Don't call into Python during Storage destruction.#10407
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colesbury wants to merge 2 commits intopytorch:masterfrom
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Don't call into Python during Storage destruction.#10407colesbury wants to merge 2 commits intopytorch:masterfrom
colesbury wants to merge 2 commits intopytorch:masterfrom
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colesbury
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Aug 10, 2018
This removes PyObjectFinalizer. We were seeing SIGSEGV at exit in some programs that use multiprocessing. The backtrace pointed to StorageRef.__del__ being called from subtype_dealloc. My guess is that the Python interpreter was shutdown before all C++ Storage objects were deallocated. Deallocating the C++ Storage called the finalizer which called back into Python after it was no longer safe to do so. This avoids a callback from C++ into Python during Storage finalization. Instead, dead Storage objects (expired weak references) are collected periodically when shared_cache exceeds a limit. The limit is scaled with 2x the number of live references, which places an upper bound on the amount of extra memory held by dead Storage objects. In practice, this should be very small.
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Summary: ``` This removes PyObjectFinalizer. We were seeing SIGSEGV at exit in some programs that use multiprocessing. The backtrace pointed to StorageRef.__del__ being called from subtype_dealloc. My guess is that the Python interpreter was shutdown before all C++ Storage objects were deallocated. Deallocating the C++ Storage called the finalizer which called back into Python after it was no longer safe to do so. This avoids a callback from C++ into Python during Storage finalization. Instead, dead Storage objects (expired weak references) are collected periodically when shared_cache exceeds a limit. The limit is scaled with 2x the number of live references, which places an upper bound on the amount of extra memory held by dead Storage objects. In practice, this should be very small. ``` Pull Request resolved: pytorch#10407 Differential Revision: D9272400 Pulled By: colesbury fbshipit-source-id: ecb14d9c6d54ffc91e134c34a4e770a4d09048a2
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