I noticed this while running test_yjit with --mjit-call-threshold=1,
which redefines `Integer#<`. When Ruby is monkey-patched,
MJIT itself could be broken.
Similarly, Ruby scripts could break MJIT in many different ways. I
prepared the same set of hooks as YJIT so that we could possibly
override it and disable it on those moments. Every constant under
RubyVM::MJIT is private and thus it's an unsupported behavior though.
When an object becomes "too complex" (in other words it has too many
variations in the shape tree), we transition it to use a "too complex"
shape and use a hash for storing instance variables.
Without this patch, there were rare cases where shape tree growth could
"explode" and cause performance degradation on what would otherwise have
been cached fast paths.
This patch puts a limit on shape tree growth, and gracefully degrades in
the rare case where there could be a factorial growth in the shape tree.
For example:
```ruby
class NG; end
HUGE_NUMBER.times do
NG.new.instance_variable_set(:"@unique_ivar_#{_1}", 1)
end
```
We consider objects to be "too complex" when the object's class has more
than SHAPE_MAX_VARIATIONS (currently 8) leaf nodes in the shape tree and
the object introduces a new variation (a new leaf node) associated with
that class.
For example, new variations on instances of the following class would be
considered "too complex" because those instances create more than 8
leaves in the shape tree:
```ruby
class Foo; end
9.times { Foo.new.instance_variable_set(":@uniq_#{_1}", 1) }
```
However, the following class is *not* too complex because it only has
one leaf in the shape tree:
```ruby
class Foo
def initialize
@a = @b = @c = @d = @e = @f = @g = @h = @i = nil
end
end
9.times { Foo.new }
``
This case is rare, so we don't expect this change to impact performance
of most applications, but it needs to be handled.
Co-Authored-By: Aaron Patterson <tenderlove@ruby-lang.org>
The internal location in ractor.rb is not usefull at all.
```
$ ruby -e 'Ractor.new {}'
<internal:ractor>:267: warning: Ractor is experimental, ...
```
Shapes provides us with an (almost) exact count of instance variables.
We only need to check for Qundef when an IV has been "undefined"
Prefer to use ROBJECT_IV_COUNT when iterating IVs
Clang says "warning: variable 'pcnt' set but not used" here. In fact it
doesn't. The intention is clear that we want to increment cnt, not pcnt.
Adding a * mark solves everything.
Ractor verification requires storing the ractor id in the top 32 bits of
the object header. Unfortunately 32 bit machines only have 32 bits in
the object header. The verification code has a 32 bit left shift which
doesn't work on i686 and will clobber existing flags.
This commit disables the verification code on i686 since i686 will crash
if it's enabled.
Co-Authored-By: John Hawthorn <john@hawthorn.email>
Co-Authored-By: Jemma Issroff <jemmaissroff@gmail.com>
Now GVL is not process *Global* so this patch try to use
another words.
* `rb_global_vm_lock_t` -> `struct rb_thread_sched`
* `gvl->owner` -> `sched->running`
* `gvl->waitq` -> `sched->readyq`
* `rb_gvl_init` -> `rb_thread_sched_init`
* `gvl_destroy` -> `rb_thread_sched_destroy`
* `gvl_acquire` -> `thread_sched_to_running` # waiting -> ready -> running
* `gvl_release` -> `thread_sched_to_waiting` # running -> waiting
* `gvl_yield` -> `thread_sched_yield`
* `GVL_UNLOCK_BEGIN` -> `THREAD_BLOCKING_BEGIN`
* `GVL_UNLOCK_END` -> `THREAD_BLOCKING_END`
* removed
* `rb_ractor_gvl`
* `rb_vm_gvl_destroy` (not used)
There are GVL functions such as `rb_thread_call_without_gvl()` yet
but I don't have good name to replace them. Maybe GVL stands for
"Greate Valuable Lock" or something like that.
I have this scripts that deadlocks after about
5 minutes if I repeatedly run it with a shell loop:
```ruby
$VERBOSE = nil
lamb = ->(main, gc) do
gc.verify_internal_consistency
gc.verify_internal_consistency
main << 1
gc.verify_internal_consistency
gc.verify_internal_consistency
main << 2
gc.verify_internal_consistency
gc.verify_internal_consistency
main << 3
gc.verify_internal_consistency
gc.verify_internal_consistency
end
lamb[[], GC]
lamb[[], GC]
r = Ractor.new Ractor.current, GC, &lamb
a = []
a << Ractor.receive_if{|msg| msg == 2}
a << Ractor.receive_if{|msg| msg == 3}
a << Ractor.receive_if{|msg| msg == 1}
```
Shell loop:
```shell
while ./miniruby deadlock.rb; do date; done
```
Once it locks up, CTRL-C doesn't interrupt the process which
led me to infer `receive_if` is looping in `ractor_receive_if()`
without checking for interrupts. This can be confirmed by
attaching a debugger to the deadlocked miniruby.
The deadlock has one thread looping in `receive_if`
and another waiting in `rb_vm_barrier()`. The barrier relies
on interrupt checking to finish. Theoretically speaking the
`rb_vm_barrier()` could come from one thread naturally starting GC.
We found this while developing YJIT but it dead locks running
with YJIT disabled. YJIT currently relies on `rb_vm_barrier()`
to synchronize before changing memory protection.
This diff adds an interrupt check in the loop in `Ractor#receive_if`
which seems to fix the deadlock.
In addition, this commit allows interrupting the following single
ractor script with CTRL-C.
```shell
ruby -e 'Ractor.current.send(3); Ractor.receive_if { false }'
```
`USE_RUBY_DEBUG_LOG` was only defined when `RUBY_DEVEL` is defined.
This patch removes this dependency (`USE_RUBY_DEBUG_LOG` is defined
independently from `RUBY_DEVEL`).
Do not commit a patch which enables `USE_RUBY_DEBUG_LOG`.
* ujit: implement opt_getinlinecache
Aggressively bet that writes to constants don't happen and invalidate
all opt_getinlinecache blocks on any and all constant writes.
Use alignment padding on block_t to track this assumption. No change to
sizeof(block_t).
* Fix compile warnings when not RUBY_DEBUG
* Fix reversed condition
* Switch to st_table to keep track of assumptions
Co-authored-by: Aaron Patterson <aaron.patterson@gmail.com>
Co-authored-by: Maxime Chevalier-Boisvert <maximechevalierb@gmail.com>
rb_objspace_reachable_objects_from requires that the GC not be active.
Since the Ractor barrier is not executed for incremental sweeping,
Ractor may call rb_objspace_reachable_objects_from after sweeping
has started to share objects. This causes a crash that looks like
the following:
```
<internal:ractor>:627: [BUG] rb_objspace_reachable_objects_from() is not supported while during_gc == true
```
Co-authored-by: Vinicius Stock <vinicius.stock@shopify.com>
When a Ractor is removed, the freelist in the Ractor cache is not
returned to the GC, leaving the freelist permanently lost. This commit
recycles the freelist when the Ractor is destroyed, preventing a memory
leak from occurring.
If the GC has been disabled we need to re-enable it so we can evacuate
the transient heap.
Fixes https://bugs.ruby-lang.org/issues/17985
[Bug #17985] [ruby-core:104260]
Co-authored-by: Aaron Patterson <tenderlove@ruby-lang.org>
Ractor.yield(obj, move: true) and
Ractor.select(..., yield_value: obj, move: true) tried to yield a
value with move semantices, but if the trial is faild, the obj
should not become a moved object.
To keep this rule, `wait_moving` wait status is introduced.
New yield/take process:
(1) If a ractor tried to yield (move:true), make taking racotr's
wait status `wait_moving` and make a moved object by
`ractor_move(obj)` and wakeup taking ractor.
(2) If a ractor tried to take a message from a ractor waiting fo
yielding (move:true), wakeup the ractor and wait for (1).
When `literal`, check if the literal about to be assigned to a
constant is ractor-shareable, otherwise raise `Ractor::Error` at
runtime instead of `SyntaxError`.
separate some fields from rb_ractor_t to rb_ractor_pub and put it
at the beggining of rb_ractor_t and declare it in vm_core.h so
vm_core.h can access rb_ractor_pub fields.
Now rb_ec_ractor_hooks() is a complete inline function and no
MJIT related issue.
Ractor has several restrictions to keep each ractor being isolated
and some operation such as `CONST="foo"` in non-main ractor raises
an exception. This kind of operation raises an error but there is
confusion (some code raises RuntimeError and some code raises
NameError).
To make clear we introduce Ractor::IsolationError which is raised
when the isolation between ractors is violated.
Takashi Kokubun
Jemma Issroff
S-H-GAMELINKS
Nobuyoshi Nakada
Aaron Patterson
卜部昌平
Yusuke Endoh
Koichi Sasada
Alan Wu
Jose Narvaez
Kazuhiro NISHIYAMA
Peter Zhu
eileencodes
Ryuta Kamizono
Marc-Andre Lafortune