From: Greg.mpls@... Date: 2018-11-08T23:04:30+00:00 Subject: [ruby-core:89760] [Ruby trunk Bug#14968] [PATCH] io.c: make all pipes nonblocking by default Issue #14968 has been updated by MSP-Greg (Greg L). @normalperson Eric, Sorry for the delay. The patch passed. I applied it to r65635... ---------------------------------------- Bug #14968: [PATCH] io.c: make all pipes nonblocking by default https://bugs.ruby-lang.org/issues/14968#change-74814 * Author: normalperson (Eric Wong) * Status: Open * Priority: Normal * Assignee: * Target version: * ruby -v: * Backport: 2.3: UNKNOWN, 2.4: UNKNOWN, 2.5: UNKNOWN ---------------------------------------- Crap, I always planned to have something like this for [Feature #13618] (auto-Fiber); but introducing a race condition for Timer-thread elimination in [Misc #14937] forced me to introduce this early. Anyways, I might have to revert and reintroduce timer-thread if this change is unnacceptable :< (I HATE timer thread) ``` io.c: make all pipes nonblocking by default All normal Ruby IO methods (IO#read, IO#gets, IO#write, ...) are all capable of appearing to be "blocking" when presented with a file description with the O_NONBLOCK flag set; so there is little risk of incompatibility within Ruby-using programs. The biggest compatibility risk is when spawning external programs. As a result, stdin, stdout, and stderr are now always made blocking before exec-family calls. Timer-thread elimination in https://bugs.ruby-lang.org/issues/14937 introduced a race condition in signal handling. It is possible to receive a signal inside BLOCKING_REGION right before read/write syscalls. If this patch cannot be accepted, I will have to revert to reintroduce timer-thread and increase resource use (which led to other failures in the past). The race condition introduced for [Misc #14937] led to rare CI failures on a few tests: - test/ruby/test_thread.rb (test_thread_timer_and_interrupt): http://www.rubyist.net/~akr/chkbuild/debian/ruby-trunk/log/20180805T080500Z.fail.html.gz - test/ruby/test_io.rb (test_race_gets_and_close): http://ci.rvm.jp/results/trunk@P895/1190369 This change is ALSO necessary to take advantage of (proposed lightweight concurrency (aka "auto-Fiber") or any similar proposal: https://bugs.ruby-lang.org/issues/13618 TODO: all sockets and FIFOs non-blocking by default, too ``` ---Files-------------------------------- 0001-io.c-make-all-pipes-nonblocking-by-default.patch (12.1 KB) -- https://bugs.ruby-lang.org/ Unsubscribe: