops = { 90 .pgo_reference = uvn_reference, 91 .pgo_detach = uvn_detach, 92 .pgo_get = uvn_get, 93 .pgo_put = uvn_put, 94 }; 95 96 /* 97 * the ops! 98 */ 99 100 /* 101 * uvn_reference 102 * 103 * duplicate a reference to a VM object. Note that the reference 104 * count must already be at least one (the passed in reference) so 105 * there is no chance of the uvn being killed or locked out here. 106 * 107 * => caller must call with object unlocked. 108 * => caller must be using the same accessprot as was used at attach time 109 */ 110 111 static void 112 uvn_reference(struct uvm_object *uobj) 113 { 114 vref((struct vnode *)uobj); 115 } 116 117 118 /* 119 * uvn_detach 120 * 121 * remove a reference to a VM object. 122 * 123 * => caller must call with object unlocked and map locked. 124 */ 125 126 static void 127 uvn_detach(struct uvm_object *uobj) 128 { 129 vrele((struct vnode *)uobj); 130 } 131 132 /* 133 * uvn_put: flush page data to backing store. 134 * 135 * => object must be locked on entry! VOP_PUTPAGES must unlock it. 136 * => flags: PGO_SYNCIO -- use sync. I/O 137 * => note: caller must set PG_CLEAN and pmap_clear_modify (if needed) 138 */ 139 140 static int 141 uvn_put(struct uvm_object *uobj, voff_t offlo, voff_t offhi, int flags) 142 { 143 struct vnode *vp = (struct vnode *)uobj; 144 int error; 145 146 KASSERT(mutex_owned(vp->v_interlock)); 147 error = VOP_PUTPAGES(vp, offlo, offhi, flags); 148 149 return error; 150 } 151 152 153 /* 154 * uvn_get: get pages (synchronously) from backing store 155 * 156 * => prefer map unlocked (not required) 157 * => object must be locked! we will _unlock_ it before starting any I/O. 158 * => flags: PGO_ALLPAGES: get all of the pages 159 * PGO_LOCKED: fault data structures are locked 160 * => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx] 161 * => NOTE: caller must check for released pages!! 162 */ 163 164 static int 165 uvn_get(struct uvm_object *uobj, voff_t offset, 166 struct vm_page **pps /* IN/OUT */, 167 int *npagesp /* IN (OUT if PGO_LOCKED)*/, 168 int centeridx, vm_prot_t access_type, int advice, int flags) 169 { 170 struct vnode *vp = (struct vnode *)uobj; 171 int error; 172 173 UVMHIST_FUNC("uvn_get"); UVMHIST_CALLED(ubchist); 174 175 UVMHIST_LOG(ubchist, "vp %p off 0x%x", vp, (int)offset, 0,0); 176 177 if (vp->v_type == VREG && (access_type & VM_PROT_WRITE) == 0 178 && (flags & PGO_LOCKED) == 0) { 179 vn_ra_allocctx(vp); 180 uvm_ra_request(vp->v_ractx, advice, uobj, offset, 181 *npagesp << PAGE_SHIFT); 182 } 183 184 error = VOP_GETPAGES(vp, offset, pps, npagesp, centeridx, 185 access_type, advice, flags); 186 187 KASSERT(((flags & PGO_LOCKED) != 0 && mutex_owned(vp->v_interlock)) || 188 (flags & PGO_LOCKED) == 0); 189 return error; 190 } 191 192 193 /* 194 * uvn_findpages: 195 * return the page for the uobj and offset requested, allocating if needed. 196 * => uobj must be locked. 197 * => returned pages will be BUSY. 198 */ 199 200 int 201 uvn_findpages(struct uvm_object *uobj, voff_t offset, int *npagesp, 202 struct vm_page **pgs, int flags) 203 { 204 int i, count, found, npages, rv; 205 206 count = found = 0; 207 npages = *npagesp; 208 if (flags & UFP_BACKWARD) { 209 for (i = npages - 1; i >= 0; i--, offset -= PAGE_SIZE) { 210 rv = uvn_findpage(uobj, offset, &pgs[i], flags); 211 if (rv == 0) { 212 if (flags & UFP_DIRTYONLY) 213 break; 214 } else 215 found++; 216 count++; 217 } 218 } else { 219 for (i = 0; i < npages; 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 } 229 *npagesp = count; 230 return (found); 231 } 232 233 static int 234 uvn_findpage(struct uvm_object *uobj, voff_t offset, struct vm_page **pgp, 235 int flags) 236 { 237 struct vm_page *pg; 238 bool dirty; 239 UVMHIST_FUNC("uvn_findpage"); UVMHIST_CALLED(ubchist); 240 UVMHIST_LOG(ubchist, "vp %p off 0x%lx", uobj, offset,0,0); 241 242 KASSERT(mutex_owned(uobj->vmobjlock)); 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, 259 UVM_FLAG_COLORMATCH); 260 if (pg == NULL) { 261 if (flags & UFP_NOWAIT) { 262 UVMHIST_LOG(ubchist, "nowait",0,0,0,0); 263 return 0; 264 } 265 mutex_exit(uobj->vmobjlock); 266 uvm_wait("uvn_fp1"); 267 mutex_enter(uobj->vmobjlock); 268 continue; 269 } 270 UVMHIST_LOG(ubchist, "alloced %p (color %u)", pg, 271 VM_PGCOLOR_BUCKET(pg), 0,0); 272 break; 273 } else if (flags & UFP_NOCACHE) { 274 UVMHIST_LOG(ubchist, "nocache",0,0,0,0); 275 return 0; 276 } 277 278 /* page is there, see if we need to wait on it */ 279 if ((pg->flags & PG_BUSY) != 0) { 280 if (flags & UFP_NOWAIT) { 281 UVMHIST_LOG(ubchist, "nowait",0,0,0,0); 282 return 0; 283 } 284 pg->flags |= PG_WANTED; 285 UVMHIST_LOG(ubchist, "wait %p (color %u)", pg, 286 VM_PGCOLOR_BUCKET(pg), 0,0); 287 UVM_UNLOCK_AND_WAIT(pg, uobj->vmobjlock, 0, 288 "uvn_fp2", 0); 289 mutex_enter(uobj->vmobjlock); 290 continue; 291 } 292 293 /* skip PG_RDONLY pages if requested */ 294 if ((flags & UFP_NORDONLY) && (pg->flags & PG_RDONLY)) { 295 UVMHIST_LOG(ubchist, "nordonly",0,0,0,0); 296 return 0; 297 } 298 299 /* stop on clean pages if requested */ 300 if (flags & UFP_DIRTYONLY) { 301 dirty = pmap_clear_modify(pg) || 302 (pg->flags & PG_CLEAN) == 0; 303 pg->flags |= PG_CLEAN; 304 if (!dirty) { 305 UVMHIST_LOG(ubchist, "dirtonly", 0,0,0,0); 306 return 0; 307 } 308 } 309 310 /* mark the page BUSY and we're done. */ 311 pg->flags |= PG_BUSY; 312 UVM_PAGE_OWN(pg, "uvn_findpage"); 313 UVMHIST_LOG(ubchist, "found %p (color %u)", 314 pg, VM_PGCOLOR_BUCKET(pg), 0,0); 315 break; 316 } 317 *pgp = pg; 318 return 1; 319 } 320 321 /* 322 * uvm_vnp_setsize: grow or shrink a vnode uobj 323 * 324 * grow => just update size value 325 * shrink => toss un-needed pages 326 * 327 * => we assume that the caller has a reference of some sort to the 328 * vnode in question so that it will not be yanked out from under 329 * us. 330 */ 331 332 void 333 uvm_vnp_setsize(struct vnode *vp, voff_t newsize) 334 { 335 struct uvm_object *uobj = &vp->v_uobj; 336 voff_t pgend = round_page(newsize); 337 voff_t oldsize; 338 UVMHIST_FUNC("uvm_vnp_setsize"); UVMHIST_CALLED(ubchist); 339 340 mutex_enter(uobj->vmobjlock); 341 UVMHIST_LOG(ubchist, "vp %p old 0x%x new 0x%x", 342 vp, vp->v_size, newsize, 0); 343 344 /* 345 * now check if the size has changed: if we shrink we had better 346 * toss some pages... 347 */ 348 349 KASSERT(newsize != VSIZENOTSET); 350 KASSERT(vp->v_size <= vp->v_writesize); 351 KASSERT(vp->v_size == vp->v_writesize || 352 newsize == vp->v_writesize || newsize <= vp->v_size); 353 354 oldsize = vp->v_writesize; 355 KASSERT(oldsize != VSIZENOTSET || pgend > oldsize); 356 357 if (oldsize > pgend) { 358 (void) uvn_put(uobj, pgend, 0, PGO_FREE | PGO_SYNCIO); 359 mutex_enter(uobj->vmobjlock); 360 } 361 vp->v_size = vp->v_writesize = newsize; 362 mutex_exit(uobj->vmobjlock); 363 } 364 365 void 366 uvm_vnp_setwritesize(struct vnode *vp, voff_t newsize) 367 { 368 369 mutex_enter(vp->v_interlock); 370 KASSERT(newsize != VSIZENOTSET); 371 KASSERT(vp->v_size != VSIZENOTSET); 372 KASSERT(vp->v_writesize != VSIZENOTSET); 373 KASSERT(vp->v_size <= vp->v_writesize); 374 KASSERT(vp->v_size <= newsize); 375 vp->v_writesize = newsize; 376 mutex_exit(vp->v_interlock); 377 } 378 379 bool 380 uvn_text_p(struct uvm_object *uobj) 381 { 382 struct vnode *vp = (struct vnode *)uobj; 383 384 return (vp->v_iflag & VI_EXECMAP) != 0; 385 } 386 387 bool 388 uvn_clean_p(struct uvm_object *uobj) 389 { 390 struct vnode *vp = (struct vnode *)uobj; 391 392 return (vp->v_iflag & VI_ONWORKLST) == 0; 393 } 394 395 bool 396 uvn_needs_writefault_p(struct uvm_object *uobj) 397 { 398 struct vnode *vp = (struct vnode *)uobj; 399 400 return uvn_clean_p(uobj) || 401 (vp->v_iflag & (VI_WRMAP|VI_WRMAPDIRTY)) == VI_WRMAP; 402 } 403