142 lines
4.3 KiB
C++
142 lines
4.3 KiB
C++
/*
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Copyright (c) 2007-2018, Arvid Norberg
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the distribution.
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* Neither the name of the author nor the names of its
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef TORRENT_DISK_BUFFER_POOL_HPP
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#define TORRENT_DISK_BUFFER_POOL_HPP
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#include "libtorrent/config.hpp"
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#if TORRENT_USE_INVARIANT_CHECKS
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#include <set>
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#endif
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#include <vector>
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#include <mutex>
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#include <functional>
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#include <memory>
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#include "libtorrent/io_service_fwd.hpp"
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#include "libtorrent/span.hpp"
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#include "libtorrent/aux_/storage_utils.hpp" // for iovec_t
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namespace libtorrent {
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namespace aux { struct session_settings; }
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struct disk_observer;
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struct TORRENT_EXTRA_EXPORT disk_buffer_pool
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{
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disk_buffer_pool(io_service& ios, std::function<void()> const& trigger_trim);
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disk_buffer_pool(disk_buffer_pool const&) = delete;
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disk_buffer_pool& operator=(disk_buffer_pool const&) = delete;
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~disk_buffer_pool();
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#if TORRENT_USE_ASSERTS
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bool is_disk_buffer(char* buffer
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, std::unique_lock<std::mutex>& l) const;
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bool is_disk_buffer(char* buffer) const;
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#endif
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char* allocate_buffer(char const* category);
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char* allocate_buffer(bool& exceeded, std::shared_ptr<disk_observer> o
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, char const* category);
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void free_buffer(char* buf);
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void free_multiple_buffers(span<char*> bufvec);
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int allocate_iovec(span<iovec_t> iov);
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void free_iovec(span<iovec_t const> iov);
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int in_use() const
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{
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std::unique_lock<std::mutex> l(m_pool_mutex);
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return m_in_use;
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}
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int num_to_evict(int num_needed = 0);
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void set_settings(aux::session_settings const& sett);
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protected:
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void free_buffer_impl(char* buf, std::unique_lock<std::mutex>& l);
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char* allocate_buffer_impl(std::unique_lock<std::mutex>& l, char const* category);
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// number of disk buffers currently allocated
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int m_in_use;
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// cache size limit
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int m_max_use;
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// if we have exceeded the limit, we won't start
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// allowing allocations again until we drop below
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// this low watermark
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int m_low_watermark;
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// if we exceed the max number of buffers, we start
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// adding up callbacks to this queue. Once the number
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// of buffers in use drops below the low watermark,
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// we start calling these functions back
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std::vector<std::weak_ptr<disk_observer>> m_observers;
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// callback used to tell the cache it needs to free up some blocks
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std::function<void()> m_trigger_cache_trim;
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// set to true to throttle more allocations
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bool m_exceeded_max_size;
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// this is the main thread io_service. Callbacks are
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// posted on this in order to have them execute in
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// the main thread.
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io_service& m_ios;
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private:
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void check_buffer_level(std::unique_lock<std::mutex>& l);
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void remove_buffer_in_use(char* buf);
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mutable std::mutex m_pool_mutex;
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// this is specifically exempt from release_asserts
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// since it's a quite costly check. Only for debug
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// builds.
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#if TORRENT_USE_INVARIANT_CHECKS
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std::set<char*> m_buffers_in_use;
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#endif
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#if TORRENT_USE_ASSERTS
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int m_magic;
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bool m_settings_set;
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#endif
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};
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}
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#endif // TORRENT_DISK_BUFFER_POOL_HPP
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