/* $NetBSD: vm_glue.c,v 1.46 1995/05/05 03:35:39 cgd Exp $ */ /* * 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. * * @(#)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 #include #include #include #include #include #include #include #include #include int avefree = 0; /* XXX */ unsigned maxdmap = MAXDSIZ; /* XXX */ unsigned maxsmap = MAXSSIZ; /* XXX */ int readbuffers = 0; /* XXX allow kgdb to read kernel buffer pool */ 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); /* * XXX there are still some things (e.g. the buffer cache) that * are managed behind the VM system's back so even though an * address is accessible in the mind of the VM system, there may * not be physical pages where the VM thinks there is. This can * lead to bogus allocation of pages in the kernel address space * or worse, inconsistencies at the pmap level. We only worry * about the buffer cache for now. */ if (!readbuffers && rv && (eaddr > (vm_offset_t)buffers && saddr < (vm_offset_t)buffers + MAXBSIZE * nbuf)) rv = FALSE; 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; #if defined(i386) || defined(pc532) /* * XXX - specially disallow access to user page tables - they are * in the map. This is here until i386 & pc532 pmaps are fixed... */ if ((vm_offset_t) addr >= VM_MAXUSER_ADDRESS || (vm_offset_t) addr + len > VM_MAXUSER_ADDRESS || (vm_offset_t) addr + len <= (vm_offset_t) addr) return (FALSE); #endif 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). * * We force the protection change at the pmap level. If we were * to use vm_map_protect a change to allow writing would be lazily- * applied meaning we would still take a protection fault, something * we really don't want to do. It would also fragment the kernel * map unnecessarily. We cannot use pmap_protect since it also won't * enforce a write-enable request. Using pmap_enter is the only way * we can ensure the change takes place properly. */ void chgkprot(addr, len, rw) register caddr_t addr; int len, rw; { vm_prot_t prot; vm_offset_t pa, sva, eva; prot = rw == B_READ ? VM_PROT_READ : VM_PROT_READ|VM_PROT_WRITE; eva = round_page(addr + len); for (sva = trunc_page(addr); sva < eva; sva += PAGE_SIZE) { /* * Extract physical address for the page. * We use a cheezy hack to differentiate physical * page 0 from an invalid mapping, not that it * really matters... */ pa = pmap_extract(pmap_kernel(), sva|1); if (pa == 0) panic("chgkprot: invalid page"); pmap_enter(pmap_kernel(), sva, pa&~1, prot, TRUE); } } #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 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; #if defined(i386) || defined(pc532) /* * 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, VM_MAXUSER_ADDRESS, VM_MAX_ADDRESS, VM_INHERIT_NONE); #endif p2->p_vmspace = vmspace_fork(p1->p_vmspace); #ifdef SYSVSHM if (p1->p_vmspace->vm_shm) shmfork(p1, p2, isvfork); #endif #if !defined(i386) && !defined(pc532) /* * Allocate a wired-down (for now) pcb and kernel stack for the process */ #ifdef pica addr = kmem_alloc_upage(kernel_map, USPACE); #else addr = kmem_alloc_pageable(kernel_map, USPACE); #endif if (addr == 0) panic("vm_fork: no more kernel virtual memory"); vm_map_pageable(kernel_map, addr, addr + USPACE, FALSE); #else /* * XXX somehow, on 386, ocassionally pageout removes active, wired down * kstack and pagetables, WITHOUT going thru vm_page_unwire! Why this * appears to work is not yet clear, yet it does... */ addr = kmem_alloc(kernel_map, USPACE); if (addr == 0) panic("vm_fork: no more kernel virtual memory"); #endif up = (struct user *)addr; 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)); #if defined(i386) || defined(pc532) { vm_offset_t addr = VM_MAXUSER_ADDRESS; struct vm_map *vp; /* ream out old pagetables and kernel stack */ vp = &p2->p_vmspace->vm_map; (void)vm_deallocate(vp, addr, VM_MAX_ADDRESS - addr); (void)vm_allocate(vp, &addr, VM_MAX_ADDRESS - addr, FALSE); (void)vm_map_inherit(vp, addr, VM_MAX_ADDRESS, VM_INHERIT_NONE); } #endif /* * 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; { /* * Set up the initial limits on process VM. * Set the maximum resident set size to be all * of (reasonably) available memory. This causes * any single, large process to start random page * replacement once it fills memory. */ 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; p->p_rlimit[RLIMIT_RSS].rlim_cur = ptoa(cnt.v_free_count); } #include #ifdef DEBUG int enableswap = 1; int swapdebug = 0; #define SDB_FOLLOW 1 #define SDB_SWAPIN 2 #define SDB_SWAPOUT 4 #endif /* * Swap in a process's u-area. */ void swapin(p) struct proc *p; { vm_offset_t addr; int s; addr = (vm_offset_t)p->p_addr; vm_map_pageable(kernel_map, addr, addr + USPACE, FALSE); /* * Some architectures need to be notified when the * user area has moved to new physical page(s) (e.g. * see pmax/pmax/vm_machdep.c). */ cpu_swapin(p); s = splstatclock(); if (p->p_stat == SRUN) setrunqueue(p); p->p_flag |= P_INMEM; splx(s); p->p_swtime = 0; } /* * Brutally simple: * 1. Attempt to swapin every swaped-out, runnable process in * order of priority. * 2. If not enough memory, wake the pageout daemon and let it * clear some space. */ void scheduler() { register struct proc *p; register int pri; struct proc *pp; int ppri; loop: #ifdef DEBUG while (!enableswap) tsleep((caddr_t)&proc0, PVM, "noswap", 0); #endif 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) == 0) { pri = p->p_swtime + p->p_slptime - p->p_nice * 8; if (pri > ppri) { pp = p; ppri = pri; } } } #ifdef DEBUG if (swapdebug & SDB_FOLLOW) printf("scheduler: running, procp %x pri %d\n", pp, ppri); #endif /* * Nothing to do, back to sleep */ if ((p = pp) == NULL) { tsleep((caddr_t)&proc0, PVM, "scheduler", 0); goto loop; } /* * We would like to bring someone in. * This part is really bogus cuz we could deadlock on memory * despite our feeble check. */ if (cnt.v_free_count > atop(USPACE)) { #ifdef DEBUG if (swapdebug & SDB_SWAPIN) printf("swapin: pid %d(%s)@%x, pri %d free %d\n", p->p_pid, p->p_comm, p->p_addr, ppri, cnt.v_free_count); #endif #ifdef pica vm_map_pageable(kernel_map, (vm_offset_t)p->p_addr, (vm_offset_t)p->p_addr + atop(USPACE), FALSE); #endif swapin(p); goto loop; } /* * Not enough memory, jab the pageout daemon and wait til the * coast is clear. */ #ifdef DEBUG if (swapdebug & SDB_FOLLOW) printf("scheduler: no room for pid %d(%s), free %d\n", p->p_pid, p->p_comm, cnt.v_free_count); #endif (void) splhigh(); VM_WAIT; (void) spl0(); #ifdef DEBUG if (swapdebug & SDB_FOLLOW) printf("scheduler: room again, free %d\n", cnt.v_free_count); #endif goto loop; } #define swappable(p) \ (((p)->p_flag & (P_SYSTEM | P_INMEM | P_WEXIT)) == P_INMEM && \ (p)->p_holdcnt == 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_threads() { register struct proc *p; struct proc *outp, *outp2; int outpri, outpri2; int didswap = 0; extern int maxslp; #ifdef DEBUG if (!enableswap) return; #endif outp = outp2 = NULL; outpri = outpri2 = 0; for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) { if (!swappable(p)) continue; switch (p->p_stat) { case SRUN: if (p->p_swtime > outpri2) { outp2 = p; outpri2 = p->p_swtime; } continue; case SSLEEP: case SSTOP: if (p->p_slptime >= maxslp) { swapout(p); didswap++; } else if (p->p_slptime > outpri) { outp = p; outpri = p->p_slptime; } continue; } } /* * If we didn't get rid of any real duds, toss out the next most * likely sleeping/stopped or running candidate. We only do this * if we are real low on memory since we don't gain much by doing * it (USPACE bytes). */ if (didswap == 0 && cnt.v_free_count <= atop(round_page(USPACE))) { if ((p = outp) == 0) p = outp2; #ifdef DEBUG if (swapdebug & SDB_SWAPOUT) printf("swapout_threads: no duds, try procp %x\n", p); #endif if (p) swapout(p); } } void swapout(p) register struct proc *p; { vm_offset_t addr; vm_size_t size; #ifdef DEBUG if (swapdebug & SDB_SWAPOUT) printf("swapout: pid %d(%s)@%x, stat %x pri %d free %d\n", p->p_pid, p->p_comm, p->p_addr, p->p_stat, p->p_slptime, cnt.v_free_count); #endif /* * Do any machine-specific actions necessary before swapout. * This can include saving floating point state, etc. */ cpu_swapout(p); /* * Unwire the to-be-swapped process's user struct and kernel stack. */ addr = (vm_offset_t) p->p_addr; size = round_page(USPACE); vm_map_pageable(kernel_map, addr, addr+size, TRUE); pmap_collect(vm_map_pmap(&p->p_vmspace->vm_map)); /* * Mark it as (potentially) swapped out. */ (void) splhigh(); p->p_flag &= ~P_INMEM; if (p->p_stat == SRUN) remrq(p); (void) spl0(); p->p_swtime = 0; } /* * The rest of these routines fake thread handling */ void assert_wait(event, ruptible) void *event; boolean_t ruptible; { #ifdef lint ruptible++; #endif curproc->p_thread = event; } void thread_block() { int s = splhigh(); if (curproc->p_thread) tsleep(curproc->p_thread, PVM, "thrd_block", 0); splx(s); } void thread_sleep(event, lock, ruptible) void *event; simple_lock_t lock; boolean_t ruptible; { int s = splhigh(); #ifdef lint ruptible++; #endif curproc->p_thread = event; simple_unlock(lock); if (curproc->p_thread) tsleep(event, PVM, "thrd_sleep", 0); splx(s); } void thread_wakeup(event) void *event; { int s = splhigh(); wakeup(event); splx(s); } /* * DEBUG stuff */ int indent = 0; #include /* see subr_prf.c */ /*ARGSUSED2*/ void #if __STDC__ iprintf(void (*pr)(const char *, ...), const char *fmt, ...) #else iprintf(pr, fmt /* , va_alist */) void (*pr)(); char *fmt; /* va_dcl */ #endif { register int i; va_list ap; for (i = indent; i >= 8; i -= 8) (*pr)("\t"); while (--i >= 0) (*pr)(" "); va_start(ap, fmt); (*pr)("%r", fmt, ap); va_end(ap); }