2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
6 * The Mach Operating System project at Carnegie-Mellon University.
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 4. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * from: @(#)vm_glue.c 8.6 (Berkeley) 1/5/94
35 * Copyright (c) 1987, 1990 Carnegie-Mellon University.
36 * All rights reserved.
38 * Permission to use, copy, modify and distribute this software and
39 * its documentation is hereby granted, provided that both the copyright
40 * notice and this permission notice appear in all copies of the
41 * software, derivative works or modified versions, and any portions
42 * thereof, and that both notices appear in supporting documentation.
44 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
45 * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND
46 * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
48 * Carnegie Mellon requests users of this software to return to
50 * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
51 * School of Computer Science
52 * Carnegie Mellon University
53 * Pittsburgh PA 15213-3890
55 * any improvements or extensions that they make and grant Carnegie the
56 * rights to redistribute these changes.
59 #include <sys/cdefs.h>
60 __FBSDID("$FreeBSD$");
63 #include "opt_kstack_pages.h"
64 #include "opt_kstack_max_pages.h"
66 #include <sys/param.h>
67 #include <sys/systm.h>
68 #include <sys/limits.h>
70 #include <sys/mutex.h>
72 #include <sys/racct.h>
73 #include <sys/resourcevar.h>
74 #include <sys/rwlock.h>
75 #include <sys/sched.h>
76 #include <sys/sf_buf.h>
78 #include <sys/vmmeter.h>
80 #include <sys/sysctl.h>
81 #include <sys/_kstack_cache.h>
82 #include <sys/eventhandler.h>
83 #include <sys/kernel.h>
85 #include <sys/unistd.h>
88 #include <vm/vm_param.h>
90 #include <vm/vm_map.h>
91 #include <vm/vm_page.h>
92 #include <vm/vm_pageout.h>
93 #include <vm/vm_object.h>
94 #include <vm/vm_kern.h>
95 #include <vm/vm_extern.h>
96 #include <vm/vm_pager.h>
97 #include <vm/swap_pager.h>
100 * System initialization
102 * THIS MUST BE THE LAST INITIALIZATION ITEM!!!
104 * Note: run scheduling should be divorced from the vm system.
106 static void scheduler(void *);
107 SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_ANY, scheduler, NULL);
110 static int swapout(struct proc *);
111 static void swapclear(struct proc *);
112 static void vm_thread_swapin(struct thread *td);
113 static void vm_thread_swapout(struct thread *td);
119 * WARNING! This code calls vm_map_check_protection() which only checks
120 * the associated vm_map_entry range. It does not determine whether the
121 * contents of the memory is actually readable or writable. In most cases
122 * just checking the vm_map_entry is sufficient within the kernel's address
126 kernacc(addr, len, rw)
131 vm_offset_t saddr, eaddr;
134 KASSERT((rw & ~VM_PROT_ALL) == 0,
135 ("illegal ``rw'' argument to kernacc (%x)\n", rw));
137 if ((vm_offset_t)addr + len > kernel_map->max_offset ||
138 (vm_offset_t)addr + len < (vm_offset_t)addr)
142 saddr = trunc_page((vm_offset_t)addr);
143 eaddr = round_page((vm_offset_t)addr + len);
144 vm_map_lock_read(kernel_map);
145 rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot);
146 vm_map_unlock_read(kernel_map);
153 * WARNING! This code calls vm_map_check_protection() which only checks
154 * the associated vm_map_entry range. It does not determine whether the
155 * contents of the memory is actually readable or writable. vmapbuf(),
156 * vm_fault_quick(), or copyin()/copout()/su*()/fu*() functions should be
157 * used in conjuction with this call.
160 useracc(addr, len, rw)
168 KASSERT((rw & ~VM_PROT_ALL) == 0,
169 ("illegal ``rw'' argument to useracc (%x)\n", rw));
171 map = &curproc->p_vmspace->vm_map;
172 if ((vm_offset_t)addr + len > vm_map_max(map) ||
173 (vm_offset_t)addr + len < (vm_offset_t)addr) {
176 vm_map_lock_read(map);
177 rv = vm_map_check_protection(map, trunc_page((vm_offset_t)addr),
178 round_page((vm_offset_t)addr + len), prot);
179 vm_map_unlock_read(map);
184 vslock(void *addr, size_t len)
186 vm_offset_t end, last, start;
190 last = (vm_offset_t)addr + len;
191 start = trunc_page((vm_offset_t)addr);
192 end = round_page(last);
193 if (last < (vm_offset_t)addr || end < (vm_offset_t)addr)
195 npages = atop(end - start);
196 if (npages > vm_page_max_wired)
202 * The limit for transient usage of wired pages should be
203 * larger than for "permanent" wired pages (mlock()).
205 * Also, the sysctl code, which is the only present user
206 * of vslock(), does a hard loop on EAGAIN.
208 if (npages + cnt.v_wire_count > vm_page_max_wired)
211 error = vm_map_wire(&curproc->p_vmspace->vm_map, start, end,
212 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
214 * Return EFAULT on error to match copy{in,out}() behaviour
215 * rather than returning ENOMEM like mlock() would.
217 return (error == KERN_SUCCESS ? 0 : EFAULT);
221 vsunlock(void *addr, size_t len)
224 /* Rely on the parameter sanity checks performed by vslock(). */
225 (void)vm_map_unwire(&curproc->p_vmspace->vm_map,
226 trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len),
227 VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES);
231 * Pin the page contained within the given object at the given offset. If the
232 * page is not resident, allocate and load it using the given object's pager.
233 * Return the pinned page if successful; otherwise, return NULL.
236 vm_imgact_hold_page(vm_object_t object, vm_ooffset_t offset)
242 VM_OBJECT_WLOCK(object);
243 pindex = OFF_TO_IDX(offset);
244 m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL | VM_ALLOC_RETRY);
245 if (m->valid != VM_PAGE_BITS_ALL) {
247 rv = vm_pager_get_pages(object, ma, 1, 0);
248 m = vm_page_lookup(object, pindex);
251 if (rv != VM_PAGER_OK) {
264 VM_OBJECT_WUNLOCK(object);
269 * Return a CPU private mapping to the page at the given offset within the
270 * given object. The page is pinned before it is mapped.
273 vm_imgact_map_page(vm_object_t object, vm_ooffset_t offset)
277 m = vm_imgact_hold_page(object, offset);
281 return (sf_buf_alloc(m, SFB_CPUPRIVATE));
285 * Destroy the given CPU private mapping and unpin the page that it mapped.
288 vm_imgact_unmap_page(struct sf_buf *sf)
301 vm_sync_icache(vm_map_t map, vm_offset_t va, vm_offset_t sz)
304 pmap_sync_icache(map->pmap, va, sz);
307 struct kstack_cache_entry *kstack_cache;
308 static int kstack_cache_size = 128;
310 static struct mtx kstack_cache_mtx;
311 MTX_SYSINIT(kstack_cache, &kstack_cache_mtx, "kstkch", MTX_DEF);
313 SYSCTL_INT(_vm, OID_AUTO, kstack_cache_size, CTLFLAG_RW, &kstack_cache_size, 0,
315 SYSCTL_INT(_vm, OID_AUTO, kstacks, CTLFLAG_RD, &kstacks, 0,
318 #ifndef KSTACK_MAX_PAGES
319 #define KSTACK_MAX_PAGES 32
323 * Create the kernel stack (including pcb for i386) for a new thread.
324 * This routine directly affects the fork perf for a process and
325 * create performance for a thread.
328 vm_thread_new(struct thread *td, int pages)
332 vm_page_t m, ma[KSTACK_MAX_PAGES];
333 struct kstack_cache_entry *ks_ce;
338 pages = KSTACK_PAGES;
339 else if (pages > KSTACK_MAX_PAGES)
340 pages = KSTACK_MAX_PAGES;
342 if (pages == KSTACK_PAGES) {
343 mtx_lock(&kstack_cache_mtx);
344 if (kstack_cache != NULL) {
345 ks_ce = kstack_cache;
346 kstack_cache = ks_ce->next_ks_entry;
347 mtx_unlock(&kstack_cache_mtx);
349 td->td_kstack_obj = ks_ce->ksobj;
350 td->td_kstack = (vm_offset_t)ks_ce;
351 td->td_kstack_pages = KSTACK_PAGES;
354 mtx_unlock(&kstack_cache_mtx);
358 * Allocate an object for the kstack.
360 ksobj = vm_object_allocate(OBJT_DEFAULT, pages);
363 * Get a kernel virtual address for this thread's kstack.
365 #if defined(__mips__)
367 * We need to align the kstack's mapped address to fit within
368 * a single TLB entry.
370 ks = kmem_alloc_nofault_space(kernel_map,
371 (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE, VMFS_TLB_ALIGNED_SPACE);
373 ks = kmem_alloc_nofault(kernel_map,
374 (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE);
377 printf("vm_thread_new: kstack allocation failed\n");
378 vm_object_deallocate(ksobj);
382 atomic_add_int(&kstacks, 1);
383 if (KSTACK_GUARD_PAGES != 0) {
384 pmap_qremove(ks, KSTACK_GUARD_PAGES);
385 ks += KSTACK_GUARD_PAGES * PAGE_SIZE;
387 td->td_kstack_obj = ksobj;
390 * Knowing the number of pages allocated is useful when you
391 * want to deallocate them.
393 td->td_kstack_pages = pages;
395 * For the length of the stack, link in a real page of ram for each
398 VM_OBJECT_WLOCK(ksobj);
399 for (i = 0; i < pages; i++) {
401 * Get a kernel stack page.
403 m = vm_page_grab(ksobj, i, VM_ALLOC_NOBUSY |
404 VM_ALLOC_NORMAL | VM_ALLOC_RETRY | VM_ALLOC_WIRED);
406 m->valid = VM_PAGE_BITS_ALL;
408 VM_OBJECT_WUNLOCK(ksobj);
409 pmap_qenter(ks, ma, pages);
414 vm_thread_stack_dispose(vm_object_t ksobj, vm_offset_t ks, int pages)
419 atomic_add_int(&kstacks, -1);
420 pmap_qremove(ks, pages);
421 VM_OBJECT_WLOCK(ksobj);
422 for (i = 0; i < pages; i++) {
423 m = vm_page_lookup(ksobj, i);
425 panic("vm_thread_dispose: kstack already missing?");
427 vm_page_unwire(m, 0);
431 VM_OBJECT_WUNLOCK(ksobj);
432 vm_object_deallocate(ksobj);
433 kmem_free(kernel_map, ks - (KSTACK_GUARD_PAGES * PAGE_SIZE),
434 (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE);
438 * Dispose of a thread's kernel stack.
441 vm_thread_dispose(struct thread *td)
445 struct kstack_cache_entry *ks_ce;
448 pages = td->td_kstack_pages;
449 ksobj = td->td_kstack_obj;
452 td->td_kstack_pages = 0;
453 if (pages == KSTACK_PAGES && kstacks <= kstack_cache_size) {
454 ks_ce = (struct kstack_cache_entry *)ks;
455 ks_ce->ksobj = ksobj;
456 mtx_lock(&kstack_cache_mtx);
457 ks_ce->next_ks_entry = kstack_cache;
458 kstack_cache = ks_ce;
459 mtx_unlock(&kstack_cache_mtx);
462 vm_thread_stack_dispose(ksobj, ks, pages);
466 vm_thread_stack_lowmem(void *nulll)
468 struct kstack_cache_entry *ks_ce, *ks_ce1;
470 mtx_lock(&kstack_cache_mtx);
471 ks_ce = kstack_cache;
473 mtx_unlock(&kstack_cache_mtx);
475 while (ks_ce != NULL) {
477 ks_ce = ks_ce->next_ks_entry;
479 vm_thread_stack_dispose(ks_ce1->ksobj, (vm_offset_t)ks_ce1,
485 kstack_cache_init(void *nulll)
488 EVENTHANDLER_REGISTER(vm_lowmem, vm_thread_stack_lowmem, NULL,
489 EVENTHANDLER_PRI_ANY);
492 SYSINIT(vm_kstacks, SI_SUB_KTHREAD_INIT, SI_ORDER_ANY, kstack_cache_init, NULL);
496 * Allow a thread's kernel stack to be paged out.
499 vm_thread_swapout(struct thread *td)
505 cpu_thread_swapout(td);
506 pages = td->td_kstack_pages;
507 ksobj = td->td_kstack_obj;
508 pmap_qremove(td->td_kstack, pages);
509 VM_OBJECT_WLOCK(ksobj);
510 for (i = 0; i < pages; i++) {
511 m = vm_page_lookup(ksobj, i);
513 panic("vm_thread_swapout: kstack already missing?");
516 vm_page_unwire(m, 0);
519 VM_OBJECT_WUNLOCK(ksobj);
523 * Bring the kernel stack for a specified thread back in.
526 vm_thread_swapin(struct thread *td)
529 vm_page_t ma[KSTACK_MAX_PAGES];
530 int i, j, k, pages, rv;
532 pages = td->td_kstack_pages;
533 ksobj = td->td_kstack_obj;
534 VM_OBJECT_WLOCK(ksobj);
535 for (i = 0; i < pages; i++)
536 ma[i] = vm_page_grab(ksobj, i, VM_ALLOC_NORMAL | VM_ALLOC_RETRY |
538 for (i = 0; i < pages; i++) {
539 if (ma[i]->valid != VM_PAGE_BITS_ALL) {
540 KASSERT(ma[i]->oflags & VPO_BUSY,
542 vm_object_pip_add(ksobj, 1);
543 for (j = i + 1; j < pages; j++) {
544 KASSERT(ma[j]->valid == VM_PAGE_BITS_ALL ||
545 (ma[j]->oflags & VPO_BUSY),
547 if (ma[j]->valid == VM_PAGE_BITS_ALL)
550 rv = vm_pager_get_pages(ksobj, ma + i, j - i, 0);
551 if (rv != VM_PAGER_OK)
552 panic("vm_thread_swapin: cannot get kstack for proc: %d",
554 vm_object_pip_wakeup(ksobj);
555 for (k = i; k < j; k++)
556 ma[k] = vm_page_lookup(ksobj, k);
557 vm_page_wakeup(ma[i]);
558 } else if (ma[i]->oflags & VPO_BUSY)
559 vm_page_wakeup(ma[i]);
561 VM_OBJECT_WUNLOCK(ksobj);
562 pmap_qenter(td->td_kstack, ma, pages);
563 cpu_thread_swapin(td);
565 #endif /* !NO_SWAPPING */
568 * Implement fork's actions on an address space.
569 * Here we arrange for the address space to be copied or referenced,
570 * allocate a user struct (pcb and kernel stack), then call the
571 * machine-dependent layer to fill those in and make the new process
572 * ready to run. The new process is set up so that it returns directly
573 * to user mode to avoid stack copying and relocation problems.
576 vm_forkproc(td, p2, td2, vm2, flags)
583 struct proc *p1 = td->td_proc;
586 if ((flags & RFPROC) == 0) {
588 * Divorce the memory, if it is shared, essentially
589 * this changes shared memory amongst threads, into
592 if ((flags & RFMEM) == 0) {
593 if (p1->p_vmspace->vm_refcnt > 1) {
594 error = vmspace_unshare(p1);
599 cpu_fork(td, p2, td2, flags);
604 p2->p_vmspace = p1->p_vmspace;
605 atomic_add_int(&p1->p_vmspace->vm_refcnt, 1);
608 while (vm_page_count_severe()) {
612 if ((flags & RFMEM) == 0) {
614 if (p1->p_vmspace->vm_shm)
619 * cpu_fork will copy and update the pcb, set up the kernel stack,
620 * and make the child ready to run.
622 cpu_fork(td, p2, td2, flags);
627 * Called after process has been wait(2)'ed apon and is being reaped.
628 * The idea is to reclaim resources that we could not reclaim while
629 * the process was still executing.
636 vmspace_exitfree(p); /* and clean-out the vmspace */
645 PROC_LOCK_ASSERT(p, MA_OWNED);
646 if ((p->p_flag & P_INMEM) == 0)
647 panic("faultin: proc swapped out with NO_SWAPPING!");
648 #else /* !NO_SWAPPING */
651 PROC_LOCK_ASSERT(p, MA_OWNED);
653 * If another process is swapping in this process,
654 * just wait until it finishes.
656 if (p->p_flag & P_SWAPPINGIN) {
657 while (p->p_flag & P_SWAPPINGIN)
658 msleep(&p->p_flag, &p->p_mtx, PVM, "faultin", 0);
661 if ((p->p_flag & P_INMEM) == 0) {
663 * Don't let another thread swap process p out while we are
664 * busy swapping it in.
667 p->p_flag |= P_SWAPPINGIN;
671 * We hold no lock here because the list of threads
672 * can not change while all threads in the process are
675 FOREACH_THREAD_IN_PROC(p, td)
676 vm_thread_swapin(td);
683 /* Allow other threads to swap p out now. */
686 #endif /* NO_SWAPPING */
690 * This swapin algorithm attempts to swap-in processes only if there
691 * is enough space for them. Of course, if a process waits for a long
692 * time, it will be swapped in anyway.
694 * Giant is held on entry.
709 mtx_assert(&Giant, MA_OWNED | MA_NOTRECURSED);
713 if (vm_page_count_min()) {
720 sx_slock(&allproc_lock);
721 FOREACH_PROC_IN_SYSTEM(p) {
723 if (p->p_state == PRS_NEW ||
724 p->p_flag & (P_SWAPPINGOUT | P_SWAPPINGIN | P_INMEM)) {
728 swtime = (ticks - p->p_swtick) / hz;
729 FOREACH_THREAD_IN_PROC(p, td) {
731 * An otherwise runnable thread of a process
732 * swapped out has only the TDI_SWAPPED bit set.
736 if (td->td_inhibitors == TDI_SWAPPED) {
737 slptime = (ticks - td->td_slptick) / hz;
738 pri = swtime + slptime;
739 if ((td->td_flags & TDF_SWAPINREQ) == 0)
740 pri -= p->p_nice * 8;
742 * if this thread is higher priority
743 * and there is enough space, then select
744 * this process instead of the previous
756 sx_sunlock(&allproc_lock);
759 * Nothing to do, back to sleep.
761 if ((p = pp) == NULL) {
762 tsleep(&proc0, PVM, "sched", MAXSLP * hz / 2);
768 * Another process may be bringing or may have already
769 * brought this process in while we traverse all threads.
770 * Or, this process may even be being swapped out again.
772 if (p->p_flag & (P_INMEM | P_SWAPPINGOUT | P_SWAPPINGIN)) {
778 * We would like to bring someone in. (only if there is space).
779 * [What checks the space? ]
796 * Swap_idle_threshold1 is the guaranteed swapped in time for a process
798 static int swap_idle_threshold1 = 2;
799 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, CTLFLAG_RW,
800 &swap_idle_threshold1, 0, "Guaranteed swapped in time for a process");
803 * Swap_idle_threshold2 is the time that a process can be idle before
804 * it will be swapped out, if idle swapping is enabled.
806 static int swap_idle_threshold2 = 10;
807 SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, CTLFLAG_RW,
808 &swap_idle_threshold2, 0, "Time before a process will be swapped out");
811 * First, if any processes have been sleeping or stopped for at least
812 * "swap_idle_threshold1" seconds, they are swapped out. If, however,
813 * no such processes exist, then the longest-sleeping or stopped
814 * process is swapped out. Finally, and only as a last resort, if
815 * there are no sleeping or stopped processes, the longest-resident
816 * process is swapped out.
819 swapout_procs(action)
827 sx_slock(&allproc_lock);
828 FOREACH_PROC_IN_SYSTEM(p) {
830 int minslptime = 100000;
834 * Watch out for a process in
835 * creation. It may have no
836 * address space or lock yet.
838 if (p->p_state == PRS_NEW)
841 * An aio daemon switches its
842 * address space while running.
843 * Perform a quick check whether
844 * a process has P_SYSTEM.
846 if ((p->p_flag & P_SYSTEM) != 0)
849 * Do not swapout a process that
850 * is waiting for VM data
851 * structures as there is a possible
852 * deadlock. Test this first as
855 * Lock the map until swapout
856 * finishes, or a thread of this
857 * process may attempt to alter
860 vm = vmspace_acquire_ref(p);
863 if (!vm_map_trylock(&vm->vm_map))
867 if (p->p_lock != 0 ||
868 (p->p_flag & (P_STOPPED_SINGLE|P_TRACED|P_SYSTEM|P_WEXIT)
873 * only aiod changes vmspace, however it will be
874 * skipped because of the if statement above checking
877 if ((p->p_flag & (P_INMEM|P_SWAPPINGOUT|P_SWAPPINGIN)) != P_INMEM)
880 switch (p->p_state) {
882 /* Don't swap out processes in any sort
883 * of 'special' state. */
888 * do not swapout a realtime process
889 * Check all the thread groups..
891 FOREACH_THREAD_IN_PROC(p, td) {
893 if (PRI_IS_REALTIME(td->td_pri_class)) {
897 slptime = (ticks - td->td_slptick) / hz;
899 * Guarantee swap_idle_threshold1
902 if (slptime < swap_idle_threshold1) {
908 * Do not swapout a process if it is
909 * waiting on a critical event of some
910 * kind or there is a thread whose
911 * pageable memory may be accessed.
913 * This could be refined to support
914 * swapping out a thread.
916 if (!thread_safetoswapout(td)) {
921 * If the system is under memory stress,
922 * or if we are swapping
923 * idle processes >= swap_idle_threshold2,
924 * then swap the process out.
926 if (((action & VM_SWAP_NORMAL) == 0) &&
927 (((action & VM_SWAP_IDLE) == 0) ||
928 (slptime < swap_idle_threshold2))) {
933 if (minslptime > slptime)
934 minslptime = slptime;
939 * If the pageout daemon didn't free enough pages,
940 * or if this process is idle and the system is
941 * configured to swap proactively, swap it out.
943 if ((action & VM_SWAP_NORMAL) ||
944 ((action & VM_SWAP_IDLE) &&
945 (minslptime > swap_idle_threshold2))) {
949 vm_map_unlock(&vm->vm_map);
951 sx_sunlock(&allproc_lock);
957 vm_map_unlock(&vm->vm_map);
962 sx_sunlock(&allproc_lock);
964 * If we swapped something out, and another process needed memory,
965 * then wakeup the sched process.
977 PROC_LOCK_ASSERT(p, MA_OWNED);
979 FOREACH_THREAD_IN_PROC(p, td) {
981 td->td_flags |= TDF_INMEM;
982 td->td_flags &= ~TDF_SWAPINREQ;
985 if (setrunnable(td)) {
988 * XXX: We just cleared TDI_SWAPPED
989 * above and set TDF_INMEM, so this
990 * should never happen.
992 panic("not waking up swapper");
997 p->p_flag &= ~(P_SWAPPINGIN|P_SWAPPINGOUT);
998 p->p_flag |= P_INMEM;
1007 PROC_LOCK_ASSERT(p, MA_OWNED);
1008 #if defined(SWAP_DEBUG)
1009 printf("swapping out %d\n", p->p_pid);
1013 * The states of this process and its threads may have changed
1014 * by now. Assuming that there is only one pageout daemon thread,
1015 * this process should still be in memory.
1017 KASSERT((p->p_flag & (P_INMEM|P_SWAPPINGOUT|P_SWAPPINGIN)) == P_INMEM,
1018 ("swapout: lost a swapout race?"));
1021 * remember the process resident count
1023 p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace);
1025 * Check and mark all threads before we proceed.
1027 p->p_flag &= ~P_INMEM;
1028 p->p_flag |= P_SWAPPINGOUT;
1029 FOREACH_THREAD_IN_PROC(p, td) {
1031 if (!thread_safetoswapout(td)) {
1036 td->td_flags &= ~TDF_INMEM;
1040 td = FIRST_THREAD_IN_PROC(p);
1041 ++td->td_ru.ru_nswap;
1045 * This list is stable because all threads are now prevented from
1046 * running. The list is only modified in the context of a running
1047 * thread in this process.
1049 FOREACH_THREAD_IN_PROC(p, td)
1050 vm_thread_swapout(td);
1053 p->p_flag &= ~P_SWAPPINGOUT;
1054 p->p_swtick = ticks;
1057 #endif /* !NO_SWAPPING */