Introduce pipe-based inter-thread messaging #154
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…andling requests as well
…might be NULL in case it is closed right after being created
kazuho
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Introduce pipe-based inter-thread messaging
kazuho
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The pipe-based IPC initializes all the pipes on the main thread. However, since h2o_socket_t::input is initialized with reference to h2o_socket_buffer_prototype which is a TLS value, race condition bug (leading to random crash) arise once the pipes are used within the worker threads. The PR fixes the issue by moving the initialization code to each thread.
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fix crash in recycling allocator (amends #154)
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At the moment H2O uses signals for notifying other threads, however it cannot be used for general purpose (e.g. sharing a prefixed number of connections upstream, or using a dedicated thread for communicating with memcached (#120)), as it has TOCTOU issues.
There are two options to fix the problem, one is to use platform-dependent features like
signalfdto integrate signal handling with poll-based event loop; the other is to switch topipebased messaging.This PR uses the latter approach (which can be optimized in case of linux by using
eventfd).