There's an exhaustive explanation of this in the linked redmine bug, but
the short version is as follows:
blocking_region_begin can spill callee-saved registers to the stack for
its own use. That means they're not saved to ec->machine by the call to
setjmp, since by that point they're already on the stack and new,
different values are in the real registers. ec->machine's end-of-stack
pointer is also bumped to accomodate this, BUT, after
blocking_region_begin returns, that points past the end of the stack!
As far as C is concerned, that's fine; the callee-saved registers are
restored when blocking_region_begin returns. But, if another thread
triggers GC, it is relying on finding references to Ruby objects by
walking the stack region pointed to by ec->machine.
If the C code in exec; subsequently does things that use that stack
memory, then the value will be overwritten and the GC might prematurely
collect something it shouldn't.
[Bug #20493]
Only emit circular dependency warning for owned thread shields [Bug
#19415]
If multiple threads attemps to load the same file concurrently
it's not a circular dependency issue.
So we check that the existing ThreadShield is owner by the current
fiber before warning about circular dependencies.
---
internal/thread.h | 1 +
load.c | 3 ++-
spec/ruby/core/kernel/shared/require.rb | 11 +++++++++++
spec/ruby/fixtures/code/concurrent_require_fixture.rb | 4 ++++
test/ruby/test_require.rb | 3 ---
thread.c | 11 +++++++++++
6 files changed, 29 insertions(+), 4 deletions(-)
create mode 100644 spec/ruby/fixtures/code/concurrent_require_fixture.rb
Use Thread.pass until thread.stop? to wait for thread to block
[Bug #19415]
It should be more reliable
---
spec/ruby/fixtures/code/concurrent_require_fixture.rb | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
First, rb_mjit_fork should call rb_thread_atfork to stop threads after
fork in the child process. Unfortunately, we cannot use rb_fork_ruby to
prevent this kind of mistakes because MJIT needs special handling of
waiting_pid and mjit_pause/resume.
Second, mjit_waitpid_finished should be checked regardless of
trap_interrupt. It doesn't seem like the flag is not set when SIGCHLD is
handled for an MJIT child process.
GCC warns of empty format strings, perhaps because they have no
effects in printf() and there are better ways than sprintf().
However, ruby_debug_log() adds informations other than the format,
this warning is not the case.
rb_ary_tmp_new suggests that the array is temporary in some way, but
that's not true, it just creates an array that's hidden and not on the
transient heap. This commit renames it to rb_ary_hidden_new.
`rb_thread_wait_for_single_fd` needs to mutate the `waiting_fds` list
that is stored on the VM. We need to delete the FD from the list before
returning, and deleting from the list requires a VM lock (because the
list is a global).
[Bug #18816] [ruby-core:108771]
Co-Authored-By: Alan Wu <alanwu@ruby-lang.org>
[Feature #18339]
After experimenting with the initial version of the API I figured there is a need
for an exit event to cleanup instrumentation data. e.g. if you record data in a
{thread_id -> data} table, you need to free associated data when a thread goes away.
Previously, because opt_aref and opt_aset don't push a frame, when they
would call rb_hash to determine the hash value of the key, the initial
level of recursion would incorrectly use the method id at the top of the
stack instead of "hash".
This commit replaces rb_exec_recursive_outer with
rb_exec_recursive_outer_mid, which takes an explicit method id, so that
we can make the hash calculation behave consistently.
rb_exec_recursive_outer was documented as being internal, so I believe
this should be okay to change.
`NON_SCALAR_THREAD_ID` shows `pthread_t` is non-scalar (non-pointer)
and only s390x is known platform. However, the supporting code is
very complex and it is only used for deubg print information.
So this patch removes the support of `NON_SCALAR_THREAD_ID`
and make the code simple.
`rb_thread_t` contained `native_thread_data_t` to represent
thread implementation dependent data. This patch separates
them and rename it `rb_native_thread` and point it from
`rb_thraed_t`.
Now, 1 Ruby thread (`rb_thread_t`) has 1 native thread (`rb_native_thread`).
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.
Use ISEQ_BODY macro to get the rb_iseq_constant_body of the ISeq. Using
this macro will make it easier for us to change the allocation strategy
of rb_iseq_constant_body when using Variable Width Allocation.
Currently the calculation only counts the size of the struct. This commit adds the size of the associated st tables, id tables, and linked lists.
Still missing is the size of the ractors and (potentially) the size of the object space.
