/*- * 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 "opt_kstack_usage_prof.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 #include #include #include #include #include #include #include #ifndef NO_SWAPPING static int swapout(struct proc *); static void swapclear(struct proc *); static void vm_thread_swapin(struct thread *td); static void vm_thread_swapout(struct thread *td); #endif /* * 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); #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 + vm_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; vm_pindex_t pindex; int rv; VM_OBJECT_WLOCK(object); pindex = OFF_TO_IDX(offset); m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL); if (m->valid != VM_PAGE_BITS_ALL) { rv = vm_pager_get_pages(object, &m, 1, 0); if (rv != VM_PAGER_OK) { vm_page_lock(m); vm_page_free(m); vm_page_unlock(m); m = NULL; goto out; } } vm_page_xunbusy(m); vm_page_lock(m); vm_page_hold(m); vm_page_activate(m); vm_page_unlock(m); out: VM_OBJECT_WUNLOCK(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(m); vm_page_unhold(m); vm_page_unlock(m); } void vm_sync_icache(vm_map_t map, vm_offset_t va, vm_offset_t sz) { pmap_sync_icache(map->pmap, va, sz); } struct kstack_cache_entry *kstack_cache; static int kstack_cache_size = 128; static int kstacks; static struct mtx kstack_cache_mtx; MTX_SYSINIT(kstack_cache, &kstack_cache_mtx, "kstkch", MTX_DEF); SYSCTL_INT(_vm, OID_AUTO, kstack_cache_size, CTLFLAG_RW, &kstack_cache_size, 0, ""); SYSCTL_INT(_vm, OID_AUTO, kstacks, CTLFLAG_RD, &kstacks, 0, ""); #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. */ int vm_thread_new(struct thread *td, int pages) { vm_object_t ksobj; vm_offset_t ks; vm_page_t m, ma[KSTACK_MAX_PAGES]; struct kstack_cache_entry *ks_ce; int i; /* Bounds check */ if (pages <= 1) pages = kstack_pages; else if (pages > KSTACK_MAX_PAGES) pages = KSTACK_MAX_PAGES; if (pages == kstack_pages) { mtx_lock(&kstack_cache_mtx); if (kstack_cache != NULL) { ks_ce = kstack_cache; kstack_cache = ks_ce->next_ks_entry; mtx_unlock(&kstack_cache_mtx); td->td_kstack_obj = ks_ce->ksobj; td->td_kstack = (vm_offset_t)ks_ce; td->td_kstack_pages = kstack_pages; return (1); } mtx_unlock(&kstack_cache_mtx); } /* * Allocate an object for the kstack. */ ksobj = vm_object_allocate(OBJT_DEFAULT, pages); /* * Get a kernel virtual address for this thread's kstack. */ #if defined(__mips__) /* * We need to align the kstack's mapped address to fit within * a single TLB entry. */ if (vmem_xalloc(kernel_arena, (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE, PAGE_SIZE * 2, 0, 0, VMEM_ADDR_MIN, VMEM_ADDR_MAX, M_BESTFIT | M_NOWAIT, &ks)) { ks = 0; } #else ks = kva_alloc((pages + KSTACK_GUARD_PAGES) * PAGE_SIZE); #endif if (ks == 0) { printf("vm_thread_new: kstack allocation failed\n"); vm_object_deallocate(ksobj); return (0); } atomic_add_int(&kstacks, 1); if (KSTACK_GUARD_PAGES != 0) { pmap_qremove(ks, KSTACK_GUARD_PAGES); ks += KSTACK_GUARD_PAGES * PAGE_SIZE; } td->td_kstack_obj = ksobj; 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_WLOCK(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_WIRED); ma[i] = m; m->valid = VM_PAGE_BITS_ALL; } VM_OBJECT_WUNLOCK(ksobj); pmap_qenter(ks, ma, pages); return (1); } static void vm_thread_stack_dispose(vm_object_t ksobj, vm_offset_t ks, int pages) { vm_page_t m; int i; atomic_add_int(&kstacks, -1); pmap_qremove(ks, pages); VM_OBJECT_WLOCK(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(m); vm_page_unwire(m, PQ_INACTIVE); vm_page_free(m); vm_page_unlock(m); } VM_OBJECT_WUNLOCK(ksobj); vm_object_deallocate(ksobj); kva_free(ks - (KSTACK_GUARD_PAGES * PAGE_SIZE), (pages + KSTACK_GUARD_PAGES) * PAGE_SIZE); } /* * Dispose of a thread's kernel stack. */ void vm_thread_dispose(struct thread *td) { vm_object_t ksobj; vm_offset_t ks; struct kstack_cache_entry *ks_ce; int pages; pages = td->td_kstack_pages; ksobj = td->td_kstack_obj; ks = td->td_kstack; td->td_kstack = 0; td->td_kstack_pages = 0; if (pages == kstack_pages && kstacks <= kstack_cache_size) { ks_ce = (struct kstack_cache_entry *)ks; ks_ce->ksobj = ksobj; mtx_lock(&kstack_cache_mtx); ks_ce->next_ks_entry = kstack_cache; kstack_cache = ks_ce; mtx_unlock(&kstack_cache_mtx); return; } vm_thread_stack_dispose(ksobj, ks, pages); } static void vm_thread_stack_lowmem(void *nulll) { struct kstack_cache_entry *ks_ce, *ks_ce1; mtx_lock(&kstack_cache_mtx); ks_ce = kstack_cache; kstack_cache = NULL; mtx_unlock(&kstack_cache_mtx); while (ks_ce != NULL) { ks_ce1 = ks_ce; ks_ce = ks_ce->next_ks_entry; vm_thread_stack_dispose(ks_ce1->ksobj, (vm_offset_t)ks_ce1, kstack_pages); } } static void kstack_cache_init(void *nulll) { EVENTHANDLER_REGISTER(vm_lowmem, vm_thread_stack_lowmem, NULL, EVENTHANDLER_PRI_ANY); } SYSINIT(vm_kstacks, SI_SUB_KTHREAD_INIT, SI_ORDER_ANY, kstack_cache_init, NULL); #ifdef KSTACK_USAGE_PROF /* * Track maximum stack used by a thread in kernel. */ static int max_kstack_used; SYSCTL_INT(_debug, OID_AUTO, max_kstack_used, CTLFLAG_RD, &max_kstack_used, 0, "Maxiumum stack depth used by a thread in kernel"); void intr_prof_stack_use(struct thread *td, struct trapframe *frame) { vm_offset_t stack_top; vm_offset_t current; int used, prev_used; /* * Testing for interrupted kernel mode isn't strictly * needed. It optimizes the execution, since interrupts from * usermode will have only the trap frame on the stack. */ if (TRAPF_USERMODE(frame)) return; stack_top = td->td_kstack + td->td_kstack_pages * PAGE_SIZE; current = (vm_offset_t)(uintptr_t)&stack_top; /* * Try to detect if interrupt is using kernel thread stack. * Hardware could use a dedicated stack for interrupt handling. */ if (stack_top <= current || current < td->td_kstack) return; used = stack_top - current; for (;;) { prev_used = max_kstack_used; if (prev_used >= used) break; if (atomic_cmpset_int(&max_kstack_used, prev_used, used)) break; } } #endif /* KSTACK_USAGE_PROF */ #ifndef NO_SWAPPING /* * Allow a thread's kernel stack to be paged out. */ static 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_WLOCK(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_dirty(m); vm_page_lock(m); vm_page_unwire(m, PQ_INACTIVE); vm_page_unlock(m); } VM_OBJECT_WUNLOCK(ksobj); } /* * Bring the kernel stack for a specified thread back in. */ static void vm_thread_swapin(struct thread *td) { vm_object_t ksobj; vm_page_t ma[KSTACK_MAX_PAGES]; int i, j, pages, rv; pages = td->td_kstack_pages; ksobj = td->td_kstack_obj; VM_OBJECT_WLOCK(ksobj); for (i = 0; i < pages; i++) ma[i] = vm_page_grab(ksobj, i, VM_ALLOC_NORMAL | VM_ALLOC_WIRED); for (i = 0; i < pages; i++) { if (ma[i]->valid != VM_PAGE_BITS_ALL) { vm_page_assert_xbusied(ma[i]); vm_object_pip_add(ksobj, 1); for (j = i + 1; j < pages; j++) { if (ma[j]->valid != VM_PAGE_BITS_ALL) vm_page_assert_xbusied(ma[j]); if (ma[j]->valid == VM_PAGE_BITS_ALL) break; } rv = vm_pager_get_pages(ksobj, ma + i, j - i, 0); if (rv != VM_PAGER_OK) panic("vm_thread_swapin: cannot get kstack for proc: %d", td->td_proc->p_pid); /* * All pages in the array are in place, due to the * pager is always the swap pager, which doesn't * free or remove wired non-req pages from object. */ vm_object_pip_wakeup(ksobj); vm_page_xunbusy(ma[i]); } else if (vm_page_xbusied(ma[i])) vm_page_xunbusy(ma[i]); } VM_OBJECT_WUNLOCK(ksobj); pmap_qenter(td->td_kstack, ma, pages); cpu_thread_swapin(td); } #endif /* !NO_SWAPPING */ /* * 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. */ int vm_forkproc(td, p2, td2, vm2, flags) struct thread *td; struct proc *p2; struct thread *td2; struct vmspace *vm2; int flags; { struct proc *p1 = td->td_proc; int error; 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) { error = vmspace_unshare(p1); if (error) return (error); } } cpu_fork(td, p2, td2, flags); return (0); } 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 = vm2; 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); return (0); } /* * 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 */ } void faultin(p) struct proc *p; { #ifdef NO_SWAPPING PROC_LOCK_ASSERT(p, MA_OWNED); if ((p->p_flag & P_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_flag & P_SWAPPINGIN) { while (p->p_flag & P_SWAPPINGIN) msleep(&p->p_flag, &p->p_mtx, PVM, "faultin", 0); return; } if ((p->p_flag & P_INMEM) == 0) { /* * Don't let another thread swap process p out while we are * busy swapping it in. */ ++p->p_lock; p->p_flag |= P_SWAPPINGIN; PROC_UNLOCK(p); /* * We hold no lock here because the list of threads * can not change while all threads in the process are * swapped out. */ FOREACH_THREAD_IN_PROC(p, td) vm_thread_swapin(td); PROC_LOCK(p); swapclear(p); p->p_swtick = ticks; wakeup(&p->p_flag); /* 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. * * Giant is held on entry. */ void swapper(void) { struct proc *p; struct thread *td; struct proc *pp; int slptime; int swtime; int ppri; int pri; loop: if (vm_page_count_min()) { VM_WAIT; goto loop; } pp = NULL; ppri = INT_MIN; sx_slock(&allproc_lock); FOREACH_PROC_IN_SYSTEM(p) { PROC_LOCK(p); if (p->p_state == PRS_NEW || p->p_flag & (P_SWAPPINGOUT | P_SWAPPINGIN | P_INMEM)) { PROC_UNLOCK(p); continue; } swtime = (ticks - p->p_swtick) / hz; FOREACH_THREAD_IN_PROC(p, td) { /* * An otherwise runnable thread of a process * swapped out has only the TDI_SWAPPED bit set. * */ thread_lock(td); if (td->td_inhibitors == TDI_SWAPPED) { slptime = (ticks - td->td_slptick) / hz; pri = swtime + slptime; if ((td->td_flags & TDF_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; } } thread_unlock(td); } PROC_UNLOCK(p); } sx_sunlock(&allproc_lock); /* * Nothing to do, back to sleep. */ if ((p = pp) == NULL) { tsleep(&proc0, PVM, "swapin", MAXSLP * hz / 2); 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_flag & (P_INMEM | P_SWAPPINGOUT | P_SWAPPINGIN)) { PROC_UNLOCK(p); goto loop; } /* * We would like to bring someone in. (only if there is space). * [What checks the space? ] */ faultin(p); PROC_UNLOCK(p); goto loop; } void kick_proc0(void) { wakeup(&proc0); } #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"); /* * First, if any processes have been sleeping or stopped for at least * "swap_idle_threshold1" seconds, they are swapped out. If, however, * no such processes exist, then the longest-sleeping or stopped * process is swapped out. Finally, and only as a last resort, if * there are no sleeping or stopped processes, the longest-resident * process is swapped out. */ 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; int slptime; /* * Watch out for a process in * creation. It may have no * address space or lock yet. */ if (p->p_state == PRS_NEW) continue; /* * 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 nextproc; } /* * only aiod changes vmspace, however it will be * skipped because of the if statement above checking * for P_SYSTEM */ if ((p->p_flag & (P_INMEM|P_SWAPPINGOUT|P_SWAPPINGIN)) != P_INMEM) goto nextproc; switch (p->p_state) { default: /* Don't swap out processes in any sort * of 'special' state. */ break; case PRS_NORMAL: /* * do not swapout a realtime process * Check all the thread groups.. */ FOREACH_THREAD_IN_PROC(p, td) { thread_lock(td); if (PRI_IS_REALTIME(td->td_pri_class)) { thread_unlock(td); goto nextproc; } slptime = (ticks - td->td_slptick) / hz; /* * Guarantee swap_idle_threshold1 * time in memory. */ if (slptime < swap_idle_threshold1) { thread_unlock(td); 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 (!thread_safetoswapout(td)) { thread_unlock(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) || (slptime < swap_idle_threshold2))) { thread_unlock(td); goto nextproc; } if (minslptime > slptime) minslptime = slptime; thread_unlock(td); } /* * 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))) { if (swapout(p) == 0) didswap++; PROC_UNLOCK(p); vm_map_unlock(&vm->vm_map); vmspace_free(vm); sx_sunlock(&allproc_lock); goto retry; } } nextproc: 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 swapclear(p) struct proc *p; { struct thread *td; PROC_LOCK_ASSERT(p, MA_OWNED); FOREACH_THREAD_IN_PROC(p, td) { thread_lock(td); td->td_flags |= TDF_INMEM; td->td_flags &= ~TDF_SWAPINREQ; TD_CLR_SWAPPED(td); if (TD_CAN_RUN(td)) if (setrunnable(td)) { #ifdef INVARIANTS /* * XXX: We just cleared TDI_SWAPPED * above and set TDF_INMEM, so this * should never happen. */ panic("not waking up swapper"); #endif } thread_unlock(td); } p->p_flag &= ~(P_SWAPPINGIN|P_SWAPPINGOUT); p->p_flag |= P_INMEM; } static int swapout(p) struct proc *p; { struct thread *td; PROC_LOCK_ASSERT(p, MA_OWNED); #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_flag & (P_INMEM|P_SWAPPINGOUT|P_SWAPPINGIN)) == P_INMEM, ("swapout: lost a swapout race?")); /* * remember the process resident count */ p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace); /* * Check and mark all threads before we proceed. */ p->p_flag &= ~P_INMEM; p->p_flag |= P_SWAPPINGOUT; FOREACH_THREAD_IN_PROC(p, td) { thread_lock(td); if (!thread_safetoswapout(td)) { thread_unlock(td); swapclear(p); return (EBUSY); } td->td_flags &= ~TDF_INMEM; TD_SET_SWAPPED(td); thread_unlock(td); } td = FIRST_THREAD_IN_PROC(p); ++td->td_ru.ru_nswap; PROC_UNLOCK(p); /* * This list is stable because all threads are now prevented from * running. The list is only modified in the context of a running * thread in this process. */ FOREACH_THREAD_IN_PROC(p, td) vm_thread_swapout(td); PROC_LOCK(p); p->p_flag &= ~P_SWAPPINGOUT; p->p_swtick = ticks; return (0); } #endif /* !NO_SWAPPING */