/* $OpenBSD: uvm_glue.c,v 1.44 2006/05/25 22:42:22 miod Exp $ */ /* $NetBSD: uvm_glue.c,v 1.44 2001/02/06 19:54:44 eeh Exp $ */ /* * Copyright (c) 1997 Charles D. Cranor and Washington University. * 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 Charles D. Cranor, * Washington University, 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 * from: Id: uvm_glue.c,v 1.1.2.8 1998/02/07 01:16:54 chs Exp * * * 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. */ /* * uvm_glue.c: glue functions */ #include #include #include #include #include #include #ifdef SYSVSHM #include #endif #include #include #include /* * local prototypes */ static void uvm_swapout(struct proc *); /* * XXXCDC: do these really belong here? */ int readbuffers = 0; /* allow KGDB to read kern buffer pool */ /* XXX: see uvm_kernacc */ /* * uvm_kernacc: can the kernel access a region of memory * * - called from malloc [DIAGNOSTIC], and /dev/kmem driver (mem.c) */ boolean_t uvm_kernacc(addr, len, rw) caddr_t addr; size_t len; int rw; { boolean_t rv; vaddr_t saddr, eaddr; vm_prot_t prot = rw == B_READ ? VM_PROT_READ : VM_PROT_WRITE; saddr = trunc_page((vaddr_t)addr); eaddr = round_page((vaddr_t)addr + len); vm_map_lock_read(kernel_map); rv = uvm_map_checkprot(kernel_map, saddr, eaddr, prot); vm_map_unlock_read(kernel_map); /* * 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 > (vaddr_t)buffers && saddr < (vaddr_t)buffers + MAXBSIZE * nbuf)) rv = FALSE; return(rv); } #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 uvm_chgkprot(addr, len, rw) caddr_t addr; size_t len; int rw; { vm_prot_t prot; paddr_t pa; vaddr_t sva, eva; prot = rw == B_READ ? VM_PROT_READ : VM_PROT_READ|VM_PROT_WRITE; eva = round_page((vaddr_t)addr + len); for (sva = trunc_page((vaddr_t)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... */ if (pmap_extract(pmap_kernel(), sva, &pa) == FALSE) panic("chgkprot: invalid page"); pmap_enter(pmap_kernel(), sva, pa, prot, PMAP_WIRED); } pmap_update(pmap_kernel()); } #endif /* * uvm_vslock: wire user memory for I/O * * - called from physio and sys___sysctl * - XXXCDC: consider nuking this (or making it a macro?) */ int uvm_vslock(p, addr, len, access_type) struct proc *p; caddr_t addr; size_t len; vm_prot_t access_type; { vm_map_t map; vaddr_t start, end; int rv; map = &p->p_vmspace->vm_map; start = trunc_page((vaddr_t)addr); end = round_page((vaddr_t)addr + len); if (end <= start) return (EINVAL); rv = uvm_fault_wire(map, start, end, access_type); return (rv); } /* * uvm_vsunlock: unwire user memory wired by uvm_vslock() * * - called from physio and sys___sysctl * - XXXCDC: consider nuking this (or making it a macro?) */ void uvm_vsunlock(p, addr, len) struct proc *p; caddr_t addr; size_t len; { vaddr_t start, end; start = trunc_page((vaddr_t)addr); end = round_page((vaddr_t)addr + len); if (end <= start) return; uvm_fault_unwire(&p->p_vmspace->vm_map, start, end); } /* * uvm_fork: fork a virtual address space * * - the address space is copied as per parent map's inherit values * - a new "user" structure is allocated for the child process * [filled in by MD layer...] * - if specified, the child gets a new user stack described by * stack and stacksize * - 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. * - XXXCDC: we need a way for this to return a failure value rather * than just hang */ void uvm_fork(p1, p2, shared, stack, stacksize, func, arg) struct proc *p1, *p2; boolean_t shared; void *stack; size_t stacksize; void (*func)(void *); void *arg; { struct user *up = p2->p_addr; int rv; if (shared == TRUE) { p2->p_vmspace = NULL; uvmspace_share(p1, p2); /* share vmspace */ } else p2->p_vmspace = uvmspace_fork(p1->p_vmspace); /* fork vmspace */ /* * Wire down the U-area for the process, which contains the PCB * and the kernel stack. Wired state is stored in p->p_flag's * P_INMEM bit rather than in the vm_map_entry's wired count * to prevent kernel_map fragmentation. * * Note the kernel stack gets read/write accesses right off * the bat. */ rv = uvm_fault_wire(kernel_map, (vaddr_t)up, (vaddr_t)up + USPACE, VM_PROT_READ | VM_PROT_WRITE); if (rv != KERN_SUCCESS) panic("uvm_fork: uvm_fault_wire failed: %d", rv); #ifdef PMAP_UAREA /* Tell the pmap this is a u-area mapping */ PMAP_UAREA((vaddr_t)up); #endif /* * p_stats currently points at a field in the user struct. Copy * parts of p_stats, and zero out the rest. */ p2->p_stats = &up->u_stats; memset(&up->u_stats.pstat_startzero, 0, ((caddr_t)&up->u_stats.pstat_endzero - (caddr_t)&up->u_stats.pstat_startzero)); memcpy(&up->u_stats.pstat_startcopy, &p1->p_stats->pstat_startcopy, ((caddr_t)&up->u_stats.pstat_endcopy - (caddr_t)&up->u_stats.pstat_startcopy)); /* * cpu_fork() copy and update the pcb, and make the child ready * to run. If this is a normal user fork, the child will exit * directly to user mode via child_return() on its first time * slice and will not return here. If this is a kernel thread, * the specified entry point will be executed. */ cpu_fork(p1, p2, stack, stacksize, func, arg); } /* * uvm_exit: exit a virtual address space * * - the process passed to us is a dead (pre-zombie) process; we * are running on a different context now (the reaper). * - we must run in a separate thread because freeing the vmspace * of the dead process may block. */ void uvm_exit(p) struct proc *p; { vaddr_t va = (vaddr_t)p->p_addr; uvmspace_free(p->p_vmspace); p->p_flag &= ~P_INMEM; uvm_fault_unwire(kernel_map, va, va + USPACE); uvm_km_free(kernel_map, va, USPACE); p->p_addr = NULL; } /* * uvm_init_limit: init per-process VM limits * * - called for process 0 and then inherited by all others. */ void uvm_init_limits(p) 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(uvmexp.free); } #ifdef DEBUG int enableswap = 1; int swapdebug = 0; #define SDB_FOLLOW 1 #define SDB_SWAPIN 2 #define SDB_SWAPOUT 4 #endif /* * uvm_swapin: swap in a process's u-area. */ void uvm_swapin(p) struct proc *p; { vaddr_t addr; int rv, s; s = splstatclock(); if (p->p_flag & P_SWAPIN) { splx(s); return; } p->p_flag |= P_SWAPIN; splx(s); addr = (vaddr_t)p->p_addr; /* make P_INMEM true */ if ((rv = uvm_fault_wire(kernel_map, addr, addr + USPACE, VM_PROT_READ | VM_PROT_WRITE)) != KERN_SUCCESS) panic("uvm_swapin: uvm_fault_wire failed: %d", rv); /* * Some architectures need to be notified when the user area has * moved to new physical page(s) (e.g. see mips/mips/vm_machdep.c). */ cpu_swapin(p); SCHED_LOCK(s); if (p->p_stat == SRUN) setrunqueue(p); p->p_flag |= P_INMEM; p->p_flag &= ~P_SWAPIN; p->p_swtime = 0; SCHED_UNLOCK(s); ++uvmexp.swapins; } /* * uvm_scheduler: process zero main loop * * - attempt to swapin every swaped-out, runnable process in order of * priority. * - if not enough memory, wake the pagedaemon and let it clear space. */ void uvm_scheduler() { struct proc *p; int pri; struct proc *pp; int ppri; loop: #ifdef DEBUG while (!enableswap) tsleep(&proc0, PVM, "noswap", 0); #endif pp = NULL; /* process to choose */ ppri = INT_MIN; /* its priority */ LIST_FOREACH(p, &allproc, p_list) { /* is it a runnable swapped out process? */ if (p->p_stat == SRUN && (p->p_flag & P_INMEM) == 0) { pri = p->p_swtime + p->p_slptime - (p->p_nice - NZERO) * 8; if (pri > ppri) { /* higher priority? remember it. */ pp = p; ppri = pri; } } } #ifdef DEBUG if (swapdebug & SDB_FOLLOW) printf("scheduler: running, procp %p pri %d\n", pp, ppri); #endif /* * Nothing to do, back to sleep */ if ((p = pp) == NULL) { tsleep(&proc0, PVM, "scheduler", 0); goto loop; } /* * we have found swapped out process which we would like to bring * back in. * * XXX: this part is really bogus because we could deadlock on memory * despite our feeble check */ if (uvmexp.free > atop(USPACE)) { #ifdef DEBUG if (swapdebug & SDB_SWAPIN) printf("swapin: pid %d(%s)@%p, pri %d free %d\n", p->p_pid, p->p_comm, p->p_addr, ppri, uvmexp.free); #endif uvm_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, uvmexp.free); #endif uvm_wait("schedpwait"); #ifdef DEBUG if (swapdebug & SDB_FOLLOW) printf("scheduler: room again, free %d\n", uvmexp.free); #endif goto loop; } /* * swappable: is process "p" swappable? */ #define swappable(p) \ (((p)->p_flag & (P_SYSTEM | P_INMEM | P_WEXIT)) == P_INMEM && \ (p)->p_holdcnt == 0) /* * swapout_threads: find threads that can be swapped and unwire their * u-areas. * * - called by the pagedaemon * - try and swap at least one processs * - processes that are sleeping or stopped for maxslp or more seconds * are swapped... otherwise the longest-sleeping or stopped process * is swapped, otherwise the longest resident process... */ void uvm_swapout_threads() { struct proc *p; struct proc *outp, *outp2; int outpri, outpri2; int didswap = 0; extern int maxslp; /* XXXCDC: should move off to uvmexp. or uvm., also in uvm_meter */ #ifdef DEBUG if (!enableswap) return; #endif /* * outp/outpri : stop/sleep process with largest sleeptime < maxslp * outp2/outpri2: the longest resident process (its swap time) */ outp = outp2 = NULL; outpri = outpri2 = 0; LIST_FOREACH(p, &allproc, p_list) { 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) { uvm_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 && uvmexp.free <= atop(round_page(USPACE))) { if ((p = outp) == NULL) p = outp2; #ifdef DEBUG if (swapdebug & SDB_SWAPOUT) printf("swapout_threads: no duds, try procp %p\n", p); #endif if (p) uvm_swapout(p); } } /* * uvm_swapout: swap out process "p" * * - currently "swapout" means "unwire U-area" and "pmap_collect()" * the pmap. * - XXXCDC: should deactivate all process' private anonymous memory */ static void uvm_swapout(p) struct proc *p; { vaddr_t addr; int s; #ifdef DEBUG if (swapdebug & SDB_SWAPOUT) printf("swapout: pid %d(%s)@%p, stat %x pri %d free %d\n", p->p_pid, p->p_comm, p->p_addr, p->p_stat, p->p_slptime, uvmexp.free); #endif /* * Mark it as (potentially) swapped out. */ SCHED_LOCK(s); if (!(p->p_flag & P_INMEM)) { SCHED_UNLOCK(s); return; } p->p_flag &= ~P_INMEM; if (p->p_stat == SRUN) remrunqueue(p); p->p_swtime = 0; SCHED_UNLOCK(s); ++uvmexp.swapouts; /* * 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 = (vaddr_t)p->p_addr; uvm_fault_unwire(kernel_map, addr, addr + USPACE); /* !P_INMEM */ pmap_collect(vm_map_pmap(&p->p_vmspace->vm_map)); }