/* * 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 1.28 2004/09/05 21:25:53 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 /* * 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_FIRST, scheduler, NULL) static void swapout (struct proc *); 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)); 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); } 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; 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. * * XXX - VM_MAXUSER_ADDRESS is an end address, not a max. It was once * only used (as an end address) in trap.c. Use it as an end address * here too. This bogusness has spread. I just fixed where it was * used as a max in vm_mmap.c. */ if ((vm_offset_t) addr + len > /* XXX */ VM_MAXUSER_ADDRESS || (vm_offset_t) addr + len < (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((vm_offset_t)addr + len), prot); map->hint = save_hint; vm_map_unlock_read(map); return (rv == TRUE); } void vslock(caddr_t addr, u_int len) { vm_map_wire(&curproc->p_vmspace->vm_map, trunc_page((vm_offset_t)addr), round_page((vm_offset_t)addr + len), 0); } void vsunlock(caddr_t addr, u_int 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. */ void vm_fork(struct proc *p1, struct proc *p2, int flags) { struct user *up; struct thread *td2; 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(p1, p2, flags); return; } if (flags & RFMEM) { p2->p_vmspace = p1->p_vmspace; p1->p_vmspace->vm_refcnt++; } while (vm_page_count_severe()) { vm_wait(); } 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); } td2 = lwkt_alloc_thread(NULL, LWKT_THREAD_STACK, -1); pmap_init_proc(p2, td2); lwkt_setpri(td2, TDPRI_KERN_USER); lwkt_set_comm(td2, "%s", p1->p_comm); up = p2->p_addr; /* * p_stats currently points at fields in the user struct * but not at &u, instead at p_addr. Copy parts of * p_stats; zero the rest of p_stats (statistics). * * If procsig->ps_refcnt is 1 and p2->p_sigacts is NULL we dont' need * to share sigacts, so we use the up->u_sigacts. */ p2->p_stats = &up->u_stats; if (p2->p_sigacts == NULL) { if (p2->p_procsig->ps_refcnt != 1) printf ("PID:%d NULL sigacts with refcnt not 1!\n",p2->p_pid); p2->p_sigacts = &up->u_sigacts; up->u_sigacts = *p1->p_sigacts; } bzero(&up->u_stats, sizeof(struct pstats)); bcopy(&p1->p_stats->p_prof, &up->u_stats.p_prof, sizeof(struct uprof)); bcopy(&p1->p_thread->td_start, &p2->p_thread->td_start, sizeof(struct timeval)); /* * cpu_fork will copy and update the pcb, set up the kernel stack, * and make the child ready to run. */ cpu_fork(p1, p2, 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(struct proc *p) { p->p_stats = NULL; cpu_proc_wait(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(void *udata) { struct proc *p = udata; 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; } void faultin(struct proc *p) { int s; if ((p->p_flag & P_INMEM) == 0) { ++p->p_lock; pmap_swapin_proc(p); s = splhigh(); /* * The process is in the kernel and controlled by LWKT, * so we just schedule it rather then call setrunqueue(). */ if (p->p_stat == SRUN) lwkt_schedule(p->p_thread); p->p_flag |= P_INMEM; /* undo the effect of setting SLOCK above */ --p->p_lock; splx(s); } } /* * 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. */ /* ARGSUSED*/ static void scheduler(void *dummy) { struct proc *p; int pri; struct proc *pp; int ppri; KKASSERT(!IN_CRITICAL_SECT(curthread)); loop: if (vm_page_count_min()) { vm_wait(); goto loop; } pp = NULL; ppri = INT_MIN; for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { if (p->p_stat == SRUN && (p->p_flag & (P_INMEM | P_SWAPPING)) == 0) { pri = p->p_swtime + p->p_slptime; if ((p->p_flag & P_SWAPINREQ) == 0) { pri -= p->p_nice * 8; } /* * if this process is higher priority and there is * enough space, then select this process instead of * the previous selection. */ if (pri > ppri) { pp = p; ppri = pri; } } } /* * Nothing to do, back to sleep. */ if ((p = pp) == NULL) { tsleep(&proc0, 0, "sched", 0); goto loop; } p->p_flag &= ~P_SWAPINREQ; /* * We would like to bring someone in. (only if there is space). */ faultin(p); p->p_swtime = 0; goto loop; } #ifndef NO_SWAPPING #define swappable(p) \ (((p)->p_lock == 0) && \ ((p)->p_flag & (P_TRACED|P_SYSTEM|P_INMEM|P_WEXIT|P_SWAPPING)) == P_INMEM) /* * 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, ""); /* * 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, ""); /* * 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(int action) { struct proc *p; struct proc *outp, *outp2; int outpri, outpri2; int didswap = 0; outp = outp2 = NULL; outpri = outpri2 = INT_MIN; retry: for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { struct vmspace *vm; if (!swappable(p)) continue; vm = p->p_vmspace; switch (p->p_stat) { default: continue; case SSLEEP: case SSTOP: /* * do not swapout a realtime process */ if (RTP_PRIO_IS_REALTIME(p->p_rtprio.type)) continue; /* * YYY do not swapout a proc waiting on a critical * event. * * Guarentee swap_idle_threshold time in memory */ if (p->p_slptime < swap_idle_threshold1) continue; /* * 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) || (p->p_slptime < swap_idle_threshold2))) continue; ++vm->vm_refcnt; /* * do not swapout a process that is waiting for VM * data structures there is a possible deadlock. */ if (lockmgr(&vm->vm_map.lock, LK_EXCLUSIVE | LK_NOWAIT, NULL, curthread)) { vmspace_free(vm); continue; } vm_map_unlock(&vm->vm_map); /* * If the process has been asleep for awhile and had * most of its pages taken away already, swap it out. */ if ((action & VM_SWAP_NORMAL) || ((action & VM_SWAP_IDLE) && (p->p_slptime > swap_idle_threshold2))) { swapout(p); vmspace_free(vm); didswap++; goto retry; } /* * cleanup our reference */ vmspace_free(vm); } } /* * If we swapped something out, and another process needed memory, * then wakeup the sched process. */ if (didswap) wakeup(&proc0); } static void swapout(struct proc *p) { #if defined(SWAP_DEBUG) printf("swapping out %d\n", p->p_pid); #endif ++p->p_stats->p_ru.ru_nswap; /* * remember the process resident count */ p->p_vmspace->vm_swrss = vmspace_resident_count(p->p_vmspace); (void) splhigh(); p->p_flag &= ~P_INMEM; p->p_flag |= P_SWAPPING; if (p->p_flag & P_ONRUNQ) remrunqueue(p); (void) spl0(); pmap_swapout_proc(p); p->p_flag &= ~P_SWAPPING; p->p_swtime = 0; } #endif /* !NO_SWAPPING */