/*- * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * The Mach Operating System project at Carnegie-Mellon University. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * from: @(#)vm_glue.c 8.6 (Berkeley) 1/5/94 * * * Copyright (c) 1987, 1990 Carnegie-Mellon University. * All rights reserved. * * Permission to use, copy, modify and distribute this software and * its documentation is hereby granted, provided that both the copyright * notice and this permission notice appear in all copies of the * software, derivative works or modified versions, and any portions * thereof, and that both notices appear in supporting documentation. * * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. * * Carnegie Mellon requests users of this software to return to * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 * * any improvements or extensions that they make and grant Carnegie the * rights to redistribute these changes. */ #include __FBSDID("$FreeBSD$"); #include "opt_vm.h" #include "opt_kstack_pages.h" #include "opt_kstack_max_pages.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include extern int maxslp; /* * System initialization * * Note: proc0 from proc.h */ static void vm_init_limits(void *); SYSINIT(vm_limits, SI_SUB_VM_CONF, SI_ORDER_FIRST, vm_init_limits, &proc0) /* * THIS MUST BE THE LAST INITIALIZATION ITEM!!! * * Note: run scheduling should be divorced from the vm system. */ static void scheduler(void *); SYSINIT(scheduler, SI_SUB_RUN_SCHEDULER, SI_ORDER_ANY, scheduler, NULL) #ifndef NO_SWAPPING static void swapout(struct proc *); #endif static volatile int proc0_rescan; /* * MPSAFE * * WARNING! This code calls vm_map_check_protection() which only checks * the associated vm_map_entry range. It does not determine whether the * contents of the memory is actually readable or writable. In most cases * just checking the vm_map_entry is sufficient within the kernel's address * space. */ int kernacc(addr, len, rw) void *addr; int len, rw; { boolean_t rv; vm_offset_t saddr, eaddr; vm_prot_t prot; KASSERT((rw & ~VM_PROT_ALL) == 0, ("illegal ``rw'' argument to kernacc (%x)\n", rw)); if ((vm_offset_t)addr + len > kernel_map->max_offset || (vm_offset_t)addr + len < (vm_offset_t)addr) return (FALSE); prot = rw; saddr = trunc_page((vm_offset_t)addr); eaddr = round_page((vm_offset_t)addr + len); vm_map_lock_read(kernel_map); rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot); vm_map_unlock_read(kernel_map); return (rv == TRUE); } /* * MPSAFE * * WARNING! This code calls vm_map_check_protection() which only checks * the associated vm_map_entry range. It does not determine whether the * contents of the memory is actually readable or writable. vmapbuf(), * vm_fault_quick(), or copyin()/copout()/su*()/fu*() functions should be * used in conjuction with this call. */ int useracc(addr, len, rw) void *addr; int len, rw; { boolean_t rv; vm_prot_t prot; vm_map_t map; KASSERT((rw & ~VM_PROT_ALL) == 0, ("illegal ``rw'' argument to useracc (%x)\n", rw)); prot = rw; map = &curproc->p_vmspace->vm_map; if ((vm_offset_t)addr + len > vm_map_max(map) || (vm_offset_t)addr + len < (vm_offset_t)addr) { return (FALSE); } vm_map_lock_read(map); rv = vm_map_check_protection(map, trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len), prot); vm_map_unlock_read(map); return (rv == TRUE); } int vslock(void *addr, size_t len) { vm_offset_t end, last, start; vm_size_t npages; int error; last = (vm_offset_t)addr + len; start = trunc_page((vm_offset_t)addr); end = round_page(last); if (last < (vm_offset_t)addr || end < (vm_offset_t)addr) return (EINVAL); npages = atop(end - start); if (npages > vm_page_max_wired) return (ENOMEM); PROC_LOCK(curproc); if (ptoa(npages + pmap_wired_count(vm_map_pmap(&curproc->p_vmspace->vm_map))) > lim_cur(curproc, RLIMIT_MEMLOCK)) { PROC_UNLOCK(curproc); return (ENOMEM); } PROC_UNLOCK(curproc); #if 0 /* * XXX - not yet * * The limit for transient usage of wired pages should be * larger than for "permanent" wired pages (mlock()). * * Also, the sysctl code, which is the only present user * of vslock(), does a hard loop on EAGAIN. */ if (npages + cnt.v_wire_count > vm_page_max_wired) return (EAGAIN); #endif error = vm_map_wire(&curproc->p_vmspace->vm_map, start, end, VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES); /* * Return EFAULT on error to match copy{in,out}() behaviour * rather than returning ENOMEM like mlock() would. */ return (error == KERN_SUCCESS ? 0 : EFAULT); } void vsunlock(void *addr, size_t len) { /* Rely on the parameter sanity checks performed by vslock(). */ (void)vm_map_unwire(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len), VM_MAP_WIRE_SYSTEM | VM_MAP_WIRE_NOHOLES); } /* * Pin the page contained within the given object at the given offset. If the * page is not resident, allocate and load it using the given object's pager. * Return the pinned page if successful; otherwise, return NULL. */ static vm_page_t vm_imgact_hold_page(vm_object_t object, vm_ooffset_t offset) { vm_page_t m, ma[1]; vm_pindex_t pindex; int rv; VM_OBJECT_LOCK(object); pindex = OFF_TO_IDX(offset); m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); if ((m->valid & VM_PAGE_BITS_ALL) != VM_PAGE_BITS_ALL) { ma[0] = m; rv = vm_pager_get_pages(object, ma, 1, 0); m = vm_page_lookup(object, pindex); if (m == NULL) goto out; if (m->valid == 0 || rv != VM_PAGER_OK) { vm_page_lock_queues(); vm_page_free(m); vm_page_unlock_queues(); m = NULL; goto out; } } vm_page_lock_queues(); vm_page_hold(m); vm_page_unlock_queues(); vm_page_wakeup(m); out: VM_OBJECT_UNLOCK(object); return (m); } /* * Return a CPU private mapping to the page at the given offset within the * given object. The page is pinned before it is mapped. */ struct sf_buf * vm_imgact_map_page(vm_object_t object, vm_ooffset_t offset) { vm_page_t m; m = vm_imgact_hold_page(object, offset); if (m == NULL) return (NULL); sched_pin(); return (sf_buf_alloc(m, SFB_CPUPRIVATE)); } /* * Destroy the given CPU private mapping and unpin the page that it mapped. */ void vm_imgact_unmap_page(struct sf_buf *sf) { vm_page_t m; m = sf_buf_page(sf); sf_buf_free(sf); sched_unpin(); vm_page_lock_queues(); vm_page_unhold(m); vm_page_unlock_queues(); } #ifndef KSTACK_MAX_PAGES #define KSTACK_MAX_PAGES 32 #endif /* * Create the kernel stack (including pcb for i386) for a new thread. * This routine directly affects the fork perf for a process and * create performance for a thread. */ void vm_thread_new(struct thread *td, int pages) { vm_object_t ksobj; vm_offset_t ks; vm_page_t m, ma[KSTACK_MAX_PAGES]; int i; /* Bounds check */ if (pages <= 1) pages = KSTACK_PAGES; else if (pages > KSTACK_MAX_PAGES) pages = KSTACK_MAX_PAGES; /* * Allocate an object for the kstack. */ ksobj = vm_object_allocate(OBJT_DEFAULT, pages); td->td_kstack_obj = ksobj; /* * Get a kernel virtual address for this thread's kstack. */ ks = kmem_alloc_nofault(kernel_map, (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE); if (ks == 0) panic("vm_thread_new: kstack allocation failed"); if (KSTACK_GUARD_PAGES != 0) { pmap_qremove(ks, KSTACK_GUARD_PAGES); ks += KSTACK_GUARD_PAGES * PAGE_SIZE; } td->td_kstack = ks; /* * Knowing the number of pages allocated is useful when you * want to deallocate them. */ td->td_kstack_pages = pages; /* * For the length of the stack, link in a real page of ram for each * page of stack. */ VM_OBJECT_LOCK(ksobj); for (i = 0; i < pages; i++) { /* * Get a kernel stack page. */ m = vm_page_grab(ksobj, i, VM_ALLOC_NOBUSY | VM_ALLOC_NORMAL | VM_ALLOC_RETRY | VM_ALLOC_WIRED); ma[i] = m; m->valid = VM_PAGE_BITS_ALL; } VM_OBJECT_UNLOCK(ksobj); pmap_qenter(ks, ma, pages); } /* * Dispose of a thread's kernel stack. */ void vm_thread_dispose(struct thread *td) { vm_object_t ksobj; vm_offset_t ks; vm_page_t m; int i, pages; pages = td->td_kstack_pages; ksobj = td->td_kstack_obj; ks = td->td_kstack; pmap_qremove(ks, pages); VM_OBJECT_LOCK(ksobj); for (i = 0; i < pages; i++) { m = vm_page_lookup(ksobj, i); if (m == NULL) panic("vm_thread_dispose: kstack already missing?"); vm_page_lock_queues(); vm_page_unwire(m, 0); vm_page_free(m); vm_page_unlock_queues(); } VM_OBJECT_UNLOCK(ksobj); vm_object_deallocate(ksobj); kmem_free(kernel_map, ks - (KSTACK_GUARD_PAGES * PAGE_SIZE), (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE); } /* * Allow a thread's kernel stack to be paged out. */ void vm_thread_swapout(struct thread *td) { vm_object_t ksobj; vm_page_t m; int i, pages; cpu_thread_swapout(td); pages = td->td_kstack_pages; ksobj = td->td_kstack_obj; pmap_qremove(td->td_kstack, pages); VM_OBJECT_LOCK(ksobj); for (i = 0; i < pages; i++) { m = vm_page_lookup(ksobj, i); if (m == NULL) panic("vm_thread_swapout: kstack already missing?"); vm_page_lock_queues(); vm_page_dirty(m); vm_page_unwire(m, 0); vm_page_unlock_queues(); } VM_OBJECT_UNLOCK(ksobj); } /* * Bring the kernel stack for a specified thread back in. */ void vm_thread_swapin(struct thread *td) { vm_object_t ksobj; vm_page_t m, ma[KSTACK_MAX_PAGES]; int i, pages, rv; pages = td->td_kstack_pages; ksobj = td->td_kstack_obj; VM_OBJECT_LOCK(ksobj); for (i = 0; i < pages; i++) { m = vm_page_grab(ksobj, i, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); if (m->valid != VM_PAGE_BITS_ALL) { rv = vm_pager_get_pages(ksobj, &m, 1, 0); if (rv != VM_PAGER_OK) panic("vm_thread_swapin: cannot get kstack for proc: %d", td->td_proc->p_pid); m = vm_page_lookup(ksobj, i); m->valid = VM_PAGE_BITS_ALL; } ma[i] = m; vm_page_lock_queues(); vm_page_wire(m); vm_page_unlock_queues(); vm_page_wakeup(m); } VM_OBJECT_UNLOCK(ksobj); pmap_qenter(td->td_kstack, ma, pages); cpu_thread_swapin(td); } /* * Set up a variable-sized alternate kstack. */ void vm_thread_new_altkstack(struct thread *td, int pages) { td->td_altkstack = td->td_kstack; td->td_altkstack_obj = td->td_kstack_obj; td->td_altkstack_pages = td->td_kstack_pages; vm_thread_new(td, pages); } /* * Restore the original kstack. */ void vm_thread_dispose_altkstack(struct thread *td) { vm_thread_dispose(td); td->td_kstack = td->td_altkstack; td->td_kstack_obj = td->td_altkstack_obj; td->td_kstack_pages = td->td_altkstack_pages; td->td_altkstack = 0; td->td_altkstack_obj = NULL; td->td_altkstack_pages = 0; } /* * Implement fork's actions on an address space. * Here we arrange for the address space to be copied or referenced, * allocate a user struct (pcb and kernel stack), then call the * machine-dependent layer to fill those in and make the new process * ready to run. The new process is set up so that it returns directly * to user mode to avoid stack copying and relocation problems. */ void vm_forkproc(td, p2, td2, flags) struct thread *td; struct proc *p2; struct thread *td2; int flags; { struct proc *p1 = td->td_proc; if ((flags & RFPROC) == 0) { /* * Divorce the memory, if it is shared, essentially * this changes shared memory amongst threads, into * COW locally. */ if ((flags & RFMEM) == 0) { if (p1->p_vmspace->vm_refcnt > 1) { vmspace_unshare(p1); } } cpu_fork(td, p2, td2, flags); return; } if (flags & RFMEM) { p2->p_vmspace = p1->p_vmspace; atomic_add_int(&p1->p_vmspace->vm_refcnt, 1); } while (vm_page_count_severe()) { VM_WAIT; } if ((flags & RFMEM) == 0) { p2->p_vmspace = vmspace_fork(p1->p_vmspace); if (p1->p_vmspace->vm_shm) shmfork(p1, p2); } /* * cpu_fork will copy and update the pcb, set up the kernel stack, * and make the child ready to run. */ cpu_fork(td, p2, td2, flags); } /* * Called after process has been wait(2)'ed apon and is being reaped. * The idea is to reclaim resources that we could not reclaim while * the process was still executing. */ void vm_waitproc(p) struct proc *p; { vmspace_exitfree(p); /* and clean-out the vmspace */ } /* * Set default limits for VM system. * Called for proc 0, and then inherited by all others. * * XXX should probably act directly on proc0. */ static void vm_init_limits(udata) void *udata; { struct proc *p = udata; struct plimit *limp; int rss_limit; /* * Set up the initial limits on process VM. Set the maximum resident * set size to be half of (reasonably) available memory. Since this * is a soft limit, it comes into effect only when the system is out * of memory - half of main memory helps to favor smaller processes, * and reduces thrashing of the object cache. */ limp = p->p_limit; limp->pl_rlimit[RLIMIT_STACK].rlim_cur = dflssiz; limp->pl_rlimit[RLIMIT_STACK].rlim_max = maxssiz; limp->pl_rlimit[RLIMIT_DATA].rlim_cur = dfldsiz; limp->pl_rlimit[RLIMIT_DATA].rlim_max = maxdsiz; /* limit the limit to no less than 2MB */ rss_limit = max(cnt.v_free_count, 512); limp->pl_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit); limp->pl_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY; } void faultin(p) struct proc *p; { #ifdef NO_SWAPPING PROC_LOCK_ASSERT(p, MA_OWNED); if ((p->p_sflag & PS_INMEM) == 0) panic("faultin: proc swapped out with NO_SWAPPING!"); #else /* !NO_SWAPPING */ struct thread *td; PROC_LOCK_ASSERT(p, MA_OWNED); /* * If another process is swapping in this process, * just wait until it finishes. */ if (p->p_sflag & PS_SWAPPINGIN) msleep(&p->p_sflag, &p->p_mtx, PVM, "faultin", 0); else if ((p->p_sflag & PS_INMEM) == 0) { /* * Don't let another thread swap process p out while we are * busy swapping it in. */ ++p->p_lock; mtx_lock_spin(&sched_lock); p->p_sflag |= PS_SWAPPINGIN; mtx_unlock_spin(&sched_lock); PROC_UNLOCK(p); FOREACH_THREAD_IN_PROC(p, td) vm_thread_swapin(td); PROC_LOCK(p); mtx_lock_spin(&sched_lock); p->p_sflag &= ~PS_SWAPPINGIN; p->p_sflag |= PS_INMEM; FOREACH_THREAD_IN_PROC(p, td) { TD_CLR_SWAPPED(td); if (TD_CAN_RUN(td)) setrunnable(td); } mtx_unlock_spin(&sched_lock); wakeup(&p->p_sflag); /* Allow other threads to swap p out now. */ --p->p_lock; } #endif /* NO_SWAPPING */ } /* * This swapin algorithm attempts to swap-in processes only if there * is enough space for them. Of course, if a process waits for a long * time, it will be swapped in anyway. * * XXXKSE - process with the thread with highest priority counts.. * * Giant is held on entry. */ /* ARGSUSED*/ static void scheduler(dummy) void *dummy; { struct proc *p; struct thread *td; int pri; struct proc *pp; int ppri; mtx_assert(&Giant, MA_OWNED | MA_NOTRECURSED); mtx_unlock(&Giant); loop: if (vm_page_count_min()) { VM_WAIT; mtx_lock_spin(&sched_lock); proc0_rescan = 0; mtx_unlock_spin(&sched_lock); goto loop; } pp = NULL; ppri = INT_MIN; sx_slock(&allproc_lock); FOREACH_PROC_IN_SYSTEM(p) { if (p->p_sflag & (PS_INMEM | PS_SWAPPINGOUT | PS_SWAPPINGIN)) { continue; } mtx_lock_spin(&sched_lock); FOREACH_THREAD_IN_PROC(p, td) { /* * An otherwise runnable thread of a process * swapped out has only the TDI_SWAPPED bit set. * */ if (td->td_inhibitors == TDI_SWAPPED) { pri = p->p_swtime + td->td_slptime; if ((p->p_sflag & PS_SWAPINREQ) == 0) { pri -= p->p_nice * 8; } /* * if this thread is higher priority * and there is enough space, then select * this process instead of the previous * selection. */ if (pri > ppri) { pp = p; ppri = pri; } } } mtx_unlock_spin(&sched_lock); } sx_sunlock(&allproc_lock); /* * Nothing to do, back to sleep. */ if ((p = pp) == NULL) { mtx_lock_spin(&sched_lock); if (!proc0_rescan) { TD_SET_IWAIT(&thread0); mi_switch(SW_VOL, NULL); } proc0_rescan = 0; mtx_unlock_spin(&sched_lock); goto loop; } PROC_LOCK(p); /* * Another process may be bringing or may have already * brought this process in while we traverse all threads. * Or, this process may even be being swapped out again. */ if (p->p_sflag & (PS_INMEM | PS_SWAPPINGOUT | PS_SWAPPINGIN)) { PROC_UNLOCK(p); mtx_lock_spin(&sched_lock); proc0_rescan = 0; mtx_unlock_spin(&sched_lock); goto loop; } mtx_lock_spin(&sched_lock); p->p_sflag &= ~PS_SWAPINREQ; mtx_unlock_spin(&sched_lock); /* * We would like to bring someone in. (only if there is space). * [What checks the space? ] */ faultin(p); PROC_UNLOCK(p); mtx_lock_spin(&sched_lock); p->p_swtime = 0; proc0_rescan = 0; mtx_unlock_spin(&sched_lock); goto loop; } void kick_proc0(void) { struct thread *td = &thread0; if (TD_AWAITING_INTR(td)) { CTR2(KTR_INTR, "%s: sched_add %d", __func__, 0); TD_CLR_IWAIT(td); sched_add(td, SRQ_INTR); } else { proc0_rescan = 1; CTR2(KTR_INTR, "%s: state %d", __func__, td->td_state); } } #ifndef NO_SWAPPING /* * Swap_idle_threshold1 is the guaranteed swapped in time for a process */ static int swap_idle_threshold1 = 2; SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, CTLFLAG_RW, &swap_idle_threshold1, 0, "Guaranteed swapped in time for a process"); /* * Swap_idle_threshold2 is the time that a process can be idle before * it will be swapped out, if idle swapping is enabled. */ static int swap_idle_threshold2 = 10; SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, CTLFLAG_RW, &swap_idle_threshold2, 0, "Time before a process will be swapped out"); /* * Swapout is driven by the pageout daemon. Very simple, we find eligible * procs and unwire their u-areas. We try to always "swap" at least one * process in case we need the room for a swapin. * If any procs have been sleeping/stopped for at least maxslp seconds, * they are swapped. Else, we swap the longest-sleeping or stopped process, * if any, otherwise the longest-resident process. */ void swapout_procs(action) int action; { struct proc *p; struct thread *td; int didswap = 0; retry: sx_slock(&allproc_lock); FOREACH_PROC_IN_SYSTEM(p) { struct vmspace *vm; int minslptime = 100000; /* * Watch out for a process in * creation. It may have no * address space or lock yet. */ mtx_lock_spin(&sched_lock); if (p->p_state == PRS_NEW) { mtx_unlock_spin(&sched_lock); continue; } mtx_unlock_spin(&sched_lock); /* * An aio daemon switches its * address space while running. * Perform a quick check whether * a process has P_SYSTEM. */ if ((p->p_flag & P_SYSTEM) != 0) continue; /* * Do not swapout a process that * is waiting for VM data * structures as there is a possible * deadlock. Test this first as * this may block. * * Lock the map until swapout * finishes, or a thread of this * process may attempt to alter * the map. */ vm = vmspace_acquire_ref(p); if (vm == NULL) continue; if (!vm_map_trylock(&vm->vm_map)) goto nextproc1; PROC_LOCK(p); if (p->p_lock != 0 || (p->p_flag & (P_STOPPED_SINGLE|P_TRACED|P_SYSTEM|P_WEXIT) ) != 0) { goto nextproc2; } /* * only aiod changes vmspace, however it will be * skipped because of the if statement above checking * for P_SYSTEM */ if ((p->p_sflag & (PS_INMEM|PS_SWAPPINGOUT|PS_SWAPPINGIN)) != PS_INMEM) goto nextproc2; switch (p->p_state) { default: /* Don't swap out processes in any sort * of 'special' state. */ break; case PRS_NORMAL: mtx_lock_spin(&sched_lock); /* * do not swapout a realtime process * Check all the thread groups.. */ FOREACH_THREAD_IN_PROC(p, td) { if (PRI_IS_REALTIME(td->td_pri_class)) goto nextproc; /* * Guarantee swap_idle_threshold1 * time in memory. */ if (td->td_slptime < swap_idle_threshold1) goto nextproc; /* * Do not swapout a process if it is * waiting on a critical event of some * kind or there is a thread whose * pageable memory may be accessed. * * This could be refined to support * swapping out a thread. */ if ((td->td_priority) < PSOCK || !thread_safetoswapout(td)) goto nextproc; /* * If the system is under memory stress, * or if we are swapping * idle processes >= swap_idle_threshold2, * then swap the process out. */ if (((action & VM_SWAP_NORMAL) == 0) && (((action & VM_SWAP_IDLE) == 0) || (td->td_slptime < swap_idle_threshold2))) goto nextproc; if (minslptime > td->td_slptime) minslptime = td->td_slptime; } /* * If the pageout daemon didn't free enough pages, * or if this process is idle and the system is * configured to swap proactively, swap it out. */ if ((action & VM_SWAP_NORMAL) || ((action & VM_SWAP_IDLE) && (minslptime > swap_idle_threshold2))) { swapout(p); didswap++; mtx_unlock_spin(&sched_lock); PROC_UNLOCK(p); vm_map_unlock(&vm->vm_map); vmspace_free(vm); sx_sunlock(&allproc_lock); goto retry; } nextproc: mtx_unlock_spin(&sched_lock); } nextproc2: PROC_UNLOCK(p); vm_map_unlock(&vm->vm_map); nextproc1: vmspace_free(vm); continue; } sx_sunlock(&allproc_lock); /* * If we swapped something out, and another process needed memory, * then wakeup the sched process. */ if (didswap) wakeup(&proc0); } static void swapout(p) struct proc *p; { struct thread *td; PROC_LOCK_ASSERT(p, MA_OWNED); mtx_assert(&sched_lock, MA_OWNED | MA_NOTRECURSED); #if defined(SWAP_DEBUG) printf("swapping out %d\n", p->p_pid); #endif /* * The states of this process and its threads may have changed * by now. Assuming that there is only one pageout daemon thread, * this process should still be in memory. */ KASSERT((p->p_sflag & (PS_INMEM|PS_SWAPPINGOUT|PS_SWAPPINGIN)) == PS_INMEM, ("swapout: lost a swapout race?")); #if defined(INVARIANTS) /* * Make sure that all threads are safe to be swapped out. * * Alternatively, we could swap out only safe threads. */ FOREACH_THREAD_IN_PROC(p, td) { KASSERT(thread_safetoswapout(td), ("swapout: there is a thread not safe for swapout")); } #endif /* INVARIANTS */ ++p->p_stats->p_ru.ru_nswap; /* * remember the process resident count */ p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace); p->p_sflag &= ~PS_INMEM; p->p_sflag |= PS_SWAPPINGOUT; PROC_UNLOCK(p); FOREACH_THREAD_IN_PROC(p, td) TD_SET_SWAPPED(td); mtx_unlock_spin(&sched_lock); FOREACH_THREAD_IN_PROC(p, td) vm_thread_swapout(td); PROC_LOCK(p); mtx_lock_spin(&sched_lock); p->p_sflag &= ~PS_SWAPPINGOUT; p->p_swtime = 0; } #endif /* !NO_SWAPPING */