1 /* $NetBSD: uvm_page.c,v 1.79 2002/09/27 15:38:09 provos Exp $ */ 2 3 /* 4 * Copyright (c) 1997 Charles D. Cranor and Washington University. 5 * Copyright (c) 1991, 1993, The Regents of the University of California. 6 * 7 * All rights reserved. 8 * 9 * This code is derived from software contributed to Berkeley by 10 * The Mach Operating System project at Carnegie-Mellon University. 11 * 12 * Redistribution and use in source and binary forms, with or without 13 * modification, are permitted provided that the following conditions 14 * are met: 15 * 1. Redistributions of source code must retain the above copyright 16 * notice, this list of conditions and the following disclaimer. 17 * 2. Redistributions in binary form must reproduce the above copyright 18 * notice, this list of conditions and the following disclaimer in the 19 * documentation and/or other materials provided with the distribution. 20 * 3. All advertising materials mentioning features or use of this software 21 * must display the following acknowledgement: 22 * This product includes software developed by Charles D. Cranor, 23 * Washington University, the University of California, Berkeley and 24 * its contributors. 25 * 4. Neither the name of the University nor the names of its contributors 26 * may be used to endorse or promote products derived from this software 27 * without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 39 * SUCH DAMAGE. 40 * 41 * @(#)vm_page.c 8.3 (Berkeley) 3/21/94 42 * from: Id: uvm_page.c,v 1.1.2.18 1998/02/06 05:24:42 chs Exp 43 * 44 * 45 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 46 * All rights reserved. 47 * 48 * Permission to use, copy, modify and distribute this software and 49 * its documentation is hereby granted, provided that both the copyright 50 * notice and this permission notice appear in all copies of the 51 * software, derivative works or modified versions, and any portions 52 * thereof, and that both notices appear in supporting documentation. 53 * 54 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 55 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 56 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 57 * 58 * Carnegie Mellon requests users of this software to return to 59 * 60 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 61 * School of Computer Science 62 * Carnegie Mellon University 63 * Pittsburgh PA 15213-3890 64 * 65 * any improvements or extensions that they make and grant Carnegie the 66 * rights to redistribute these changes. 67 */ 68 69 /* 70 * uvm_page.c: page ops. 71 */ 72 73 #include <sys/cdefs.h> 74 __KERNEL_RCSID(0, "$NetBSD: uvm_page.c,v 1.79 2002/09/27 15:38:09 provos Exp $"); 75 76 #include "opt_uvmhist.h" 77 78 #include <sys/param.h> 79 #include <sys/systm.h> 80 #include <sys/malloc.h> 81 #include <sys/sched.h> 82 #include <sys/kernel.h> 83 #include <sys/vnode.h> 84 #include <sys/proc.h> 85 86 #define UVM_PAGE /* pull in uvm_page.h functions */ 87 #include <uvm/uvm.h> 88 89 /* 90 * global vars... XXXCDC: move to uvm. structure. 91 */ 92 93 /* 94 * physical memory config is stored in vm_physmem. 95 */ 96 97 struct vm_physseg vm_physmem[VM_PHYSSEG_MAX]; /* XXXCDC: uvm.physmem */ 98 int vm_nphysseg = 0; /* XXXCDC: uvm.nphysseg */ 99 100 /* 101 * Some supported CPUs in a given architecture don't support all 102 * of the things necessary to do idle page zero'ing efficiently. 103 * We therefore provide a way to disable it from machdep code here. 104 */ 105 /* 106 * XXX disabled until we can find a way to do this without causing 107 * problems for either cpu caches or DMA latency. 108 */ 109 boolean_t vm_page_zero_enable = FALSE; 110 111 /* 112 * local variables 113 */ 114 115 /* 116 * these variables record the values returned by vm_page_bootstrap, 117 * for debugging purposes. The implementation of uvm_pageboot_alloc 118 * and pmap_startup here also uses them internally. 119 */ 120 121 static vaddr_t virtual_space_start; 122 static vaddr_t virtual_space_end; 123 124 /* 125 * we use a hash table with only one bucket during bootup. we will 126 * later rehash (resize) the hash table once the allocator is ready. 127 * we static allocate the one bootstrap bucket below... 128 */ 129 130 static struct pglist uvm_bootbucket; 131 132 /* 133 * we allocate an initial number of page colors in uvm_page_init(), 134 * and remember them. We may re-color pages as cache sizes are 135 * discovered during the autoconfiguration phase. But we can never 136 * free the initial set of buckets, since they are allocated using 137 * uvm_pageboot_alloc(). 138 */ 139 140 static boolean_t have_recolored_pages /* = FALSE */; 141 142 /* 143 * local prototypes 144 */ 145 146 static void uvm_pageinsert __P((struct vm_page *)); 147 static void uvm_pageremove __P((struct vm_page *)); 148 149 /* 150 * inline functions 151 */ 152 153 /* 154 * uvm_pageinsert: insert a page in the object and the hash table 155 * 156 * => caller must lock object 157 * => caller must lock page queues 158 * => call should have already set pg's object and offset pointers 159 * and bumped the version counter 160 */ 161 162 __inline static void 163 uvm_pageinsert(pg) 164 struct vm_page *pg; 165 { 166 struct pglist *buck; 167 struct uvm_object *uobj = pg->uobject; 168 169 KASSERT((pg->flags & PG_TABLED) == 0); 170 buck = &uvm.page_hash[uvm_pagehash(uobj, pg->offset)]; 171 simple_lock(&uvm.hashlock); 172 TAILQ_INSERT_TAIL(buck, pg, hashq); 173 simple_unlock(&uvm.hashlock); 174 175 if (UVM_OBJ_IS_AOBJ(uobj)) { 176 uvmexp.anonpages++; 177 } 178 179 TAILQ_INSERT_TAIL(&uobj->memq, pg, listq); 180 pg->flags |= PG_TABLED; 181 uobj->uo_npages++; 182 } 183 184 /* 185 * uvm_page_remove: remove page from object and hash 186 * 187 * => caller must lock object 188 * => caller must lock page queues 189 */ 190 191 static __inline void 192 uvm_pageremove(pg) 193 struct vm_page *pg; 194 { 195 struct pglist *buck; 196 struct uvm_object *uobj = pg->uobject; 197 198 KASSERT(pg->flags & PG_TABLED); 199 buck = &uvm.page_hash[uvm_pagehash(uobj ,pg->offset)]; 200 simple_lock(&uvm.hashlock); 201 TAILQ_REMOVE(buck, pg, hashq); 202 simple_unlock(&uvm.hashlock); 203 204 if (UVM_OBJ_IS_VTEXT(uobj)) { 205 uvmexp.execpages--; 206 } else if (UVM_OBJ_IS_VNODE(uobj)) { 207 uvmexp.filepages--; 208 } else if (UVM_OBJ_IS_AOBJ(uobj)) { 209 uvmexp.anonpages--; 210 } 211 212 /* object should be locked */ 213 uobj->uo_npages--; 214 TAILQ_REMOVE(&uobj->memq, pg, listq); 215 pg->flags &= ~PG_TABLED; 216 pg->uobject = NULL; 217 } 218 219 static void 220 uvm_page_init_buckets(struct pgfreelist *pgfl) 221 { 222 int color, i; 223 224 for (color = 0; color < uvmexp.ncolors; color++) { 225 for (i = 0; i < PGFL_NQUEUES; i++) { 226 TAILQ_INIT(&pgfl->pgfl_buckets[ 227 color].pgfl_queues[i]); 228 } 229 } 230 } 231 232 /* 233 * uvm_page_init: init the page system. called from uvm_init(). 234 * 235 * => we return the range of kernel virtual memory in kvm_startp/kvm_endp 236 */ 237 238 void 239 uvm_page_init(kvm_startp, kvm_endp) 240 vaddr_t *kvm_startp, *kvm_endp; 241 { 242 vsize_t freepages, pagecount, bucketcount, n; 243 struct pgflbucket *bucketarray; 244 struct vm_page *pagearray; 245 int lcv, i; 246 paddr_t paddr; 247 248 /* 249 * init the page queues and page queue locks, except the free 250 * list; we allocate that later (with the initial vm_page 251 * structures). 252 */ 253 254 TAILQ_INIT(&uvm.page_active); 255 TAILQ_INIT(&uvm.page_inactive); 256 simple_lock_init(&uvm.pageqlock); 257 simple_lock_init(&uvm.fpageqlock); 258 259 /* 260 * init the <obj,offset> => <page> hash table. for now 261 * we just have one bucket (the bootstrap bucket). later on we 262 * will allocate new buckets as we dynamically resize the hash table. 263 */ 264 265 uvm.page_nhash = 1; /* 1 bucket */ 266 uvm.page_hashmask = 0; /* mask for hash function */ 267 uvm.page_hash = &uvm_bootbucket; /* install bootstrap bucket */ 268 TAILQ_INIT(uvm.page_hash); /* init hash table */ 269 simple_lock_init(&uvm.hashlock); /* init hash table lock */ 270 271 /* 272 * allocate vm_page structures. 273 */ 274 275 /* 276 * sanity check: 277 * before calling this function the MD code is expected to register 278 * some free RAM with the uvm_page_physload() function. our job 279 * now is to allocate vm_page structures for this memory. 280 */ 281 282 if (vm_nphysseg == 0) 283 panic("uvm_page_bootstrap: no memory pre-allocated"); 284 285 /* 286 * first calculate the number of free pages... 287 * 288 * note that we use start/end rather than avail_start/avail_end. 289 * this allows us to allocate extra vm_page structures in case we 290 * want to return some memory to the pool after booting. 291 */ 292 293 freepages = 0; 294 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 295 freepages += (vm_physmem[lcv].end - vm_physmem[lcv].start); 296 297 /* 298 * Let MD code initialize the number of colors, or default 299 * to 1 color if MD code doesn't care. 300 */ 301 if (uvmexp.ncolors == 0) 302 uvmexp.ncolors = 1; 303 uvmexp.colormask = uvmexp.ncolors - 1; 304 305 /* 306 * we now know we have (PAGE_SIZE * freepages) bytes of memory we can 307 * use. for each page of memory we use we need a vm_page structure. 308 * thus, the total number of pages we can use is the total size of 309 * the memory divided by the PAGE_SIZE plus the size of the vm_page 310 * structure. we add one to freepages as a fudge factor to avoid 311 * truncation errors (since we can only allocate in terms of whole 312 * pages). 313 */ 314 315 bucketcount = uvmexp.ncolors * VM_NFREELIST; 316 pagecount = ((freepages + 1) << PAGE_SHIFT) / 317 (PAGE_SIZE + sizeof(struct vm_page)); 318 319 bucketarray = (void *)uvm_pageboot_alloc((bucketcount * 320 sizeof(struct pgflbucket)) + (pagecount * 321 sizeof(struct vm_page))); 322 pagearray = (struct vm_page *)(bucketarray + bucketcount); 323 324 for (lcv = 0; lcv < VM_NFREELIST; lcv++) { 325 uvm.page_free[lcv].pgfl_buckets = 326 (bucketarray + (lcv * uvmexp.ncolors)); 327 uvm_page_init_buckets(&uvm.page_free[lcv]); 328 } 329 memset(pagearray, 0, pagecount * sizeof(struct vm_page)); 330 331 /* 332 * init the vm_page structures and put them in the correct place. 333 */ 334 335 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) { 336 n = vm_physmem[lcv].end - vm_physmem[lcv].start; 337 338 /* set up page array pointers */ 339 vm_physmem[lcv].pgs = pagearray; 340 pagearray += n; 341 pagecount -= n; 342 vm_physmem[lcv].lastpg = vm_physmem[lcv].pgs + (n - 1); 343 344 /* init and free vm_pages (we've already zeroed them) */ 345 paddr = ptoa(vm_physmem[lcv].start); 346 for (i = 0 ; i < n ; i++, paddr += PAGE_SIZE) { 347 vm_physmem[lcv].pgs[i].phys_addr = paddr; 348 #ifdef __HAVE_VM_PAGE_MD 349 VM_MDPAGE_INIT(&vm_physmem[lcv].pgs[i]); 350 #endif 351 if (atop(paddr) >= vm_physmem[lcv].avail_start && 352 atop(paddr) <= vm_physmem[lcv].avail_end) { 353 uvmexp.npages++; 354 /* add page to free pool */ 355 uvm_pagefree(&vm_physmem[lcv].pgs[i]); 356 } 357 } 358 } 359 360 /* 361 * pass up the values of virtual_space_start and 362 * virtual_space_end (obtained by uvm_pageboot_alloc) to the upper 363 * layers of the VM. 364 */ 365 366 *kvm_startp = round_page(virtual_space_start); 367 *kvm_endp = trunc_page(virtual_space_end); 368 369 /* 370 * init locks for kernel threads 371 */ 372 373 simple_lock_init(&uvm.pagedaemon_lock); 374 simple_lock_init(&uvm.aiodoned_lock); 375 376 /* 377 * init various thresholds. 378 */ 379 380 uvmexp.reserve_pagedaemon = 1; 381 uvmexp.reserve_kernel = 5; 382 uvmexp.anonminpct = 10; 383 uvmexp.fileminpct = 10; 384 uvmexp.execminpct = 5; 385 uvmexp.anonmaxpct = 80; 386 uvmexp.filemaxpct = 50; 387 uvmexp.execmaxpct = 30; 388 uvmexp.anonmin = uvmexp.anonminpct * 256 / 100; 389 uvmexp.filemin = uvmexp.fileminpct * 256 / 100; 390 uvmexp.execmin = uvmexp.execminpct * 256 / 100; 391 uvmexp.anonmax = uvmexp.anonmaxpct * 256 / 100; 392 uvmexp.filemax = uvmexp.filemaxpct * 256 / 100; 393 uvmexp.execmax = uvmexp.execmaxpct * 256 / 100; 394 395 /* 396 * determine if we should zero pages in the idle loop. 397 */ 398 399 uvm.page_idle_zero = vm_page_zero_enable; 400 401 /* 402 * done! 403 */ 404 405 uvm.page_init_done = TRUE; 406 } 407 408 /* 409 * uvm_setpagesize: set the page size 410 * 411 * => sets page_shift and page_mask from uvmexp.pagesize. 412 */ 413 414 void 415 uvm_setpagesize() 416 { 417 if (uvmexp.pagesize == 0) 418 uvmexp.pagesize = DEFAULT_PAGE_SIZE; 419 uvmexp.pagemask = uvmexp.pagesize - 1; 420 if ((uvmexp.pagemask & uvmexp.pagesize) != 0) 421 panic("uvm_setpagesize: page size not a power of two"); 422 for (uvmexp.pageshift = 0; ; uvmexp.pageshift++) 423 if ((1 << uvmexp.pageshift) == uvmexp.pagesize) 424 break; 425 } 426 427 /* 428 * uvm_pageboot_alloc: steal memory from physmem for bootstrapping 429 */ 430 431 vaddr_t 432 uvm_pageboot_alloc(size) 433 vsize_t size; 434 { 435 static boolean_t initialized = FALSE; 436 vaddr_t addr; 437 #if !defined(PMAP_STEAL_MEMORY) 438 vaddr_t vaddr; 439 paddr_t paddr; 440 #endif 441 442 /* 443 * on first call to this function, initialize ourselves. 444 */ 445 if (initialized == FALSE) { 446 pmap_virtual_space(&virtual_space_start, &virtual_space_end); 447 448 /* round it the way we like it */ 449 virtual_space_start = round_page(virtual_space_start); 450 virtual_space_end = trunc_page(virtual_space_end); 451 452 initialized = TRUE; 453 } 454 455 /* round to page size */ 456 size = round_page(size); 457 458 #if defined(PMAP_STEAL_MEMORY) 459 460 /* 461 * defer bootstrap allocation to MD code (it may want to allocate 462 * from a direct-mapped segment). pmap_steal_memory should adjust 463 * virtual_space_start/virtual_space_end if necessary. 464 */ 465 466 addr = pmap_steal_memory(size, &virtual_space_start, 467 &virtual_space_end); 468 469 return(addr); 470 471 #else /* !PMAP_STEAL_MEMORY */ 472 473 /* 474 * allocate virtual memory for this request 475 */ 476 if (virtual_space_start == virtual_space_end || 477 (virtual_space_end - virtual_space_start) < size) 478 panic("uvm_pageboot_alloc: out of virtual space"); 479 480 addr = virtual_space_start; 481 482 #ifdef PMAP_GROWKERNEL 483 /* 484 * If the kernel pmap can't map the requested space, 485 * then allocate more resources for it. 486 */ 487 if (uvm_maxkaddr < (addr + size)) { 488 uvm_maxkaddr = pmap_growkernel(addr + size); 489 if (uvm_maxkaddr < (addr + size)) 490 panic("uvm_pageboot_alloc: pmap_growkernel() failed"); 491 } 492 #endif 493 494 virtual_space_start += size; 495 496 /* 497 * allocate and mapin physical pages to back new virtual pages 498 */ 499 500 for (vaddr = round_page(addr) ; vaddr < addr + size ; 501 vaddr += PAGE_SIZE) { 502 503 if (!uvm_page_physget(&paddr)) 504 panic("uvm_pageboot_alloc: out of memory"); 505 506 /* 507 * Note this memory is no longer managed, so using 508 * pmap_kenter is safe. 509 */ 510 pmap_kenter_pa(vaddr, paddr, VM_PROT_READ|VM_PROT_WRITE); 511 } 512 pmap_update(pmap_kernel()); 513 return(addr); 514 #endif /* PMAP_STEAL_MEMORY */ 515 } 516 517 #if !defined(PMAP_STEAL_MEMORY) 518 /* 519 * uvm_page_physget: "steal" one page from the vm_physmem structure. 520 * 521 * => attempt to allocate it off the end of a segment in which the "avail" 522 * values match the start/end values. if we can't do that, then we 523 * will advance both values (making them equal, and removing some 524 * vm_page structures from the non-avail area). 525 * => return false if out of memory. 526 */ 527 528 /* subroutine: try to allocate from memory chunks on the specified freelist */ 529 static boolean_t uvm_page_physget_freelist __P((paddr_t *, int)); 530 531 static boolean_t 532 uvm_page_physget_freelist(paddrp, freelist) 533 paddr_t *paddrp; 534 int freelist; 535 { 536 int lcv, x; 537 538 /* pass 1: try allocating from a matching end */ 539 #if (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST) 540 for (lcv = vm_nphysseg - 1 ; lcv >= 0 ; lcv--) 541 #else 542 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 543 #endif 544 { 545 546 if (uvm.page_init_done == TRUE) 547 panic("uvm_page_physget: called _after_ bootstrap"); 548 549 if (vm_physmem[lcv].free_list != freelist) 550 continue; 551 552 /* try from front */ 553 if (vm_physmem[lcv].avail_start == vm_physmem[lcv].start && 554 vm_physmem[lcv].avail_start < vm_physmem[lcv].avail_end) { 555 *paddrp = ptoa(vm_physmem[lcv].avail_start); 556 vm_physmem[lcv].avail_start++; 557 vm_physmem[lcv].start++; 558 /* nothing left? nuke it */ 559 if (vm_physmem[lcv].avail_start == 560 vm_physmem[lcv].end) { 561 if (vm_nphysseg == 1) 562 panic("vum_page_physget: out of memory!"); 563 vm_nphysseg--; 564 for (x = lcv ; x < vm_nphysseg ; x++) 565 /* structure copy */ 566 vm_physmem[x] = vm_physmem[x+1]; 567 } 568 return (TRUE); 569 } 570 571 /* try from rear */ 572 if (vm_physmem[lcv].avail_end == vm_physmem[lcv].end && 573 vm_physmem[lcv].avail_start < vm_physmem[lcv].avail_end) { 574 *paddrp = ptoa(vm_physmem[lcv].avail_end - 1); 575 vm_physmem[lcv].avail_end--; 576 vm_physmem[lcv].end--; 577 /* nothing left? nuke it */ 578 if (vm_physmem[lcv].avail_end == 579 vm_physmem[lcv].start) { 580 if (vm_nphysseg == 1) 581 panic("uvm_page_physget: out of memory!"); 582 vm_nphysseg--; 583 for (x = lcv ; x < vm_nphysseg ; x++) 584 /* structure copy */ 585 vm_physmem[x] = vm_physmem[x+1]; 586 } 587 return (TRUE); 588 } 589 } 590 591 /* pass2: forget about matching ends, just allocate something */ 592 #if (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST) 593 for (lcv = vm_nphysseg - 1 ; lcv >= 0 ; lcv--) 594 #else 595 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 596 #endif 597 { 598 599 /* any room in this bank? */ 600 if (vm_physmem[lcv].avail_start >= vm_physmem[lcv].avail_end) 601 continue; /* nope */ 602 603 *paddrp = ptoa(vm_physmem[lcv].avail_start); 604 vm_physmem[lcv].avail_start++; 605 /* truncate! */ 606 vm_physmem[lcv].start = vm_physmem[lcv].avail_start; 607 608 /* nothing left? nuke it */ 609 if (vm_physmem[lcv].avail_start == vm_physmem[lcv].end) { 610 if (vm_nphysseg == 1) 611 panic("uvm_page_physget: out of memory!"); 612 vm_nphysseg--; 613 for (x = lcv ; x < vm_nphysseg ; x++) 614 /* structure copy */ 615 vm_physmem[x] = vm_physmem[x+1]; 616 } 617 return (TRUE); 618 } 619 620 return (FALSE); /* whoops! */ 621 } 622 623 boolean_t 624 uvm_page_physget(paddrp) 625 paddr_t *paddrp; 626 { 627 int i; 628 629 /* try in the order of freelist preference */ 630 for (i = 0; i < VM_NFREELIST; i++) 631 if (uvm_page_physget_freelist(paddrp, i) == TRUE) 632 return (TRUE); 633 return (FALSE); 634 } 635 #endif /* PMAP_STEAL_MEMORY */ 636 637 /* 638 * uvm_page_physload: load physical memory into VM system 639 * 640 * => all args are PFs 641 * => all pages in start/end get vm_page structures 642 * => areas marked by avail_start/avail_end get added to the free page pool 643 * => we are limited to VM_PHYSSEG_MAX physical memory segments 644 */ 645 646 void 647 uvm_page_physload(start, end, avail_start, avail_end, free_list) 648 paddr_t start, end, avail_start, avail_end; 649 int free_list; 650 { 651 int preload, lcv; 652 psize_t npages; 653 struct vm_page *pgs; 654 struct vm_physseg *ps; 655 656 if (uvmexp.pagesize == 0) 657 panic("uvm_page_physload: page size not set!"); 658 if (free_list >= VM_NFREELIST || free_list < VM_FREELIST_DEFAULT) 659 panic("uvm_page_physload: bad free list %d", free_list); 660 if (start >= end) 661 panic("uvm_page_physload: start >= end"); 662 663 /* 664 * do we have room? 665 */ 666 667 if (vm_nphysseg == VM_PHYSSEG_MAX) { 668 printf("uvm_page_physload: unable to load physical memory " 669 "segment\n"); 670 printf("\t%d segments allocated, ignoring 0x%llx -> 0x%llx\n", 671 VM_PHYSSEG_MAX, (long long)start, (long long)end); 672 printf("\tincrease VM_PHYSSEG_MAX\n"); 673 return; 674 } 675 676 /* 677 * check to see if this is a "preload" (i.e. uvm_mem_init hasn't been 678 * called yet, so malloc is not available). 679 */ 680 681 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) { 682 if (vm_physmem[lcv].pgs) 683 break; 684 } 685 preload = (lcv == vm_nphysseg); 686 687 /* 688 * if VM is already running, attempt to malloc() vm_page structures 689 */ 690 691 if (!preload) { 692 #if defined(VM_PHYSSEG_NOADD) 693 panic("uvm_page_physload: tried to add RAM after vm_mem_init"); 694 #else 695 /* XXXCDC: need some sort of lockout for this case */ 696 paddr_t paddr; 697 npages = end - start; /* # of pages */ 698 pgs = malloc(sizeof(struct vm_page) * npages, 699 M_VMPAGE, M_NOWAIT); 700 if (pgs == NULL) { 701 printf("uvm_page_physload: can not malloc vm_page " 702 "structs for segment\n"); 703 printf("\tignoring 0x%lx -> 0x%lx\n", start, end); 704 return; 705 } 706 /* zero data, init phys_addr and free_list, and free pages */ 707 memset(pgs, 0, sizeof(struct vm_page) * npages); 708 for (lcv = 0, paddr = ptoa(start) ; 709 lcv < npages ; lcv++, paddr += PAGE_SIZE) { 710 pgs[lcv].phys_addr = paddr; 711 pgs[lcv].free_list = free_list; 712 if (atop(paddr) >= avail_start && 713 atop(paddr) <= avail_end) 714 uvm_pagefree(&pgs[lcv]); 715 } 716 /* XXXCDC: incomplete: need to update uvmexp.free, what else? */ 717 /* XXXCDC: need hook to tell pmap to rebuild pv_list, etc... */ 718 #endif 719 } else { 720 pgs = NULL; 721 npages = 0; 722 } 723 724 /* 725 * now insert us in the proper place in vm_physmem[] 726 */ 727 728 #if (VM_PHYSSEG_STRAT == VM_PSTRAT_RANDOM) 729 /* random: put it at the end (easy!) */ 730 ps = &vm_physmem[vm_nphysseg]; 731 #elif (VM_PHYSSEG_STRAT == VM_PSTRAT_BSEARCH) 732 { 733 int x; 734 /* sort by address for binary search */ 735 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 736 if (start < vm_physmem[lcv].start) 737 break; 738 ps = &vm_physmem[lcv]; 739 /* move back other entries, if necessary ... */ 740 for (x = vm_nphysseg ; x > lcv ; x--) 741 /* structure copy */ 742 vm_physmem[x] = vm_physmem[x - 1]; 743 } 744 #elif (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST) 745 { 746 int x; 747 /* sort by largest segment first */ 748 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 749 if ((end - start) > 750 (vm_physmem[lcv].end - vm_physmem[lcv].start)) 751 break; 752 ps = &vm_physmem[lcv]; 753 /* move back other entries, if necessary ... */ 754 for (x = vm_nphysseg ; x > lcv ; x--) 755 /* structure copy */ 756 vm_physmem[x] = vm_physmem[x - 1]; 757 } 758 #else 759 panic("uvm_page_physload: unknown physseg strategy selected!"); 760 #endif 761 762 ps->start = start; 763 ps->end = end; 764 ps->avail_start = avail_start; 765 ps->avail_end = avail_end; 766 if (preload) { 767 ps->pgs = NULL; 768 } else { 769 ps->pgs = pgs; 770 ps->lastpg = pgs + npages - 1; 771 } 772 ps->free_list = free_list; 773 vm_nphysseg++; 774 775 if (!preload) 776 uvm_page_rehash(); 777 } 778 779 /* 780 * uvm_page_rehash: reallocate hash table based on number of free pages. 781 */ 782 783 void 784 uvm_page_rehash() 785 { 786 int freepages, lcv, bucketcount, oldcount; 787 struct pglist *newbuckets, *oldbuckets; 788 struct vm_page *pg; 789 size_t newsize, oldsize; 790 791 /* 792 * compute number of pages that can go in the free pool 793 */ 794 795 freepages = 0; 796 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 797 freepages += 798 (vm_physmem[lcv].avail_end - vm_physmem[lcv].avail_start); 799 800 /* 801 * compute number of buckets needed for this number of pages 802 */ 803 804 bucketcount = 1; 805 while (bucketcount < freepages) 806 bucketcount = bucketcount * 2; 807 808 /* 809 * compute the size of the current table and new table. 810 */ 811 812 oldbuckets = uvm.page_hash; 813 oldcount = uvm.page_nhash; 814 oldsize = round_page(sizeof(struct pglist) * oldcount); 815 newsize = round_page(sizeof(struct pglist) * bucketcount); 816 817 /* 818 * allocate the new buckets 819 */ 820 821 newbuckets = (struct pglist *) uvm_km_alloc(kernel_map, newsize); 822 if (newbuckets == NULL) { 823 printf("uvm_page_physrehash: WARNING: could not grow page " 824 "hash table\n"); 825 return; 826 } 827 for (lcv = 0 ; lcv < bucketcount ; lcv++) 828 TAILQ_INIT(&newbuckets[lcv]); 829 830 /* 831 * now replace the old buckets with the new ones and rehash everything 832 */ 833 834 simple_lock(&uvm.hashlock); 835 uvm.page_hash = newbuckets; 836 uvm.page_nhash = bucketcount; 837 uvm.page_hashmask = bucketcount - 1; /* power of 2 */ 838 839 /* ... and rehash */ 840 for (lcv = 0 ; lcv < oldcount ; lcv++) { 841 while ((pg = oldbuckets[lcv].tqh_first) != NULL) { 842 TAILQ_REMOVE(&oldbuckets[lcv], pg, hashq); 843 TAILQ_INSERT_TAIL( 844 &uvm.page_hash[uvm_pagehash(pg->uobject, pg->offset)], 845 pg, hashq); 846 } 847 } 848 simple_unlock(&uvm.hashlock); 849 850 /* 851 * free old bucket array if is not the boot-time table 852 */ 853 854 if (oldbuckets != &uvm_bootbucket) 855 uvm_km_free(kernel_map, (vaddr_t) oldbuckets, oldsize); 856 } 857 858 /* 859 * uvm_page_recolor: Recolor the pages if the new bucket count is 860 * larger than the old one. 861 */ 862 863 void 864 uvm_page_recolor(int newncolors) 865 { 866 struct pgflbucket *bucketarray, *oldbucketarray; 867 struct pgfreelist pgfl; 868 struct vm_page *pg; 869 vsize_t bucketcount; 870 int s, lcv, color, i, ocolors; 871 872 if (newncolors <= uvmexp.ncolors) 873 return; 874 875 if (uvm.page_init_done == FALSE) { 876 uvmexp.ncolors = newncolors; 877 return; 878 } 879 880 bucketcount = newncolors * VM_NFREELIST; 881 bucketarray = malloc(bucketcount * sizeof(struct pgflbucket), 882 M_VMPAGE, M_NOWAIT); 883 if (bucketarray == NULL) { 884 printf("WARNING: unable to allocate %ld page color buckets\n", 885 (long) bucketcount); 886 return; 887 } 888 889 s = uvm_lock_fpageq(); 890 891 /* Make sure we should still do this. */ 892 if (newncolors <= uvmexp.ncolors) { 893 uvm_unlock_fpageq(s); 894 free(bucketarray, M_VMPAGE); 895 return; 896 } 897 898 oldbucketarray = uvm.page_free[0].pgfl_buckets; 899 ocolors = uvmexp.ncolors; 900 901 uvmexp.ncolors = newncolors; 902 uvmexp.colormask = uvmexp.ncolors - 1; 903 904 for (lcv = 0; lcv < VM_NFREELIST; lcv++) { 905 pgfl.pgfl_buckets = (bucketarray + (lcv * newncolors)); 906 uvm_page_init_buckets(&pgfl); 907 for (color = 0; color < ocolors; color++) { 908 for (i = 0; i < PGFL_NQUEUES; i++) { 909 while ((pg = TAILQ_FIRST(&uvm.page_free[ 910 lcv].pgfl_buckets[color].pgfl_queues[i])) 911 != NULL) { 912 TAILQ_REMOVE(&uvm.page_free[ 913 lcv].pgfl_buckets[ 914 color].pgfl_queues[i], pg, pageq); 915 TAILQ_INSERT_TAIL(&pgfl.pgfl_buckets[ 916 VM_PGCOLOR_BUCKET(pg)].pgfl_queues[ 917 i], pg, pageq); 918 } 919 } 920 } 921 uvm.page_free[lcv].pgfl_buckets = pgfl.pgfl_buckets; 922 } 923 924 if (have_recolored_pages) { 925 uvm_unlock_fpageq(s); 926 free(oldbucketarray, M_VMPAGE); 927 return; 928 } 929 930 have_recolored_pages = TRUE; 931 uvm_unlock_fpageq(s); 932 } 933 934 /* 935 * uvm_pagealloc_pgfl: helper routine for uvm_pagealloc_strat 936 */ 937 938 static __inline struct vm_page * 939 uvm_pagealloc_pgfl(struct pgfreelist *pgfl, int try1, int try2, 940 int *trycolorp) 941 { 942 struct pglist *freeq; 943 struct vm_page *pg; 944 int color, trycolor = *trycolorp; 945 946 color = trycolor; 947 do { 948 if ((pg = TAILQ_FIRST((freeq = 949 &pgfl->pgfl_buckets[color].pgfl_queues[try1]))) != NULL) 950 goto gotit; 951 if ((pg = TAILQ_FIRST((freeq = 952 &pgfl->pgfl_buckets[color].pgfl_queues[try2]))) != NULL) 953 goto gotit; 954 color = (color + 1) & uvmexp.colormask; 955 } while (color != trycolor); 956 957 return (NULL); 958 959 gotit: 960 TAILQ_REMOVE(freeq, pg, pageq); 961 uvmexp.free--; 962 963 /* update zero'd page count */ 964 if (pg->flags & PG_ZERO) 965 uvmexp.zeropages--; 966 967 if (color == trycolor) 968 uvmexp.colorhit++; 969 else { 970 uvmexp.colormiss++; 971 *trycolorp = color; 972 } 973 974 return (pg); 975 } 976 977 /* 978 * uvm_pagealloc_strat: allocate vm_page from a particular free list. 979 * 980 * => return null if no pages free 981 * => wake up pagedaemon if number of free pages drops below low water mark 982 * => if obj != NULL, obj must be locked (to put in hash) 983 * => if anon != NULL, anon must be locked (to put in anon) 984 * => only one of obj or anon can be non-null 985 * => caller must activate/deactivate page if it is not wired. 986 * => free_list is ignored if strat == UVM_PGA_STRAT_NORMAL. 987 * => policy decision: it is more important to pull a page off of the 988 * appropriate priority free list than it is to get a zero'd or 989 * unknown contents page. This is because we live with the 990 * consequences of a bad free list decision for the entire 991 * lifetime of the page, e.g. if the page comes from memory that 992 * is slower to access. 993 */ 994 995 struct vm_page * 996 uvm_pagealloc_strat(obj, off, anon, flags, strat, free_list) 997 struct uvm_object *obj; 998 voff_t off; 999 int flags; 1000 struct vm_anon *anon; 1001 int strat, free_list; 1002 { 1003 int lcv, try1, try2, s, zeroit = 0, color; 1004 struct vm_page *pg; 1005 boolean_t use_reserve; 1006 1007 KASSERT(obj == NULL || anon == NULL); 1008 KASSERT(off == trunc_page(off)); 1009 LOCK_ASSERT(obj == NULL || simple_lock_held(&obj->vmobjlock)); 1010 LOCK_ASSERT(anon == NULL || simple_lock_held(&anon->an_lock)); 1011 1012 s = uvm_lock_fpageq(); 1013 1014 /* 1015 * This implements a global round-robin page coloring 1016 * algorithm. 1017 * 1018 * XXXJRT: Should we make the `nextcolor' per-cpu? 1019 * XXXJRT: What about virtually-indexed caches? 1020 */ 1021 1022 color = uvm.page_free_nextcolor; 1023 1024 /* 1025 * check to see if we need to generate some free pages waking 1026 * the pagedaemon. 1027 */ 1028 1029 UVM_KICK_PDAEMON(); 1030 1031 /* 1032 * fail if any of these conditions is true: 1033 * [1] there really are no free pages, or 1034 * [2] only kernel "reserved" pages remain and 1035 * the page isn't being allocated to a kernel object. 1036 * [3] only pagedaemon "reserved" pages remain and 1037 * the requestor isn't the pagedaemon. 1038 */ 1039 1040 use_reserve = (flags & UVM_PGA_USERESERVE) || 1041 (obj && UVM_OBJ_IS_KERN_OBJECT(obj)); 1042 if ((uvmexp.free <= uvmexp.reserve_kernel && !use_reserve) || 1043 (uvmexp.free <= uvmexp.reserve_pagedaemon && 1044 !(use_reserve && curproc == uvm.pagedaemon_proc))) 1045 goto fail; 1046 1047 #if PGFL_NQUEUES != 2 1048 #error uvm_pagealloc_strat needs to be updated 1049 #endif 1050 1051 /* 1052 * If we want a zero'd page, try the ZEROS queue first, otherwise 1053 * we try the UNKNOWN queue first. 1054 */ 1055 if (flags & UVM_PGA_ZERO) { 1056 try1 = PGFL_ZEROS; 1057 try2 = PGFL_UNKNOWN; 1058 } else { 1059 try1 = PGFL_UNKNOWN; 1060 try2 = PGFL_ZEROS; 1061 } 1062 1063 again: 1064 switch (strat) { 1065 case UVM_PGA_STRAT_NORMAL: 1066 /* Check all freelists in descending priority order. */ 1067 for (lcv = 0; lcv < VM_NFREELIST; lcv++) { 1068 pg = uvm_pagealloc_pgfl(&uvm.page_free[lcv], 1069 try1, try2, &color); 1070 if (pg != NULL) 1071 goto gotit; 1072 } 1073 1074 /* No pages free! */ 1075 goto fail; 1076 1077 case UVM_PGA_STRAT_ONLY: 1078 case UVM_PGA_STRAT_FALLBACK: 1079 /* Attempt to allocate from the specified free list. */ 1080 KASSERT(free_list >= 0 && free_list < VM_NFREELIST); 1081 pg = uvm_pagealloc_pgfl(&uvm.page_free[free_list], 1082 try1, try2, &color); 1083 if (pg != NULL) 1084 goto gotit; 1085 1086 /* Fall back, if possible. */ 1087 if (strat == UVM_PGA_STRAT_FALLBACK) { 1088 strat = UVM_PGA_STRAT_NORMAL; 1089 goto again; 1090 } 1091 1092 /* No pages free! */ 1093 goto fail; 1094 1095 default: 1096 panic("uvm_pagealloc_strat: bad strat %d", strat); 1097 /* NOTREACHED */ 1098 } 1099 1100 gotit: 1101 /* 1102 * We now know which color we actually allocated from; set 1103 * the next color accordingly. 1104 */ 1105 1106 uvm.page_free_nextcolor = (color + 1) & uvmexp.colormask; 1107 1108 /* 1109 * update allocation statistics and remember if we have to 1110 * zero the page 1111 */ 1112 1113 if (flags & UVM_PGA_ZERO) { 1114 if (pg->flags & PG_ZERO) { 1115 uvmexp.pga_zerohit++; 1116 zeroit = 0; 1117 } else { 1118 uvmexp.pga_zeromiss++; 1119 zeroit = 1; 1120 } 1121 } 1122 uvm_unlock_fpageq(s); 1123 1124 pg->offset = off; 1125 pg->uobject = obj; 1126 pg->uanon = anon; 1127 pg->flags = PG_BUSY|PG_CLEAN|PG_FAKE; 1128 if (anon) { 1129 anon->u.an_page = pg; 1130 pg->pqflags = PQ_ANON; 1131 uvmexp.anonpages++; 1132 } else { 1133 if (obj) { 1134 uvm_pageinsert(pg); 1135 } 1136 pg->pqflags = 0; 1137 } 1138 #if defined(UVM_PAGE_TRKOWN) 1139 pg->owner_tag = NULL; 1140 #endif 1141 UVM_PAGE_OWN(pg, "new alloc"); 1142 1143 if (flags & UVM_PGA_ZERO) { 1144 /* 1145 * A zero'd page is not clean. If we got a page not already 1146 * zero'd, then we have to zero it ourselves. 1147 */ 1148 pg->flags &= ~PG_CLEAN; 1149 if (zeroit) 1150 pmap_zero_page(VM_PAGE_TO_PHYS(pg)); 1151 } 1152 1153 return(pg); 1154 1155 fail: 1156 uvm_unlock_fpageq(s); 1157 return (NULL); 1158 } 1159 1160 /* 1161 * uvm_pagerealloc: reallocate a page from one object to another 1162 * 1163 * => both objects must be locked 1164 */ 1165 1166 void 1167 uvm_pagerealloc(pg, newobj, newoff) 1168 struct vm_page *pg; 1169 struct uvm_object *newobj; 1170 voff_t newoff; 1171 { 1172 /* 1173 * remove it from the old object 1174 */ 1175 1176 if (pg->uobject) { 1177 uvm_pageremove(pg); 1178 } 1179 1180 /* 1181 * put it in the new object 1182 */ 1183 1184 if (newobj) { 1185 pg->uobject = newobj; 1186 pg->offset = newoff; 1187 uvm_pageinsert(pg); 1188 } 1189 } 1190 1191 /* 1192 * uvm_pagefree: free page 1193 * 1194 * => erase page's identity (i.e. remove from hash/object) 1195 * => put page on free list 1196 * => caller must lock owning object (either anon or uvm_object) 1197 * => caller must lock page queues 1198 * => assumes all valid mappings of pg are gone 1199 */ 1200 1201 void 1202 uvm_pagefree(pg) 1203 struct vm_page *pg; 1204 { 1205 int s; 1206 1207 KASSERT((pg->flags & PG_PAGEOUT) == 0); 1208 LOCK_ASSERT(simple_lock_held(&uvm.pageqlock) || 1209 (pg->pqflags & (PQ_ACTIVE|PQ_INACTIVE)) == 0); 1210 LOCK_ASSERT(pg->uobject == NULL || 1211 simple_lock_held(&pg->uobject->vmobjlock)); 1212 LOCK_ASSERT(pg->uobject != NULL || pg->uanon == NULL || 1213 simple_lock_held(&pg->uanon->an_lock)); 1214 1215 #ifdef DEBUG 1216 if (pg->uobject == (void *)0xdeadbeef && 1217 pg->uanon == (void *)0xdeadbeef) { 1218 panic("uvm_pagefree: freeing free page %p", pg); 1219 } 1220 #endif 1221 1222 /* 1223 * if the page is loaned, resolve the loan instead of freeing. 1224 */ 1225 1226 if (pg->loan_count) { 1227 KASSERT(pg->wire_count == 0); 1228 1229 /* 1230 * if the page is owned by an anon then we just want to 1231 * drop anon ownership. the kernel will free the page when 1232 * it is done with it. if the page is owned by an object, 1233 * remove it from the object and mark it dirty for the benefit 1234 * of possible anon owners. 1235 * 1236 * regardless of previous ownership, wakeup any waiters, 1237 * unbusy the page, and we're done. 1238 */ 1239 1240 if (pg->uobject != NULL) { 1241 uvm_pageremove(pg); 1242 pg->flags &= ~PG_CLEAN; 1243 } else if (pg->uanon != NULL) { 1244 if ((pg->pqflags & PQ_ANON) == 0) { 1245 pg->loan_count--; 1246 } else { 1247 pg->pqflags &= ~PQ_ANON; 1248 } 1249 pg->uanon = NULL; 1250 } 1251 if (pg->flags & PG_WANTED) { 1252 wakeup(pg); 1253 } 1254 pg->flags &= ~(PG_WANTED|PG_BUSY|PG_RELEASED); 1255 #ifdef UVM_PAGE_TRKOWN 1256 pg->owner_tag = NULL; 1257 #endif 1258 if (pg->loan_count) { 1259 uvm_pagedequeue(pg); 1260 return; 1261 } 1262 } 1263 1264 /* 1265 * remove page from its object or anon. 1266 */ 1267 1268 if (pg->uobject != NULL) { 1269 uvm_pageremove(pg); 1270 } else if (pg->uanon != NULL) { 1271 pg->uanon->u.an_page = NULL; 1272 uvmexp.anonpages--; 1273 } 1274 1275 /* 1276 * now remove the page from the queues. 1277 */ 1278 1279 uvm_pagedequeue(pg); 1280 1281 /* 1282 * if the page was wired, unwire it now. 1283 */ 1284 1285 if (pg->wire_count) { 1286 pg->wire_count = 0; 1287 uvmexp.wired--; 1288 } 1289 1290 /* 1291 * and put on free queue 1292 */ 1293 1294 pg->flags &= ~PG_ZERO; 1295 1296 s = uvm_lock_fpageq(); 1297 TAILQ_INSERT_TAIL(&uvm.page_free[ 1298 uvm_page_lookup_freelist(pg)].pgfl_buckets[ 1299 VM_PGCOLOR_BUCKET(pg)].pgfl_queues[PGFL_UNKNOWN], pg, pageq); 1300 pg->pqflags = PQ_FREE; 1301 #ifdef DEBUG 1302 pg->uobject = (void *)0xdeadbeef; 1303 pg->offset = 0xdeadbeef; 1304 pg->uanon = (void *)0xdeadbeef; 1305 #endif 1306 uvmexp.free++; 1307 1308 if (uvmexp.zeropages < UVM_PAGEZERO_TARGET) 1309 uvm.page_idle_zero = vm_page_zero_enable; 1310 1311 uvm_unlock_fpageq(s); 1312 } 1313 1314 /* 1315 * uvm_page_unbusy: unbusy an array of pages. 1316 * 1317 * => pages must either all belong to the same object, or all belong to anons. 1318 * => if pages are object-owned, object must be locked. 1319 * => if pages are anon-owned, anons must be locked. 1320 * => caller must lock page queues if pages may be released. 1321 */ 1322 1323 void 1324 uvm_page_unbusy(pgs, npgs) 1325 struct vm_page **pgs; 1326 int npgs; 1327 { 1328 struct vm_page *pg; 1329 int i; 1330 UVMHIST_FUNC("uvm_page_unbusy"); UVMHIST_CALLED(ubchist); 1331 1332 for (i = 0; i < npgs; i++) { 1333 pg = pgs[i]; 1334 if (pg == NULL) { 1335 continue; 1336 } 1337 if (pg->flags & PG_WANTED) { 1338 wakeup(pg); 1339 } 1340 if (pg->flags & PG_RELEASED) { 1341 UVMHIST_LOG(ubchist, "releasing pg %p", pg,0,0,0); 1342 pg->flags &= ~PG_RELEASED; 1343 uvm_pagefree(pg); 1344 } else { 1345 UVMHIST_LOG(ubchist, "unbusying pg %p", pg,0,0,0); 1346 pg->flags &= ~(PG_WANTED|PG_BUSY); 1347 UVM_PAGE_OWN(pg, NULL); 1348 } 1349 } 1350 } 1351 1352 #if defined(UVM_PAGE_TRKOWN) 1353 /* 1354 * uvm_page_own: set or release page ownership 1355 * 1356 * => this is a debugging function that keeps track of who sets PG_BUSY 1357 * and where they do it. it can be used to track down problems 1358 * such a process setting "PG_BUSY" and never releasing it. 1359 * => page's object [if any] must be locked 1360 * => if "tag" is NULL then we are releasing page ownership 1361 */ 1362 void 1363 uvm_page_own(pg, tag) 1364 struct vm_page *pg; 1365 char *tag; 1366 { 1367 KASSERT((pg->flags & (PG_PAGEOUT|PG_RELEASED)) == 0); 1368 1369 /* gain ownership? */ 1370 if (tag) { 1371 if (pg->owner_tag) { 1372 printf("uvm_page_own: page %p already owned " 1373 "by proc %d [%s]\n", pg, 1374 pg->owner, pg->owner_tag); 1375 panic("uvm_page_own"); 1376 } 1377 pg->owner = (curproc) ? curproc->p_pid : (pid_t) -1; 1378 pg->owner_tag = tag; 1379 return; 1380 } 1381 1382 /* drop ownership */ 1383 if (pg->owner_tag == NULL) { 1384 printf("uvm_page_own: dropping ownership of an non-owned " 1385 "page (%p)\n", pg); 1386 panic("uvm_page_own"); 1387 } 1388 KASSERT((pg->pqflags & (PQ_ACTIVE|PQ_INACTIVE)) || 1389 (pg->uanon == NULL && pg->uobject == NULL) || 1390 pg->uobject == uvm.kernel_object || 1391 pg->wire_count > 0 || 1392 (pg->loan_count == 1 && pg->uanon == NULL) || 1393 pg->loan_count > 1); 1394 pg->owner_tag = NULL; 1395 } 1396 #endif 1397 1398 /* 1399 * uvm_pageidlezero: zero free pages while the system is idle. 1400 * 1401 * => try to complete one color bucket at a time, to reduce our impact 1402 * on the CPU cache. 1403 * => we loop until we either reach the target or whichqs indicates that 1404 * there is a process ready to run. 1405 */ 1406 void 1407 uvm_pageidlezero() 1408 { 1409 struct vm_page *pg; 1410 struct pgfreelist *pgfl; 1411 int free_list, s, firstbucket; 1412 static int nextbucket; 1413 1414 s = uvm_lock_fpageq(); 1415 firstbucket = nextbucket; 1416 do { 1417 if (sched_whichqs != 0) { 1418 uvm_unlock_fpageq(s); 1419 return; 1420 } 1421 if (uvmexp.zeropages >= UVM_PAGEZERO_TARGET) { 1422 uvm.page_idle_zero = FALSE; 1423 uvm_unlock_fpageq(s); 1424 return; 1425 } 1426 for (free_list = 0; free_list < VM_NFREELIST; free_list++) { 1427 pgfl = &uvm.page_free[free_list]; 1428 while ((pg = TAILQ_FIRST(&pgfl->pgfl_buckets[ 1429 nextbucket].pgfl_queues[PGFL_UNKNOWN])) != NULL) { 1430 if (sched_whichqs != 0) { 1431 uvm_unlock_fpageq(s); 1432 return; 1433 } 1434 1435 TAILQ_REMOVE(&pgfl->pgfl_buckets[ 1436 nextbucket].pgfl_queues[PGFL_UNKNOWN], 1437 pg, pageq); 1438 uvmexp.free--; 1439 uvm_unlock_fpageq(s); 1440 #ifdef PMAP_PAGEIDLEZERO 1441 if (!PMAP_PAGEIDLEZERO(VM_PAGE_TO_PHYS(pg))) { 1442 1443 /* 1444 * The machine-dependent code detected 1445 * some reason for us to abort zeroing 1446 * pages, probably because there is a 1447 * process now ready to run. 1448 */ 1449 1450 s = uvm_lock_fpageq(); 1451 TAILQ_INSERT_HEAD(&pgfl->pgfl_buckets[ 1452 nextbucket].pgfl_queues[ 1453 PGFL_UNKNOWN], pg, pageq); 1454 uvmexp.free++; 1455 uvmexp.zeroaborts++; 1456 uvm_unlock_fpageq(s); 1457 return; 1458 } 1459 #else 1460 pmap_zero_page(VM_PAGE_TO_PHYS(pg)); 1461 #endif /* PMAP_PAGEIDLEZERO */ 1462 pg->flags |= PG_ZERO; 1463 1464 s = uvm_lock_fpageq(); 1465 TAILQ_INSERT_HEAD(&pgfl->pgfl_buckets[ 1466 nextbucket].pgfl_queues[PGFL_ZEROS], 1467 pg, pageq); 1468 uvmexp.free++; 1469 uvmexp.zeropages++; 1470 } 1471 } 1472 nextbucket = (nextbucket + 1) & uvmexp.colormask; 1473 } while (nextbucket != firstbucket); 1474 uvm_unlock_fpageq(s); 1475 } 1476