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Eric Wong authored
Relying on ubf_select + ubf_list for main thread is not guaranteed to wake a process up as it does not acquire sigwait_fd and all other threads may be sleeping. native_cond_sleep and the sigwait_fd path are immune to TOCTOU issues, but native_ppoll_sleep may have its wakeup stolen by sigwait_fd sleeper and the RUBY_VM_INTERRUPTED check is insufficient. Note: for pthreads platforms without POSIX timers, this becomes more expensive than Ruby 2.5, as six pipe FDs come into use. Linux is best off with only two descriptors for eventfd. [ruby-core:89655] cf. http://ci.rvm.jp/results/trunk-mjit@silicon-docker/1437559 http://ci.rvm.jp/results/trunk-mjit-wait@silicon-docker/1437673 git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65495 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Eric Wong authoredRelying on ubf_select + ubf_list for main thread is not guaranteed to wake a process up as it does not acquire sigwait_fd and all other threads may be sleeping. native_cond_sleep and the sigwait_fd path are immune to TOCTOU issues, but native_ppoll_sleep may have its wakeup stolen by sigwait_fd sleeper and the RUBY_VM_INTERRUPTED check is insufficient. Note: for pthreads platforms without POSIX timers, this becomes more expensive than Ruby 2.5, as six pipe FDs come into use. Linux is best off with only two descriptors for eventfd. [ruby-core:89655] cf. http://ci.rvm.jp/results/trunk-mjit@silicon-docker/1437559 http://ci.rvm.jp/results/trunk-mjit-wait@silicon-docker/1437673 git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65495 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
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