1 /* $NetBSD: uvm_glue.c,v 1.140 2009/08/10 16:50:18 matt 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_glue.c 8.6 (Berkeley) 1/5/94 42 * from: Id: uvm_glue.c,v 1.1.2.8 1998/02/07 01:16:54 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 #include <sys/cdefs.h> 70 __KERNEL_RCSID(0, "$NetBSD: uvm_glue.c,v 1.140 2009/08/10 16:50:18 matt Exp $"); 71 72 #include "opt_kgdb.h" 73 #include "opt_kstack.h" 74 #include "opt_uvmhist.h" 75 76 /* 77 * uvm_glue.c: glue functions 78 */ 79 80 #include <sys/param.h> 81 #include <sys/systm.h> 82 #include <sys/proc.h> 83 #include <sys/resourcevar.h> 84 #include <sys/buf.h> 85 #include <sys/user.h> 86 #include <sys/syncobj.h> 87 #include <sys/cpu.h> 88 #include <sys/atomic.h> 89 90 #include <uvm/uvm.h> 91 92 /* 93 * local prototypes 94 */ 95 96 static int uarea_swapin(vaddr_t); 97 static void uvm_swapout(struct lwp *); 98 99 /* 100 * XXXCDC: do these really belong here? 101 */ 102 103 /* 104 * uvm_kernacc: can the kernel access a region of memory 105 * 106 * - used only by /dev/kmem driver (mem.c) 107 */ 108 109 bool 110 uvm_kernacc(void *addr, size_t len, int rw) 111 { 112 bool rv; 113 vaddr_t saddr, eaddr; 114 vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; 115 116 saddr = trunc_page((vaddr_t)addr); 117 eaddr = round_page((vaddr_t)addr + len); 118 vm_map_lock_read(kernel_map); 119 rv = uvm_map_checkprot(kernel_map, saddr, eaddr, prot); 120 vm_map_unlock_read(kernel_map); 121 122 return(rv); 123 } 124 125 #ifdef KGDB 126 /* 127 * Change protections on kernel pages from addr to addr+len 128 * (presumably so debugger can plant a breakpoint). 129 * 130 * We force the protection change at the pmap level. If we were 131 * to use vm_map_protect a change to allow writing would be lazily- 132 * applied meaning we would still take a protection fault, something 133 * we really don't want to do. It would also fragment the kernel 134 * map unnecessarily. We cannot use pmap_protect since it also won't 135 * enforce a write-enable request. Using pmap_enter is the only way 136 * we can ensure the change takes place properly. 137 */ 138 void 139 uvm_chgkprot(void *addr, size_t len, int rw) 140 { 141 vm_prot_t prot; 142 paddr_t pa; 143 vaddr_t sva, eva; 144 145 prot = rw == B_READ ? VM_PROT_READ : VM_PROT_READ|VM_PROT_WRITE; 146 eva = round_page((vaddr_t)addr + len); 147 for (sva = trunc_page((vaddr_t)addr); sva < eva; sva += PAGE_SIZE) { 148 /* 149 * Extract physical address for the page. 150 */ 151 if (pmap_extract(pmap_kernel(), sva, &pa) == false) 152 panic("%s: invalid page", __func__); 153 pmap_enter(pmap_kernel(), sva, pa, prot, PMAP_WIRED); 154 } 155 pmap_update(pmap_kernel()); 156 } 157 #endif 158 159 /* 160 * uvm_vslock: wire user memory for I/O 161 * 162 * - called from physio and sys___sysctl 163 * - XXXCDC: consider nuking this (or making it a macro?) 164 */ 165 166 int 167 uvm_vslock(struct vmspace *vs, void *addr, size_t len, vm_prot_t access_type) 168 { 169 struct vm_map *map; 170 vaddr_t start, end; 171 int error; 172 173 map = &vs->vm_map; 174 start = trunc_page((vaddr_t)addr); 175 end = round_page((vaddr_t)addr + len); 176 error = uvm_fault_wire(map, start, end, access_type, 0); 177 return error; 178 } 179 180 /* 181 * uvm_vsunlock: unwire user memory wired by uvm_vslock() 182 * 183 * - called from physio and sys___sysctl 184 * - XXXCDC: consider nuking this (or making it a macro?) 185 */ 186 187 void 188 uvm_vsunlock(struct vmspace *vs, void *addr, size_t len) 189 { 190 uvm_fault_unwire(&vs->vm_map, trunc_page((vaddr_t)addr), 191 round_page((vaddr_t)addr + len)); 192 } 193 194 /* 195 * uvm_proc_fork: fork a virtual address space 196 * 197 * - the address space is copied as per parent map's inherit values 198 */ 199 void 200 uvm_proc_fork(struct proc *p1, struct proc *p2, bool shared) 201 { 202 203 if (shared == true) { 204 p2->p_vmspace = NULL; 205 uvmspace_share(p1, p2); 206 } else { 207 p2->p_vmspace = uvmspace_fork(p1->p_vmspace); 208 } 209 210 cpu_proc_fork(p1, p2); 211 } 212 213 214 /* 215 * uvm_lwp_fork: fork a thread 216 * 217 * - a new "user" structure is allocated for the child process 218 * [filled in by MD layer...] 219 * - if specified, the child gets a new user stack described by 220 * stack and stacksize 221 * - NOTE: the kernel stack may be at a different location in the child 222 * process, and thus addresses of automatic variables may be invalid 223 * after cpu_lwp_fork returns in the child process. We do nothing here 224 * after cpu_lwp_fork returns. 225 * - XXXCDC: we need a way for this to return a failure value rather 226 * than just hang 227 */ 228 void 229 uvm_lwp_fork(struct lwp *l1, struct lwp *l2, void *stack, size_t stacksize, 230 void (*func)(void *), void *arg) 231 { 232 233 /* 234 * Wire down the U-area for the process, which contains the PCB 235 * and the kernel stack. Wired state is stored in l->l_flag's 236 * L_INMEM bit rather than in the vm_map_entry's wired count 237 * to prevent kernel_map fragmentation. If we reused a cached U-area, 238 * L_INMEM will already be set and we don't need to do anything. 239 * 240 * Note the kernel stack gets read/write accesses right off the bat. 241 */ 242 243 if ((l2->l_flag & LW_INMEM) == 0) { 244 #ifdef VMSWAP_UAREA 245 vaddr_t uarea = USER_TO_UAREA(l2->l_addr); 246 int error; 247 248 if ((error = uarea_swapin(uarea)) != 0) 249 panic("%s: uvm_fault_wire failed: %d", __func__, error); 250 #ifdef PMAP_UAREA 251 /* Tell the pmap this is a u-area mapping */ 252 PMAP_UAREA(uarea); 253 #endif 254 #endif /* VMSWAP_UAREA */ 255 l2->l_flag |= LW_INMEM; 256 } 257 258 /* Fill stack with magic number. */ 259 kstack_setup_magic(l2); 260 261 /* 262 * cpu_lwp_fork() copy and update the pcb, and make the child ready 263 * to run. If this is a normal user fork, the child will exit 264 * directly to user mode via child_return() on its first time 265 * slice and will not return here. If this is a kernel thread, 266 * the specified entry point will be executed. 267 */ 268 cpu_lwp_fork(l1, l2, stack, stacksize, func, arg); 269 270 /* Inactive emap for new LWP. */ 271 l2->l_emap_gen = UVM_EMAP_INACTIVE; 272 } 273 274 static int 275 uarea_swapin(vaddr_t addr) 276 { 277 278 return uvm_fault_wire(kernel_map, addr, addr + USPACE, 279 VM_PROT_READ | VM_PROT_WRITE, 0); 280 } 281 282 #ifdef VMSWAP_UAREA 283 static void 284 uarea_swapout(vaddr_t addr) 285 { 286 287 uvm_fault_unwire(kernel_map, addr, addr + USPACE); 288 } 289 #endif /* VMSWAP_UAREA */ 290 291 #ifndef USPACE_ALIGN 292 #define USPACE_ALIGN 0 293 #endif 294 295 static pool_cache_t uvm_uarea_cache; 296 297 static int 298 uarea_ctor(void *arg, void *obj, int flags) 299 { 300 #if defined(PMAP_MAP_POOLPAGE) && !defined(VMSWAP_UAREA) 301 if (USPACE == PAGE_SIZE && USPACE_ALIGN == 0) 302 return 0; 303 #endif 304 KASSERT((flags & PR_WAITOK) != 0); 305 return uarea_swapin((vaddr_t)obj); 306 } 307 308 static void * 309 uarea_poolpage_alloc(struct pool *pp, int flags) 310 { 311 #if defined(PMAP_MAP_POOLPAGE) && !defined(VMSWAP_UAREA) 312 if (USPACE == PAGE_SIZE && USPACE_ALIGN == 0) { 313 struct vm_page *pg; 314 vaddr_t va; 315 316 pg = uvm_pagealloc(NULL, 0, NULL, 317 ((flags & PR_WAITOK) == 0 ? UVM_KMF_NOWAIT : 0)); 318 if (pg == NULL) 319 return NULL; 320 va = PMAP_MAP_POOLPAGE(VM_PAGE_TO_PHYS(pg)); 321 if (va == 0) 322 uvm_pagefree(pg); 323 return (void *)va; 324 } 325 #endif 326 return (void *)uvm_km_alloc(kernel_map, pp->pr_alloc->pa_pagesz, 327 USPACE_ALIGN, UVM_KMF_PAGEABLE | 328 ((flags & PR_WAITOK) != 0 ? UVM_KMF_WAITVA : 329 (UVM_KMF_NOWAIT | UVM_KMF_TRYLOCK))); 330 } 331 332 static void 333 uarea_poolpage_free(struct pool *pp, void *addr) 334 { 335 #if defined(PMAP_MAP_POOLPAGE) && !defined(VMSWAP_UAREA) 336 if (USPACE == PAGE_SIZE && USPACE_ALIGN == 0) { 337 paddr_t pa; 338 339 pa = PMAP_UNMAP_POOLPAGE((vaddr_t) addr); 340 KASSERT(pa != 0); 341 uvm_pagefree(PHYS_TO_VM_PAGE(pa)); 342 return; 343 } 344 #endif 345 uvm_km_free(kernel_map, (vaddr_t)addr, pp->pr_alloc->pa_pagesz, 346 UVM_KMF_PAGEABLE); 347 } 348 349 static struct pool_allocator uvm_uarea_allocator = { 350 .pa_alloc = uarea_poolpage_alloc, 351 .pa_free = uarea_poolpage_free, 352 .pa_pagesz = USPACE, 353 }; 354 355 void 356 uvm_uarea_init(void) 357 { 358 int flags = PR_NOTOUCH; 359 360 /* 361 * specify PR_NOALIGN unless the alignment provided by 362 * the backend (USPACE_ALIGN) is sufficient to provide 363 * pool page size (UPSACE) alignment. 364 */ 365 366 if ((USPACE_ALIGN == 0 && USPACE != PAGE_SIZE) || 367 (USPACE_ALIGN % USPACE) != 0) { 368 flags |= PR_NOALIGN; 369 } 370 371 uvm_uarea_cache = pool_cache_init(USPACE, USPACE_ALIGN, 0, flags, 372 "uarea", &uvm_uarea_allocator, IPL_NONE, uarea_ctor, NULL, NULL); 373 } 374 375 /* 376 * uvm_uarea_alloc: allocate a u-area 377 */ 378 379 bool 380 uvm_uarea_alloc(vaddr_t *uaddrp) 381 { 382 383 *uaddrp = (vaddr_t)pool_cache_get(uvm_uarea_cache, PR_WAITOK); 384 return true; 385 } 386 387 /* 388 * uvm_uarea_free: free a u-area 389 */ 390 391 void 392 uvm_uarea_free(vaddr_t uaddr, struct cpu_info *ci) 393 { 394 395 pool_cache_put(uvm_uarea_cache, (void *)uaddr); 396 } 397 398 /* 399 * uvm_proc_exit: exit a virtual address space 400 * 401 * - borrow proc0's address space because freeing the vmspace 402 * of the dead process may block. 403 */ 404 405 void 406 uvm_proc_exit(struct proc *p) 407 { 408 struct lwp *l = curlwp; /* XXX */ 409 struct vmspace *ovm; 410 411 KASSERT(p == l->l_proc); 412 ovm = p->p_vmspace; 413 414 /* 415 * borrow proc0's address space. 416 */ 417 KPREEMPT_DISABLE(l); 418 pmap_deactivate(l); 419 p->p_vmspace = proc0.p_vmspace; 420 pmap_activate(l); 421 KPREEMPT_ENABLE(l); 422 423 uvmspace_free(ovm); 424 } 425 426 void 427 uvm_lwp_exit(struct lwp *l) 428 { 429 vaddr_t va = USER_TO_UAREA(l->l_addr); 430 431 l->l_flag &= ~LW_INMEM; 432 uvm_uarea_free(va, l->l_cpu); 433 l->l_addr = NULL; 434 } 435 436 /* 437 * uvm_init_limit: init per-process VM limits 438 * 439 * - called for process 0 and then inherited by all others. 440 */ 441 442 void 443 uvm_init_limits(struct proc *p) 444 { 445 446 /* 447 * Set up the initial limits on process VM. Set the maximum 448 * resident set size to be all of (reasonably) available memory. 449 * This causes any single, large process to start random page 450 * replacement once it fills memory. 451 */ 452 453 p->p_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ; 454 p->p_rlimit[RLIMIT_STACK].rlim_max = maxsmap; 455 p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ; 456 p->p_rlimit[RLIMIT_DATA].rlim_max = maxdmap; 457 p->p_rlimit[RLIMIT_AS].rlim_cur = RLIM_INFINITY; 458 p->p_rlimit[RLIMIT_AS].rlim_max = RLIM_INFINITY; 459 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(uvmexp.free); 460 } 461 462 #ifdef DEBUG 463 int enableswap = 1; 464 int swapdebug = 0; 465 #define SDB_FOLLOW 1 466 #define SDB_SWAPIN 2 467 #define SDB_SWAPOUT 4 468 #endif 469 470 /* 471 * uvm_swapin: swap in an lwp's u-area. 472 * 473 * - must be called with the LWP's swap lock held. 474 * - naturally, must not be called with l == curlwp 475 */ 476 477 void 478 uvm_swapin(struct lwp *l) 479 { 480 #ifdef VMSWAP_UAREA 481 int error; 482 #endif 483 484 KASSERT(mutex_owned(&l->l_swaplock)); 485 KASSERT(l != curlwp); 486 487 #ifdef VMSWAP_UAREA 488 error = uarea_swapin(USER_TO_UAREA(l->l_addr)); 489 if (error) { 490 panic("%s: rewiring stack failed: %d", __func__, error); 491 } 492 493 /* 494 * Some architectures need to be notified when the user area has 495 * moved to new physical page(s) (e.g. see mips/mips/vm_machdep.c). 496 */ 497 cpu_swapin(l); 498 #endif 499 lwp_lock(l); 500 if (l->l_stat == LSRUN) 501 sched_enqueue(l, false); 502 l->l_flag |= LW_INMEM; 503 l->l_swtime = 0; 504 lwp_unlock(l); 505 ++uvmexp.swapins; 506 } 507 508 /* 509 * uvm_kick_scheduler: kick the scheduler into action if not running. 510 * 511 * - called when swapped out processes have been awoken. 512 */ 513 514 void 515 uvm_kick_scheduler(void) 516 { 517 518 if (uvm.swap_running == false) 519 return; 520 521 mutex_enter(&uvm_scheduler_mutex); 522 uvm.scheduler_kicked = true; 523 cv_signal(&uvm.scheduler_cv); 524 mutex_exit(&uvm_scheduler_mutex); 525 } 526 527 /* 528 * uvm_scheduler: process zero main loop 529 * 530 * - attempt to swapin every swaped-out, runnable process in order of 531 * priority. 532 * - if not enough memory, wake the pagedaemon and let it clear space. 533 */ 534 535 void 536 uvm_scheduler(void) 537 { 538 struct lwp *l, *ll; 539 int pri; 540 int ppri; 541 542 l = curlwp; 543 lwp_lock(l); 544 l->l_priority = PRI_VM; 545 l->l_class = SCHED_FIFO; 546 lwp_unlock(l); 547 548 for (;;) { 549 #ifdef DEBUG 550 mutex_enter(&uvm_scheduler_mutex); 551 while (!enableswap) 552 cv_wait(&uvm.scheduler_cv, &uvm_scheduler_mutex); 553 mutex_exit(&uvm_scheduler_mutex); 554 #endif 555 ll = NULL; /* process to choose */ 556 ppri = INT_MIN; /* its priority */ 557 558 mutex_enter(proc_lock); 559 LIST_FOREACH(l, &alllwp, l_list) { 560 /* is it a runnable swapped out process? */ 561 if (l->l_stat == LSRUN && !(l->l_flag & LW_INMEM)) { 562 pri = l->l_swtime + l->l_slptime - 563 (l->l_proc->p_nice - NZERO) * 8; 564 if (pri > ppri) { /* higher priority? */ 565 ll = l; 566 ppri = pri; 567 } 568 } 569 } 570 #ifdef DEBUG 571 if (swapdebug & SDB_FOLLOW) 572 printf("%s: running, procp %p pri %d\n", __func__, ll, 573 ppri); 574 #endif 575 /* 576 * Nothing to do, back to sleep 577 */ 578 if ((l = ll) == NULL) { 579 mutex_exit(proc_lock); 580 mutex_enter(&uvm_scheduler_mutex); 581 if (uvm.scheduler_kicked == false) 582 cv_wait(&uvm.scheduler_cv, 583 &uvm_scheduler_mutex); 584 uvm.scheduler_kicked = false; 585 mutex_exit(&uvm_scheduler_mutex); 586 continue; 587 } 588 589 /* 590 * we have found swapped out process which we would like 591 * to bring back in. 592 * 593 * XXX: this part is really bogus cuz we could deadlock 594 * on memory despite our feeble check 595 */ 596 if (uvmexp.free > atop(USPACE)) { 597 #ifdef DEBUG 598 if (swapdebug & SDB_SWAPIN) 599 printf("swapin: pid %d(%s)@%p, pri %d " 600 "free %d\n", l->l_proc->p_pid, 601 l->l_proc->p_comm, l->l_addr, ppri, 602 uvmexp.free); 603 #endif 604 mutex_enter(&l->l_swaplock); 605 mutex_exit(proc_lock); 606 uvm_swapin(l); 607 mutex_exit(&l->l_swaplock); 608 continue; 609 } else { 610 /* 611 * not enough memory, jab the pageout daemon and 612 * wait til the coast is clear 613 */ 614 mutex_exit(proc_lock); 615 #ifdef DEBUG 616 if (swapdebug & SDB_FOLLOW) 617 printf("%s: no room for pid %d(%s)," 618 " free %d\n", __func__, l->l_proc->p_pid, 619 l->l_proc->p_comm, uvmexp.free); 620 #endif 621 uvm_wait("schedpwait"); 622 #ifdef DEBUG 623 if (swapdebug & SDB_FOLLOW) 624 printf("%s: room again, free %d\n", __func__, 625 uvmexp.free); 626 #endif 627 } 628 } 629 } 630 631 /* 632 * swappable: is LWP "l" swappable? 633 */ 634 635 static bool 636 swappable(struct lwp *l) 637 { 638 639 if ((l->l_flag & (LW_INMEM|LW_SYSTEM|LW_WEXIT)) != LW_INMEM) 640 return false; 641 if ((l->l_pflag & LP_RUNNING) != 0) 642 return false; 643 if (l->l_holdcnt != 0) 644 return false; 645 if (l->l_class != SCHED_OTHER) 646 return false; 647 if (l->l_syncobj == &rw_syncobj || l->l_syncobj == &mutex_syncobj) 648 return false; 649 if (l->l_proc->p_stat != SACTIVE && l->l_proc->p_stat != SSTOP) 650 return false; 651 return true; 652 } 653 654 /* 655 * swapout_threads: find threads that can be swapped and unwire their 656 * u-areas. 657 * 658 * - called by the pagedaemon 659 * - try and swap at least one processs 660 * - processes that are sleeping or stopped for maxslp or more seconds 661 * are swapped... otherwise the longest-sleeping or stopped process 662 * is swapped, otherwise the longest resident process... 663 */ 664 665 void 666 uvm_swapout_threads(void) 667 { 668 struct lwp *l; 669 struct lwp *outl, *outl2; 670 int outpri, outpri2; 671 int didswap = 0; 672 extern int maxslp; 673 bool gotit; 674 675 /* XXXCDC: should move off to uvmexp. or uvm., also in uvm_meter */ 676 677 #ifdef DEBUG 678 if (!enableswap) 679 return; 680 #endif 681 682 /* 683 * outl/outpri : stop/sleep thread with largest sleeptime < maxslp 684 * outl2/outpri2: the longest resident thread (its swap time) 685 */ 686 outl = outl2 = NULL; 687 outpri = outpri2 = 0; 688 689 restart: 690 mutex_enter(proc_lock); 691 LIST_FOREACH(l, &alllwp, l_list) { 692 KASSERT(l->l_proc != NULL); 693 if (!mutex_tryenter(&l->l_swaplock)) 694 continue; 695 if (!swappable(l)) { 696 mutex_exit(&l->l_swaplock); 697 continue; 698 } 699 switch (l->l_stat) { 700 case LSONPROC: 701 break; 702 703 case LSRUN: 704 if (l->l_swtime > outpri2) { 705 outl2 = l; 706 outpri2 = l->l_swtime; 707 } 708 break; 709 710 case LSSLEEP: 711 case LSSTOP: 712 if (l->l_slptime >= maxslp) { 713 mutex_exit(proc_lock); 714 uvm_swapout(l); 715 /* 716 * Locking in the wrong direction - 717 * try to prevent the LWP from exiting. 718 */ 719 gotit = mutex_tryenter(proc_lock); 720 mutex_exit(&l->l_swaplock); 721 didswap++; 722 if (!gotit) 723 goto restart; 724 continue; 725 } else if (l->l_slptime > outpri) { 726 outl = l; 727 outpri = l->l_slptime; 728 } 729 break; 730 } 731 mutex_exit(&l->l_swaplock); 732 } 733 734 /* 735 * If we didn't get rid of any real duds, toss out the next most 736 * likely sleeping/stopped or running candidate. We only do this 737 * if we are real low on memory since we don't gain much by doing 738 * it (USPACE bytes). 739 */ 740 if (didswap == 0 && uvmexp.free <= atop(round_page(USPACE))) { 741 if ((l = outl) == NULL) 742 l = outl2; 743 #ifdef DEBUG 744 if (swapdebug & SDB_SWAPOUT) 745 printf("%s: no duds, try procp %p\n", __func__, l); 746 #endif 747 if (l) { 748 mutex_enter(&l->l_swaplock); 749 mutex_exit(proc_lock); 750 if (swappable(l)) 751 uvm_swapout(l); 752 mutex_exit(&l->l_swaplock); 753 return; 754 } 755 } 756 757 mutex_exit(proc_lock); 758 } 759 760 /* 761 * uvm_swapout: swap out lwp "l" 762 * 763 * - currently "swapout" means "unwire U-area" and "pmap_collect()" 764 * the pmap. 765 * - must be called with l->l_swaplock held. 766 * - XXXCDC: should deactivate all process' private anonymous memory 767 */ 768 769 static void 770 uvm_swapout(struct lwp *l) 771 { 772 struct vm_map *map; 773 774 KASSERT(mutex_owned(&l->l_swaplock)); 775 776 #ifdef DEBUG 777 if (swapdebug & SDB_SWAPOUT) 778 printf("%s: lid %d.%d(%s)@%p, stat %x pri %d free %d\n", 779 __func__, l->l_proc->p_pid, l->l_lid, l->l_proc->p_comm, 780 l->l_addr, l->l_stat, l->l_slptime, uvmexp.free); 781 #endif 782 783 /* 784 * Mark it as (potentially) swapped out. 785 */ 786 lwp_lock(l); 787 if (!swappable(l)) { 788 KDASSERT(l->l_cpu != curcpu()); 789 lwp_unlock(l); 790 return; 791 } 792 l->l_flag &= ~LW_INMEM; 793 l->l_swtime = 0; 794 if (l->l_stat == LSRUN) 795 sched_dequeue(l); 796 lwp_unlock(l); 797 l->l_ru.ru_nswap++; 798 ++uvmexp.swapouts; 799 800 #ifdef VMSWAP_UAREA 801 /* 802 * Do any machine-specific actions necessary before swapout. 803 * This can include saving floating point state, etc. 804 */ 805 cpu_swapout(l); 806 807 /* 808 * Unwire the to-be-swapped process's user struct and kernel stack. 809 */ 810 uarea_swapout(USER_TO_UAREA(l->l_addr)); 811 #endif 812 map = &l->l_proc->p_vmspace->vm_map; 813 if (vm_map_lock_try(map)) { 814 pmap_collect(vm_map_pmap(map)); 815 vm_map_unlock(map); 816 } 817 } 818 819 /* 820 * uvm_lwp_hold: prevent lwp "l" from being swapped out, and bring 821 * back into memory if it is currently swapped. 822 */ 823 824 void 825 uvm_lwp_hold(struct lwp *l) 826 { 827 828 if (l == curlwp) { 829 atomic_inc_uint(&l->l_holdcnt); 830 } else { 831 mutex_enter(&l->l_swaplock); 832 if (atomic_inc_uint_nv(&l->l_holdcnt) == 1 && 833 (l->l_flag & LW_INMEM) == 0) 834 uvm_swapin(l); 835 mutex_exit(&l->l_swaplock); 836 } 837 } 838 839 /* 840 * uvm_lwp_rele: release a hold on lwp "l". when the holdcount 841 * drops to zero, it's eligable to be swapped. 842 */ 843 844 void 845 uvm_lwp_rele(struct lwp *l) 846 { 847 848 KASSERT(l->l_holdcnt != 0); 849 850 atomic_dec_uint(&l->l_holdcnt); 851 } 852