X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/c0fea4742e91338fffdcf79f86a7c1d5e2b97eb1..4452a7af2eac33dbad800bcc91f2399d62c18f53:/osfmk/vm/vm_object.c diff --git a/osfmk/vm/vm_object.c b/osfmk/vm/vm_object.c index 1520fb6d7..83b3a0eeb 100644 --- a/osfmk/vm/vm_object.c +++ b/osfmk/vm/vm_object.c @@ -1,23 +1,29 @@ /* * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved. * - * @APPLE_LICENSE_HEADER_START@ + * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ * - * The contents of this file constitute Original Code as defined in and - * are subject to the Apple Public Source License Version 1.1 (the - * "License"). You may not use this file except in compliance with the - * License. Please obtain a copy of the License at - * http://www.apple.com/publicsource and read it before using this file. + * This file contains Original Code and/or Modifications of Original Code + * as defined in and that are subject to the Apple Public Source License + * Version 2.0 (the 'License'). You may not use this file except in + * compliance with the License. The rights granted to you under the License + * may not be used to create, or enable the creation or redistribution of, + * unlawful or unlicensed copies of an Apple operating system, or to + * circumvent, violate, or enable the circumvention or violation of, any + * terms of an Apple operating system software license agreement. * - * This Original Code and all software distributed under the License are - * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER + * Please obtain a copy of the License at + * http://www.opensource.apple.com/apsl/ and read it before using this file. + * + * The Original Code and all software distributed under the License are + * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the - * License for the specific language governing rights and limitations - * under the License. + * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. + * Please see the License for the specific language governing rights and + * limitations under the License. * - * @APPLE_LICENSE_HEADER_END@ + * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /* * @OSF_COPYRIGHT@ @@ -281,6 +287,13 @@ typedef struct vm_object_hash_entry *vm_object_hash_entry_t; void vm_object_hash_entry_free( vm_object_hash_entry_t entry); +static void vm_object_reap(vm_object_t object); +static void vm_object_reap_async(vm_object_t object); +static void vm_object_reaper_thread(void); +static queue_head_t vm_object_reaper_queue; /* protected by vm_object_cache_lock() */ +unsigned int vm_object_reap_count = 0; +unsigned int vm_object_reap_count_async = 0; + /* * vm_object_hash_lookup looks up a pager in the hashtable * and returns the corresponding entry, with optional removal. @@ -526,6 +539,24 @@ vm_object_bootstrap(void) #endif /* MACH_PAGEMAP */ } +void +vm_object_reaper_init(void) +{ + kern_return_t kr; + thread_t thread; + + queue_init(&vm_object_reaper_queue); + kr = kernel_thread_start_priority( + (thread_continue_t) vm_object_reaper_thread, + NULL, + BASEPRI_PREEMPT - 1, + &thread); + if (kr != KERN_SUCCESS) { + panic("failed to launch vm_object_reaper_thread kr=0x%x\n", kr); + } + thread_deallocate(thread); +} + __private_extern__ void vm_object_init(void) { @@ -923,7 +954,6 @@ static kern_return_t vm_object_terminate( register vm_object_t object) { - memory_object_t pager; register vm_page_t p; vm_object_t shadow_object; @@ -1039,12 +1069,72 @@ vm_object_terminate( vm_object_unlock(shadow_object); } + if (FALSE && object->paging_in_progress != 0) { + /* + * There are still some paging_in_progress references + * on this object, meaning that there are some paging + * or other I/O operations in progress for this VM object. + * Such operations take some paging_in_progress references + * up front to ensure that the object doesn't go away, but + * they may also need to acquire a reference on the VM object, + * to map it in kernel space, for example. That means that + * they may end up releasing the last reference on the VM + * object, triggering its termination, while still holding + * paging_in_progress references. Waiting for these + * pending paging_in_progress references to go away here would + * deadlock. + * + * To avoid deadlocking, we'll let the vm_object_reaper_thread + * complete the VM object termination if it still holds + * paging_in_progress references at this point. + * + * No new paging_in_progress should appear now that the + * VM object is "terminating" and not "alive". + */ + vm_object_reap_async(object); + vm_object_cache_unlock(); + vm_object_unlock(object); + return KERN_SUCCESS; + } + + /* complete the VM object termination */ + vm_object_reap(object); + object = VM_OBJECT_NULL; + /* cache lock and object lock were released by vm_object_reap() */ + + return KERN_SUCCESS; +} + +/* + * vm_object_reap(): + * + * Complete the termination of a VM object after it's been marked + * as "terminating" and "!alive" by vm_object_terminate(). + * + * The VM object cache and the VM object must be locked by caller. + * The locks will be released on return and the VM object is no longer valid. + */ +void +vm_object_reap( + vm_object_t object) +{ + memory_object_t pager; + vm_page_t p; + +#if DEBUG + mutex_assert(&vm_object_cached_lock_data, MA_OWNED); + mutex_assert(&object->Lock, MA_OWNED); +#endif /* DEBUG */ + + vm_object_reap_count++; + /* - * The pageout daemon might be playing with our pages. - * Now that the object is dead, it won't touch any more - * pages, but some pages might already be on their way out. - * Hence, we wait until the active paging activities have ceased - * before we break the association with the pager itself. + * The pageout daemon might be playing with our pages. + * Now that the object is dead, it won't touch any more + * pages, but some pages might already be on their way out. + * Hence, we wait until the active paging activities have + * ceased before we break the association with the pager + * itself. */ while (object->paging_in_progress != 0) { vm_object_cache_unlock(); @@ -1055,6 +1145,7 @@ vm_object_terminate( vm_object_lock(object); } + assert(object->paging_in_progress == 0); pager = object->pager; object->pager = MEMORY_OBJECT_NULL; @@ -1075,8 +1166,7 @@ vm_object_terminate( * if some faults on this object were aborted. */ if (object->pageout) { - assert(shadow_object != VM_OBJECT_NULL); - assert(shadow_object == object->shadow); + assert(object->shadow != VM_OBJECT_NULL); vm_pageout_object_terminate(object); @@ -1089,7 +1179,7 @@ vm_object_terminate( VM_PAGE_FREE(p); } } else if (!queue_empty(&object->memq)) { - panic("vm_object_terminate: queue just emptied isn't"); + panic("vm_object_reap: queue just emptied isn't"); } assert(object->paging_in_progress == 0); @@ -1120,7 +1210,55 @@ vm_object_terminate( * Free the space for the object. */ zfree(vm_object_zone, object); - return KERN_SUCCESS; + object = VM_OBJECT_NULL; +} + +void +vm_object_reap_async( + vm_object_t object) +{ +#if DEBUG + mutex_assert(&vm_object_cached_lock_data, MA_OWNED); + mutex_assert(&object->Lock, MA_OWNED); +#endif /* DEBUG */ + + vm_object_reap_count_async++; + + /* enqueue the VM object... */ + queue_enter(&vm_object_reaper_queue, object, + vm_object_t, cached_list); + /* ... and wake up the reaper thread */ + thread_wakeup((event_t) &vm_object_reaper_queue); +} + +void +vm_object_reaper_thread(void) +{ + vm_object_t object; + + vm_object_cache_lock(); + + while (!queue_empty(&vm_object_reaper_queue)) { + queue_remove_first(&vm_object_reaper_queue, + object, + vm_object_t, + cached_list); + vm_object_lock(object); + assert(object->terminating); + assert(!object->alive); + + vm_object_reap(object); + /* cache is unlocked and object is no longer valid */ + object = VM_OBJECT_NULL; + + vm_object_cache_lock(); + } + + /* wait for more work... */ + assert_wait((event_t) &vm_object_reaper_queue, THREAD_UNINT); + vm_object_cache_unlock(); + thread_block((thread_continue_t) vm_object_reaper_thread); + /*NOTREACHED*/ } /*