constant cache `IC` is accessed by non-atomic manner and there are
thread-safety issues, so Ruby 3.0 disables to use const cache on
non-main ractors.
This patch enables it by introducing `imemo_constcache` and allocates
it by every re-fill of const cache like `imemo_callcache`.
[Bug #17510]
Now `IC` only has one entry `IC::entry` and it points to
`iseq_inline_constant_cache_entry`, managed by T_IMEMO object.
`IC` is atomic data structure so `rb_mjit_before_vm_ic_update()` and
`rb_mjit_after_vm_ic_update()` is not needed.
to avoid SEGV on mjit_recompile and compact_all_jit_code.
For some reason, ISeqs on stack are sometimes GC-ed (why?) and therefore
it may run mjit_recompile on a GC-ed ISeq, which I expected d07183ec85
to fix but apparently it may refer to random things if already GC-ed.
Marking active_units would workaround the situation.
http://ci.rvm.jp/results/trunk-mjit-wait@phosphorus-docker/3292740
Also, while compact_all_jit_code was executed, we saw some SEGVs where
CCs seemed to be already GC-ed, meaning their owner ISeq was not marked
properly. Even if units are still in active_units, it's not guaranteed
that their ISeqs are in use. So in this case we need to mark active_units
for a legitimate reason.
http://ci.rvm.jp/results/trunk-mjit-wait@phosphorus-docker/3293277http://ci.rvm.jp/results/trunk-mjit-wait@phosphorus-docker/3293090
The original motivation of this marking was https://github.com/k0kubun/yarv-mjit/issues/20.
As wanabe said, there are multiple options to mitigate the issue, and
Eric Wong introduced another fix at 143776f6fe by checking unit->iseq
inside the lock.
Therefore this particular condition has been covered in two ways, and
the script given by wanabe no longer crashes without mjit_mark().
to avoid "Too many JIT code, but skipped unloading units for JIT compaction".
Now we can forget the `in_compact` locking.
Moving some functions from mjit.c to mjit_worker.c because mjit_worker.c
should have functions executed in the JIT worker.
This has been a TODO since 79df14c04b. While adcf0316d1 covered the
root_fiber of the initial thread, it didn't cover root_fibers of other
threads. Now it's hooked properly in rb_threadptr_root_fiber_setup.
With regards to "XXX: Is this mjit_cont `mjit_cont_free`d?", when
rb_threadptr_root_fiber_release is called, although I'm not sure when
th->root_fiber is truthy, fiber_free seems to call cont_free and
mjit_cont_free. So mjit_conts of root_fibers seem to be freed properly.
_MSC_VER used to be the macro to switch JIT compaction. However, since
d4381d2ceb, the correct macro to switch it was changed from _MSC_VER
to _WIN32. As I didn't properly replace all relevant _MSC_VER usages
to _WIN32, these macros have been used inconsistently.
nobu replaced _WIN32 with USE_HEADER_TRANSFORMATION in 5eb446d12f.
Therefore we had USE_HEADER_TRANSFORMATION and _MSC_VER. This commit
makes sure such inconsistent _MSC_VER usages will be unified to the new
header, also renaming it to USE_JIT_COMPACTION to be more precise about
the requirements. The header transformation itself is not quite relevant
to places changed in this commit.
We are seeing an error where code that is generated with MJIT contains
references to objects that have been moved. I believe this is due to a
race condition in the compaction function.
`gc_compact` has two steps:
1. Run a full GC to pin objects
2. Compact / update references
Step one is executed with `garbage_collect`. `garbage_collect` calls
`gc_enter` / `gc_exit`, these functions acquire a JIT lock and release a
JIT lock. So a lock is held for the duration of step 1.
Step two is executed by `gc_compact_after_gc`. It also holds a JIT
lock.
I believe the problem is that the JIT is free to execute between step 1
and step 2. It copies call cache values, but doesn't pin them when it
copies them. So the compactor thinks it's OK to move the call cache
even though it is not safe.
We need to hold a lock for the duration of `garbage_collect` *and*
`gc_compact_after_gc`. This patch introduces a lock level which
increments and decrements. The compaction function can increment and
decrement the lock level and prevent MJIT from executing during both
steps.
This commit introduces Ractor mechanism to run Ruby program in
parallel. See doc/ractor.md for more details about Ractor.
See ticket [Feature #17100] to see the implementation details
and discussions.
[Feature #17100]
This commit does not complete the implementation. You can find
many bugs on using Ractor. Also the specification will be changed
so that this feature is experimental. You will see a warning when
you make the first Ractor with `Ractor.new`.
I hope this feature can help programmers from thread-safety issues.
by calling combined functions specialized for each cancel type.
I'm hoping to improve locality of hot code, but this patch's impact should
be insignificant.
Running C compiler for JIT compaction inside a critical section may lock
main thread for a long time when it triggers GC. As I'm planning to
increase this duration a bit, I'd like to make sure this doesn't stop
the world.
For now, I chose to give up unloading units when it's during JIT
compaction, assuming other calls may unload them later.
jit_unit to avoid marking wrong cc entries when inlined iseq is compiled
multiple times, resolving the TODO added by daf7c48d88.
This obviates pseudo jit_unit in inlined iseq introduced by 7ec2359374
and fixes memory leak of the adhoc unit.
ALLOC_N() can causes GC. Sometimes `mjit_copy_job_handler()`
can be called by mjit_worker thread which is not a Ruby thread,
so we need to prevent GC in this function. This patch has some
issues, but I introduce it to pass the tests.
This patch contains several ideas:
(1) Disposable inline method cache (IMC) for race-free inline method cache
* Making call-cache (CC) as a RVALUE (GC target object) and allocate new
CC on cache miss.
* This technique allows race-free access from parallel processing
elements like RCU.
(2) Introduce per-Class method cache (pCMC)
* Instead of fixed-size global method cache (GMC), pCMC allows flexible
cache size.
* Caching CCs reduces CC allocation and allow sharing CC's fast-path
between same call-info (CI) call-sites.
(3) Invalidate an inline method cache by invalidating corresponding method
entries (MEs)
* Instead of using class serials, we set "invalidated" flag for method
entry itself to represent cache invalidation.
* Compare with using class serials, the impact of method modification
(add/overwrite/delete) is small.
* Updating class serials invalidate all method caches of the class and
sub-classes.
* Proposed approach only invalidate the method cache of only one ME.
See [Feature #16614] for more details.
Now, rb_call_info contains how to call the method with tuple of
(mid, orig_argc, flags, kwarg). Most of cases, kwarg == NULL and
mid+argc+flags only requires 64bits. So this patch packed
rb_call_info to VALUE (1 word) on such cases. If we can not
represent it in VALUE, then use imemo_callinfo which contains
conventional callinfo (rb_callinfo, renamed from rb_call_info).
iseq->body->ci_kw_size is removed because all of callinfo is VALUE
size (packed ci or a pointer to imemo_callinfo).
To access ci information, we need to use these functions:
vm_ci_mid(ci), _flag(ci), _argc(ci), _kwarg(ci).
struct rb_call_info_kw_arg is renamed to rb_callinfo_kwarg.
rb_funcallv_with_cc() and rb_method_basic_definition_p_with_cc()
is temporary removed because cd->ci should be marked.
Saves comitters' daily life by avoid #include-ing everything from
internal.h to make each file do so instead. This would significantly
speed up incremental builds.
We take the following inclusion order in this changeset:
1. "ruby/config.h", where _GNU_SOURCE is defined (must be the very
first thing among everything).
2. RUBY_EXTCONF_H if any.
3. Standard C headers, sorted alphabetically.
4. Other system headers, maybe guarded by #ifdef
5. Everything else, sorted alphabetically.
Exceptions are those win32-related headers, which tend not be self-
containing (headers have inclusion order dependencies).
Koichi Sasada
Takashi Kokubun
Aaron Patterson
卜部昌平
Yusuke Endoh