/*- * 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. * 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_object.c 8.5 (Berkeley) 3/22/94 * * * Copyright (c) 1987, 1990 Carnegie-Mellon University. * All rights reserved. * * Authors: Avadis Tevanian, Jr., Michael Wayne Young * * 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. */ /* * Virtual memory object module. */ #include __FBSDID("$FreeBSD$"); #include "opt_vm.h" #include #include #include #include #include #include #include #include #include /* for curproc, pageproc */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define EASY_SCAN_FACTOR 8 #define MSYNC_FLUSH_HARDSEQ 0x01 #define MSYNC_FLUSH_SOFTSEQ 0x02 /* * msync / VM object flushing optimizations */ static int msync_flush_flags = MSYNC_FLUSH_HARDSEQ | MSYNC_FLUSH_SOFTSEQ; SYSCTL_INT(_vm, OID_AUTO, msync_flush_flags, CTLFLAG_RW, &msync_flush_flags, 0, "Enable sequential iteration optimization"); static int old_msync; SYSCTL_INT(_vm, OID_AUTO, old_msync, CTLFLAG_RW, &old_msync, 0, "Use old (insecure) msync behavior"); static void vm_object_qcollapse(vm_object_t object); static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags); static void vm_object_vndeallocate(vm_object_t object); /* * Virtual memory objects maintain the actual data * associated with allocated virtual memory. A given * page of memory exists within exactly one object. * * An object is only deallocated when all "references" * are given up. Only one "reference" to a given * region of an object should be writeable. * * Associated with each object is a list of all resident * memory pages belonging to that object; this list is * maintained by the "vm_page" module, and locked by the object's * lock. * * Each object also records a "pager" routine which is * used to retrieve (and store) pages to the proper backing * storage. In addition, objects may be backed by other * objects from which they were virtual-copied. * * The only items within the object structure which are * modified after time of creation are: * reference count locked by object's lock * pager routine locked by object's lock * */ struct object_q vm_object_list; struct mtx vm_object_list_mtx; /* lock for object list and count */ struct vm_object kernel_object_store; struct vm_object kmem_object_store; SYSCTL_NODE(_vm_stats, OID_AUTO, object, CTLFLAG_RD, 0, "VM object stats"); static long object_collapses; SYSCTL_LONG(_vm_stats_object, OID_AUTO, collapses, CTLFLAG_RD, &object_collapses, 0, "VM object collapses"); static long object_bypasses; SYSCTL_LONG(_vm_stats_object, OID_AUTO, bypasses, CTLFLAG_RD, &object_bypasses, 0, "VM object bypasses"); static uma_zone_t obj_zone; static int vm_object_zinit(void *mem, int size, int flags); #ifdef INVARIANTS static void vm_object_zdtor(void *mem, int size, void *arg); static void vm_object_zdtor(void *mem, int size, void *arg) { vm_object_t object; object = (vm_object_t)mem; KASSERT(TAILQ_EMPTY(&object->memq), ("object %p has resident pages", object)); #if VM_NRESERVLEVEL > 0 KASSERT(LIST_EMPTY(&object->rvq), ("object %p has reservations", object)); #endif KASSERT(object->cache == NULL, ("object %p has cached pages", object)); KASSERT(object->paging_in_progress == 0, ("object %p paging_in_progress = %d", object, object->paging_in_progress)); KASSERT(object->resident_page_count == 0, ("object %p resident_page_count = %d", object, object->resident_page_count)); KASSERT(object->shadow_count == 0, ("object %p shadow_count = %d", object, object->shadow_count)); } #endif static int vm_object_zinit(void *mem, int size, int flags) { vm_object_t object; object = (vm_object_t)mem; bzero(&object->mtx, sizeof(object->mtx)); VM_OBJECT_LOCK_INIT(object, "standard object"); /* These are true for any object that has been freed */ object->paging_in_progress = 0; object->resident_page_count = 0; object->shadow_count = 0; return (0); } void _vm_object_allocate(objtype_t type, vm_pindex_t size, vm_object_t object) { TAILQ_INIT(&object->memq); LIST_INIT(&object->shadow_head); object->root = NULL; object->type = type; object->size = size; object->generation = 1; object->ref_count = 1; object->memattr = VM_MEMATTR_DEFAULT; object->flags = 0; object->uip = NULL; object->charge = 0; if ((object->type == OBJT_DEFAULT) || (object->type == OBJT_SWAP)) object->flags = OBJ_ONEMAPPING; object->pg_color = 0; object->handle = NULL; object->backing_object = NULL; object->backing_object_offset = (vm_ooffset_t) 0; #if VM_NRESERVLEVEL > 0 LIST_INIT(&object->rvq); #endif object->cache = NULL; mtx_lock(&vm_object_list_mtx); TAILQ_INSERT_TAIL(&vm_object_list, object, object_list); mtx_unlock(&vm_object_list_mtx); } /* * vm_object_init: * * Initialize the VM objects module. */ void vm_object_init(void) { TAILQ_INIT(&vm_object_list); mtx_init(&vm_object_list_mtx, "vm object_list", NULL, MTX_DEF); VM_OBJECT_LOCK_INIT(&kernel_object_store, "kernel object"); _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), kernel_object); #if VM_NRESERVLEVEL > 0 kernel_object->flags |= OBJ_COLORED; kernel_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS); #endif VM_OBJECT_LOCK_INIT(&kmem_object_store, "kmem object"); _vm_object_allocate(OBJT_PHYS, OFF_TO_IDX(VM_MAX_KERNEL_ADDRESS - VM_MIN_KERNEL_ADDRESS), kmem_object); #if VM_NRESERVLEVEL > 0 kmem_object->flags |= OBJ_COLORED; kmem_object->pg_color = (u_short)atop(VM_MIN_KERNEL_ADDRESS); #endif /* * The lock portion of struct vm_object must be type stable due * to vm_pageout_fallback_object_lock locking a vm object * without holding any references to it. */ obj_zone = uma_zcreate("VM OBJECT", sizeof (struct vm_object), NULL, #ifdef INVARIANTS vm_object_zdtor, #else NULL, #endif vm_object_zinit, NULL, UMA_ALIGN_PTR, UMA_ZONE_VM|UMA_ZONE_NOFREE); } void vm_object_clear_flag(vm_object_t object, u_short bits) { VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); object->flags &= ~bits; } /* * Sets the default memory attribute for the specified object. Pages * that are allocated to this object are by default assigned this memory * attribute. * * Presently, this function must be called before any pages are allocated * to the object. In the future, this requirement may be relaxed for * "default" and "swap" objects. */ int vm_object_set_memattr(vm_object_t object, vm_memattr_t memattr) { VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); switch (object->type) { case OBJT_DEFAULT: case OBJT_DEVICE: case OBJT_PHYS: case OBJT_SG: case OBJT_SWAP: case OBJT_VNODE: if (!TAILQ_EMPTY(&object->memq)) return (KERN_FAILURE); break; case OBJT_DEAD: return (KERN_INVALID_ARGUMENT); } object->memattr = memattr; return (KERN_SUCCESS); } void vm_object_pip_add(vm_object_t object, short i) { VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); object->paging_in_progress += i; } void vm_object_pip_subtract(vm_object_t object, short i) { VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); object->paging_in_progress -= i; } void vm_object_pip_wakeup(vm_object_t object) { VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); object->paging_in_progress--; if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { vm_object_clear_flag(object, OBJ_PIPWNT); wakeup(object); } } void vm_object_pip_wakeupn(vm_object_t object, short i) { VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); if (i) object->paging_in_progress -= i; if ((object->flags & OBJ_PIPWNT) && object->paging_in_progress == 0) { vm_object_clear_flag(object, OBJ_PIPWNT); wakeup(object); } } void vm_object_pip_wait(vm_object_t object, char *waitid) { VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); while (object->paging_in_progress) { object->flags |= OBJ_PIPWNT; msleep(object, VM_OBJECT_MTX(object), PVM, waitid, 0); } } /* * vm_object_allocate: * * Returns a new object with the given size. */ vm_object_t vm_object_allocate(objtype_t type, vm_pindex_t size) { vm_object_t object; object = (vm_object_t)uma_zalloc(obj_zone, M_WAITOK); _vm_object_allocate(type, size, object); return (object); } /* * vm_object_reference: * * Gets another reference to the given object. Note: OBJ_DEAD * objects can be referenced during final cleaning. */ void vm_object_reference(vm_object_t object) { if (object == NULL) return; VM_OBJECT_LOCK(object); vm_object_reference_locked(object); VM_OBJECT_UNLOCK(object); } /* * vm_object_reference_locked: * * Gets another reference to the given object. * * The object must be locked. */ void vm_object_reference_locked(vm_object_t object) { struct vnode *vp; VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); object->ref_count++; if (object->type == OBJT_VNODE) { vp = object->handle; vref(vp); } } /* * Handle deallocating an object of type OBJT_VNODE. */ static void vm_object_vndeallocate(vm_object_t object) { struct vnode *vp = (struct vnode *) object->handle; VFS_ASSERT_GIANT(vp->v_mount); VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); KASSERT(object->type == OBJT_VNODE, ("vm_object_vndeallocate: not a vnode object")); KASSERT(vp != NULL, ("vm_object_vndeallocate: missing vp")); #ifdef INVARIANTS if (object->ref_count == 0) { vprint("vm_object_vndeallocate", vp); panic("vm_object_vndeallocate: bad object reference count"); } #endif object->ref_count--; if (object->ref_count == 0) { mp_fixme("Unlocked vflag access."); vp->v_vflag &= ~VV_TEXT; } VM_OBJECT_UNLOCK(object); /* * vrele may need a vop lock */ vrele(vp); } /* * vm_object_deallocate: * * Release a reference to the specified object, * gained either through a vm_object_allocate * or a vm_object_reference call. When all references * are gone, storage associated with this object * may be relinquished. * * No object may be locked. */ void vm_object_deallocate(vm_object_t object) { vm_object_t temp; while (object != NULL) { int vfslocked; vfslocked = 0; restart: VM_OBJECT_LOCK(object); if (object->type == OBJT_VNODE) { struct vnode *vp = (struct vnode *) object->handle; /* * Conditionally acquire Giant for a vnode-backed * object. We have to be careful since the type of * a vnode object can change while the object is * unlocked. */ if (VFS_NEEDSGIANT(vp->v_mount) && !vfslocked) { vfslocked = 1; if (!mtx_trylock(&Giant)) { VM_OBJECT_UNLOCK(object); mtx_lock(&Giant); goto restart; } } vm_object_vndeallocate(object); VFS_UNLOCK_GIANT(vfslocked); return; } else /* * This is to handle the case that the object * changed type while we dropped its lock to * obtain Giant. */ VFS_UNLOCK_GIANT(vfslocked); KASSERT(object->ref_count != 0, ("vm_object_deallocate: object deallocated too many times: %d", object->type)); /* * If the reference count goes to 0 we start calling * vm_object_terminate() on the object chain. * A ref count of 1 may be a special case depending on the * shadow count being 0 or 1. */ object->ref_count--; if (object->ref_count > 1) { VM_OBJECT_UNLOCK(object); return; } else if (object->ref_count == 1) { if (object->shadow_count == 0 && object->handle == NULL && (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { vm_object_set_flag(object, OBJ_ONEMAPPING); } else if ((object->shadow_count == 1) && (object->handle == NULL) && (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { vm_object_t robject; robject = LIST_FIRST(&object->shadow_head); KASSERT(robject != NULL, ("vm_object_deallocate: ref_count: %d, shadow_count: %d", object->ref_count, object->shadow_count)); if (!VM_OBJECT_TRYLOCK(robject)) { /* * Avoid a potential deadlock. */ object->ref_count++; VM_OBJECT_UNLOCK(object); /* * More likely than not the thread * holding robject's lock has lower * priority than the current thread. * Let the lower priority thread run. */ pause("vmo_de", 1); continue; } /* * Collapse object into its shadow unless its * shadow is dead. In that case, object will * be deallocated by the thread that is * deallocating its shadow. */ if ((robject->flags & OBJ_DEAD) == 0 && (robject->handle == NULL) && (robject->type == OBJT_DEFAULT || robject->type == OBJT_SWAP)) { robject->ref_count++; retry: if (robject->paging_in_progress) { VM_OBJECT_UNLOCK(object); vm_object_pip_wait(robject, "objde1"); temp = robject->backing_object; if (object == temp) { VM_OBJECT_LOCK(object); goto retry; } } else if (object->paging_in_progress) { VM_OBJECT_UNLOCK(robject); object->flags |= OBJ_PIPWNT; msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "objde2", 0); VM_OBJECT_LOCK(robject); temp = robject->backing_object; if (object == temp) { VM_OBJECT_LOCK(object); goto retry; } } else VM_OBJECT_UNLOCK(object); if (robject->ref_count == 1) { robject->ref_count--; object = robject; goto doterm; } object = robject; vm_object_collapse(object); VM_OBJECT_UNLOCK(object); continue; } VM_OBJECT_UNLOCK(robject); } VM_OBJECT_UNLOCK(object); return; } doterm: temp = object->backing_object; if (temp != NULL) { VM_OBJECT_LOCK(temp); LIST_REMOVE(object, shadow_list); temp->shadow_count--; temp->generation++; VM_OBJECT_UNLOCK(temp); object->backing_object = NULL; } /* * Don't double-terminate, we could be in a termination * recursion due to the terminate having to sync data * to disk. */ if ((object->flags & OBJ_DEAD) == 0) vm_object_terminate(object); else VM_OBJECT_UNLOCK(object); object = temp; } } /* * vm_object_destroy removes the object from the global object list * and frees the space for the object. */ void vm_object_destroy(vm_object_t object) { /* * Remove the object from the global object list. */ mtx_lock(&vm_object_list_mtx); TAILQ_REMOVE(&vm_object_list, object, object_list); mtx_unlock(&vm_object_list_mtx); /* * Release the allocation charge. */ if (object->uip != NULL) { KASSERT(object->type == OBJT_DEFAULT || object->type == OBJT_SWAP, ("vm_object_terminate: non-swap obj %p has uip", object)); swap_release_by_uid(object->charge, object->uip); object->charge = 0; uifree(object->uip); object->uip = NULL; } /* * Free the space for the object. */ uma_zfree(obj_zone, object); } /* * vm_object_terminate actually destroys the specified object, freeing * up all previously used resources. * * The object must be locked. * This routine may block. */ void vm_object_terminate(vm_object_t object) { vm_page_t p; VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); /* * Make sure no one uses us. */ vm_object_set_flag(object, OBJ_DEAD); /* * wait for the pageout daemon to be done with the object */ vm_object_pip_wait(object, "objtrm"); KASSERT(!object->paging_in_progress, ("vm_object_terminate: pageout in progress")); /* * Clean and free the pages, as appropriate. All references to the * object are gone, so we don't need to lock it. */ if (object->type == OBJT_VNODE) { struct vnode *vp = (struct vnode *)object->handle; /* * Clean pages and flush buffers. */ vm_object_page_clean(object, 0, 0, OBJPC_SYNC); VM_OBJECT_UNLOCK(object); vinvalbuf(vp, V_SAVE, 0, 0); VM_OBJECT_LOCK(object); } KASSERT(object->ref_count == 0, ("vm_object_terminate: object with references, ref_count=%d", object->ref_count)); /* * Now free any remaining pages. For internal objects, this also * removes them from paging queues. Don't free wired pages, just * remove them from the object. */ while ((p = TAILQ_FIRST(&object->memq)) != NULL) { KASSERT(!p->busy && (p->oflags & VPO_BUSY) == 0, ("vm_object_terminate: freeing busy page %p " "p->busy = %d, p->oflags %x\n", p, p->busy, p->oflags)); vm_page_lock(p); if (p->wire_count == 0) { vm_page_free(p); PCPU_INC(cnt.v_pfree); } else vm_page_remove(p); vm_page_unlock(p); } #if VM_NRESERVLEVEL > 0 if (__predict_false(!LIST_EMPTY(&object->rvq))) vm_reserv_break_all(object); #endif if (__predict_false(object->cache != NULL)) vm_page_cache_free(object, 0, 0); /* * Let the pager know object is dead. */ vm_pager_deallocate(object); VM_OBJECT_UNLOCK(object); vm_object_destroy(object); } /* * vm_object_page_clean * * Clean all dirty pages in the specified range of object. Leaves page * on whatever queue it is currently on. If NOSYNC is set then do not * write out pages with VPO_NOSYNC set (originally comes from MAP_NOSYNC), * leaving the object dirty. * * When stuffing pages asynchronously, allow clustering. XXX we need a * synchronous clustering mode implementation. * * Odd semantics: if start == end, we clean everything. * * The object must be locked. */ void vm_object_page_clean(vm_object_t object, vm_pindex_t start, vm_pindex_t end, int flags) { vm_page_t p, np; vm_pindex_t tstart, tend; vm_pindex_t pi; int clearobjflags; int pagerflags; int curgeneration; mtx_assert(&vm_page_queue_mtx, MA_NOTOWNED); VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); if ((object->flags & OBJ_MIGHTBEDIRTY) == 0) return; KASSERT(object->type == OBJT_VNODE, ("Not a vnode object")); pagerflags = (flags & (OBJPC_SYNC | OBJPC_INVAL)) ? VM_PAGER_PUT_SYNC : VM_PAGER_CLUSTER_OK; pagerflags |= (flags & OBJPC_INVAL) ? VM_PAGER_PUT_INVAL : 0; vm_object_set_flag(object, OBJ_CLEANING); tstart = start; if (end == 0) { tend = object->size; } else { tend = end; } /* * If the caller is smart and only msync()s a range he knows is * dirty, we may be able to avoid an object scan. This results in * a phenominal improvement in performance. We cannot do this * as a matter of course because the object may be huge - e.g. * the size might be in the gigabytes or terrabytes. */ if (msync_flush_flags & MSYNC_FLUSH_HARDSEQ) { vm_pindex_t tscan; int scanlimit; int scanreset; scanreset = object->resident_page_count / EASY_SCAN_FACTOR; if (scanreset < 16) scanreset = 16; pagerflags |= VM_PAGER_IGNORE_CLEANCHK; scanlimit = scanreset; tscan = tstart; while (tscan < tend) { curgeneration = object->generation; p = vm_page_lookup(object, tscan); if (p == NULL || p->valid == 0) { if (--scanlimit == 0) break; ++tscan; continue; } vm_page_lock(p); vm_page_lock_queues(); vm_page_test_dirty(p); if (p->dirty == 0) { vm_page_unlock_queues(); vm_page_unlock(p); if (--scanlimit == 0) break; ++tscan; continue; } vm_page_unlock_queues(); vm_page_unlock(p); /* * If we have been asked to skip nosync pages and * this is a nosync page, we can't continue. */ if ((flags & OBJPC_NOSYNC) && (p->oflags & VPO_NOSYNC)) { if (--scanlimit == 0) break; ++tscan; continue; } scanlimit = scanreset; /* * This returns 0 if it was unable to busy the first * page (i.e. had to sleep). */ tscan += vm_object_page_collect_flush(object, p, curgeneration, pagerflags); } /* * If everything was dirty and we flushed it successfully, * and the requested range is not the entire object, we * don't have to mess with CLEANCHK or MIGHTBEDIRTY and can * return immediately. */ if (tscan >= tend && (tstart || tend < object->size)) { vm_object_clear_flag(object, OBJ_CLEANING); return; } pagerflags &= ~VM_PAGER_IGNORE_CLEANCHK; } /* * Generally set CLEANCHK interlock and make the page read-only so * we can then clear the object flags. * * However, if this is a nosync mmap then the object is likely to * stay dirty so do not mess with the page and do not clear the * object flags. */ clearobjflags = 1; TAILQ_FOREACH(p, &object->memq, listq) { p->oflags |= VPO_CLEANCHK; if ((flags & OBJPC_NOSYNC) && (p->oflags & VPO_NOSYNC)) clearobjflags = 0; else pmap_remove_write(p); } if (clearobjflags && (tstart == 0) && (tend == object->size)) vm_object_clear_flag(object, OBJ_MIGHTBEDIRTY); rescan: curgeneration = object->generation; for (p = TAILQ_FIRST(&object->memq); p; p = np) { int n; np = TAILQ_NEXT(p, listq); again: pi = p->pindex; if ((p->oflags & VPO_CLEANCHK) == 0 || (pi < tstart) || (pi >= tend) || p->valid == 0) { p->oflags &= ~VPO_CLEANCHK; continue; } vm_page_lock(p); vm_page_lock_queues(); vm_page_test_dirty(p); if (p->dirty == 0) { vm_page_unlock_queues(); vm_page_unlock(p); p->oflags &= ~VPO_CLEANCHK; continue; } vm_page_unlock_queues(); vm_page_unlock(p); /* * If we have been asked to skip nosync pages and this is a * nosync page, skip it. Note that the object flags were * not cleared in this case so we do not have to set them. */ if ((flags & OBJPC_NOSYNC) && (p->oflags & VPO_NOSYNC)) { p->oflags &= ~VPO_CLEANCHK; continue; } n = vm_object_page_collect_flush(object, p, curgeneration, pagerflags); if (n == 0) goto rescan; if (object->generation != curgeneration) goto rescan; /* * Try to optimize the next page. If we can't we pick up * our (random) scan where we left off. */ if (msync_flush_flags & MSYNC_FLUSH_SOFTSEQ) if ((p = vm_page_lookup(object, pi + n)) != NULL) goto again; } #if 0 VOP_FSYNC(vp, (pagerflags & VM_PAGER_PUT_SYNC)?MNT_WAIT:0, curproc); #endif vm_object_clear_flag(object, OBJ_CLEANING); return; } static int vm_object_page_collect_flush(vm_object_t object, vm_page_t p, int curgeneration, int pagerflags) { int runlen; int maxf; int chkb; int maxb; int i; vm_pindex_t pi; vm_page_t maf[vm_pageout_page_count]; vm_page_t mab[vm_pageout_page_count]; vm_page_t ma[vm_pageout_page_count]; mtx_assert(&vm_page_queue_mtx, MA_NOTOWNED); vm_page_lock_assert(p, MA_NOTOWNED); VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); pi = p->pindex; while (vm_page_sleep_if_busy(p, TRUE, "vpcwai")) { if (object->generation != curgeneration) { return(0); } } maxf = 0; for(i = 1; i < vm_pageout_page_count; i++) { vm_page_t tp; if ((tp = vm_page_lookup(object, pi + i)) != NULL) { if ((tp->oflags & VPO_BUSY) || ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 && (tp->oflags & VPO_CLEANCHK) == 0) || (tp->busy != 0)) break; vm_page_lock(tp); vm_page_lock_queues(); vm_page_test_dirty(tp); if (tp->dirty == 0) { vm_page_unlock(tp); vm_page_unlock_queues(); tp->oflags &= ~VPO_CLEANCHK; break; } vm_page_unlock(tp); vm_page_unlock_queues(); maf[ i - 1 ] = tp; maxf++; continue; } break; } maxb = 0; chkb = vm_pageout_page_count - maxf; if (chkb) { for(i = 1; i < chkb;i++) { vm_page_t tp; if ((tp = vm_page_lookup(object, pi - i)) != NULL) { if ((tp->oflags & VPO_BUSY) || ((pagerflags & VM_PAGER_IGNORE_CLEANCHK) == 0 && (tp->oflags & VPO_CLEANCHK) == 0) || (tp->busy != 0)) break; vm_page_lock(tp); vm_page_lock_queues(); vm_page_test_dirty(tp); if (tp->dirty == 0) { vm_page_unlock_queues(); vm_page_unlock(tp); tp->oflags &= ~VPO_CLEANCHK; break; } vm_page_unlock_queues(); vm_page_unlock(tp); mab[ i - 1 ] = tp; maxb++; continue; } break; } } for(i = 0; i < maxb; i++) { int index = (maxb - i) - 1; ma[index] = mab[i]; ma[index]->oflags &= ~VPO_CLEANCHK; } p->oflags &= ~VPO_CLEANCHK; ma[maxb] = p; for(i = 0; i < maxf; i++) { int index = (maxb + i) + 1; ma[index] = maf[i]; ma[index]->oflags &= ~VPO_CLEANCHK; } runlen = maxb + maxf + 1; vm_pageout_flush(ma, runlen, pagerflags); for (i = 0; i < runlen; i++) { if (ma[i]->dirty) { pmap_remove_write(ma[i]); ma[i]->oflags |= VPO_CLEANCHK; /* * maxf will end up being the actual number of pages * we wrote out contiguously, non-inclusive of the * first page. We do not count look-behind pages. */ if (i >= maxb + 1 && (maxf > i - maxb - 1)) maxf = i - maxb - 1; } } return(maxf + 1); } /* * Note that there is absolutely no sense in writing out * anonymous objects, so we track down the vnode object * to write out. * We invalidate (remove) all pages from the address space * for semantic correctness. * * Note: certain anonymous maps, such as MAP_NOSYNC maps, * may start out with a NULL object. */ void vm_object_sync(vm_object_t object, vm_ooffset_t offset, vm_size_t size, boolean_t syncio, boolean_t invalidate) { vm_object_t backing_object; struct vnode *vp; struct mount *mp; int flags; if (object == NULL) return; VM_OBJECT_LOCK(object); while ((backing_object = object->backing_object) != NULL) { VM_OBJECT_LOCK(backing_object); offset += object->backing_object_offset; VM_OBJECT_UNLOCK(object); object = backing_object; if (object->size < OFF_TO_IDX(offset + size)) size = IDX_TO_OFF(object->size) - offset; } /* * Flush pages if writing is allowed, invalidate them * if invalidation requested. Pages undergoing I/O * will be ignored by vm_object_page_remove(). * * We cannot lock the vnode and then wait for paging * to complete without deadlocking against vm_fault. * Instead we simply call vm_object_page_remove() and * allow it to block internally on a page-by-page * basis when it encounters pages undergoing async * I/O. */ if (object->type == OBJT_VNODE && (object->flags & OBJ_MIGHTBEDIRTY) != 0) { int vfslocked; vp = object->handle; VM_OBJECT_UNLOCK(object); (void) vn_start_write(vp, &mp, V_WAIT); vfslocked = VFS_LOCK_GIANT(vp->v_mount); vn_lock(vp, LK_EXCLUSIVE | LK_RETRY); flags = (syncio || invalidate) ? OBJPC_SYNC : 0; flags |= invalidate ? OBJPC_INVAL : 0; VM_OBJECT_LOCK(object); vm_object_page_clean(object, OFF_TO_IDX(offset), OFF_TO_IDX(offset + size + PAGE_MASK), flags); VM_OBJECT_UNLOCK(object); VOP_UNLOCK(vp, 0); VFS_UNLOCK_GIANT(vfslocked); vn_finished_write(mp); VM_OBJECT_LOCK(object); } if ((object->type == OBJT_VNODE || object->type == OBJT_DEVICE) && invalidate) { boolean_t purge; purge = old_msync || (object->type == OBJT_DEVICE); vm_object_page_remove(object, OFF_TO_IDX(offset), OFF_TO_IDX(offset + size + PAGE_MASK), purge ? FALSE : TRUE); } VM_OBJECT_UNLOCK(object); } /* * vm_object_madvise: * * Implements the madvise function at the object/page level. * * MADV_WILLNEED (any object) * * Activate the specified pages if they are resident. * * MADV_DONTNEED (any object) * * Deactivate the specified pages if they are resident. * * MADV_FREE (OBJT_DEFAULT/OBJT_SWAP objects, * OBJ_ONEMAPPING only) * * Deactivate and clean the specified pages if they are * resident. This permits the process to reuse the pages * without faulting or the kernel to reclaim the pages * without I/O. */ void vm_object_madvise(vm_object_t object, vm_pindex_t pindex, int count, int advise) { vm_pindex_t end, tpindex; vm_object_t backing_object, tobject; vm_page_t m; if (object == NULL) return; VM_OBJECT_LOCK(object); end = pindex + count; /* * Locate and adjust resident pages */ for (; pindex < end; pindex += 1) { relookup: tobject = object; tpindex = pindex; shadowlookup: /* * MADV_FREE only operates on OBJT_DEFAULT or OBJT_SWAP pages * and those pages must be OBJ_ONEMAPPING. */ if (advise == MADV_FREE) { if ((tobject->type != OBJT_DEFAULT && tobject->type != OBJT_SWAP) || (tobject->flags & OBJ_ONEMAPPING) == 0) { goto unlock_tobject; } } else if (tobject->type == OBJT_PHYS) goto unlock_tobject; m = vm_page_lookup(tobject, tpindex); if (m == NULL && advise == MADV_WILLNEED) { /* * If the page is cached, reactivate it. */ m = vm_page_alloc(tobject, tpindex, VM_ALLOC_IFCACHED | VM_ALLOC_NOBUSY); } if (m == NULL) { /* * There may be swap even if there is no backing page */ if (advise == MADV_FREE && tobject->type == OBJT_SWAP) swap_pager_freespace(tobject, tpindex, 1); /* * next object */ backing_object = tobject->backing_object; if (backing_object == NULL) goto unlock_tobject; VM_OBJECT_LOCK(backing_object); tpindex += OFF_TO_IDX(tobject->backing_object_offset); if (tobject != object) VM_OBJECT_UNLOCK(tobject); tobject = backing_object; goto shadowlookup; } else if (m->valid != VM_PAGE_BITS_ALL) goto unlock_tobject; /* * If the page is not in a normal state, skip it. */ vm_page_lock(m); vm_page_lock_queues(); if (m->hold_count != 0 || m->wire_count != 0) { vm_page_unlock_queues(); vm_page_unlock(m); goto unlock_tobject; } if ((m->oflags & VPO_BUSY) || m->busy) { if (advise == MADV_WILLNEED) /* * Reference the page before unlocking and * sleeping so that the page daemon is less * likely to reclaim it. */ vm_page_flag_set(m, PG_REFERENCED); vm_page_unlock_queues(); vm_page_unlock(m); if (object != tobject) VM_OBJECT_UNLOCK(object); m->oflags |= VPO_WANTED; msleep(m, VM_OBJECT_MTX(tobject), PDROP | PVM, "madvpo", 0); VM_OBJECT_LOCK(object); goto relookup; } if (advise == MADV_WILLNEED) { vm_page_activate(m); } else if (advise == MADV_DONTNEED) { vm_page_dontneed(m); } else if (advise == MADV_FREE) { /* * Mark the page clean. This will allow the page * to be freed up by the system. However, such pages * are often reused quickly by malloc()/free() * so we do not do anything that would cause * a page fault if we can help it. * * Specifically, we do not try to actually free * the page now nor do we try to put it in the * cache (which would cause a page fault on reuse). * * But we do make the page is freeable as we * can without actually taking the step of unmapping * it. */ pmap_clear_modify(m); m->dirty = 0; m->act_count = 0; vm_page_dontneed(m); } vm_page_unlock_queues(); vm_page_unlock(m); if (advise == MADV_FREE && tobject->type == OBJT_SWAP) swap_pager_freespace(tobject, tpindex, 1); unlock_tobject: if (tobject != object) VM_OBJECT_UNLOCK(tobject); } VM_OBJECT_UNLOCK(object); } /* * vm_object_shadow: * * Create a new object which is backed by the * specified existing object range. The source * object reference is deallocated. * * The new object and offset into that object * are returned in the source parameters. */ void vm_object_shadow( vm_object_t *object, /* IN/OUT */ vm_ooffset_t *offset, /* IN/OUT */ vm_size_t length) { vm_object_t source; vm_object_t result; source = *object; /* * Don't create the new object if the old object isn't shared. */ if (source != NULL) { VM_OBJECT_LOCK(source); if (source->ref_count == 1 && source->handle == NULL && (source->type == OBJT_DEFAULT || source->type == OBJT_SWAP)) { VM_OBJECT_UNLOCK(source); return; } VM_OBJECT_UNLOCK(source); } /* * Allocate a new object with the given length. */ result = vm_object_allocate(OBJT_DEFAULT, length); /* * The new object shadows the source object, adding a reference to it. * Our caller changes his reference to point to the new object, * removing a reference to the source object. Net result: no change * of reference count. * * Try to optimize the result object's page color when shadowing * in order to maintain page coloring consistency in the combined * shadowed object. */ result->backing_object = source; /* * Store the offset into the source object, and fix up the offset into * the new object. */ result->backing_object_offset = *offset; if (source != NULL) { VM_OBJECT_LOCK(source); LIST_INSERT_HEAD(&source->shadow_head, result, shadow_list); source->shadow_count++; source->generation++; #if VM_NRESERVLEVEL > 0 result->flags |= source->flags & OBJ_COLORED; result->pg_color = (source->pg_color + OFF_TO_IDX(*offset)) & ((1 << (VM_NFREEORDER - 1)) - 1); #endif VM_OBJECT_UNLOCK(source); } /* * Return the new things */ *offset = 0; *object = result; } /* * vm_object_split: * * Split the pages in a map entry into a new object. This affords * easier removal of unused pages, and keeps object inheritance from * being a negative impact on memory usage. */ void vm_object_split(vm_map_entry_t entry) { vm_page_t m, m_next; vm_object_t orig_object, new_object, source; vm_pindex_t idx, offidxstart; vm_size_t size; orig_object = entry->object.vm_object; if (orig_object->type != OBJT_DEFAULT && orig_object->type != OBJT_SWAP) return; if (orig_object->ref_count <= 1) return; VM_OBJECT_UNLOCK(orig_object); offidxstart = OFF_TO_IDX(entry->offset); size = atop(entry->end - entry->start); /* * If swap_pager_copy() is later called, it will convert new_object * into a swap object. */ new_object = vm_object_allocate(OBJT_DEFAULT, size); /* * At this point, the new object is still private, so the order in * which the original and new objects are locked does not matter. */ VM_OBJECT_LOCK(new_object); VM_OBJECT_LOCK(orig_object); source = orig_object->backing_object; if (source != NULL) { VM_OBJECT_LOCK(source); if ((source->flags & OBJ_DEAD) != 0) { VM_OBJECT_UNLOCK(source); VM_OBJECT_UNLOCK(orig_object); VM_OBJECT_UNLOCK(new_object); vm_object_deallocate(new_object); VM_OBJECT_LOCK(orig_object); return; } LIST_INSERT_HEAD(&source->shadow_head, new_object, shadow_list); source->shadow_count++; source->generation++; vm_object_reference_locked(source); /* for new_object */ vm_object_clear_flag(source, OBJ_ONEMAPPING); VM_OBJECT_UNLOCK(source); new_object->backing_object_offset = orig_object->backing_object_offset + entry->offset; new_object->backing_object = source; } if (orig_object->uip != NULL) { new_object->uip = orig_object->uip; uihold(orig_object->uip); new_object->charge = ptoa(size); KASSERT(orig_object->charge >= ptoa(size), ("orig_object->charge < 0")); orig_object->charge -= ptoa(size); } retry: if ((m = TAILQ_FIRST(&orig_object->memq)) != NULL) { if (m->pindex < offidxstart) { m = vm_page_splay(offidxstart, orig_object->root); if ((orig_object->root = m)->pindex < offidxstart) m = TAILQ_NEXT(m, listq); } } for (; m != NULL && (idx = m->pindex - offidxstart) < size; m = m_next) { m_next = TAILQ_NEXT(m, listq); /* * We must wait for pending I/O to complete before we can * rename the page. * * We do not have to VM_PROT_NONE the page as mappings should * not be changed by this operation. */ if ((m->oflags & VPO_BUSY) || m->busy) { VM_OBJECT_UNLOCK(new_object); m->oflags |= VPO_WANTED; msleep(m, VM_OBJECT_MTX(orig_object), PVM, "spltwt", 0); VM_OBJECT_LOCK(new_object); goto retry; } vm_page_lock(m); vm_page_rename(m, new_object, idx); vm_page_unlock(m); /* page automatically made dirty by rename and cache handled */ vm_page_busy(m); } if (orig_object->type == OBJT_SWAP) { /* * swap_pager_copy() can sleep, in which case the orig_object's * and new_object's locks are released and reacquired. */ swap_pager_copy(orig_object, new_object, offidxstart, 0); /* * Transfer any cached pages from orig_object to new_object. */ if (__predict_false(orig_object->cache != NULL)) vm_page_cache_transfer(orig_object, offidxstart, new_object); } VM_OBJECT_UNLOCK(orig_object); TAILQ_FOREACH(m, &new_object->memq, listq) vm_page_wakeup(m); VM_OBJECT_UNLOCK(new_object); entry->object.vm_object = new_object; entry->offset = 0LL; vm_object_deallocate(orig_object); VM_OBJECT_LOCK(new_object); } #define OBSC_TEST_ALL_SHADOWED 0x0001 #define OBSC_COLLAPSE_NOWAIT 0x0002 #define OBSC_COLLAPSE_WAIT 0x0004 static int vm_object_backing_scan(vm_object_t object, int op) { int r = 1; vm_page_t p; vm_object_t backing_object; vm_pindex_t backing_offset_index; VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); VM_OBJECT_LOCK_ASSERT(object->backing_object, MA_OWNED); backing_object = object->backing_object; backing_offset_index = OFF_TO_IDX(object->backing_object_offset); /* * Initial conditions */ if (op & OBSC_TEST_ALL_SHADOWED) { /* * We do not want to have to test for the existence of cache * or swap pages in the backing object. XXX but with the * new swapper this would be pretty easy to do. * * XXX what about anonymous MAP_SHARED memory that hasn't * been ZFOD faulted yet? If we do not test for this, the * shadow test may succeed! XXX */ if (backing_object->type != OBJT_DEFAULT) { return (0); } } if (op & OBSC_COLLAPSE_WAIT) { vm_object_set_flag(backing_object, OBJ_DEAD); } /* * Our scan */ p = TAILQ_FIRST(&backing_object->memq); while (p) { vm_page_t next = TAILQ_NEXT(p, listq); vm_pindex_t new_pindex = p->pindex - backing_offset_index; if (op & OBSC_TEST_ALL_SHADOWED) { vm_page_t pp; /* * Ignore pages outside the parent object's range * and outside the parent object's mapping of the * backing object. * * note that we do not busy the backing object's * page. */ if ( p->pindex < backing_offset_index || new_pindex >= object->size ) { p = next; continue; } /* * See if the parent has the page or if the parent's * object pager has the page. If the parent has the * page but the page is not valid, the parent's * object pager must have the page. * * If this fails, the parent does not completely shadow * the object and we might as well give up now. */ pp = vm_page_lookup(object, new_pindex); if ( (pp == NULL || pp->valid == 0) && !vm_pager_has_page(object, new_pindex, NULL, NULL) ) { r = 0; break; } } /* * Check for busy page */ if (op & (OBSC_COLLAPSE_WAIT | OBSC_COLLAPSE_NOWAIT)) { vm_page_t pp; if (op & OBSC_COLLAPSE_NOWAIT) { if ((p->oflags & VPO_BUSY) || !p->valid || p->busy) { p = next; continue; } } else if (op & OBSC_COLLAPSE_WAIT) { if ((p->oflags & VPO_BUSY) || p->busy) { VM_OBJECT_UNLOCK(object); p->oflags |= VPO_WANTED; msleep(p, VM_OBJECT_MTX(backing_object), PDROP | PVM, "vmocol", 0); VM_OBJECT_LOCK(object); VM_OBJECT_LOCK(backing_object); /* * If we slept, anything could have * happened. Since the object is * marked dead, the backing offset * should not have changed so we * just restart our scan. */ p = TAILQ_FIRST(&backing_object->memq); continue; } } KASSERT( p->object == backing_object, ("vm_object_backing_scan: object mismatch") ); /* * Destroy any associated swap */ if (backing_object->type == OBJT_SWAP) { swap_pager_freespace( backing_object, p->pindex, 1 ); } if ( p->pindex < backing_offset_index || new_pindex >= object->size ) { /* * Page is out of the parent object's range, we * can simply destroy it. */ vm_page_lock(p); KASSERT(!pmap_page_is_mapped(p), ("freeing mapped page %p", p)); if (p->wire_count == 0) vm_page_free(p); else vm_page_remove(p); vm_page_unlock(p); p = next; continue; } pp = vm_page_lookup(object, new_pindex); if ( pp != NULL || vm_pager_has_page(object, new_pindex, NULL, NULL) ) { /* * page already exists in parent OR swap exists * for this location in the parent. Destroy * the original page from the backing object. * * Leave the parent's page alone */ vm_page_lock(p); KASSERT(!pmap_page_is_mapped(p), ("freeing mapped page %p", p)); if (p->wire_count == 0) vm_page_free(p); else vm_page_remove(p); vm_page_unlock(p); p = next; continue; } #if VM_NRESERVLEVEL > 0 /* * Rename the reservation. */ vm_reserv_rename(p, object, backing_object, backing_offset_index); #endif /* * Page does not exist in parent, rename the * page from the backing object to the main object. * * If the page was mapped to a process, it can remain * mapped through the rename. */ vm_page_lock(p); vm_page_rename(p, object, new_pindex); vm_page_unlock(p); /* page automatically made dirty by rename */ } p = next; } return (r); } /* * this version of collapse allows the operation to occur earlier and * when paging_in_progress is true for an object... This is not a complete * operation, but should plug 99.9% of the rest of the leaks. */ static void vm_object_qcollapse(vm_object_t object) { vm_object_t backing_object = object->backing_object; VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); VM_OBJECT_LOCK_ASSERT(backing_object, MA_OWNED); if (backing_object->ref_count != 1) return; vm_object_backing_scan(object, OBSC_COLLAPSE_NOWAIT); } /* * vm_object_collapse: * * Collapse an object with the object backing it. * Pages in the backing object are moved into the * parent, and the backing object is deallocated. */ void vm_object_collapse(vm_object_t object) { VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); while (TRUE) { vm_object_t backing_object; /* * Verify that the conditions are right for collapse: * * The object exists and the backing object exists. */ if ((backing_object = object->backing_object) == NULL) break; /* * we check the backing object first, because it is most likely * not collapsable. */ VM_OBJECT_LOCK(backing_object); if (backing_object->handle != NULL || (backing_object->type != OBJT_DEFAULT && backing_object->type != OBJT_SWAP) || (backing_object->flags & OBJ_DEAD) || object->handle != NULL || (object->type != OBJT_DEFAULT && object->type != OBJT_SWAP) || (object->flags & OBJ_DEAD)) { VM_OBJECT_UNLOCK(backing_object); break; } if ( object->paging_in_progress != 0 || backing_object->paging_in_progress != 0 ) { vm_object_qcollapse(object); VM_OBJECT_UNLOCK(backing_object); break; } /* * We know that we can either collapse the backing object (if * the parent is the only reference to it) or (perhaps) have * the parent bypass the object if the parent happens to shadow * all the resident pages in the entire backing object. * * This is ignoring pager-backed pages such as swap pages. * vm_object_backing_scan fails the shadowing test in this * case. */ if (backing_object->ref_count == 1) { /* * If there is exactly one reference to the backing * object, we can collapse it into the parent. */ vm_object_backing_scan(object, OBSC_COLLAPSE_WAIT); #if VM_NRESERVLEVEL > 0 /* * Break any reservations from backing_object. */ if (__predict_false(!LIST_EMPTY(&backing_object->rvq))) vm_reserv_break_all(backing_object); #endif /* * Move the pager from backing_object to object. */ if (backing_object->type == OBJT_SWAP) { /* * swap_pager_copy() can sleep, in which case * the backing_object's and object's locks are * released and reacquired. */ swap_pager_copy( backing_object, object, OFF_TO_IDX(object->backing_object_offset), TRUE); /* * Free any cached pages from backing_object. */ if (__predict_false(backing_object->cache != NULL)) vm_page_cache_free(backing_object, 0, 0); } /* * Object now shadows whatever backing_object did. * Note that the reference to * backing_object->backing_object moves from within * backing_object to within object. */ LIST_REMOVE(object, shadow_list); backing_object->shadow_count--; backing_object->generation++; if (backing_object->backing_object) { VM_OBJECT_LOCK(backing_object->backing_object); LIST_REMOVE(backing_object, shadow_list); LIST_INSERT_HEAD( &backing_object->backing_object->shadow_head, object, shadow_list); /* * The shadow_count has not changed. */ backing_object->backing_object->generation++; VM_OBJECT_UNLOCK(backing_object->backing_object); } object->backing_object = backing_object->backing_object; object->backing_object_offset += backing_object->backing_object_offset; /* * Discard backing_object. * * Since the backing object has no pages, no pager left, * and no object references within it, all that is * necessary is to dispose of it. */ KASSERT(backing_object->ref_count == 1, ( "backing_object %p was somehow re-referenced during collapse!", backing_object)); VM_OBJECT_UNLOCK(backing_object); vm_object_destroy(backing_object); object_collapses++; } else { vm_object_t new_backing_object; /* * If we do not entirely shadow the backing object, * there is nothing we can do so we give up. */ if (object->resident_page_count != object->size && vm_object_backing_scan(object, OBSC_TEST_ALL_SHADOWED) == 0) { VM_OBJECT_UNLOCK(backing_object); break; } /* * Make the parent shadow the next object in the * chain. Deallocating backing_object will not remove * it, since its reference count is at least 2. */ LIST_REMOVE(object, shadow_list); backing_object->shadow_count--; backing_object->generation++; new_backing_object = backing_object->backing_object; if ((object->backing_object = new_backing_object) != NULL) { VM_OBJECT_LOCK(new_backing_object); LIST_INSERT_HEAD( &new_backing_object->shadow_head, object, shadow_list ); new_backing_object->shadow_count++; new_backing_object->generation++; vm_object_reference_locked(new_backing_object); VM_OBJECT_UNLOCK(new_backing_object); object->backing_object_offset += backing_object->backing_object_offset; } /* * Drop the reference count on backing_object. Since * its ref_count was at least 2, it will not vanish. */ backing_object->ref_count--; VM_OBJECT_UNLOCK(backing_object); object_bypasses++; } /* * Try again with this object's new backing object. */ } } /* * vm_object_page_remove: * * For the given object, either frees or invalidates each of the * specified pages. In general, a page is freed. However, if a * page is wired for any reason other than the existence of a * managed, wired mapping, then it may be invalidated but not * removed from the object. Pages are specified by the given * range ["start", "end") and Boolean "clean_only". As a * special case, if "end" is zero, then the range extends from * "start" to the end of the object. If "clean_only" is TRUE, * then only the non-dirty pages within the specified range are * affected. * * In general, this operation should only be performed on objects * that contain managed pages. There are two exceptions. First, * it may be performed on the kernel and kmem objects. Second, * it may be used by msync(..., MS_INVALIDATE) to invalidate * device-backed pages. In both of these cases, "clean_only" * must be FALSE. * * The object must be locked. */ void vm_object_page_remove(vm_object_t object, vm_pindex_t start, vm_pindex_t end, boolean_t clean_only) { vm_page_t p, next; int wirings; VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); if (object->resident_page_count == 0) goto skipmemq; /* * Since physically-backed objects do not use managed pages, we can't * remove pages from the object (we must instead remove the page * references, and then destroy the object). */ KASSERT(object->type != OBJT_PHYS || object == kernel_object || object == kmem_object, ("attempt to remove pages from a physical object")); vm_object_pip_add(object, 1); again: if ((p = TAILQ_FIRST(&object->memq)) != NULL) { if (p->pindex < start) { p = vm_page_splay(start, object->root); if ((object->root = p)->pindex < start) p = TAILQ_NEXT(p, listq); } } /* * Assert: the variable p is either (1) the page with the * least pindex greater than or equal to the parameter pindex * or (2) NULL. */ for (; p != NULL && (p->pindex < end || end == 0); p = next) { next = TAILQ_NEXT(p, listq); /* * If the page is wired for any reason besides the * existence of managed, wired mappings, then it cannot * be freed. For example, fictitious pages, which * represent device memory, are inherently wired and * cannot be freed. They can, however, be invalidated * if "clean_only" is FALSE. */ vm_page_lock(p); if ((wirings = p->wire_count) != 0 && (wirings = pmap_page_wired_mappings(p)) != p->wire_count) { /* Fictitious pages do not have managed mappings. */ if ((p->flags & PG_FICTITIOUS) == 0) pmap_remove_all(p); /* Account for removal of managed, wired mappings. */ p->wire_count -= wirings; if (!clean_only) { p->valid = 0; vm_page_undirty(p); } vm_page_unlock(p); continue; } if (vm_page_sleep_if_busy(p, TRUE, "vmopar")) goto again; KASSERT((p->flags & PG_FICTITIOUS) == 0, ("vm_object_page_remove: page %p is fictitious", p)); if (clean_only && p->valid) { pmap_remove_write(p); if (p->dirty) { vm_page_unlock(p); continue; } } pmap_remove_all(p); /* Account for removal of managed, wired mappings. */ if (wirings != 0) p->wire_count -= wirings; vm_page_free(p); vm_page_unlock(p); } vm_object_pip_wakeup(object); skipmemq: if (__predict_false(object->cache != NULL)) vm_page_cache_free(object, start, end); } /* * Populate the specified range of the object with valid pages. Returns * TRUE if the range is successfully populated and FALSE otherwise. * * Note: This function should be optimized to pass a larger array of * pages to vm_pager_get_pages() before it is applied to a non- * OBJT_DEVICE object. * * The object must be locked. */ boolean_t vm_object_populate(vm_object_t object, vm_pindex_t start, vm_pindex_t end) { vm_page_t m, ma[1]; vm_pindex_t pindex; int rv; VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); for (pindex = start; pindex < end; pindex++) { m = vm_page_grab(object, pindex, VM_ALLOC_NORMAL | VM_ALLOC_RETRY); if (m->valid != VM_PAGE_BITS_ALL) { ma[0] = m; rv = vm_pager_get_pages(object, ma, 1, 0); m = vm_page_lookup(object, pindex); if (m == NULL) break; if (rv != VM_PAGER_OK) { vm_page_lock(m); vm_page_free(m); vm_page_unlock(m); break; } } /* * Keep "m" busy because a subsequent iteration may unlock * the object. */ } if (pindex > start) { m = vm_page_lookup(object, start); while (m != NULL && m->pindex < pindex) { vm_page_wakeup(m); m = TAILQ_NEXT(m, listq); } } return (pindex == end); } /* * Routine: vm_object_coalesce * Function: Coalesces two objects backing up adjoining * regions of memory into a single object. * * returns TRUE if objects were combined. * * NOTE: Only works at the moment if the second object is NULL - * if it's not, which object do we lock first? * * Parameters: * prev_object First object to coalesce * prev_offset Offset into prev_object * prev_size Size of reference to prev_object * next_size Size of reference to the second object * reserved Indicator that extension region has * swap accounted for * * Conditions: * The object must *not* be locked. */ boolean_t vm_object_coalesce(vm_object_t prev_object, vm_ooffset_t prev_offset, vm_size_t prev_size, vm_size_t next_size, boolean_t reserved) { vm_pindex_t next_pindex; if (prev_object == NULL) return (TRUE); VM_OBJECT_LOCK(prev_object); if (prev_object->type != OBJT_DEFAULT && prev_object->type != OBJT_SWAP) { VM_OBJECT_UNLOCK(prev_object); return (FALSE); } /* * Try to collapse the object first */ vm_object_collapse(prev_object); /* * Can't coalesce if: . more than one reference . paged out . shadows * another object . has a copy elsewhere (any of which mean that the * pages not mapped to prev_entry may be in use anyway) */ if (prev_object->backing_object != NULL) { VM_OBJECT_UNLOCK(prev_object); return (FALSE); } prev_size >>= PAGE_SHIFT; next_size >>= PAGE_SHIFT; next_pindex = OFF_TO_IDX(prev_offset) + prev_size; if ((prev_object->ref_count > 1) && (prev_object->size != next_pindex)) { VM_OBJECT_UNLOCK(prev_object); return (FALSE); } /* * Account for the charge. */ if (prev_object->uip != NULL) { /* * If prev_object was charged, then this mapping, * althought not charged now, may become writable * later. Non-NULL uip in the object would prevent * swap reservation during enabling of the write * access, so reserve swap now. Failed reservation * cause allocation of the separate object for the map * entry, and swap reservation for this entry is * managed in appropriate time. */ if (!reserved && !swap_reserve_by_uid(ptoa(next_size), prev_object->uip)) { return (FALSE); } prev_object->charge += ptoa(next_size); } /* * Remove any pages that may still be in the object from a previous * deallocation. */ if (next_pindex < prev_object->size) { vm_object_page_remove(prev_object, next_pindex, next_pindex + next_size, FALSE); if (prev_object->type == OBJT_SWAP) swap_pager_freespace(prev_object, next_pindex, next_size); #if 0 if (prev_object->uip != NULL) { KASSERT(prev_object->charge >= ptoa(prev_object->size - next_pindex), ("object %p overcharged 1 %jx %jx", prev_object, (uintmax_t)next_pindex, (uintmax_t)next_size)); prev_object->charge -= ptoa(prev_object->size - next_pindex); } #endif } /* * Extend the object if necessary. */ if (next_pindex + next_size > prev_object->size) prev_object->size = next_pindex + next_size; VM_OBJECT_UNLOCK(prev_object); return (TRUE); } void vm_object_set_writeable_dirty(vm_object_t object) { VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); if (object->type != OBJT_VNODE || (object->flags & OBJ_MIGHTBEDIRTY) != 0) return; vm_object_set_flag(object, OBJ_MIGHTBEDIRTY); } #include "opt_ddb.h" #ifdef DDB #include #include #include static int _vm_object_in_map(vm_map_t map, vm_object_t object, vm_map_entry_t entry) { vm_map_t tmpm; vm_map_entry_t tmpe; vm_object_t obj; int entcount; if (map == 0) return 0; if (entry == 0) { tmpe = map->header.next; entcount = map->nentries; while (entcount-- && (tmpe != &map->header)) { if (_vm_object_in_map(map, object, tmpe)) { return 1; } tmpe = tmpe->next; } } else if (entry->eflags & MAP_ENTRY_IS_SUB_MAP) { tmpm = entry->object.sub_map; tmpe = tmpm->header.next; entcount = tmpm->nentries; while (entcount-- && tmpe != &tmpm->header) { if (_vm_object_in_map(tmpm, object, tmpe)) { return 1; } tmpe = tmpe->next; } } else if ((obj = entry->object.vm_object) != NULL) { for (; obj; obj = obj->backing_object) if (obj == object) { return 1; } } return 0; } static int vm_object_in_map(vm_object_t object) { struct proc *p; /* sx_slock(&allproc_lock); */ FOREACH_PROC_IN_SYSTEM(p) { if (!p->p_vmspace /* || (p->p_flag & (P_SYSTEM|P_WEXIT)) */) continue; if (_vm_object_in_map(&p->p_vmspace->vm_map, object, 0)) { /* sx_sunlock(&allproc_lock); */ return 1; } } /* sx_sunlock(&allproc_lock); */ if (_vm_object_in_map(kernel_map, object, 0)) return 1; if (_vm_object_in_map(kmem_map, object, 0)) return 1; if (_vm_object_in_map(pager_map, object, 0)) return 1; if (_vm_object_in_map(buffer_map, object, 0)) return 1; return 0; } DB_SHOW_COMMAND(vmochk, vm_object_check) { vm_object_t object; /* * make sure that internal objs are in a map somewhere * and none have zero ref counts. */ TAILQ_FOREACH(object, &vm_object_list, object_list) { if (object->handle == NULL && (object->type == OBJT_DEFAULT || object->type == OBJT_SWAP)) { if (object->ref_count == 0) { db_printf("vmochk: internal obj has zero ref count: %ld\n", (long)object->size); } if (!vm_object_in_map(object)) { db_printf( "vmochk: internal obj is not in a map: " "ref: %d, size: %lu: 0x%lx, backing_object: %p\n", object->ref_count, (u_long)object->size, (u_long)object->size, (void *)object->backing_object); } } } } /* * vm_object_print: [ debug ] */ DB_SHOW_COMMAND(object, vm_object_print_static) { /* XXX convert args. */ vm_object_t object = (vm_object_t)addr; boolean_t full = have_addr; vm_page_t p; /* XXX count is an (unused) arg. Avoid shadowing it. */ #define count was_count int count; if (object == NULL) return; db_iprintf( "Object %p: type=%d, size=0x%jx, res=%d, ref=%d, flags=0x%x uip %d charge %jx\n", object, (int)object->type, (uintmax_t)object->size, object->resident_page_count, object->ref_count, object->flags, object->uip ? object->uip->ui_uid : -1, (uintmax_t)object->charge); db_iprintf(" sref=%d, backing_object(%d)=(%p)+0x%jx\n", object->shadow_count, object->backing_object ? object->backing_object->ref_count : 0, object->backing_object, (uintmax_t)object->backing_object_offset); if (!full) return; db_indent += 2; count = 0; TAILQ_FOREACH(p, &object->memq, listq) { if (count == 0) db_iprintf("memory:="); else if (count == 6) { db_printf("\n"); db_iprintf(" ..."); count = 0; } else db_printf(","); count++; db_printf("(off=0x%jx,page=0x%jx)", (uintmax_t)p->pindex, (uintmax_t)VM_PAGE_TO_PHYS(p)); } if (count != 0) db_printf("\n"); db_indent -= 2; } /* XXX. */ #undef count /* XXX need this non-static entry for calling from vm_map_print. */ void vm_object_print( /* db_expr_t */ long addr, boolean_t have_addr, /* db_expr_t */ long count, char *modif) { vm_object_print_static(addr, have_addr, count, modif); } DB_SHOW_COMMAND(vmopag, vm_object_print_pages) { vm_object_t object; vm_pindex_t fidx; vm_paddr_t pa; vm_page_t m, prev_m; int rcount, nl, c; nl = 0; TAILQ_FOREACH(object, &vm_object_list, object_list) { db_printf("new object: %p\n", (void *)object); if (nl > 18) { c = cngetc(); if (c != ' ') return; nl = 0; } nl++; rcount = 0; fidx = 0; pa = -1; TAILQ_FOREACH(m, &object->memq, listq) { if (m->pindex > 128) break; if ((prev_m = TAILQ_PREV(m, pglist, listq)) != NULL && prev_m->pindex + 1 != m->pindex) { if (rcount) { db_printf(" index(%ld)run(%d)pa(0x%lx)\n", (long)fidx, rcount, (long)pa); if (nl > 18) { c = cngetc(); if (c != ' ') return; nl = 0; } nl++; rcount = 0; } } if (rcount && (VM_PAGE_TO_PHYS(m) == pa + rcount * PAGE_SIZE)) { ++rcount; continue; } if (rcount) { db_printf(" index(%ld)run(%d)pa(0x%lx)\n", (long)fidx, rcount, (long)pa); if (nl > 18) { c = cngetc(); if (c != ' ') return; nl = 0; } nl++; } fidx = m->pindex; pa = VM_PAGE_TO_PHYS(m); rcount = 1; } if (rcount) { db_printf(" index(%ld)run(%d)pa(0x%lx)\n", (long)fidx, rcount, (long)pa); if (nl > 18) { c = cngetc(); if (c != ' ') return; nl = 0; } nl++; } } } #endif /* DDB */