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* When a vm_cache is merged with another one, we now remove the consumer; that allows

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for an extra check in vm_cache_release_ref() as the cache shouldn't have any areas
  or consumers at this point.
* Fixed a locking problem in vm_cache_remove_consumer(): the cache was acquired after
  its lock was gone, so someone else might have released in the mean time.
* if the cache's source is to be replaced, we now no longer release its lock after
  having merged it.


git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@19570 a95241bf-73f2-0310-859d-f6bbb57e9c96
This commit is contained in:
Axel Dörfler 2006-12-20 12:30:07 +00:00
parent 6346c8941c
commit eb445177f9
1 changed files with 10 additions and 8 deletions
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18
src/system/kernel/vm/vm_cache.c
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@ -183,6 +183,11 @@ vm_cache_release_ref(vm_cache_ref *cacheRef)
// delete this cache
if (cacheRef->areas != NULL)
panic("cache to be deleted still has areas");
if (!list_is_empty(&cacheRef->cache->consumers))
panic("cache %p to be deleted still has consumers", cacheRef->cache);
// delete the cache's backing store
cacheRef->cache->store->ops->destroy(cacheRef->cache->store);
@ -415,7 +420,7 @@ vm_cache_remove_consumer(vm_cache_ref *cacheRef, vm_cache *consumer)
vm_cache_ref *consumerRef;
vm_page *page, *nextPage;
consumer = list_get_first_item(&cache->consumers);
consumer = list_remove_head_item(&cache->consumers);
consumerRef = consumer->ref;
mutex_lock(&consumerRef->lock);
@ -445,12 +450,8 @@ vm_cache_remove_consumer(vm_cache_ref *cacheRef, vm_cache *consumer)
mutex_unlock(&consumerRef->lock);
}
mutex_unlock(&cacheRef->lock);
if (newSource != NULL) {
// The remaining consumer has gotten a new source
mutex_lock(&cacheRef->lock);
list_remove_item(&newSource->consumers, cache);
list_add_item(&newSource->consumers, consumer);
consumer->source = newSource;
@ -461,7 +462,8 @@ vm_cache_remove_consumer(vm_cache_ref *cacheRef, vm_cache *consumer)
// Release the other reference to the cache - we take over
// its reference of its source cache
vm_cache_release_ref(cacheRef);
}
} else
mutex_unlock(&cacheRef->lock);
vm_cache_release_ref(cacheRef);
}
@ -481,9 +483,9 @@ vm_cache_add_consumer(vm_cache_ref *cacheRef, vm_cache *consumer)
consumer->source = cacheRef->cache;
list_add_item(&cacheRef->cache->consumers, consumer);
mutex_unlock(&cacheRef->lock);
vm_cache_acquire_ref(cacheRef);
mutex_unlock(&cacheRef->lock);
}