/* $NetBSD: uvm_glue.c,v 1.135 2009/01/31 09:13:09 yamt 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. */ #include __KERNEL_RCSID(0, "$NetBSD: uvm_glue.c,v 1.135 2009/01/31 09:13:09 yamt Exp $"); #include "opt_kgdb.h" #include "opt_kstack.h" #include "opt_uvmhist.h" /* * uvm_glue.c: glue functions */ #include #include #include #include #include #include #include #include #include #include /* * local prototypes */ static void uvm_swapout(struct lwp *); static int uarea_swapin(vaddr_t); /* * XXXCDC: do these really belong here? */ /* * uvm_kernacc: can the kernel access a region of memory * * - used only by /dev/kmem driver (mem.c) */ bool uvm_kernacc(void *addr, size_t len, int rw) { bool 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); 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(void *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. */ if (pmap_extract(pmap_kernel(), sva, &pa) == false) panic("%s: invalid page", __func__); 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(struct vmspace *vs, void *addr, size_t len, vm_prot_t access_type) { struct vm_map *map; vaddr_t start, end; int error; map = &vs->vm_map; start = trunc_page((vaddr_t)addr); end = round_page((vaddr_t)addr + len); error = uvm_fault_wire(map, start, end, access_type, 0); return error; } /* * 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(struct vmspace *vs, void *addr, size_t len) { uvm_fault_unwire(&vs->vm_map, trunc_page((vaddr_t)addr), round_page((vaddr_t)addr + len)); } /* * uvm_proc_fork: fork a virtual address space * * - the address space is copied as per parent map's inherit values */ void uvm_proc_fork(struct proc *p1, struct proc *p2, bool shared) { if (shared == true) { p2->p_vmspace = NULL; uvmspace_share(p1, p2); } else { p2->p_vmspace = uvmspace_fork(p1->p_vmspace); } cpu_proc_fork(p1, p2); } /* * uvm_lwp_fork: fork a thread * * - 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_lwp_fork returns in the child process. We do nothing here * after cpu_lwp_fork returns. * - XXXCDC: we need a way for this to return a failure value rather * than just hang */ void uvm_lwp_fork(struct lwp *l1, struct lwp *l2, void *stack, size_t stacksize, void (*func)(void *), void *arg) { int error; /* * Wire down the U-area for the process, which contains the PCB * and the kernel stack. Wired state is stored in l->l_flag's * L_INMEM bit rather than in the vm_map_entry's wired count * to prevent kernel_map fragmentation. If we reused a cached U-area, * L_INMEM will already be set and we don't need to do anything. * * Note the kernel stack gets read/write accesses right off the bat. */ if ((l2->l_flag & LW_INMEM) == 0) { vaddr_t uarea = USER_TO_UAREA(l2->l_addr); if ((error = uarea_swapin(uarea)) != 0) panic("%s: uvm_fault_wire failed: %d", __func__, error); #ifdef PMAP_UAREA /* Tell the pmap this is a u-area mapping */ PMAP_UAREA(uarea); #endif l2->l_flag |= LW_INMEM; } #ifdef KSTACK_CHECK_MAGIC /* * fill stack with magic number */ kstack_setup_magic(l2); #endif /* * cpu_lwp_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_lwp_fork(l1, l2, stack, stacksize, func, arg); } static int uarea_swapin(vaddr_t addr) { return uvm_fault_wire(kernel_map, addr, addr + USPACE, VM_PROT_READ | VM_PROT_WRITE, 0); } static void uarea_swapout(vaddr_t addr) { uvm_fault_unwire(kernel_map, addr, addr + USPACE); } #ifndef USPACE_ALIGN #define USPACE_ALIGN 0 #endif static pool_cache_t uvm_uarea_cache; static int uarea_ctor(void *arg, void *obj, int flags) { KASSERT((flags & PR_WAITOK) != 0); return uarea_swapin((vaddr_t)obj); } static void * uarea_poolpage_alloc(struct pool *pp, int flags) { return (void *)uvm_km_alloc(kernel_map, pp->pr_alloc->pa_pagesz, USPACE_ALIGN, UVM_KMF_PAGEABLE | ((flags & PR_WAITOK) != 0 ? UVM_KMF_WAITVA : (UVM_KMF_NOWAIT | UVM_KMF_TRYLOCK))); } static void uarea_poolpage_free(struct pool *pp, void *addr) { uvm_km_free(kernel_map, (vaddr_t)addr, pp->pr_alloc->pa_pagesz, UVM_KMF_PAGEABLE); } static struct pool_allocator uvm_uarea_allocator = { .pa_alloc = uarea_poolpage_alloc, .pa_free = uarea_poolpage_free, .pa_pagesz = USPACE, }; void uvm_uarea_init(void) { int flags = PR_NOTOUCH; /* * specify PR_NOALIGN unless the alignment provided by * the backend (USPACE_ALIGN) is sufficient to provide * pool page size (UPSACE) alignment. */ if ((USPACE_ALIGN == 0 && USPACE != PAGE_SIZE) || (USPACE_ALIGN % USPACE) != 0) { flags |= PR_NOALIGN; } uvm_uarea_cache = pool_cache_init(USPACE, USPACE_ALIGN, 0, flags, "uarea", &uvm_uarea_allocator, IPL_NONE, uarea_ctor, NULL, NULL); } /* * uvm_uarea_alloc: allocate a u-area */ bool uvm_uarea_alloc(vaddr_t *uaddrp) { *uaddrp = (vaddr_t)pool_cache_get(uvm_uarea_cache, PR_WAITOK); return true; } /* * uvm_uarea_free: free a u-area */ void uvm_uarea_free(vaddr_t uaddr, struct cpu_info *ci) { pool_cache_put(uvm_uarea_cache, (void *)uaddr); } /* * uvm_proc_exit: exit a virtual address space * * - borrow proc0's address space because freeing the vmspace * of the dead process may block. */ void uvm_proc_exit(struct proc *p) { struct lwp *l = curlwp; /* XXX */ struct vmspace *ovm; KASSERT(p == l->l_proc); ovm = p->p_vmspace; /* * borrow proc0's address space. */ KPREEMPT_DISABLE(l); pmap_deactivate(l); p->p_vmspace = proc0.p_vmspace; pmap_activate(l); KPREEMPT_ENABLE(l); uvmspace_free(ovm); } void uvm_lwp_exit(struct lwp *l) { vaddr_t va = USER_TO_UAREA(l->l_addr); l->l_flag &= ~LW_INMEM; uvm_uarea_free(va, l->l_cpu); l->l_addr = NULL; } /* * uvm_init_limit: init per-process VM limits * * - called for process 0 and then inherited by all others. */ void uvm_init_limits(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 = maxsmap; p->p_rlimit[RLIMIT_DATA].rlim_cur = DFLDSIZ; p->p_rlimit[RLIMIT_DATA].rlim_max = maxdmap; 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 an lwp's u-area. * * - must be called with the LWP's swap lock held. * - naturally, must not be called with l == curlwp */ void uvm_swapin(struct lwp *l) { int error; KASSERT(mutex_owned(&l->l_swaplock)); KASSERT(l != curlwp); error = uarea_swapin(USER_TO_UAREA(l->l_addr)); if (error) { panic("%s: rewiring stack failed: %d", __func__, error); } /* * 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(l); lwp_lock(l); if (l->l_stat == LSRUN) sched_enqueue(l, false); l->l_flag |= LW_INMEM; l->l_swtime = 0; lwp_unlock(l); ++uvmexp.swapins; } /* * uvm_kick_scheduler: kick the scheduler into action if not running. * * - called when swapped out processes have been awoken. */ void uvm_kick_scheduler(void) { if (uvm.swap_running == false) return; mutex_enter(&uvm_scheduler_mutex); uvm.scheduler_kicked = true; cv_signal(&uvm.scheduler_cv); mutex_exit(&uvm_scheduler_mutex); } /* * 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(void) { struct lwp *l, *ll; int pri; int ppri; l = curlwp; lwp_lock(l); l->l_priority = PRI_VM; l->l_class = SCHED_FIFO; lwp_unlock(l); for (;;) { #ifdef DEBUG mutex_enter(&uvm_scheduler_mutex); while (!enableswap) cv_wait(&uvm.scheduler_cv, &uvm_scheduler_mutex); mutex_exit(&uvm_scheduler_mutex); #endif ll = NULL; /* process to choose */ ppri = INT_MIN; /* its priority */ mutex_enter(proc_lock); LIST_FOREACH(l, &alllwp, l_list) { /* is it a runnable swapped out process? */ if (l->l_stat == LSRUN && !(l->l_flag & LW_INMEM)) { pri = l->l_swtime + l->l_slptime - (l->l_proc->p_nice - NZERO) * 8; if (pri > ppri) { /* higher priority? */ ll = l; ppri = pri; } } } #ifdef DEBUG if (swapdebug & SDB_FOLLOW) printf("%s: running, procp %p pri %d\n", __func__, ll, ppri); #endif /* * Nothing to do, back to sleep */ if ((l = ll) == NULL) { mutex_exit(proc_lock); mutex_enter(&uvm_scheduler_mutex); if (uvm.scheduler_kicked == false) cv_wait(&uvm.scheduler_cv, &uvm_scheduler_mutex); uvm.scheduler_kicked = false; mutex_exit(&uvm_scheduler_mutex); continue; } /* * we have found swapped out process which we would like * to bring back in. * * XXX: this part is really bogus cuz 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", l->l_proc->p_pid, l->l_proc->p_comm, l->l_addr, ppri, uvmexp.free); #endif mutex_enter(&l->l_swaplock); mutex_exit(proc_lock); uvm_swapin(l); mutex_exit(&l->l_swaplock); continue; } else { /* * not enough memory, jab the pageout daemon and * wait til the coast is clear */ mutex_exit(proc_lock); #ifdef DEBUG if (swapdebug & SDB_FOLLOW) printf("%s: no room for pid %d(%s)," " free %d\n", __func__, l->l_proc->p_pid, l->l_proc->p_comm, uvmexp.free); #endif uvm_wait("schedpwait"); #ifdef DEBUG if (swapdebug & SDB_FOLLOW) printf("%s: room again, free %d\n", __func__, uvmexp.free); #endif } } } /* * swappable: is LWP "l" swappable? */ static bool swappable(struct lwp *l) { if ((l->l_flag & (LW_INMEM|LW_SYSTEM|LW_WEXIT)) != LW_INMEM) return false; if ((l->l_pflag & LP_RUNNING) != 0) return false; if (l->l_holdcnt != 0) return false; if (l->l_class != SCHED_OTHER) return false; if (l->l_syncobj == &rw_syncobj || l->l_syncobj == &mutex_syncobj) return false; if (l->l_proc->p_stat != SACTIVE && l->l_proc->p_stat != SSTOP) return false; return true; } /* * 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(void) { struct lwp *l; struct lwp *outl, *outl2; int outpri, outpri2; int didswap = 0; extern int maxslp; bool gotit; /* XXXCDC: should move off to uvmexp. or uvm., also in uvm_meter */ #ifdef DEBUG if (!enableswap) return; #endif /* * outl/outpri : stop/sleep thread with largest sleeptime < maxslp * outl2/outpri2: the longest resident thread (its swap time) */ outl = outl2 = NULL; outpri = outpri2 = 0; restart: mutex_enter(proc_lock); LIST_FOREACH(l, &alllwp, l_list) { KASSERT(l->l_proc != NULL); if (!mutex_tryenter(&l->l_swaplock)) continue; if (!swappable(l)) { mutex_exit(&l->l_swaplock); continue; } switch (l->l_stat) { case LSONPROC: break; case LSRUN: if (l->l_swtime > outpri2) { outl2 = l; outpri2 = l->l_swtime; } break; case LSSLEEP: case LSSTOP: if (l->l_slptime >= maxslp) { mutex_exit(proc_lock); uvm_swapout(l); /* * Locking in the wrong direction - * try to prevent the LWP from exiting. */ gotit = mutex_tryenter(proc_lock); mutex_exit(&l->l_swaplock); didswap++; if (!gotit) goto restart; continue; } else if (l->l_slptime > outpri) { outl = l; outpri = l->l_slptime; } break; } mutex_exit(&l->l_swaplock); } /* * 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 ((l = outl) == NULL) l = outl2; #ifdef DEBUG if (swapdebug & SDB_SWAPOUT) printf("%s: no duds, try procp %p\n", __func__, l); #endif if (l) { mutex_enter(&l->l_swaplock); mutex_exit(proc_lock); if (swappable(l)) uvm_swapout(l); mutex_exit(&l->l_swaplock); return; } } mutex_exit(proc_lock); } /* * uvm_swapout: swap out lwp "l" * * - currently "swapout" means "unwire U-area" and "pmap_collect()" * the pmap. * - must be called with l->l_swaplock held. * - XXXCDC: should deactivate all process' private anonymous memory */ static void uvm_swapout(struct lwp *l) { struct vm_map *map; KASSERT(mutex_owned(&l->l_swaplock)); #ifdef DEBUG if (swapdebug & SDB_SWAPOUT) printf("%s: lid %d.%d(%s)@%p, stat %x pri %d free %d\n", __func__, l->l_proc->p_pid, l->l_lid, l->l_proc->p_comm, l->l_addr, l->l_stat, l->l_slptime, uvmexp.free); #endif /* * Mark it as (potentially) swapped out. */ lwp_lock(l); if (!swappable(l)) { KDASSERT(l->l_cpu != curcpu()); lwp_unlock(l); return; } l->l_flag &= ~LW_INMEM; l->l_swtime = 0; if (l->l_stat == LSRUN) sched_dequeue(l); lwp_unlock(l); l->l_ru.ru_nswap++; ++uvmexp.swapouts; /* * Do any machine-specific actions necessary before swapout. * This can include saving floating point state, etc. */ cpu_swapout(l); /* * Unwire the to-be-swapped process's user struct and kernel stack. */ uarea_swapout(USER_TO_UAREA(l->l_addr)); map = &l->l_proc->p_vmspace->vm_map; if (vm_map_lock_try(map)) { pmap_collect(vm_map_pmap(map)); vm_map_unlock(map); } } /* * uvm_lwp_hold: prevent lwp "l" from being swapped out, and bring * back into memory if it is currently swapped. */ void uvm_lwp_hold(struct lwp *l) { if (l == curlwp) { atomic_inc_uint(&l->l_holdcnt); } else { mutex_enter(&l->l_swaplock); if (atomic_inc_uint_nv(&l->l_holdcnt) == 1 && (l->l_flag & LW_INMEM) == 0) uvm_swapin(l); mutex_exit(&l->l_swaplock); } } /* * uvm_lwp_rele: release a hold on lwp "l". when the holdcount * drops to zero, it's eligable to be swapped. */ void uvm_lwp_rele(struct lwp *l) { KASSERT(l->l_holdcnt != 0); atomic_dec_uint(&l->l_holdcnt); }