/* * (MPSAFE) * * 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. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 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. * * $FreeBSD: src/sys/vm/vm_glue.c,v 1.94.2.4 2003/01/13 22:51:17 dillon Exp $ * $DragonFly: src/sys/vm/vm_glue.c,v 1.56 2008/07/01 02:02:56 dillon Exp $ */ #include "opt_vm.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 /* * 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_FIRST, scheduler, NULL) #ifdef INVARIANTS static int swap_debug = 0; SYSCTL_INT(_vm, OID_AUTO, swap_debug, CTLFLAG_RW, &swap_debug, 0, ""); #endif static int scheduler_notify; static void swapout (struct proc *); /* * No requirements. */ int kernacc(c_caddr_t addr, int len, int 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)); /* * The globaldata space is not part of the kernel_map proper, * check access separately. */ if (is_globaldata_space((vm_offset_t)addr, (vm_offset_t)(addr + len))) return (TRUE); /* * Nominal kernel memory access - check access via kernel_map. */ 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); rv = vm_map_check_protection(&kernel_map, saddr, eaddr, prot, FALSE); return (rv == TRUE); } /* * No requirements. */ int useracc(c_caddr_t addr, int len, int rw) { boolean_t rv; vm_prot_t prot; vm_map_t map; vm_map_entry_t save_hint; vm_offset_t wrap; KASSERT((rw & (~VM_PROT_ALL)) == 0, ("illegal ``rw'' argument to useracc (%x)\n", rw)); prot = rw; /* * XXX - check separately to disallow access to user area and user * page tables - they are in the map. */ wrap = (vm_offset_t)addr + len; if (wrap > VM_MAX_USER_ADDRESS || wrap < (vm_offset_t)addr) { return (FALSE); } map = &curproc->p_vmspace->vm_map; vm_map_lock_read(map); /* * We save the map hint, and restore it. Useracc appears to distort * the map hint unnecessarily. */ save_hint = map->hint; rv = vm_map_check_protection(map, trunc_page((vm_offset_t)addr), round_page(wrap), prot, TRUE); map->hint = save_hint; vm_map_unlock_read(map); return (rv == TRUE); } /* * No requirements. */ void vslock(caddr_t addr, u_int len) { if (len) { vm_map_wire(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len), 0); } } /* * No requirements. */ void vsunlock(caddr_t addr, u_int len) { if (len) { vm_map_wire(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len), KM_PAGEABLE); } } /* * 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. * * No requirements. */ void vm_fork(struct proc *p1, struct proc *p2, int flags) { 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_sysref.refcnt > 1) { vmspace_unshare(p1); } } cpu_fork(ONLY_LWP_IN_PROC(p1), NULL, flags); return; } if (flags & RFMEM) { p2->p_vmspace = p1->p_vmspace; sysref_get(&p1->p_vmspace->vm_sysref); } while (vm_page_count_severe()) { vm_wait(0); } if ((flags & RFMEM) == 0) { p2->p_vmspace = vmspace_fork(p1->p_vmspace); pmap_pinit2(vmspace_pmap(p2->p_vmspace)); if (p1->p_vmspace->vm_shm) shmfork(p1, p2); } pmap_init_proc(p2); } /* * Set default limits for VM system. Call during proc0's initialization. * * Called from the low level boot code only. */ void vm_init_limits(struct proc *p) { 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. */ p->p_rlimit[RLIMIT_STACK].rlim_cur = dflssiz; p->p_rlimit[RLIMIT_STACK].rlim_max = maxssiz; p->p_rlimit[RLIMIT_DATA].rlim_cur = dfldsiz; p->p_rlimit[RLIMIT_DATA].rlim_max = maxdsiz; /* limit the limit to no less than 2MB */ rss_limit = max(vmstats.v_free_count, 512); p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(rss_limit); p->p_rlimit[RLIMIT_RSS].rlim_max = RLIM_INFINITY; } /* * Faultin the specified process. Note that the process can be in any * state. Just clear P_SWAPPEDOUT and call wakeup in case the process is * sleeping. * * No requirements. */ void faultin(struct proc *p) { if (p->p_flags & P_SWAPPEDOUT) { /* * The process is waiting in the kernel to return to user * mode but cannot until P_SWAPPEDOUT gets cleared. */ lwkt_gettoken(&p->p_token); p->p_flags &= ~(P_SWAPPEDOUT | P_SWAPWAIT); #ifdef INVARIANTS if (swap_debug) kprintf("swapping in %d (%s)\n", p->p_pid, p->p_comm); #endif wakeup(p); lwkt_reltoken(&p->p_token); } } /* * Kernel initialization eventually falls through to this function, * which is process 0. * * 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. */ struct scheduler_info { struct proc *pp; int ppri; }; static int scheduler_callback(struct proc *p, void *data); static void scheduler(void *dummy) { struct scheduler_info info; struct proc *p; KKASSERT(!IN_CRITICAL_SECT(curthread)); loop: scheduler_notify = 0; /* * Don't try to swap anything in if we are low on memory. */ if (vm_page_count_severe()) { vm_wait(0); goto loop; } /* * Look for a good candidate to wake up */ info.pp = NULL; info.ppri = INT_MIN; allproc_scan(scheduler_callback, &info); /* * Nothing to do, back to sleep for at least 1/10 of a second. If * we are woken up, immediately process the next request. If * multiple requests have built up the first is processed * immediately and the rest are staggered. */ if ((p = info.pp) == NULL) { tsleep(&proc0, 0, "nowork", hz / 10); if (scheduler_notify == 0) tsleep(&scheduler_notify, 0, "nowork", 0); goto loop; } /* * Fault the selected process in, then wait for a short period of * time and loop up. * * XXX we need a heuristic to get a measure of system stress and * then adjust our stagger wakeup delay accordingly. */ lwkt_gettoken(&proc_token); faultin(p); p->p_swtime = 0; PRELE(p); lwkt_reltoken(&proc_token); tsleep(&proc0, 0, "swapin", hz / 10); goto loop; } /* * The caller must hold proc_token. */ static int scheduler_callback(struct proc *p, void *data) { struct scheduler_info *info = data; struct lwp *lp; segsz_t pgs; int pri; if (p->p_flags & P_SWAPWAIT) { pri = 0; FOREACH_LWP_IN_PROC(lp, p) { /* XXX lwp might need a different metric */ pri += lp->lwp_slptime; } pri += p->p_swtime - p->p_nice * 8; /* * The more pages paged out while we were swapped, * the more work we have to do to get up and running * again and the lower our wakeup priority. * * Each second of sleep time is worth ~1MB */ lwkt_gettoken(&p->p_vmspace->vm_map.token); pgs = vmspace_resident_count(p->p_vmspace); if (pgs < p->p_vmspace->vm_swrss) { pri -= (p->p_vmspace->vm_swrss - pgs) / (1024 * 1024 / PAGE_SIZE); } lwkt_reltoken(&p->p_vmspace->vm_map.token); /* * If this process is higher priority and there is * enough space, then select this process instead of * the previous selection. */ if (pri > info->ppri) { if (info->pp) PRELE(info->pp); PHOLD(p); info->pp = p; info->ppri = pri; } } return(0); } /* * SMP races ok. * No requirements. */ void swapin_request(void) { if (scheduler_notify == 0) { scheduler_notify = 1; wakeup(&scheduler_notify); } } #ifndef NO_SWAPPING #define swappable(p) \ (((p)->p_lock == 0) && \ ((p)->p_flags & (P_TRACED|P_SYSTEM|P_SWAPPEDOUT|P_WEXIT)) == 0) /* * Swap_idle_threshold1 is the guaranteed swapped in time for a process */ static int swap_idle_threshold1 = 15; SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold1, CTLFLAG_RW, &swap_idle_threshold1, 0, "Guaranteed process resident time (sec)"); /* * Swap_idle_threshold2 is the time that a process can be idle before * it will be swapped out, if idle swapping is enabled. Default is * one minute. */ static int swap_idle_threshold2 = 60; SYSCTL_INT(_vm, OID_AUTO, swap_idle_threshold2, CTLFLAG_RW, &swap_idle_threshold2, 0, "Time (sec) a process can idle before being swapped"); /* * Swapout is driven by the pageout daemon. Very simple, we find eligible * procs and mark them as being swapped out. This will cause the kernel * to prefer to pageout those proc's pages first and the procs in question * will not return to user mode until the swapper tells them they can. * * 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. */ static int swapout_procs_callback(struct proc *p, void *data); /* * No requirements. */ void swapout_procs(int action) { allproc_scan(swapout_procs_callback, &action); } /* * The caller must hold proc_token */ static int swapout_procs_callback(struct proc *p, void *data) { struct vmspace *vm; struct lwp *lp; int action = *(int *)data; int minslp = -1; if (!swappable(p)) return(0); lwkt_gettoken(&p->p_token); vm = p->p_vmspace; /* * We only consider active processes. */ if (p->p_stat != SACTIVE && p->p_stat != SSTOP) { lwkt_reltoken(&p->p_token); return(0); } FOREACH_LWP_IN_PROC(lp, p) { /* * do not swap out a realtime process */ if (RTP_PRIO_IS_REALTIME(lp->lwp_rtprio.type)) { lwkt_reltoken(&p->p_token); return(0); } /* * Guarentee swap_idle_threshold time in memory */ if (lp->lwp_slptime < swap_idle_threshold1) { lwkt_reltoken(&p->p_token); return(0); } /* * 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) || (lp->lwp_slptime < swap_idle_threshold2))) { lwkt_reltoken(&p->p_token); return(0); } if (minslp == -1 || lp->lwp_slptime < minslp) minslp = lp->lwp_slptime; } /* * If the process has been asleep for awhile, swap * it out. */ if ((action & VM_SWAP_NORMAL) || ((action & VM_SWAP_IDLE) && (minslp > swap_idle_threshold2))) { swapout(p); } /* * cleanup our reference */ lwkt_reltoken(&p->p_token); return(0); } /* * The caller must hold proc_token and p->p_token */ static void swapout(struct proc *p) { #ifdef INVARIANTS if (swap_debug) kprintf("swapping out %d (%s)\n", p->p_pid, p->p_comm); #endif ++p->p_ru.ru_nswap; /* * remember the process resident count */ p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace); p->p_flags |= P_SWAPPEDOUT; p->p_swtime = 0; } #endif /* !NO_SWAPPING */