zlib and bignum both contain unblocking functions which are
async-signal-safe and do not require spawning additional
threads.
We can execute those functions directly in signal handlers
without incurring overhead of extra threads, so provide C-API
users the ability to deal with that. Other C-API users may
have similar need.
This flexible API can supercede existing uses of
rb_thread_call_without_gvl and rb_thread_call_without_gvl2 by
introducing a flags argument to control behavior.
Note: this API is NOT finalized. It needs approval from other
committers. I prefer shorter name than previous
rb_thread_call_without_gvl* functions because my eyes requires
big fonts.
[Bug #15499]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66712 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
We need another native thread to call some unblocking functions
which aren't RUBY_UBF_IO or RUBY_UBF_PROCESS. Instead of a
permanent thread in <= 2.5, we can now rely on the thread cache
feature to perform interrupts.
[ruby-core:90865] [Bug #15499]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66708 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
The following race may happen if ubf_timer_destroy calls
timer_delete before ubf_timer_disarm gets called from
a different thread. Consider the following timelines:
ubf_timer_destroy | ubf_timer_disarm
-------------------------------------+-----------------------------
| CAS(ARM => DISARM)
CAS(DISARM => DEAD) |
timer_delete |
| timer_settime(disarm)
Another option may be to add an intermediate "RTIMER_DISARMING"
state to the transition, but I figure the EINVAL check is
simpler and less intrusive code-wise.
cf. http://ci.rvm.jp/results/trunk-iseq_binary@silicon-docker/1545794
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66457 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Constantly forking a single-threaded process in a loop leads to
a memory leak when using POSIX timers. This fixes the leak for
GNU/Linux systems running glibc.
v2: disarm before timer_delete
v3: ubf_timer_arm prevents double-arming
This unreverts r66291 / commit ab73ef6b70
Example Linux-only reproduction may be found in:
r66290 / commit 043047a8fd
Note: FreeBSD 11.2 still leaks, I'm not sure why, yet.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66413 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
We don't use ubf_select after r65495 / 5de7b3b4f2
("thread_pthread.c (native_ppoll_sleep): new eventfd (or pipe) for ubf"),
so we don't need to unregister the thread from the ubf list.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66382 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Uncontended GVL waitqueue could mean a single CPU setup where
threads are starved and can't even insert themselves into our
waitqueue. So we force other threads to run upon releasing
the GVL in an uncontended state, in the hope that we can
avoid entering the slow path of ppoll and similar syscalls.
This should prevent test/ruby/test_thread.rb::test_signal_at_join
timeout problems on our single CPU FreeBSD CI machine.
[ruby-core:90417] [Bug #15398]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66381 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This reverts r66290 / commit 043047a8fd.
Still fails on CI, and I'm not able to reproduce the failure, either :<
http://ci.rvm.jp/results/trunk-test@ruby-sky1/1508228
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66291 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Constantly forking a single-threaded process in a loop leads to
a memory leak when using POSIX timers.
v2: disarm before timer_delete
==> fork_leapfrog.rb <==
require 'io/wait'
Dir.chdir '/proc'
prev = 0
loop do
pid = fork
exit!(0) if pid
# show the number of 4K pages used (Linux-only)
n = File.read("#$$/statm").split(-' ')[1].to_i
if n > prev
puts "#{prev} => #{n}"
prev = n
end
# since Ctrl-C from a terminal can't stop this loop,
# allow the user to just hit any key to stop
break if STDIN.wait(0)
end
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66290 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Constantly forking a single-threaded process in a loop leads to
a memory leak when using POSIX timers.
==> fork_leapfrog.rb <==
require 'io/wait'
Dir.chdir '/proc'
prev = 0
loop do
pid = fork
exit!(0) if pid
# show the number of 4K pages used (Linux-only)
n = File.read("#$$/statm").split(-' ')[1].to_i
if n > prev
puts "#{prev} => #{n}"
prev = n
end
# since Ctrl-C from a terminal can't stop this loop,
# allow the user to just hit any key to stop
break if STDIN.wait(0)
end
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@66288 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Negative-numbered FDs are never valid FDs on POSIX-like
platforms, and we initialize our self-pipes/eventfd values
to "-1", so stop treating -1 as a reserved FD if our system
is too low on resources to allocate FDs at startup.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65832 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
I already forgot why we needed to jump through such hoops :x
[ruby-core:88102]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65648 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* vm_core.h (rb_thread_struct): introduce new fields `invoke_type`
and `invoke_arg`.
There are two types threads: invoking proc (normal Ruby thread
created by `Thread.new do ... end`) and invoking func, created
by C-API. `invoke_type` shows the types.
* thread.c (thread_do_start): copy `invoke_arg.proc.args` contents
from Array to ALLOCA stack memory if args length is enough small (<8).
We don't need to keep Array and don't need to cancel using transient heap.
* vm.c (thread_mark): For func invoking threads, they can pass (void *)
parameter (rb_thread_t::invoke_arg::func::arg). However, a rubyspec test
(thread_spec.c) passes an Array object and it expect to mark it.
Clealy it is out of scope (misuse of `rb_thread_create` C-API). However,
I'm not sure someone else has such kind of misunderstanding.
So now we mark conservatively this (void *) arg with rb_gc_mark_maybe.
This misuse is found by this error log.
http://ci.rvm.jp/results/trunk-theap-asserts@silicon-docker/1448164
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65622 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
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/1437559http://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
vm->gvl.lock can be held by another thread, we must not wait
on it when called by the MJIT worker thread when it migrates
work to another thread. ubf_select is designed to do retrying
anyways, so it has no obligation to wake up a timer thread.
cf. http://ci.rvm.jp/results/trunk-mjit-wait@silicon-docker/1437880
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65465 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* configure.ac: introduce new configure option `--enable-mjit` and
`--disable-mjit`. Default is "enable".
`--disable-mjit` disables all of MJIT features so that `ruby --jit`
can't enable MJIT.
This option affect a macro `USE_MJIT`.
This change remove `--enable/disable-install-mjit-header` option.
* Makefile.in: introduce the `ENABLE_MJIT` variable.
* common.mk: use `ENABLE_MJIT` option.
* internal.h: respect `USE_MJIT`. Same as other *.c, *.h.
* test/ruby/test_jit.rb: check `ENABLE_MJIT` key of rbconfg.rb.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65204 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
rb_hrtime_t is a more pleasant type to use and this can make
future changes around sleeping/scheduling easier.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@65182 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
`acquired' was an old boolean variable, but nowadays it is a
rb_thread_t pointer; "gvl.owner" seems like a more appropriate
name. And document the contended path including waitq, timer,
and timer_err.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64581 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Introduce a new rb_thread_sleep_interruptible that does not
execute interrupts before sleeping. Skipping the interrupt
check before sleep is required for out-of-GVL ruby_waitpid_all
to function properly when setting waitpid_state.ret
Now that ubf_select can be called by the gvl.timer thread
without recursive locking gvl.lock, we can safely use
rb_threadptr_interrupt to deal with waking up sleeping
processes,
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64576 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This simplifies the locking logic somewhat.
While we're at it, designate_timer_thread is worthless in
ubf_select because gvl_acquire_common already guarantees there
is a gvl.timer if gvl->waitq is populated.
In the future (for auto-fiber), this will allow using
th->unblock.func for rb_waitpid callers (via rb_sigchld_handler).
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64575 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
We need to ensure Signal.trap handlers can function if the main
thread is sleeping after a subthread has grabbed sigwait_fd,
but later exited.
Consider the following timeline:
main_thread sub-thread
-----------------------------------------
Signal.trap() { ... }
get sigwait_fd
ppoll on sigwait_fd
native_cond_sleep
(via pthread_cond_wait)
ppoll times-out
put sigwait_fd
sub-thread exits
only thread alive
SIGNAL HITS
The problem is pthread_cond_wait cannot return EINTR,
so we can never run the Signal.trap handler. So we
will avoid using native_cond_sleep in the main thread
and always use ppoll to sleep when in the main thread.
This can guarantee the main thread remains aware of
signals; even if it cannot safely read off sigwait_fd
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64538 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Relying on "struct timespec" was too annoying API-wise and
used more stack space. "double" was a bit wacky w.r.t rounding
in the past, so now we'll switch to using a 64-bit type.
Unsigned 64-bit integer is able to give us over nearly 585
years of range with nanoseconds. This range is good enough
for the Linux kernel internal time representation, so it
ought to be good enough for us.
This reduces the stack usage of functions while GVL is held
(and thus subject to marking) on x86-64 Linux (with ppoll):
rb_wait_for_single_fd 120 => 104
do_select 120 => 88
[ruby-core:88582] [Misc #15014]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64533 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Based on r64478, any regular user creating more than 1024 pipes
on Linux will end up with tiny pipes with only a single page
capacity. So avoid wasting user resources and use lighter
eventfd on Linux.
[ruby-core:88563] [Misc #15011]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64527 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
TIMER_THREAD_CREATED_P already checks that pid, and glibc 2.25+
no longer caches getpid(2).
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64524 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
It's possible for the ubf_list_head to be populated with dead
threads at fork or the ubf_list_lock to be held, so reinitialize
both at startup.
And while we're at it, use a static initializer at startup
to save a library call and kill some ifdef.
[ruby-core:88578] [Bug #15013]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64485 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This matches the behavior of old timer thread more closely
and seems to fix [Bug #14999] when limited to a single CPU.
I cannot reproduce the error on a multi-core system unless
I use schedtool to force affinity to a single CPU:
schedtool -a 0x01 -e make test-spec \
MSPECOPT='-R1000 spec/ruby/library/conditionvariable/wait_spec.rb'
While it may be good enough to pass the spec, I don't have
huge degree of confidence in the interrupt handling robustness
under extremely heavy load (these may be ancient bugs, though).
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64467 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This is not called in signal handlers, so there's no reason for
it. glibc 2.25+ no longer caches getpid(), so it will cost a
syscall for those users.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64403 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
We do not need to rely on SIGVTALRM for non-sighandler wakeups.
This will reduce spurious wakeups in cases where sigwait_fd
is not grabbed again, soon.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64389 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
For (rare) blocking functions which are not affected by signals,
we need to call the appropriate unblocking function via
`threadptr_trap_interrupt'
While we're at it, handling waitpid/SIGCHLD from gvl.timer isn't
harmful, here.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64388 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This hopefully clarifies the roles of UBF_TIMER and vm->gvl.timer
[ruby-core:88475] [Misc #14937]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64377 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Do not waste extra memory for each thread, but make
thread_pthread.c easier-to-follow as a result.
[ruby-core:88475] [Misc #14937]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64375 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
These functions will not be exported outside of thread_pthread.c
and we need to clarify the timer here is used for ubf and not
timeslice.
[ruby-core:88475] [Misc #14937]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64373 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This data structure has nothing to do with timers or threads.
[ruby-core:88475] [Misc #14937]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64372 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Hopefully this makes the code easier-to-follow
[ruby-core:88475] [Misc #14937]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64371 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
I'm not sure what's causing this failure in Solaris and only
on rubyspec, since rb_io_wait_readable is a well-exercised
code path in other places. But maybe using a pthread for
timing (similar to old timer-thread) can solve the issue.
cf. http://rubyci.s3.amazonaws.com/unstable11s/ruby-trunk/log/20180814T042506Z.fail.html.gz
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64357 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
timer_create does not seem to support CLOCK_MONOTONIC on Solaris,
and CLOCK_HIRES seems like it could fail with insufficient permissions:
https://docs.oracle.com/cd/E86824_01/html/E54766/timer-create-3c.html
(Only tested on Linux and FreeBSD)
[ruby-core:88360] [Misc #14937]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64356 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
It looks like I forgot to account for a situation involving 3
threads.
[ruby-core:88360] [Misc #14937]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64354 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This closes race condition where GVL is uncontended and a thread
receives a signal immediately before calling the blocking
function when releasing GVL:
1) check interrupts
2) release GVL
3) blocking function
If signal fires after 1) but before 3), that thread may never
wake up if GVL is uncontended
We also need to wakeup the ubf_list unconditionally on
gvl_yield; because two threads can be yielding to each other
while waiting on IO#close while waiting on threads in IO#read or
IO#gets.
[ruby-core:88360] [Misc #14937]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64353 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This reverts commit 194a6a2c68 (r64203).
Race conditions which caused the original reversion will be fixed
in the subsequent commit.
[ruby-core:88360] [Misc #14937]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@64352 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
normal
svn
ko1
duerst