uvm_vnode.c revision 1.100
1 /* $NetBSD: uvm_vnode.c,v 1.100 2015/08/24 22:50:32 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. 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 1.100 2015/08/24 22:50:32 pooka Exp $"); 49 50 #ifdef _KERNEL_OPT 51 #include "opt_uvmhist.h" 52 #endif 53 54 #include <sys/param.h> 55 #include <sys/systm.h> 56 #include <sys/kernel.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 #ifdef UVMHIST 71 UVMHIST_DEFINE(ubchist); 72 #endif 73 74 /* 75 * functions 76 */ 77 78 static void uvn_detach(struct uvm_object *); 79 static int uvn_get(struct uvm_object *, voff_t, struct vm_page **, int *, 80 int, vm_prot_t, int, int); 81 static int uvn_put(struct uvm_object *, voff_t, voff_t, int); 82 static void uvn_reference(struct uvm_object *); 83 84 static int uvn_findpage(struct uvm_object *, voff_t, struct vm_page **, 85 int); 86 87 /* 88 * master pager structure 89 */ 90 91 const struct uvm_pagerops uvm_vnodeops = { 92 .pgo_reference = uvn_reference, 93 .pgo_detach = uvn_detach, 94 .pgo_get = uvn_get, 95 .pgo_put = uvn_put, 96 }; 97 98 /* 99 * the ops! 100 */ 101 102 /* 103 * uvn_reference 104 * 105 * duplicate a reference to a VM object. Note that the reference 106 * count must already be at least one (the passed in reference) so 107 * there is no chance of the uvn being killed or locked out here. 108 * 109 * => caller must call with object unlocked. 110 * => caller must be using the same accessprot as was used at attach time 111 */ 112 113 static void 114 uvn_reference(struct uvm_object *uobj) 115 { 116 vref((struct vnode *)uobj); 117 } 118 119 120 /* 121 * uvn_detach 122 * 123 * remove a reference to a VM object. 124 * 125 * => caller must call with object unlocked and map locked. 126 */ 127 128 static void 129 uvn_detach(struct uvm_object *uobj) 130 { 131 vrele((struct vnode *)uobj); 132 } 133 134 /* 135 * uvn_put: flush page data to backing store. 136 * 137 * => object must be locked on entry! VOP_PUTPAGES must unlock it. 138 * => flags: PGO_SYNCIO -- use sync. I/O 139 * => note: caller must set PG_CLEAN and pmap_clear_modify (if needed) 140 */ 141 142 static int 143 uvn_put(struct uvm_object *uobj, voff_t offlo, voff_t offhi, int flags) 144 { 145 struct vnode *vp = (struct vnode *)uobj; 146 int error; 147 148 KASSERT(mutex_owned(vp->v_interlock)); 149 error = VOP_PUTPAGES(vp, offlo, offhi, flags); 150 151 return error; 152 } 153 154 155 /* 156 * uvn_get: get pages (synchronously) from backing store 157 * 158 * => prefer map unlocked (not required) 159 * => object must be locked! we will _unlock_ it before starting any I/O. 160 * => flags: PGO_ALLPAGES: get all of the pages 161 * PGO_LOCKED: fault data structures are locked 162 * => NOTE: offset is the offset of pps[0], _NOT_ pps[centeridx] 163 * => NOTE: caller must check for released pages!! 164 */ 165 166 static int 167 uvn_get(struct uvm_object *uobj, voff_t offset, 168 struct vm_page **pps /* IN/OUT */, 169 int *npagesp /* IN (OUT if PGO_LOCKED)*/, 170 int centeridx, vm_prot_t access_type, int advice, int flags) 171 { 172 struct vnode *vp = (struct vnode *)uobj; 173 int error; 174 175 UVMHIST_FUNC("uvn_get"); UVMHIST_CALLED(ubchist); 176 177 UVMHIST_LOG(ubchist, "vp %p off 0x%x", vp, (int)offset, 0,0); 178 179 if (vp->v_type == VREG && (access_type & VM_PROT_WRITE) == 0 180 && (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 KASSERT(mutex_owned(uobj->vmobjlock)); 245 246 if (*pgp != NULL) { 247 UVMHIST_LOG(ubchist, "dontcare", 0,0,0,0); 248 return 0; 249 } 250 for (;;) { 251 /* look for an existing page */ 252 pg = uvm_pagelookup(uobj, offset); 253 254 /* nope? allocate one now */ 255 if (pg == NULL) { 256 if (flags & UFP_NOALLOC) { 257 UVMHIST_LOG(ubchist, "noalloc", 0,0,0,0); 258 return 0; 259 } 260 pg = uvm_pagealloc(uobj, offset, NULL, 261 UVM_FLAG_COLORMATCH); 262 if (pg == NULL) { 263 if (flags & UFP_NOWAIT) { 264 UVMHIST_LOG(ubchist, "nowait",0,0,0,0); 265 return 0; 266 } 267 mutex_exit(uobj->vmobjlock); 268 uvm_wait("uvn_fp1"); 269 mutex_enter(uobj->vmobjlock); 270 continue; 271 } 272 UVMHIST_LOG(ubchist, "alloced %p (color %u)", pg, 273 VM_PGCOLOR_BUCKET(pg), 0,0); 274 break; 275 } else if (flags & UFP_NOCACHE) { 276 UVMHIST_LOG(ubchist, "nocache",0,0,0,0); 277 return 0; 278 } 279 280 /* page is there, see if we need to wait on it */ 281 if ((pg->flags & PG_BUSY) != 0) { 282 if (flags & UFP_NOWAIT) { 283 UVMHIST_LOG(ubchist, "nowait",0,0,0,0); 284 return 0; 285 } 286 pg->flags |= PG_WANTED; 287 UVMHIST_LOG(ubchist, "wait %p (color %u)", pg, 288 VM_PGCOLOR_BUCKET(pg), 0,0); 289 UVM_UNLOCK_AND_WAIT(pg, uobj->vmobjlock, 0, 290 "uvn_fp2", 0); 291 mutex_enter(uobj->vmobjlock); 292 continue; 293 } 294 295 /* skip PG_RDONLY pages if requested */ 296 if ((flags & UFP_NORDONLY) && (pg->flags & PG_RDONLY)) { 297 UVMHIST_LOG(ubchist, "nordonly",0,0,0,0); 298 return 0; 299 } 300 301 /* stop on clean pages if requested */ 302 if (flags & UFP_DIRTYONLY) { 303 dirty = pmap_clear_modify(pg) || 304 (pg->flags & PG_CLEAN) == 0; 305 pg->flags |= PG_CLEAN; 306 if (!dirty) { 307 UVMHIST_LOG(ubchist, "dirtonly", 0,0,0,0); 308 return 0; 309 } 310 } 311 312 /* mark the page BUSY and we're done. */ 313 pg->flags |= PG_BUSY; 314 UVM_PAGE_OWN(pg, "uvn_findpage"); 315 UVMHIST_LOG(ubchist, "found %p (color %u)", 316 pg, VM_PGCOLOR_BUCKET(pg), 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 mutex_enter(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 mutex_enter(uobj->vmobjlock); 362 } 363 vp->v_size = vp->v_writesize = newsize; 364 mutex_exit(uobj->vmobjlock); 365 } 366 367 void 368 uvm_vnp_setwritesize(struct vnode *vp, voff_t newsize) 369 { 370 371 mutex_enter(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 mutex_exit(vp->v_interlock); 379 } 380 381 bool 382 uvn_text_p(struct uvm_object *uobj) 383 { 384 struct vnode *vp = (struct vnode *)uobj; 385 386 return (vp->v_iflag & VI_EXECMAP) != 0; 387 } 388 389 bool 390 uvn_clean_p(struct uvm_object *uobj) 391 { 392 struct vnode *vp = (struct vnode *)uobj; 393 394 return (vp->v_iflag & VI_ONWORKLST) == 0; 395 } 396 397 bool 398 uvn_needs_writefault_p(struct uvm_object *uobj) 399 { 400 struct vnode *vp = (struct vnode *)uobj; 401 402 return uvn_clean_p(uobj) || 403 (vp->v_iflag & (VI_WRMAP|VI_WRMAPDIRTY)) == VI_WRMAP; 404 } 405
Indexes created Mon Sep 22 05:09:51 GMT 2025