/* * 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. * * $Id: vm_glue.c,v 1.22 1995/07/10 08:53:20 davidg Exp $ */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include extern char kstack[]; /* vm_map_t upages_map; */ int kernacc(addr, len, rw) caddr_t addr; int len, rw; { boolean_t rv; vm_offset_t saddr, eaddr; vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; saddr = trunc_page(addr); eaddr = round_page(addr + len); rv = vm_map_check_protection(kernel_map, saddr, eaddr, prot); return (rv == TRUE); } int useracc(addr, len, rw) caddr_t addr; int len, rw; { boolean_t rv; vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; /* * 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); } rv = vm_map_check_protection(&curproc->p_vmspace->vm_map, trunc_page(addr), round_page(addr + len), prot); return (rv == TRUE); } #ifdef KGDB /* * Change protections on kernel pages from addr to addr+len * (presumably so debugger can plant a breakpoint). * All addresses are assumed to reside in the Sysmap, */ chgkprot(addr, len, rw) register caddr_t addr; int len, rw; { vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; vm_map_protect(kernel_map, trunc_page(addr), round_page(addr + len), prot, FALSE); } #endif void vslock(addr, len) caddr_t addr; u_int len; { vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page(addr), round_page(addr + len), FALSE); } void vsunlock(addr, len, dirtied) caddr_t addr; u_int len; int dirtied; { #ifdef lint dirtied++; #endif /* lint */ vm_map_pageable(&curproc->p_vmspace->vm_map, trunc_page(addr), round_page(addr + len), TRUE); } /* * 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. * NOTE: the kernel stack may be at a different location in the child * process, and thus addresses of automatic variables may be invalid * after cpu_fork returns in the child process. We do nothing here * after cpu_fork returns. */ int vm_fork(p1, p2, isvfork) register struct proc *p1, *p2; int isvfork; { register struct user *up; vm_offset_t addr, ptaddr; int i; struct vm_map *vp; while ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min) { VM_WAIT; } /* * avoid copying any of the parent's pagetables or other per-process * objects that reside in the map by marking all of them * non-inheritable */ (void) vm_map_inherit(&p1->p_vmspace->vm_map, UPT_MIN_ADDRESS - UPAGES * NBPG, VM_MAX_ADDRESS, VM_INHERIT_NONE); p2->p_vmspace = vmspace_fork(p1->p_vmspace); #ifdef SYSVSHM if (p1->p_vmspace->vm_shm) shmfork(p1, p2, isvfork); #endif /* * Allocate a wired-down (for now) pcb and kernel stack for the * process */ addr = (vm_offset_t) kstack; vp = &p2->p_vmspace->vm_map; /* get new pagetables and kernel stack */ (void) vm_map_find(vp, NULL, 0, &addr, UPT_MAX_ADDRESS - addr, FALSE); /* force in the page table encompassing the UPAGES */ ptaddr = trunc_page((u_int) vtopte(addr)); vm_map_pageable(vp, ptaddr, ptaddr + NBPG, FALSE); /* and force in (demand-zero) the UPAGES */ vm_map_pageable(vp, addr, addr + UPAGES * NBPG, FALSE); /* get a kernel virtual address for the UPAGES for this proc */ up = (struct user *) kmem_alloc_pageable(u_map, UPAGES * NBPG); if (up == NULL) panic("vm_fork: u_map allocation failed"); /* and force-map the upages into the kernel pmap */ for (i = 0; i < UPAGES; i++) pmap_enter(vm_map_pmap(u_map), ((vm_offset_t) up) + NBPG * i, pmap_extract(vp->pmap, addr + NBPG * i), VM_PROT_READ | VM_PROT_WRITE, 1); p2->p_addr = up; /* * p_stats and p_sigacts currently point at fields in the user struct * but not at &u, instead at p_addr. Copy p_sigacts and parts of * p_stats; zero the rest of p_stats (statistics). */ p2->p_stats = &up->u_stats; p2->p_sigacts = &up->u_sigacts; up->u_sigacts = *p1->p_sigacts; bzero(&up->u_stats.pstat_startzero, (unsigned) ((caddr_t) &up->u_stats.pstat_endzero - (caddr_t) &up->u_stats.pstat_startzero)); bcopy(&p1->p_stats->pstat_startcopy, &up->u_stats.pstat_startcopy, ((caddr_t) &up->u_stats.pstat_endcopy - (caddr_t) &up->u_stats.pstat_startcopy)); /* * cpu_fork will copy and update the kernel stack and pcb, and make * the child ready to run. It marks the child so that it can return * differently than the parent. It returns twice, once in the parent * process and once in the child. */ return (cpu_fork(p1, p2)); } /* * Set default limits for VM system. * Called for proc 0, and then inherited by all others. */ void vm_init_limits(p) register 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(cnt.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(p) struct proc *p; { vm_offset_t i; vm_offset_t ptaddr; int s; if ((p->p_flag & P_INMEM) == 0) { vm_map_t map; ++p->p_lock; map = &p->p_vmspace->vm_map; /* force the page table encompassing the kernel stack (upages) */ ptaddr = trunc_page((u_int) vtopte(kstack)); vm_map_pageable(map, ptaddr, ptaddr + NBPG, FALSE); /* wire in the UPAGES */ vm_map_pageable(map, (vm_offset_t) kstack, (vm_offset_t) kstack + UPAGES * NBPG, FALSE); /* and map them nicely into the kernel pmap */ for (i = 0; i < UPAGES; i++) { vm_offset_t off = i * NBPG; vm_offset_t pa = (vm_offset_t) pmap_extract(&p->p_vmspace->vm_pmap, (vm_offset_t) kstack + off); pmap_enter(vm_map_pmap(u_map), ((vm_offset_t) p->p_addr) + off, pa, VM_PROT_READ | VM_PROT_WRITE, 1); } s = splhigh(); if (p->p_stat == SRUN) setrunqueue(p); p->p_flag |= P_INMEM; /* undo the effect of setting SLOCK above */ --p->p_lock; splx(s); } } /* * 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. */ void scheduler() { register struct proc *p; register int pri; struct proc *pp; int ppri; loop: while ((cnt.v_free_count + cnt.v_cache_count) < (cnt.v_free_reserved + UPAGES + 2)) { VM_WAIT; tsleep(&proc0, PVM, "schedm", 0); } pp = NULL; ppri = INT_MIN; for (p = (struct proc *) allproc; p != NULL; p = p->p_next) { if (p->p_stat == SRUN && (p->p_flag & (P_INMEM | P_SWAPPING)) == 0) { int mempri; pri = p->p_swtime + p->p_slptime - p->p_nice * 8; mempri = pri > 0 ? pri : 0; /* * 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, PVM, "sched", 0); goto loop; } /* * We would like to bring someone in. (only if there is space). */ faultin(p); p->p_swtime = 0; goto loop; } #define swappable(p) \ (((p)->p_lock == 0) && \ ((p)->p_flag & (P_TRACED|P_NOSWAP|P_SYSTEM|P_INMEM|P_WEXIT|P_PHYSIO|P_SWAPPING)) == P_INMEM) extern int vm_pageout_free_min; /* * 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() { register struct proc *p; struct proc *outp, *outp2; int outpri, outpri2; int didswap = 0; outp = outp2 = NULL; outpri = outpri2 = INT_MIN; retry: for (p = (struct proc *) allproc; p != NULL; p = p->p_next) { if (!swappable(p)) continue; switch (p->p_stat) { default: continue; case SSLEEP: case SSTOP: /* * do not swapout a realtime process */ if (p->p_rtprio.type == RTP_PRIO_REALTIME) continue; /* * do not swapout a process waiting on a critical * event of some kind */ if ((p->p_priority & 0x7f) < PSOCK) continue; vm_map_reference(&p->p_vmspace->vm_map); /* * do not swapout a process that is waiting for VM * datastructures there is a possible deadlock. */ if (!lock_try_write(&p->p_vmspace->vm_map.lock)) { vm_map_deallocate(&p->p_vmspace->vm_map); continue; } vm_map_unlock(&p->p_vmspace->vm_map); /* * If the process has been asleep for awhile and had * most of its pages taken away already, swap it out. */ if (p->p_slptime > 4) { swapout(p); vm_map_deallocate(&p->p_vmspace->vm_map); didswap++; goto retry; } vm_map_deallocate(&p->p_vmspace->vm_map); } } /* * If we swapped something out, and another process needed memory, * then wakeup the sched process. */ if (didswap) wakeup(&proc0); } void swapout(p) register struct proc *p; { vm_map_t map = &p->p_vmspace->vm_map; vm_offset_t ptaddr; ++p->p_stats->p_ru.ru_nswap; /* * remember the process resident count */ p->p_vmspace->vm_swrss = p->p_vmspace->vm_pmap.pm_stats.resident_count; (void) splhigh(); p->p_flag &= ~P_INMEM; if (p->p_stat == SRUN) remrq(p); (void) spl0(); p->p_flag |= P_SWAPPING; /* * let the upages be paged */ pmap_remove(vm_map_pmap(u_map), (vm_offset_t) p->p_addr, ((vm_offset_t) p->p_addr) + UPAGES * NBPG); vm_map_pageable(map, (vm_offset_t) kstack, (vm_offset_t) kstack + UPAGES * NBPG, TRUE); ptaddr = trunc_page((u_int) vtopte(kstack)); vm_map_pageable(map, ptaddr, ptaddr + NBPG, TRUE); p->p_flag &= ~P_SWAPPING; p->p_swtime = 0; } #ifdef DDB /* * DEBUG stuff */ int indent; #include /* see subr_prf.c */ /*ARGSUSED2*/ void #if __STDC__ iprintf(const char *fmt,...) #else iprintf(fmt /* , va_alist */ ) char *fmt; /* va_dcl */ #endif { register int i; va_list ap; for (i = indent; i >= 8; i -= 8) printf("\t"); while (--i >= 0) printf(" "); va_start(ap, fmt); printf("%r", fmt, ap); va_end(ap); } #endif /* DDB */