/* * Copyright (C) 2017-2018 Apple Inc. All rights reserved. * * 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. * * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``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 APPLE INC. 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. */ #pragma once #include "Bits.h" #include "EligibilityResult.h" #include "IsoPage.h" #include "Vector.h" namespace bmalloc { template<typename Config> class IsoHeapImpl; class IsoDirectoryBaseBase { public: IsoDirectoryBaseBase() { } virtual ~IsoDirectoryBaseBase() { } virtual void didDecommit(unsigned index) = 0; }; template<typename Config> class IsoDirectoryBase : public IsoDirectoryBaseBase { public: IsoDirectoryBase(IsoHeapImpl<Config>&); IsoHeapImpl<Config>& heap() { return m_heap; } virtual void didBecome(IsoPage<Config>*, IsoPageTrigger) = 0; protected: IsoHeapImpl<Config>& m_heap; }; template<typename Config, unsigned passedNumPages> class IsoDirectory : public IsoDirectoryBase<Config> { public: static constexpr unsigned numPages = passedNumPages; IsoDirectory(IsoHeapImpl<Config>&); // Find the first page that is eligible for allocation and return it. May return null if there is no // such thing. May allocate a new page if we have an uncommitted page. EligibilityResult<Config> takeFirstEligible(); void didBecome(IsoPage<Config>*, IsoPageTrigger) override; // This gets called from a bulk decommit function in the Scavenger, so no locks are held. This function // needs to get the heap lock. void didDecommit(unsigned index) override; // Iterate over all empty and committed pages, and put them into the vector. This also records the // pages as being decommitted. It's the caller's job to do the actual decommitting. void scavenge(Vector<DeferredDecommit>&); void scavengeToHighWatermark(Vector<DeferredDecommit>&); template<typename Func> void forEachCommittedPage(const Func&); private: void scavengePage(size_t, Vector<DeferredDecommit>&); // NOTE: I suppose that this could be two bitvectors. But from working on the GC, I found that the // number of bitvectors does not matter as much as whether or not they make intuitive sense. Bits<numPages> m_eligible; Bits<numPages> m_empty; Bits<numPages> m_committed; std::array<IsoPage<Config>*, numPages> m_pages; unsigned m_firstEligible { 0 }; unsigned m_highWatermark { 0 }; }; } // namespace bmalloc