1 /* $NetBSD: uvm_glue.c,v 1.136 2009/03/29 01:02:51 mrg 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 1.136 2009/03/29 01:02:51 mrg 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 void uvm_swapout(struct lwp *); 97 static int uarea_swapin(vaddr_t); 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 int error; 233 234 /* 235 * Wire down the U-area for the process, which contains the PCB 236 * and the kernel stack. Wired state is stored in l->l_flag's 237 * L_INMEM bit rather than in the vm_map_entry's wired count 238 * to prevent kernel_map fragmentation. If we reused a cached U-area, 239 * L_INMEM will already be set and we don't need to do anything. 240 * 241 * Note the kernel stack gets read/write accesses right off the bat. 242 */ 243 244 if ((l2->l_flag & LW_INMEM) == 0) { 245 vaddr_t uarea = USER_TO_UAREA(l2->l_addr); 246 247 if ((error = uarea_swapin(uarea)) != 0) 248 panic("%s: uvm_fault_wire failed: %d", __func__, error); 249 #ifdef PMAP_UAREA 250 /* Tell the pmap this is a u-area mapping */ 251 PMAP_UAREA(uarea); 252 #endif 253 l2->l_flag |= LW_INMEM; 254 } 255 256 #ifdef KSTACK_CHECK_MAGIC 257 /* 258 * fill stack with magic number 259 */ 260 kstack_setup_magic(l2); 261 #endif 262 263 /* 264 * cpu_lwp_fork() copy and update the pcb, and make the child ready 265 * to run. If this is a normal user fork, the child will exit 266 * directly to user mode via child_return() on its first time 267 * slice and will not return here. If this is a kernel thread, 268 * the specified entry point will be executed. 269 */ 270 cpu_lwp_fork(l1, l2, stack, stacksize, func, arg); 271 } 272 273 static int 274 uarea_swapin(vaddr_t addr) 275 { 276 277 return uvm_fault_wire(kernel_map, addr, addr + USPACE, 278 VM_PROT_READ | VM_PROT_WRITE, 0); 279 } 280 281 static void 282 uarea_swapout(vaddr_t addr) 283 { 284 285 uvm_fault_unwire(kernel_map, addr, addr + USPACE); 286 } 287 288 #ifndef USPACE_ALIGN 289 #define USPACE_ALIGN 0 290 #endif 291 292 static pool_cache_t uvm_uarea_cache; 293 294 static int 295 uarea_ctor(void *arg, void *obj, int flags) 296 { 297 298 KASSERT((flags & PR_WAITOK) != 0); 299 return uarea_swapin((vaddr_t)obj); 300 } 301 302 static void * 303 uarea_poolpage_alloc(struct pool *pp, int flags) 304 { 305 306 return (void *)uvm_km_alloc(kernel_map, pp->pr_alloc->pa_pagesz, 307 USPACE_ALIGN, UVM_KMF_PAGEABLE | 308 ((flags & PR_WAITOK) != 0 ? UVM_KMF_WAITVA : 309 (UVM_KMF_NOWAIT | UVM_KMF_TRYLOCK))); 310 } 311 312 static void 313 uarea_poolpage_free(struct pool *pp, void *addr) 314 { 315 316 uvm_km_free(kernel_map, (vaddr_t)addr, pp->pr_alloc->pa_pagesz, 317 UVM_KMF_PAGEABLE); 318 } 319 320 static struct pool_allocator uvm_uarea_allocator = { 321 .pa_alloc = uarea_poolpage_alloc, 322 .pa_free = uarea_poolpage_free, 323 .pa_pagesz = USPACE, 324 }; 325 326 void 327 uvm_uarea_init(void) 328 { 329 int flags = PR_NOTOUCH; 330 331 /* 332 * specify PR_NOALIGN unless the alignment provided by 333 * the backend (USPACE_ALIGN) is sufficient to provide 334 * pool page size (UPSACE) alignment. 335 */ 336 337 if ((USPACE_ALIGN == 0 && USPACE != PAGE_SIZE) || 338 (USPACE_ALIGN % USPACE) != 0) { 339 flags |= PR_NOALIGN; 340 } 341 342 uvm_uarea_cache = pool_cache_init(USPACE, USPACE_ALIGN, 0, flags, 343 "uarea", &uvm_uarea_allocator, IPL_NONE, uarea_ctor, NULL, NULL); 344 } 345 346 /* 347 * uvm_uarea_alloc: allocate a u-area 348 */ 349 350 bool 351 uvm_uarea_alloc(vaddr_t *uaddrp) 352 { 353 354 *uaddrp = (vaddr_t)pool_cache_get(uvm_uarea_cache, PR_WAITOK); 355 return true; 356 } 357 358 /* 359 * uvm_uarea_free: free a u-area 360 */ 361 362 void 363 uvm_uarea_free(vaddr_t uaddr, struct cpu_info *ci) 364 { 365 366 pool_cache_put(uvm_uarea_cache, (void *)uaddr); 367 } 368 369 /* 370 * uvm_proc_exit: exit a virtual address space 371 * 372 * - borrow proc0's address space because freeing the vmspace 373 * of the dead process may block. 374 */ 375 376 void 377 uvm_proc_exit(struct proc *p) 378 { 379 struct lwp *l = curlwp; /* XXX */ 380 struct vmspace *ovm; 381 382 KASSERT(p == l->l_proc); 383 ovm = p->p_vmspace; 384 385 /* 386 * borrow proc0's address space. 387 */ 388 KPREEMPT_DISABLE(l); 389 pmap_deactivate(l); 390 p->p_vmspace = proc0.p_vmspace; 391 pmap_activate(l); 392 KPREEMPT_ENABLE(l); 393 394 uvmspace_free(ovm); 395 } 396 397 void 398 uvm_lwp_exit(struct lwp *l) 399 { 400 vaddr_t va = USER_TO_UAREA(l->l_addr); 401 402 l->l_flag &= ~LW_INMEM; 403 uvm_uarea_free(va, l->l_cpu); 404 l->l_addr = NULL; 405 } 406 407 /* 408 * uvm_init_limit: init per-process VM limits 409 * 410 * - called for process 0 and then inherited by all others. 411 */ 412 413 void 414 uvm_init_limits(struct proc *p) 415 { 416 417 /* 418 * Set up the initial limits on process VM. Set the maximum 419 * resident set size to be all of (reasonably) available memory. 420 * This causes any single, large process to start random page 421 * replacement once it fills memory. 422 */ 423 424 p->p_rlimit[RLIMIT_STACK].rlim_cur = DFLSSIZ; 425 p->p_rlimit[RLIMIT_STACK].rlim_max = maxsmap; 426 p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ; 427 p->p_rlimit[RLIMIT_DATA].rlim_max = maxdmap; 428 p->p_rlimit[RLIMIT_AS].rlim_cur = RLIM_INFINITY; 429 p->p_rlimit[RLIMIT_AS].rlim_max = RLIM_INFINITY; 430 p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(uvmexp.free); 431 } 432 433 #ifdef DEBUG 434 int enableswap = 1; 435 int swapdebug = 0; 436 #define SDB_FOLLOW 1 437 #define SDB_SWAPIN 2 438 #define SDB_SWAPOUT 4 439 #endif 440 441 /* 442 * uvm_swapin: swap in an lwp's u-area. 443 * 444 * - must be called with the LWP's swap lock held. 445 * - naturally, must not be called with l == curlwp 446 */ 447 448 void 449 uvm_swapin(struct lwp *l) 450 { 451 int error; 452 453 KASSERT(mutex_owned(&l->l_swaplock)); 454 KASSERT(l != curlwp); 455 456 error = uarea_swapin(USER_TO_UAREA(l->l_addr)); 457 if (error) { 458 panic("%s: rewiring stack failed: %d", __func__, error); 459 } 460 461 /* 462 * Some architectures need to be notified when the user area has 463 * moved to new physical page(s) (e.g. see mips/mips/vm_machdep.c). 464 */ 465 cpu_swapin(l); 466 lwp_lock(l); 467 if (l->l_stat == LSRUN) 468 sched_enqueue(l, false); 469 l->l_flag |= LW_INMEM; 470 l->l_swtime = 0; 471 lwp_unlock(l); 472 ++uvmexp.swapins; 473 } 474 475 /* 476 * uvm_kick_scheduler: kick the scheduler into action if not running. 477 * 478 * - called when swapped out processes have been awoken. 479 */ 480 481 void 482 uvm_kick_scheduler(void) 483 { 484 485 if (uvm.swap_running == false) 486 return; 487 488 mutex_enter(&uvm_scheduler_mutex); 489 uvm.scheduler_kicked = true; 490 cv_signal(&uvm.scheduler_cv); 491 mutex_exit(&uvm_scheduler_mutex); 492 } 493 494 /* 495 * uvm_scheduler: process zero main loop 496 * 497 * - attempt to swapin every swaped-out, runnable process in order of 498 * priority. 499 * - if not enough memory, wake the pagedaemon and let it clear space. 500 */ 501 502 void 503 uvm_scheduler(void) 504 { 505 struct lwp *l, *ll; 506 int pri; 507 int ppri; 508 509 l = curlwp; 510 lwp_lock(l); 511 l->l_priority = PRI_VM; 512 l->l_class = SCHED_FIFO; 513 lwp_unlock(l); 514 515 for (;;) { 516 #ifdef DEBUG 517 mutex_enter(&uvm_scheduler_mutex); 518 while (!enableswap) 519 cv_wait(&uvm.scheduler_cv, &uvm_scheduler_mutex); 520 mutex_exit(&uvm_scheduler_mutex); 521 #endif 522 ll = NULL; /* process to choose */ 523 ppri = INT_MIN; /* its priority */ 524 525 mutex_enter(proc_lock); 526 LIST_FOREACH(l, &alllwp, l_list) { 527 /* is it a runnable swapped out process? */ 528 if (l->l_stat == LSRUN && !(l->l_flag & LW_INMEM)) { 529 pri = l->l_swtime + l->l_slptime - 530 (l->l_proc->p_nice - NZERO) * 8; 531 if (pri > ppri) { /* higher priority? */ 532 ll = l; 533 ppri = pri; 534 } 535 } 536 } 537 #ifdef DEBUG 538 if (swapdebug & SDB_FOLLOW) 539 printf("%s: running, procp %p pri %d\n", __func__, ll, 540 ppri); 541 #endif 542 /* 543 * Nothing to do, back to sleep 544 */ 545 if ((l = ll) == NULL) { 546 mutex_exit(proc_lock); 547 mutex_enter(&uvm_scheduler_mutex); 548 if (uvm.scheduler_kicked == false) 549 cv_wait(&uvm.scheduler_cv, 550 &uvm_scheduler_mutex); 551 uvm.scheduler_kicked = false; 552 mutex_exit(&uvm_scheduler_mutex); 553 continue; 554 } 555 556 /* 557 * we have found swapped out process which we would like 558 * to bring back in. 559 * 560 * XXX: this part is really bogus cuz we could deadlock 561 * on memory despite our feeble check 562 */ 563 if (uvmexp.free > atop(USPACE)) { 564 #ifdef DEBUG 565 if (swapdebug & SDB_SWAPIN) 566 printf("swapin: pid %d(%s)@%p, pri %d " 567 "free %d\n", l->l_proc->p_pid, 568 l->l_proc->p_comm, l->l_addr, ppri, 569 uvmexp.free); 570 #endif 571 mutex_enter(&l->l_swaplock); 572 mutex_exit(proc_lock); 573 uvm_swapin(l); 574 mutex_exit(&l->l_swaplock); 575 continue; 576 } else { 577 /* 578 * not enough memory, jab the pageout daemon and 579 * wait til the coast is clear 580 */ 581 mutex_exit(proc_lock); 582 #ifdef DEBUG 583 if (swapdebug & SDB_FOLLOW) 584 printf("%s: no room for pid %d(%s)," 585 " free %d\n", __func__, l->l_proc->p_pid, 586 l->l_proc->p_comm, uvmexp.free); 587 #endif 588 uvm_wait("schedpwait"); 589 #ifdef DEBUG 590 if (swapdebug & SDB_FOLLOW) 591 printf("%s: room again, free %d\n", __func__, 592 uvmexp.free); 593 #endif 594 } 595 } 596 } 597 598 /* 599 * swappable: is LWP "l" swappable? 600 */ 601 602 static bool 603 swappable(struct lwp *l) 604 { 605 606 if ((l->l_flag & (LW_INMEM|LW_SYSTEM|LW_WEXIT)) != LW_INMEM) 607 return false; 608 if ((l->l_pflag & LP_RUNNING) != 0) 609 return false; 610 if (l->l_holdcnt != 0) 611 return false; 612 if (l->l_class != SCHED_OTHER) 613 return false; 614 if (l->l_syncobj == &rw_syncobj || l->l_syncobj == &mutex_syncobj) 615 return false; 616 if (l->l_proc->p_stat != SACTIVE && l->l_proc->p_stat != SSTOP) 617 return false; 618 return true; 619 } 620 621 /* 622 * swapout_threads: find threads that can be swapped and unwire their 623 * u-areas. 624 * 625 * - called by the pagedaemon 626 * - try and swap at least one processs 627 * - processes that are sleeping or stopped for maxslp or more seconds 628 * are swapped... otherwise the longest-sleeping or stopped process 629 * is swapped, otherwise the longest resident process... 630 */ 631 632 void 633 uvm_swapout_threads(void) 634 { 635 struct lwp *l; 636 struct lwp *outl, *outl2; 637 int outpri, outpri2; 638 int didswap = 0; 639 extern int maxslp; 640 bool gotit; 641 642 /* XXXCDC: should move off to uvmexp. or uvm., also in uvm_meter */ 643 644 #ifdef DEBUG 645 if (!enableswap) 646 return; 647 #endif 648 649 /* 650 * outl/outpri : stop/sleep thread with largest sleeptime < maxslp 651 * outl2/outpri2: the longest resident thread (its swap time) 652 */ 653 outl = outl2 = NULL; 654 outpri = outpri2 = 0; 655 656 restart: 657 mutex_enter(proc_lock); 658 LIST_FOREACH(l, &alllwp, l_list) { 659 KASSERT(l->l_proc != NULL); 660 if (!mutex_tryenter(&l->l_swaplock)) 661 continue; 662 if (!swappable(l)) { 663 mutex_exit(&l->l_swaplock); 664 continue; 665 } 666 switch (l->l_stat) { 667 case LSONPROC: 668 break; 669 670 case LSRUN: 671 if (l->l_swtime > outpri2) { 672 outl2 = l; 673 outpri2 = l->l_swtime; 674 } 675 break; 676 677 case LSSLEEP: 678 case LSSTOP: 679 if (l->l_slptime >= maxslp) { 680 mutex_exit(proc_lock); 681 uvm_swapout(l); 682 /* 683 * Locking in the wrong direction - 684 * try to prevent the LWP from exiting. 685 */ 686 gotit = mutex_tryenter(proc_lock); 687 mutex_exit(&l->l_swaplock); 688 didswap++; 689 if (!gotit) 690 goto restart; 691 continue; 692 } else if (l->l_slptime > outpri) { 693 outl = l; 694 outpri = l->l_slptime; 695 } 696 break; 697 } 698 mutex_exit(&l->l_swaplock); 699 } 700 701 /* 702 * If we didn't get rid of any real duds, toss out the next most 703 * likely sleeping/stopped or running candidate. We only do this 704 * if we are real low on memory since we don't gain much by doing 705 * it (USPACE bytes). 706 */ 707 if (didswap == 0 && uvmexp.free <= atop(round_page(USPACE))) { 708 if ((l = outl) == NULL) 709 l = outl2; 710 #ifdef DEBUG 711 if (swapdebug & SDB_SWAPOUT) 712 printf("%s: no duds, try procp %p\n", __func__, l); 713 #endif 714 if (l) { 715 mutex_enter(&l->l_swaplock); 716 mutex_exit(proc_lock); 717 if (swappable(l)) 718 uvm_swapout(l); 719 mutex_exit(&l->l_swaplock); 720 return; 721 } 722 } 723 724 mutex_exit(proc_lock); 725 } 726 727 /* 728 * uvm_swapout: swap out lwp "l" 729 * 730 * - currently "swapout" means "unwire U-area" and "pmap_collect()" 731 * the pmap. 732 * - must be called with l->l_swaplock held. 733 * - XXXCDC: should deactivate all process' private anonymous memory 734 */ 735 736 static void 737 uvm_swapout(struct lwp *l) 738 { 739 struct vm_map *map; 740 741 KASSERT(mutex_owned(&l->l_swaplock)); 742 743 #ifdef DEBUG 744 if (swapdebug & SDB_SWAPOUT) 745 printf("%s: lid %d.%d(%s)@%p, stat %x pri %d free %d\n", 746 __func__, l->l_proc->p_pid, l->l_lid, l->l_proc->p_comm, 747 l->l_addr, l->l_stat, l->l_slptime, uvmexp.free); 748 #endif 749 750 /* 751 * Mark it as (potentially) swapped out. 752 */ 753 lwp_lock(l); 754 if (!swappable(l)) { 755 KDASSERT(l->l_cpu != curcpu()); 756 lwp_unlock(l); 757 return; 758 } 759 l->l_flag &= ~LW_INMEM; 760 l->l_swtime = 0; 761 if (l->l_stat == LSRUN) 762 sched_dequeue(l); 763 lwp_unlock(l); 764 l->l_ru.ru_nswap++; 765 ++uvmexp.swapouts; 766 767 /* 768 * Do any machine-specific actions necessary before swapout. 769 * This can include saving floating point state, etc. 770 */ 771 cpu_swapout(l); 772 773 /* 774 * Unwire the to-be-swapped process's user struct and kernel stack. 775 */ 776 uarea_swapout(USER_TO_UAREA(l->l_addr)); 777 map = &l->l_proc->p_vmspace->vm_map; 778 if (vm_map_lock_try(map)) { 779 pmap_collect(vm_map_pmap(map)); 780 vm_map_unlock(map); 781 } 782 } 783 784 /* 785 * uvm_lwp_hold: prevent lwp "l" from being swapped out, and bring 786 * back into memory if it is currently swapped. 787 */ 788 789 void 790 uvm_lwp_hold(struct lwp *l) 791 { 792 793 if (l == curlwp) { 794 atomic_inc_uint(&l->l_holdcnt); 795 } else { 796 mutex_enter(&l->l_swaplock); 797 if (atomic_inc_uint_nv(&l->l_holdcnt) == 1 && 798 (l->l_flag & LW_INMEM) == 0) 799 uvm_swapin(l); 800 mutex_exit(&l->l_swaplock); 801 } 802 } 803 804 /* 805 * uvm_lwp_rele: release a hold on lwp "l". when the holdcount 806 * drops to zero, it's eligable to be swapped. 807 */ 808 809 void 810 uvm_lwp_rele(struct lwp *l) 811 { 812 813 KASSERT(l->l_holdcnt != 0); 814 815 atomic_dec_uint(&l->l_holdcnt); 816 } 817