Embedded shared strings cannot be moved because strings point into the
slot of the shared string. There may be code using the RSTRING_PTR on
the stack, which would pin the string but not pin the shared string,
causing it to move.
When generic instance variable has a shape, it is marked movable. If it
it transitions to too complex, it needs to update references otherwise
it may have incorrect references.
This is required for the same reason that super CC needs it.
See 36023d5cb7.
Reproducer:
def cached_foo_callsite(obj) = obj.foo
class Foo
def foo = :v1
module R
refine Foo do
def foo = :unused
end
end
end
obj = Foo.new
cached_foo_callsite(obj) # set up cc with cme for foo=:v1
class Foo
def foo = :v2
end
GC.start # cme for foo=:v1 collected, if not reachable by cached_foo_callsite
cached_foo_callsite(obj)
[Bug #19994]
On large Ruby applications, shutdown may be slow if a major GC has just
started because rb_objspace_call_finalizer completes the GC.
This commit adds gc_abort which discards the mark stack if during
incremental marking and stops sweeping if during lazy sweeping.
Previously, because gc_update_object_references() did not update the
VALUEs in the too_complex ivar st_table for T_CLASS and T_MODULE
objects, GC compaction could finish with corrupted objects.
- start with `klass`, not too_complex
- GC incremental step marks `klass` and its ivars
- ruby code makes `klass` too_complex
- GC compaction runs and move `klass` ivars, but because `klass` is
too_complex, its ivars are not updated by gc_update_object_references(),
leaving T_NONE or T_MOVED objects in the ivar table.
Co-authored-by: Peter Zhu <peter@peterzhu.ca>
Marking both keys and values versus marking just values is an important
distinction, but previously, gc_update_tbl_refs() and gc_update_table_refs()
had names that were too similar.
The st_table storing ivars for too_complex T_OBJECTs have IDs as keys,
but we were marking the IDs unnecessary previously, maybe due to the
confusing naming.
Previously, it tripped the assert about too_complex in
ROBJECT_IV_CAPACITY(). This fixes double faults for some crashes and
helps with use during development.
Since the callback defined in the objspace module might give up the GVL,
we need to make sure the right cr->mfd value is set back after the GVL
is re-obtained.
The previous implementation was using the pointer given
by `DATA_PTR` in all cases. But in the case of an embedded
TypedData, that pointer is garbage, we need to use RTYPEDDATA_GET_DATA
to get the proper data pointer.
Co-Authored-By: Étienne Barrié <etienne.barrie@gmail.com>
This commit adds a new flag RUBY_TYPED_EMBEDDABLE that allows the data
of a TypedData object to be embedded after the object itself. This will
improve cache locality and allow us to save the 8 byte data pointer.
Co-Authored-By: Jean Boussier <byroot@ruby-lang.org>
Tracks other callinfo that references the same kwargs and frees them when all references are cleared.
[bug #19906]
Co-authored-by: Peter Zhu <peter@peterzhu.ca>
fix memory leak in vm_method
This introduces a unified reference_count to clarify who is referencing a method.
This also allows us to treat the refinement method as the def owner since it counts itself as a reference
Co-authored-by: Peter Zhu <peter@peterzhu.ca>
By compacting into slots with pinned objects first, we improve the
efficiency of compaction. As it is less likely that there will exist
pages containing only pinned objects after compaction. This will
increase the number of free pages left after compaction and enable us to
free them.
This used to be the default compaction method before it was removed
(inadvertently?) during the introduction of auto_compaction.
This commit will sort the pages by the pinned slot count at the start of
a major GC that has been triggered by explicitly calling GC.compact (and
thus setting objspace->flags.during_compaction).
It works using the same method by which we sort the heap by empty slot
count during GC.verify_compaction_references.
Previously it was only being sorted during the verify compaction
references stage - so would only happen during testing.
This commit allows us to sort the heap prior to each explicit GC.compact
run
Previously, configuring any GC event hook would cause all allocations to
go through the newobj slowpath. We should only need to do that when the
newobj specifically is subscribed to.
This renames flags.has_hook to flags.has_newobj_hook, to make this new
usage clear. newobj_of0 was the only place which previously checked this
flag.
This should help fix the following flaky test:
```
1) Failure:
TestProcess#test_warmup_frees_pages [test/ruby/test_process.rb:2751]:
<0> expected but was
<1>.
```
If we're during incremental marking, then Ruby code can execute that
deallocates certain memory buffers that have been called with
rb_gc_mark_weak, which can cause use-after-free bugs.
The term "shady object" was renamed to "uncollectible write barrier
unprotected object", so rename `has_uncollectible_shady_objects` to
`has_uncollectible_wb_unprotected_objects` for consistency.
We always sweep at least 2048 slots per sweep step, but only pool one
page. For large size pools, 2048 slots is many pages but one page is
very few slots. This commit changes it so that at least 1024 slots are
placed in the pooled pages per sweep step.
We move all pooled pages to free pages at the start of incremental
marking, so we shouldn't run incremental marking only when we have run
out of free pages. This causes incremental marking to always complete
in a single step.
If we are in a minor GC and the object to mark is old, then the old
object should already be marked and cannot be reclaimed in this GC cycle
so we don't need to add it to the weak refences list.
Peter Zhu
Alan Wu
KJ Tsanaktsidis
Aaron Patterson
Jean Boussier
Jean Boussier
KJ Tsanaktsidis
Nobuyoshi Nakada
Yusuke Endoh
HParker
Adam Hess
Matt Valentine-House
John Hawthorn