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e57be410b5
Currently we require that memory be freed on the same cpu it was allocated. This does not impose difficulties on the user code, since our code is already smp-unsafe, and so must use message-passing to run the destructor on the origin cpu, so memory is naturally freed there as well. However, library code does not run under our assumptions, specifically std::exception_ptr, which we do transport across cores. To support this use case, add low-performance support for cross-cpu frees, using an atomic singly linked list per core.
65 lines
1.6 KiB
C++
65 lines
1.6 KiB
C++
/*
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* Copyright (C) 2014 Cloudius Systems, Ltd.
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*/
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#ifndef MEMORY_HH_
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#define MEMORY_HH_
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#include "resource.hh"
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#include <new>
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#include <functional>
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#include <vector>
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namespace memory {
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void configure(std::vector<resource::memory> m,
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std::experimental::optional<std::string> hugetlbfs_path = {});
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void* allocate_reclaimable(size_t size);
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class reclaimer {
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std::function<void ()> _reclaim;
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public:
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reclaimer(std::function<void ()> reclaim);
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~reclaimer();
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void do_reclaim() { _reclaim(); }
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};
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// Call periodically to recycle objects that were freed
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// on cpu other than the one they were allocated on.
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//
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// Returns @true if any work was actually performed.
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bool drain_cross_cpu_freelist();
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// We don't want the memory code calling back into the rest of
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// the system, so allow the rest of the system to tell the memory
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// code how to initiate reclaim.
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//
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// When memory is low, calling hook(fn) will result in fn being called
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// in a safe place wrt. allocations.
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void set_reclaim_hook(
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std::function<void (std::function<void ()>)> hook);
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class statistics;
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statistics stats();
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class statistics {
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uint64_t _mallocs;
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uint64_t _frees;
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uint64_t _cross_cpu_frees;
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private:
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statistics(uint64_t mallocs, uint64_t frees, uint64_t cross_cpu_frees)
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: _mallocs(mallocs), _frees(frees), _cross_cpu_frees(cross_cpu_frees) {}
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public:
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uint64_t mallocs() const { return _mallocs; }
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uint64_t frees() const { return _frees; }
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uint64_t cross_cpu_frees() const { return _cross_cpu_frees; }
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size_t live_objects() const { return mallocs() - frees(); }
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friend statistics stats();
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};
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}
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#endif /* MEMORY_HH_ */
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