uvm_page.c revision 1.65
1/* $OpenBSD: uvm_page.c,v 1.65 2008/04/09 16:58:11 deraadt Exp $ */ 2/* $NetBSD: uvm_page.c,v 1.44 2000/11/27 08:40:04 chs Exp $ */ 3 4/* 5 * Copyright (c) 1997 Charles D. Cranor and Washington University. 6 * Copyright (c) 1991, 1993, The Regents of the University of California. 7 * 8 * All rights reserved. 9 * 10 * This code is derived from software contributed to Berkeley by 11 * The Mach Operating System project at Carnegie-Mellon University. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. All advertising materials mentioning features or use of this software 22 * must display the following acknowledgement: 23 * This product includes software developed by Charles D. Cranor, 24 * Washington University, the University of California, Berkeley and 25 * its contributors. 26 * 4. Neither the name of the University nor the names of its contributors 27 * may be used to endorse or promote products derived from this software 28 * without specific prior written permission. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 33 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 40 * SUCH DAMAGE. 41 * 42 * @(#)vm_page.c 8.3 (Berkeley) 3/21/94 43 * from: Id: uvm_page.c,v 1.1.2.18 1998/02/06 05:24:42 chs Exp 44 * 45 * 46 * Copyright (c) 1987, 1990 Carnegie-Mellon University. 47 * All rights reserved. 48 * 49 * Permission to use, copy, modify and distribute this software and 50 * its documentation is hereby granted, provided that both the copyright 51 * notice and this permission notice appear in all copies of the 52 * software, derivative works or modified versions, and any portions 53 * thereof, and that both notices appear in supporting documentation. 54 * 55 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" 56 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND 57 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. 58 * 59 * Carnegie Mellon requests users of this software to return to 60 * 61 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU 62 * School of Computer Science 63 * Carnegie Mellon University 64 * Pittsburgh PA 15213-3890 65 * 66 * any improvements or extensions that they make and grant Carnegie the 67 * rights to redistribute these changes. 68 */ 69 70/* 71 * uvm_page.c: page ops. 72 */ 73 74#define UVM_PAGE /* pull in uvm_page.h functions */ 75#include <sys/param.h> 76#include <sys/systm.h> 77#include <sys/malloc.h> 78#include <sys/sched.h> 79#include <sys/kernel.h> 80#include <sys/vnode.h> 81 82#include <uvm/uvm.h> 83 84/* 85 * global vars... XXXCDC: move to uvm. structure. 86 */ 87 88/* 89 * physical memory config is stored in vm_physmem. 90 */ 91 92struct vm_physseg vm_physmem[VM_PHYSSEG_MAX]; /* XXXCDC: uvm.physmem */ 93int vm_nphysseg = 0; /* XXXCDC: uvm.nphysseg */ 94 95/* 96 * Some supported CPUs in a given architecture don't support all 97 * of the things necessary to do idle page zero'ing efficiently. 98 * We therefore provide a way to disable it from machdep code here. 99 */ 100 101/* 102 * XXX disabled until we can find a way to do this without causing 103 * problems for either cpu caches or DMA latency. 104 */ 105boolean_t vm_page_zero_enable = FALSE; 106 107/* 108 * local variables 109 */ 110 111/* 112 * these variables record the values returned by vm_page_bootstrap, 113 * for debugging purposes. The implementation of uvm_pageboot_alloc 114 * and pmap_startup here also uses them internally. 115 */ 116 117static vaddr_t virtual_space_start; 118static vaddr_t virtual_space_end; 119 120/* 121 * we use a hash table with only one bucket during bootup. we will 122 * later rehash (resize) the hash table once the allocator is ready. 123 * we static allocate the one bootstrap bucket below... 124 */ 125 126static struct pglist uvm_bootbucket; 127 128/* 129 * History 130 */ 131UVMHIST_DECL(pghist); 132 133/* 134 * local prototypes 135 */ 136 137static void uvm_pageinsert(struct vm_page *); 138static void uvm_pageremove(struct vm_page *); 139 140/* 141 * inline functions 142 */ 143 144/* 145 * uvm_pageinsert: insert a page in the object and the hash table 146 * 147 * => caller must lock object 148 * => caller must lock page queues 149 * => call should have already set pg's object and offset pointers 150 * and bumped the version counter 151 */ 152 153__inline static void 154uvm_pageinsert(struct vm_page *pg) 155{ 156 struct pglist *buck; 157 int s; 158 UVMHIST_FUNC("uvm_pageinsert"); UVMHIST_CALLED(pghist); 159 160 KASSERT((pg->pg_flags & PG_TABLED) == 0); 161 buck = &uvm.page_hash[uvm_pagehash(pg->uobject,pg->offset)]; 162 s = splvm(); 163 simple_lock(&uvm.hashlock); 164 TAILQ_INSERT_TAIL(buck, pg, hashq); /* put in hash */ 165 simple_unlock(&uvm.hashlock); 166 splx(s); 167 168 TAILQ_INSERT_TAIL(&pg->uobject->memq, pg, listq); /* put in object */ 169 atomic_setbits_int(&pg->pg_flags, PG_TABLED); 170 pg->uobject->uo_npages++; 171} 172 173/* 174 * uvm_page_remove: remove page from object and hash 175 * 176 * => caller must lock object 177 * => caller must lock page queues 178 */ 179 180static __inline void 181uvm_pageremove(struct vm_page *pg) 182{ 183 struct pglist *buck; 184 int s; 185 UVMHIST_FUNC("uvm_pageremove"); UVMHIST_CALLED(pghist); 186 187 KASSERT(pg->pg_flags & PG_TABLED); 188 buck = &uvm.page_hash[uvm_pagehash(pg->uobject,pg->offset)]; 189 s = splvm(); 190 simple_lock(&uvm.hashlock); 191 TAILQ_REMOVE(buck, pg, hashq); 192 simple_unlock(&uvm.hashlock); 193 splx(s); 194 195#ifdef UBC 196 if (pg->uobject->pgops == &uvm_vnodeops) { 197 uvm_pgcnt_vnode--; 198 } 199#endif 200 201 /* object should be locked */ 202 TAILQ_REMOVE(&pg->uobject->memq, pg, listq); 203 204 atomic_clearbits_int(&pg->pg_flags, PG_TABLED); 205 pg->uobject->uo_npages--; 206 pg->uobject = NULL; 207 pg->pg_version++; 208} 209 210/* 211 * uvm_page_init: init the page system. called from uvm_init(). 212 * 213 * => we return the range of kernel virtual memory in kvm_startp/kvm_endp 214 */ 215 216void 217uvm_page_init(kvm_startp, kvm_endp) 218 vaddr_t *kvm_startp, *kvm_endp; 219{ 220 vsize_t freepages, pagecount, n; 221 vm_page_t pagearray; 222 int lcv, i; 223 paddr_t paddr; 224#if defined(UVMHIST) 225 static struct uvm_history_ent pghistbuf[100]; 226#endif 227 228 UVMHIST_FUNC("uvm_page_init"); 229 UVMHIST_INIT_STATIC(pghist, pghistbuf); 230 UVMHIST_CALLED(pghist); 231 232 /* 233 * init the page queues and page queue locks 234 */ 235 236 for (lcv = 0; lcv < VM_NFREELIST; lcv++) { 237 for (i = 0; i < PGFL_NQUEUES; i++) 238 TAILQ_INIT(&uvm.page_free[lcv].pgfl_queues[i]); 239 } 240 TAILQ_INIT(&uvm.page_active); 241 TAILQ_INIT(&uvm.page_inactive_swp); 242 TAILQ_INIT(&uvm.page_inactive_obj); 243 simple_lock_init(&uvm.pageqlock); 244 mtx_init(&uvm.fpageqlock, IPL_VM); 245 246 /* 247 * init the <obj,offset> => <page> hash table. for now 248 * we just have one bucket (the bootstrap bucket). later on we 249 * will allocate new buckets as we dynamically resize the hash table. 250 */ 251 252 uvm.page_nhash = 1; /* 1 bucket */ 253 uvm.page_hashmask = 0; /* mask for hash function */ 254 uvm.page_hash = &uvm_bootbucket; /* install bootstrap bucket */ 255 TAILQ_INIT(uvm.page_hash); /* init hash table */ 256 simple_lock_init(&uvm.hashlock); /* init hash table lock */ 257 258 /* 259 * allocate vm_page structures. 260 */ 261 262 /* 263 * sanity check: 264 * before calling this function the MD code is expected to register 265 * some free RAM with the uvm_page_physload() function. our job 266 * now is to allocate vm_page structures for this memory. 267 */ 268 269 if (vm_nphysseg == 0) 270 panic("uvm_page_bootstrap: no memory pre-allocated"); 271 272 /* 273 * first calculate the number of free pages... 274 * 275 * note that we use start/end rather than avail_start/avail_end. 276 * this allows us to allocate extra vm_page structures in case we 277 * want to return some memory to the pool after booting. 278 */ 279 280 freepages = 0; 281 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 282 freepages += (vm_physmem[lcv].end - vm_physmem[lcv].start); 283 284 /* 285 * we now know we have (PAGE_SIZE * freepages) bytes of memory we can 286 * use. for each page of memory we use we need a vm_page structure. 287 * thus, the total number of pages we can use is the total size of 288 * the memory divided by the PAGE_SIZE plus the size of the vm_page 289 * structure. we add one to freepages as a fudge factor to avoid 290 * truncation errors (since we can only allocate in terms of whole 291 * pages). 292 */ 293 294 pagecount = (((paddr_t)freepages + 1) << PAGE_SHIFT) / 295 (PAGE_SIZE + sizeof(struct vm_page)); 296 pagearray = (vm_page_t)uvm_pageboot_alloc(pagecount * 297 sizeof(struct vm_page)); 298 memset(pagearray, 0, pagecount * sizeof(struct vm_page)); 299 300 /* 301 * init the vm_page structures and put them in the correct place. 302 */ 303 304 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) { 305 n = vm_physmem[lcv].end - vm_physmem[lcv].start; 306 if (n > pagecount) { 307 printf("uvm_page_init: lost %ld page(s) in init\n", 308 (long)(n - pagecount)); 309 panic("uvm_page_init"); /* XXXCDC: shouldn't happen? */ 310 /* n = pagecount; */ 311 } 312 313 /* set up page array pointers */ 314 vm_physmem[lcv].pgs = pagearray; 315 pagearray += n; 316 pagecount -= n; 317 vm_physmem[lcv].lastpg = vm_physmem[lcv].pgs + (n - 1); 318 319 /* init and free vm_pages (we've already zeroed them) */ 320 paddr = ptoa(vm_physmem[lcv].start); 321 for (i = 0 ; i < n ; i++, paddr += PAGE_SIZE) { 322 vm_physmem[lcv].pgs[i].phys_addr = paddr; 323#ifdef __HAVE_VM_PAGE_MD 324 VM_MDPAGE_INIT(&vm_physmem[lcv].pgs[i]); 325#endif 326 if (atop(paddr) >= vm_physmem[lcv].avail_start && 327 atop(paddr) <= vm_physmem[lcv].avail_end) { 328 uvmexp.npages++; 329 /* add page to free pool */ 330 uvm_pagefree(&vm_physmem[lcv].pgs[i]); 331 } 332 } 333 } 334 335 /* 336 * pass up the values of virtual_space_start and 337 * virtual_space_end (obtained by uvm_pageboot_alloc) to the upper 338 * layers of the VM. 339 */ 340 341 *kvm_startp = round_page(virtual_space_start); 342 *kvm_endp = trunc_page(virtual_space_end); 343 344 /* 345 * init locks for kernel threads 346 */ 347 348 simple_lock_init(&uvm.pagedaemon_lock); 349 simple_lock_init(&uvm.aiodoned_lock); 350 351 /* 352 * init reserve thresholds 353 * XXXCDC - values may need adjusting 354 */ 355 uvmexp.reserve_pagedaemon = 4; 356 uvmexp.reserve_kernel = 6; 357 uvmexp.anonminpct = 10; 358 uvmexp.vnodeminpct = 10; 359 uvmexp.vtextminpct = 5; 360 uvmexp.anonmin = uvmexp.anonminpct * 256 / 100; 361 uvmexp.vnodemin = uvmexp.vnodeminpct * 256 / 100; 362 uvmexp.vtextmin = uvmexp.vtextminpct * 256 / 100; 363 364 /* 365 * determine if we should zero pages in the idle loop. 366 */ 367 368 uvm.page_idle_zero = vm_page_zero_enable; 369 370 /* 371 * done! 372 */ 373 374 uvm.page_init_done = TRUE; 375} 376 377/* 378 * uvm_setpagesize: set the page size 379 * 380 * => sets page_shift and page_mask from uvmexp.pagesize. 381 */ 382 383void 384uvm_setpagesize() 385{ 386 if (uvmexp.pagesize == 0) 387 uvmexp.pagesize = DEFAULT_PAGE_SIZE; 388 uvmexp.pagemask = uvmexp.pagesize - 1; 389 if ((uvmexp.pagemask & uvmexp.pagesize) != 0) 390 panic("uvm_setpagesize: page size not a power of two"); 391 for (uvmexp.pageshift = 0; ; uvmexp.pageshift++) 392 if ((1 << uvmexp.pageshift) == uvmexp.pagesize) 393 break; 394} 395 396/* 397 * uvm_pageboot_alloc: steal memory from physmem for bootstrapping 398 */ 399 400vaddr_t 401uvm_pageboot_alloc(size) 402 vsize_t size; 403{ 404#if defined(PMAP_STEAL_MEMORY) 405 vaddr_t addr; 406 407 /* 408 * defer bootstrap allocation to MD code (it may want to allocate 409 * from a direct-mapped segment). pmap_steal_memory should round 410 * off virtual_space_start/virtual_space_end. 411 */ 412 413 addr = pmap_steal_memory(size, &virtual_space_start, 414 &virtual_space_end); 415 416 return(addr); 417 418#else /* !PMAP_STEAL_MEMORY */ 419 420 static boolean_t initialized = FALSE; 421 vaddr_t addr, vaddr; 422 paddr_t paddr; 423 424 /* round to page size */ 425 size = round_page(size); 426 427 /* 428 * on first call to this function, initialize ourselves. 429 */ 430 if (initialized == FALSE) { 431 pmap_virtual_space(&virtual_space_start, &virtual_space_end); 432 433 /* round it the way we like it */ 434 virtual_space_start = round_page(virtual_space_start); 435 virtual_space_end = trunc_page(virtual_space_end); 436 437 initialized = TRUE; 438 } 439 440 /* 441 * allocate virtual memory for this request 442 */ 443 if (virtual_space_start == virtual_space_end || 444 (virtual_space_end - virtual_space_start) < size) 445 panic("uvm_pageboot_alloc: out of virtual space"); 446 447 addr = virtual_space_start; 448 449#ifdef PMAP_GROWKERNEL 450 /* 451 * If the kernel pmap can't map the requested space, 452 * then allocate more resources for it. 453 */ 454 if (uvm_maxkaddr < (addr + size)) { 455 uvm_maxkaddr = pmap_growkernel(addr + size); 456 if (uvm_maxkaddr < (addr + size)) 457 panic("uvm_pageboot_alloc: pmap_growkernel() failed"); 458 } 459#endif 460 461 virtual_space_start += size; 462 463 /* 464 * allocate and mapin physical pages to back new virtual pages 465 */ 466 467 for (vaddr = round_page(addr) ; vaddr < addr + size ; 468 vaddr += PAGE_SIZE) { 469 470 if (!uvm_page_physget(&paddr)) 471 panic("uvm_pageboot_alloc: out of memory"); 472 473 /* 474 * Note this memory is no longer managed, so using 475 * pmap_kenter is safe. 476 */ 477 pmap_kenter_pa(vaddr, paddr, VM_PROT_READ|VM_PROT_WRITE); 478 } 479 pmap_update(pmap_kernel()); 480 return(addr); 481#endif /* PMAP_STEAL_MEMORY */ 482} 483 484#if !defined(PMAP_STEAL_MEMORY) 485/* 486 * uvm_page_physget: "steal" one page from the vm_physmem structure. 487 * 488 * => attempt to allocate it off the end of a segment in which the "avail" 489 * values match the start/end values. if we can't do that, then we 490 * will advance both values (making them equal, and removing some 491 * vm_page structures from the non-avail area). 492 * => return false if out of memory. 493 */ 494 495/* subroutine: try to allocate from memory chunks on the specified freelist */ 496static boolean_t uvm_page_physget_freelist(paddr_t *, int); 497 498static boolean_t 499uvm_page_physget_freelist(paddrp, freelist) 500 paddr_t *paddrp; 501 int freelist; 502{ 503 int lcv, x; 504 UVMHIST_FUNC("uvm_page_physget_freelist"); UVMHIST_CALLED(pghist); 505 506 /* pass 1: try allocating from a matching end */ 507#if (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST) || \ 508 (VM_PHYSSEG_STRAT == VM_PSTRAT_BSEARCH) 509 for (lcv = vm_nphysseg - 1 ; lcv >= 0 ; lcv--) 510#else 511 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 512#endif 513 { 514 515 if (uvm.page_init_done == TRUE) 516 panic("uvm_page_physget: called _after_ bootstrap"); 517 518 if (vm_physmem[lcv].free_list != freelist) 519 continue; 520 521 /* try from front */ 522 if (vm_physmem[lcv].avail_start == vm_physmem[lcv].start && 523 vm_physmem[lcv].avail_start < vm_physmem[lcv].avail_end) { 524 *paddrp = ptoa(vm_physmem[lcv].avail_start); 525 vm_physmem[lcv].avail_start++; 526 vm_physmem[lcv].start++; 527 /* nothing left? nuke it */ 528 if (vm_physmem[lcv].avail_start == 529 vm_physmem[lcv].end) { 530 if (vm_nphysseg == 1) 531 panic("uvm_page_physget: out of memory!"); 532 vm_nphysseg--; 533 for (x = lcv ; x < vm_nphysseg ; x++) 534 /* structure copy */ 535 vm_physmem[x] = vm_physmem[x+1]; 536 } 537 return (TRUE); 538 } 539 540 /* try from rear */ 541 if (vm_physmem[lcv].avail_end == vm_physmem[lcv].end && 542 vm_physmem[lcv].avail_start < vm_physmem[lcv].avail_end) { 543 *paddrp = ptoa(vm_physmem[lcv].avail_end - 1); 544 vm_physmem[lcv].avail_end--; 545 vm_physmem[lcv].end--; 546 /* nothing left? nuke it */ 547 if (vm_physmem[lcv].avail_end == 548 vm_physmem[lcv].start) { 549 if (vm_nphysseg == 1) 550 panic("uvm_page_physget: out of memory!"); 551 vm_nphysseg--; 552 for (x = lcv ; x < vm_nphysseg ; x++) 553 /* structure copy */ 554 vm_physmem[x] = vm_physmem[x+1]; 555 } 556 return (TRUE); 557 } 558 } 559 560 /* pass2: forget about matching ends, just allocate something */ 561#if (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST) || \ 562 (VM_PHYSSEG_STRAT == VM_PSTRAT_BSEARCH) 563 for (lcv = vm_nphysseg - 1 ; lcv >= 0 ; lcv--) 564#else 565 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 566#endif 567 { 568 569 /* any room in this bank? */ 570 if (vm_physmem[lcv].avail_start >= vm_physmem[lcv].avail_end) 571 continue; /* nope */ 572 573 *paddrp = ptoa(vm_physmem[lcv].avail_start); 574 vm_physmem[lcv].avail_start++; 575 /* truncate! */ 576 vm_physmem[lcv].start = vm_physmem[lcv].avail_start; 577 578 /* nothing left? nuke it */ 579 if (vm_physmem[lcv].avail_start == vm_physmem[lcv].end) { 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 return (FALSE); /* whoops! */ 591} 592 593boolean_t 594uvm_page_physget(paddrp) 595 paddr_t *paddrp; 596{ 597 int i; 598 UVMHIST_FUNC("uvm_page_physget"); UVMHIST_CALLED(pghist); 599 600 /* try in the order of freelist preference */ 601 for (i = 0; i < VM_NFREELIST; i++) 602 if (uvm_page_physget_freelist(paddrp, i) == TRUE) 603 return (TRUE); 604 return (FALSE); 605} 606#endif /* PMAP_STEAL_MEMORY */ 607 608/* 609 * uvm_page_physload: load physical memory into VM system 610 * 611 * => all args are PFs 612 * => all pages in start/end get vm_page structures 613 * => areas marked by avail_start/avail_end get added to the free page pool 614 * => we are limited to VM_PHYSSEG_MAX physical memory segments 615 */ 616 617void 618uvm_page_physload(start, end, avail_start, avail_end, free_list) 619 paddr_t start, end, avail_start, avail_end; 620 int free_list; 621{ 622 int preload, lcv; 623 psize_t npages; 624 struct vm_page *pgs; 625 struct vm_physseg *ps; 626 627 if (uvmexp.pagesize == 0) 628 panic("uvm_page_physload: page size not set!"); 629 630 if (free_list >= VM_NFREELIST || free_list < VM_FREELIST_DEFAULT) 631 panic("uvm_page_physload: bad free list %d", free_list); 632 633 if (start >= end) 634 panic("uvm_page_physload: start >= end"); 635 636 /* 637 * do we have room? 638 */ 639 if (vm_nphysseg == VM_PHYSSEG_MAX) { 640 printf("uvm_page_physload: unable to load physical memory " 641 "segment\n"); 642 printf("\t%d segments allocated, ignoring 0x%llx -> 0x%llx\n", 643 VM_PHYSSEG_MAX, (long long)start, (long long)end); 644 printf("\tincrease VM_PHYSSEG_MAX\n"); 645 return; 646 } 647 648 /* 649 * check to see if this is a "preload" (i.e. uvm_mem_init hasn't been 650 * called yet, so malloc is not available). 651 */ 652 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) { 653 if (vm_physmem[lcv].pgs) 654 break; 655 } 656 preload = (lcv == vm_nphysseg); 657 658 /* 659 * if VM is already running, attempt to malloc() vm_page structures 660 */ 661 if (!preload) { 662#if defined(VM_PHYSSEG_NOADD) 663 panic("uvm_page_physload: tried to add RAM after vm_mem_init"); 664#else 665 /* XXXCDC: need some sort of lockout for this case */ 666 paddr_t paddr; 667 npages = end - start; /* # of pages */ 668 pgs = (vm_page *)uvm_km_alloc(kernel_map, 669 sizeof(struct vm_page) * npages); 670 if (pgs == NULL) { 671 printf("uvm_page_physload: can not malloc vm_page " 672 "structs for segment\n"); 673 printf("\tignoring 0x%lx -> 0x%lx\n", start, end); 674 return; 675 } 676 /* zero data, init phys_addr and free_list, and free pages */ 677 memset(pgs, 0, sizeof(struct vm_page) * npages); 678 for (lcv = 0, paddr = ptoa(start) ; 679 lcv < npages ; lcv++, paddr += PAGE_SIZE) { 680 pgs[lcv].phys_addr = paddr; 681 pgs[lcv].free_list = free_list; 682 if (atop(paddr) >= avail_start && 683 atop(paddr) <= avail_end) 684 uvm_pagefree(&pgs[lcv]); 685 } 686 /* XXXCDC: incomplete: need to update uvmexp.free, what else? */ 687 /* XXXCDC: need hook to tell pmap to rebuild pv_list, etc... */ 688#endif 689 } else { 690 691 /* gcc complains if these don't get init'd */ 692 pgs = NULL; 693 npages = 0; 694 695 } 696 697 /* 698 * now insert us in the proper place in vm_physmem[] 699 */ 700 701#if (VM_PHYSSEG_STRAT == VM_PSTRAT_RANDOM) 702 703 /* random: put it at the end (easy!) */ 704 ps = &vm_physmem[vm_nphysseg]; 705 706#elif (VM_PHYSSEG_STRAT == VM_PSTRAT_BSEARCH) 707 708 { 709 int x; 710 /* sort by address for binary search */ 711 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 712 if (start < vm_physmem[lcv].start) 713 break; 714 ps = &vm_physmem[lcv]; 715 /* move back other entries, if necessary ... */ 716 for (x = vm_nphysseg ; x > lcv ; x--) 717 /* structure copy */ 718 vm_physmem[x] = vm_physmem[x - 1]; 719 } 720 721#elif (VM_PHYSSEG_STRAT == VM_PSTRAT_BIGFIRST) 722 723 { 724 int x; 725 /* sort by largest segment first */ 726 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 727 if ((end - start) > 728 (vm_physmem[lcv].end - vm_physmem[lcv].start)) 729 break; 730 ps = &vm_physmem[lcv]; 731 /* move back other entries, if necessary ... */ 732 for (x = vm_nphysseg ; x > lcv ; x--) 733 /* structure copy */ 734 vm_physmem[x] = vm_physmem[x - 1]; 735 } 736 737#else 738 739 panic("uvm_page_physload: unknown physseg strategy selected!"); 740 741#endif 742 743 ps->start = start; 744 ps->end = end; 745 ps->avail_start = avail_start; 746 ps->avail_end = avail_end; 747 if (preload) { 748 ps->pgs = NULL; 749 } else { 750 ps->pgs = pgs; 751 ps->lastpg = pgs + npages - 1; 752 } 753 ps->free_list = free_list; 754 vm_nphysseg++; 755 756 /* 757 * done! 758 */ 759 760 if (!preload) 761 uvm_page_rehash(); 762 763 return; 764} 765 766/* 767 * uvm_page_rehash: reallocate hash table based on number of free pages. 768 */ 769 770void 771uvm_page_rehash() 772{ 773 int freepages, lcv, bucketcount, s, oldcount; 774 struct pglist *newbuckets, *oldbuckets; 775 struct vm_page *pg; 776 size_t newsize, oldsize; 777 778 /* 779 * compute number of pages that can go in the free pool 780 */ 781 782 freepages = 0; 783 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 784 freepages += 785 (vm_physmem[lcv].avail_end - vm_physmem[lcv].avail_start); 786 787 /* 788 * compute number of buckets needed for this number of pages 789 */ 790 791 bucketcount = 1; 792 while (bucketcount < freepages) 793 bucketcount = bucketcount * 2; 794 795 /* 796 * compute the size of the current table and new table. 797 */ 798 799 oldbuckets = uvm.page_hash; 800 oldcount = uvm.page_nhash; 801 oldsize = round_page(sizeof(struct pglist) * oldcount); 802 newsize = round_page(sizeof(struct pglist) * bucketcount); 803 804 /* 805 * allocate the new buckets 806 */ 807 808 newbuckets = (struct pglist *) uvm_km_alloc(kernel_map, newsize); 809 if (newbuckets == NULL) { 810 printf("uvm_page_physrehash: WARNING: could not grow page " 811 "hash table\n"); 812 return; 813 } 814 for (lcv = 0 ; lcv < bucketcount ; lcv++) 815 TAILQ_INIT(&newbuckets[lcv]); 816 817 /* 818 * now replace the old buckets with the new ones and rehash everything 819 */ 820 821 s = splvm(); 822 simple_lock(&uvm.hashlock); 823 uvm.page_hash = newbuckets; 824 uvm.page_nhash = bucketcount; 825 uvm.page_hashmask = bucketcount - 1; /* power of 2 */ 826 827 /* ... and rehash */ 828 for (lcv = 0 ; lcv < oldcount ; lcv++) { 829 while ((pg = TAILQ_FIRST(&oldbuckets[lcv])) != NULL) { 830 TAILQ_REMOVE(&oldbuckets[lcv], pg, hashq); 831 TAILQ_INSERT_TAIL( 832 &uvm.page_hash[uvm_pagehash(pg->uobject, pg->offset)], 833 pg, hashq); 834 } 835 } 836 simple_unlock(&uvm.hashlock); 837 splx(s); 838 839 /* 840 * free old bucket array if is not the boot-time table 841 */ 842 843 if (oldbuckets != &uvm_bootbucket) 844 uvm_km_free(kernel_map, (vaddr_t) oldbuckets, oldsize); 845 846 /* 847 * done 848 */ 849 return; 850} 851 852 853#ifdef DDB /* XXXCDC: TMP TMP TMP DEBUG DEBUG DEBUG */ 854 855void uvm_page_physdump(void); /* SHUT UP GCC */ 856 857/* call from DDB */ 858void 859uvm_page_physdump() 860{ 861 int lcv; 862 863 printf("rehash: physical memory config [segs=%d of %d]:\n", 864 vm_nphysseg, VM_PHYSSEG_MAX); 865 for (lcv = 0 ; lcv < vm_nphysseg ; lcv++) 866 printf("0x%llx->0x%llx [0x%llx->0x%llx]\n", 867 (long long)vm_physmem[lcv].start, 868 (long long)vm_physmem[lcv].end, 869 (long long)vm_physmem[lcv].avail_start, 870 (long long)vm_physmem[lcv].avail_end); 871 printf("STRATEGY = "); 872 switch (VM_PHYSSEG_STRAT) { 873 case VM_PSTRAT_RANDOM: printf("RANDOM\n"); break; 874 case VM_PSTRAT_BSEARCH: printf("BSEARCH\n"); break; 875 case VM_PSTRAT_BIGFIRST: printf("BIGFIRST\n"); break; 876 default: printf("<<UNKNOWN>>!!!!\n"); 877 } 878 printf("number of buckets = %d\n", uvm.page_nhash); 879} 880#endif 881 882void 883uvm_shutdown(void) 884{ 885} 886 887/* 888 * uvm_pagealloc_strat: allocate vm_page from a particular free list. 889 * 890 * => return null if no pages free 891 * => wake up pagedaemon if number of free pages drops below low water mark 892 * => if obj != NULL, obj must be locked (to put in hash) 893 * => if anon != NULL, anon must be locked (to put in anon) 894 * => only one of obj or anon can be non-null 895 * => caller must activate/deactivate page if it is not wired. 896 * => free_list is ignored if strat == UVM_PGA_STRAT_NORMAL. 897 * => policy decision: it is more important to pull a page off of the 898 * appropriate priority free list than it is to get a zero'd or 899 * unknown contents page. This is because we live with the 900 * consequences of a bad free list decision for the entire 901 * lifetime of the page, e.g. if the page comes from memory that 902 * is slower to access. 903 */ 904 905struct vm_page * 906uvm_pagealloc_strat(obj, off, anon, flags, strat, free_list) 907 struct uvm_object *obj; 908 voff_t off; 909 int flags; 910 struct vm_anon *anon; 911 int strat, free_list; 912{ 913 int lcv, try1, try2, zeroit = 0; 914 struct vm_page *pg; 915 struct pglist *freeq; 916 struct pgfreelist *pgfl; 917 boolean_t use_reserve; 918 UVMHIST_FUNC("uvm_pagealloc_strat"); UVMHIST_CALLED(pghist); 919 920 KASSERT(obj == NULL || anon == NULL); 921 KASSERT(off == trunc_page(off)); 922 923 uvm_lock_fpageq(); 924 925 /* 926 * check to see if we need to generate some free pages waking 927 * the pagedaemon. 928 */ 929 930#ifdef UBC 931 if (uvmexp.free + uvmexp.paging < uvmexp.freemin || 932 (uvmexp.free + uvmexp.paging < uvmexp.freetarg && 933 uvmexp.inactive < uvmexp.inactarg)) { 934 wakeup(&uvm.pagedaemon); 935 } 936#else 937 if (uvmexp.free < uvmexp.freemin || (uvmexp.free < uvmexp.freetarg && 938 uvmexp.inactive < uvmexp.inactarg)) 939 wakeup(&uvm.pagedaemon); 940#endif 941 942 /* 943 * fail if any of these conditions is true: 944 * [1] there really are no free pages, or 945 * [2] only kernel "reserved" pages remain and 946 * the page isn't being allocated to a kernel object. 947 * [3] only pagedaemon "reserved" pages remain and 948 * the requestor isn't the pagedaemon. 949 */ 950 951 use_reserve = (flags & UVM_PGA_USERESERVE) || 952 (obj && UVM_OBJ_IS_KERN_OBJECT(obj)); 953 if ((uvmexp.free <= uvmexp.reserve_kernel && !use_reserve) || 954 (uvmexp.free <= uvmexp.reserve_pagedaemon && 955 !(use_reserve && (curproc == uvm.pagedaemon_proc || 956 curproc == syncerproc)))) 957 goto fail; 958 959#if PGFL_NQUEUES != 2 960#error uvm_pagealloc_strat needs to be updated 961#endif 962 963 /* 964 * If we want a zero'd page, try the ZEROS queue first, otherwise 965 * we try the UNKNOWN queue first. 966 */ 967 if (flags & UVM_PGA_ZERO) { 968 try1 = PGFL_ZEROS; 969 try2 = PGFL_UNKNOWN; 970 } else { 971 try1 = PGFL_UNKNOWN; 972 try2 = PGFL_ZEROS; 973 } 974 975 UVMHIST_LOG(pghist, "obj=%p off=%lx anon=%p flags=%lx", 976 obj, (u_long)off, anon, flags); 977 UVMHIST_LOG(pghist, "strat=%ld free_list=%ld", strat, free_list, 0, 0); 978 again: 979 switch (strat) { 980 case UVM_PGA_STRAT_NORMAL: 981 /* Check all freelists in descending priority order. */ 982 for (lcv = 0; lcv < VM_NFREELIST; lcv++) { 983 pgfl = &uvm.page_free[lcv]; 984 if ((pg = TAILQ_FIRST((freeq = 985 &pgfl->pgfl_queues[try1]))) != NULL || 986 (pg = TAILQ_FIRST((freeq = 987 &pgfl->pgfl_queues[try2]))) != NULL) 988 goto gotit; 989 } 990 991 /* No pages free! */ 992 goto fail; 993 994 case UVM_PGA_STRAT_ONLY: 995 case UVM_PGA_STRAT_FALLBACK: 996 /* Attempt to allocate from the specified free list. */ 997 KASSERT(free_list >= 0 && free_list < VM_NFREELIST); 998 pgfl = &uvm.page_free[free_list]; 999 if ((pg = TAILQ_FIRST((freeq = 1000 &pgfl->pgfl_queues[try1]))) != NULL || 1001 (pg = TAILQ_FIRST((freeq = 1002 &pgfl->pgfl_queues[try2]))) != NULL) 1003 goto gotit; 1004 1005 /* Fall back, if possible. */ 1006 if (strat == UVM_PGA_STRAT_FALLBACK) { 1007 strat = UVM_PGA_STRAT_NORMAL; 1008 goto again; 1009 } 1010 1011 /* No pages free! */ 1012 goto fail; 1013 1014 default: 1015 panic("uvm_pagealloc_strat: bad strat %d", strat); 1016 /* NOTREACHED */ 1017 } 1018 1019 gotit: 1020 TAILQ_REMOVE(freeq, pg, pageq); 1021 uvmexp.free--; 1022 1023 /* update zero'd page count */ 1024 if (pg->pg_flags & PG_ZERO) 1025 uvmexp.zeropages--; 1026 1027 /* 1028 * update allocation statistics and remember if we have to 1029 * zero the page 1030 */ 1031 if (flags & UVM_PGA_ZERO) { 1032 if (pg->pg_flags & PG_ZERO) { 1033 uvmexp.pga_zerohit++; 1034 zeroit = 0; 1035 } else { 1036 uvmexp.pga_zeromiss++; 1037 zeroit = 1; 1038 } 1039 } 1040 1041 uvm_unlock_fpageq(); /* unlock free page queue */ 1042 1043 pg->offset = off; 1044 pg->uobject = obj; 1045 pg->uanon = anon; 1046 pg->pg_flags = PG_BUSY|PG_CLEAN|PG_FAKE; 1047 pg->pg_version++; 1048 if (anon) { 1049 anon->an_page = pg; 1050 atomic_setbits_int(&pg->pg_flags, PQ_ANON); 1051#ifdef UBC 1052 uvm_pgcnt_anon++; 1053#endif 1054 } else { 1055 if (obj) 1056 uvm_pageinsert(pg); 1057 } 1058#if defined(UVM_PAGE_TRKOWN) 1059 pg->owner_tag = NULL; 1060#endif 1061 UVM_PAGE_OWN(pg, "new alloc"); 1062 1063 if (flags & UVM_PGA_ZERO) { 1064 /* 1065 * A zero'd page is not clean. If we got a page not already 1066 * zero'd, then we have to zero it ourselves. 1067 */ 1068 atomic_clearbits_int(&pg->pg_flags, PG_CLEAN); 1069 if (zeroit) 1070 pmap_zero_page(pg); 1071 } 1072 1073 UVMHIST_LOG(pghist, "allocated pg %p/%lx", pg, 1074 (u_long)VM_PAGE_TO_PHYS(pg), 0, 0); 1075 return(pg); 1076 1077 fail: 1078 uvm_unlock_fpageq(); 1079 UVMHIST_LOG(pghist, "failed!", 0, 0, 0, 0); 1080 return (NULL); 1081} 1082 1083/* 1084 * uvm_pagerealloc: reallocate a page from one object to another 1085 * 1086 * => both objects must be locked 1087 */ 1088 1089void 1090uvm_pagerealloc(pg, newobj, newoff) 1091 struct vm_page *pg; 1092 struct uvm_object *newobj; 1093 voff_t newoff; 1094{ 1095 1096 UVMHIST_FUNC("uvm_pagerealloc"); UVMHIST_CALLED(pghist); 1097 1098 /* 1099 * remove it from the old object 1100 */ 1101 1102 if (pg->uobject) { 1103 uvm_pageremove(pg); 1104 } 1105 1106 /* 1107 * put it in the new object 1108 */ 1109 1110 if (newobj) { 1111 pg->uobject = newobj; 1112 pg->offset = newoff; 1113 pg->pg_version++; 1114 uvm_pageinsert(pg); 1115 } 1116} 1117 1118 1119/* 1120 * uvm_pagefree: free page 1121 * 1122 * => erase page's identity (i.e. remove from hash/object) 1123 * => put page on free list 1124 * => caller must lock owning object (either anon or uvm_object) 1125 * => caller must lock page queues 1126 * => assumes all valid mappings of pg are gone 1127 */ 1128 1129void 1130uvm_pagefree(struct vm_page *pg) 1131{ 1132 int saved_loan_count = pg->loan_count; 1133 UVMHIST_FUNC("uvm_pagefree"); UVMHIST_CALLED(pghist); 1134 1135#ifdef DEBUG 1136 if (pg->uobject == (void *)0xdeadbeef && 1137 pg->uanon == (void *)0xdeadbeef) { 1138 panic("uvm_pagefree: freeing free page %p", pg); 1139 } 1140#endif 1141 1142 UVMHIST_LOG(pghist, "freeing pg %p/%lx", pg, 1143 (u_long)VM_PAGE_TO_PHYS(pg), 0, 0); 1144 1145 /* 1146 * if the page was an object page (and thus "TABLED"), remove it 1147 * from the object. 1148 */ 1149 1150 if (pg->pg_flags & PG_TABLED) { 1151 1152 /* 1153 * if the object page is on loan we are going to drop ownership. 1154 * it is possible that an anon will take over as owner for this 1155 * page later on. the anon will want a !PG_CLEAN page so that 1156 * it knows it needs to allocate swap if it wants to page the 1157 * page out. 1158 */ 1159 1160 /* in case an anon takes over */ 1161 if (saved_loan_count) 1162 atomic_clearbits_int(&pg->pg_flags, PG_CLEAN); 1163 uvm_pageremove(pg); 1164 1165 /* 1166 * if our page was on loan, then we just lost control over it 1167 * (in fact, if it was loaned to an anon, the anon may have 1168 * already taken over ownership of the page by now and thus 1169 * changed the loan_count [e.g. in uvmfault_anonget()]) we just 1170 * return (when the last loan is dropped, then the page can be 1171 * freed by whatever was holding the last loan). 1172 */ 1173 1174 if (saved_loan_count) 1175 return; 1176 } else if (saved_loan_count && pg->uanon) { 1177 /* 1178 * if our page is owned by an anon and is loaned out to the 1179 * kernel then we just want to drop ownership and return. 1180 * the kernel must free the page when all its loans clear ... 1181 * note that the kernel can't change the loan status of our 1182 * page as long as we are holding PQ lock. 1183 */ 1184 atomic_clearbits_int(&pg->pg_flags, PQ_ANON); 1185 pg->uanon->an_page = NULL; 1186 pg->uanon = NULL; 1187 return; 1188 } 1189 KASSERT(saved_loan_count == 0); 1190 1191 /* 1192 * now remove the page from the queues 1193 */ 1194 1195 if (pg->pg_flags & PQ_ACTIVE) { 1196 TAILQ_REMOVE(&uvm.page_active, pg, pageq); 1197 atomic_clearbits_int(&pg->pg_flags, PQ_ACTIVE); 1198 uvmexp.active--; 1199 } 1200 if (pg->pg_flags & PQ_INACTIVE) { 1201 if (pg->pg_flags & PQ_SWAPBACKED) 1202 TAILQ_REMOVE(&uvm.page_inactive_swp, pg, pageq); 1203 else 1204 TAILQ_REMOVE(&uvm.page_inactive_obj, pg, pageq); 1205 atomic_clearbits_int(&pg->pg_flags, PQ_INACTIVE); 1206 uvmexp.inactive--; 1207 } 1208 1209 /* 1210 * if the page was wired, unwire it now. 1211 */ 1212 1213 if (pg->wire_count) { 1214 pg->wire_count = 0; 1215 uvmexp.wired--; 1216 } 1217 if (pg->uanon) { 1218 pg->uanon->an_page = NULL; 1219#ifdef UBC 1220 uvm_pgcnt_anon--; 1221#endif 1222 } 1223 1224 /* 1225 * and put on free queue 1226 */ 1227 1228 atomic_clearbits_int(&pg->pg_flags, PG_ZERO); 1229 1230 uvm_lock_fpageq(); 1231 TAILQ_INSERT_TAIL(&uvm.page_free[ 1232 uvm_page_lookup_freelist(pg)].pgfl_queues[PGFL_UNKNOWN], pg, pageq); 1233 atomic_clearbits_int(&pg->pg_flags, PQ_MASK); 1234 atomic_setbits_int(&pg->pg_flags, PQ_FREE); 1235#ifdef DEBUG 1236 pg->uobject = (void *)0xdeadbeef; 1237 pg->offset = 0xdeadbeef; 1238 pg->uanon = (void *)0xdeadbeef; 1239#endif 1240 uvmexp.free++; 1241 1242 if (uvmexp.zeropages < UVM_PAGEZERO_TARGET) 1243 uvm.page_idle_zero = vm_page_zero_enable; 1244 1245 uvm_unlock_fpageq(); 1246} 1247 1248/* 1249 * uvm_page_unbusy: unbusy an array of pages. 1250 * 1251 * => pages must either all belong to the same object, or all belong to anons. 1252 * => if pages are object-owned, object must be locked. 1253 * => if pages are anon-owned, anons must be unlockd and have 0 refcount. 1254 */ 1255 1256void 1257uvm_page_unbusy(pgs, npgs) 1258 struct vm_page **pgs; 1259 int npgs; 1260{ 1261 struct vm_page *pg; 1262 struct uvm_object *uobj; 1263 int i; 1264 UVMHIST_FUNC("uvm_page_unbusy"); UVMHIST_CALLED(pdhist); 1265 1266 for (i = 0; i < npgs; i++) { 1267 pg = pgs[i]; 1268 1269 if (pg == NULL || pg == PGO_DONTCARE) { 1270 continue; 1271 } 1272 if (pg->pg_flags & PG_WANTED) { 1273 wakeup(pg); 1274 } 1275 if (pg->pg_flags & PG_RELEASED) { 1276 UVMHIST_LOG(pdhist, "releasing pg %p", pg,0,0,0); 1277 uobj = pg->uobject; 1278 if (uobj != NULL) { 1279 uobj->pgops->pgo_releasepg(pg, NULL); 1280 } else { 1281 atomic_clearbits_int(&pg->pg_flags, PG_BUSY); 1282 UVM_PAGE_OWN(pg, NULL); 1283 uvm_anfree(pg->uanon); 1284 } 1285 } else { 1286 UVMHIST_LOG(pdhist, "unbusying pg %p", pg,0,0,0); 1287 atomic_clearbits_int(&pg->pg_flags, PG_WANTED|PG_BUSY); 1288 UVM_PAGE_OWN(pg, NULL); 1289 } 1290 } 1291} 1292 1293#if defined(UVM_PAGE_TRKOWN) 1294/* 1295 * uvm_page_own: set or release page ownership 1296 * 1297 * => this is a debugging function that keeps track of who sets PG_BUSY 1298 * and where they do it. it can be used to track down problems 1299 * such a process setting "PG_BUSY" and never releasing it. 1300 * => page's object [if any] must be locked 1301 * => if "tag" is NULL then we are releasing page ownership 1302 */ 1303void 1304uvm_page_own(pg, tag) 1305 struct vm_page *pg; 1306 char *tag; 1307{ 1308 /* gain ownership? */ 1309 if (tag) { 1310 if (pg->owner_tag) { 1311 printf("uvm_page_own: page %p already owned " 1312 "by proc %d [%s]\n", pg, 1313 pg->owner, pg->owner_tag); 1314 panic("uvm_page_own"); 1315 } 1316 pg->owner = (curproc) ? curproc->p_pid : (pid_t) -1; 1317 pg->owner_tag = tag; 1318 return; 1319 } 1320 1321 /* drop ownership */ 1322 if (pg->owner_tag == NULL) { 1323 printf("uvm_page_own: dropping ownership of an non-owned " 1324 "page (%p)\n", pg); 1325 panic("uvm_page_own"); 1326 } 1327 pg->owner_tag = NULL; 1328 return; 1329} 1330#endif 1331 1332/* 1333 * uvm_pageidlezero: zero free pages while the system is idle. 1334 * 1335 * => we do at least one iteration per call, if we are below the target. 1336 * => we loop until we either reach the target or whichqs indicates that 1337 * there is a process ready to run. 1338 */ 1339void 1340uvm_pageidlezero() 1341{ 1342 struct vm_page *pg; 1343 struct pgfreelist *pgfl; 1344 int free_list; 1345 UVMHIST_FUNC("uvm_pageidlezero"); UVMHIST_CALLED(pghist); 1346 1347 do { 1348 uvm_lock_fpageq(); 1349 1350 if (uvmexp.zeropages >= UVM_PAGEZERO_TARGET) { 1351 uvm.page_idle_zero = FALSE; 1352 uvm_unlock_fpageq(); 1353 return; 1354 } 1355 1356 for (free_list = 0; free_list < VM_NFREELIST; free_list++) { 1357 pgfl = &uvm.page_free[free_list]; 1358 if ((pg = TAILQ_FIRST(&pgfl->pgfl_queues[ 1359 PGFL_UNKNOWN])) != NULL) 1360 break; 1361 } 1362 1363 if (pg == NULL) { 1364 /* 1365 * No non-zero'd pages; don't bother trying again 1366 * until we know we have non-zero'd pages free. 1367 */ 1368 uvm.page_idle_zero = FALSE; 1369 uvm_unlock_fpageq(); 1370 return; 1371 } 1372 1373 TAILQ_REMOVE(&pgfl->pgfl_queues[PGFL_UNKNOWN], pg, pageq); 1374 uvmexp.free--; 1375 uvm_unlock_fpageq(); 1376 1377#ifdef PMAP_PAGEIDLEZERO 1378 if (PMAP_PAGEIDLEZERO(pg) == FALSE) { 1379 /* 1380 * The machine-dependent code detected some 1381 * reason for us to abort zeroing pages, 1382 * probably because there is a process now 1383 * ready to run. 1384 */ 1385 uvm_lock_fpageq(); 1386 TAILQ_INSERT_HEAD(&pgfl->pgfl_queues[PGFL_UNKNOWN], 1387 pg, pageq); 1388 uvmexp.free++; 1389 uvmexp.zeroaborts++; 1390 uvm_unlock_fpageq(); 1391 return; 1392 } 1393#else 1394 /* 1395 * XXX This will toast the cache unless the pmap_zero_page() 1396 * XXX implementation does uncached access. 1397 */ 1398 pmap_zero_page(pg); 1399#endif 1400 atomic_setbits_int(&pg->pg_flags, PG_ZERO); 1401 1402 uvm_lock_fpageq(); 1403 TAILQ_INSERT_HEAD(&pgfl->pgfl_queues[PGFL_ZEROS], pg, pageq); 1404 uvmexp.free++; 1405 uvmexp.zeropages++; 1406 uvm_unlock_fpageq(); 1407 } while (sched_is_idle()); 1408} 1409