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>
Renames rb_id_table_foreach_with_replace to
rb_id_table_foreach_values_with_replace and passes only the value to the
callback. We can use this in GC compaction when we cannot access the
global symbol array.
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).
This reverts commits: 10d6a3aca78ba48c1b85fba8627dc1dd883de5ba6c6a25feca167e6b48f17cb96d41a53207979278595b3c4fdd1521f7cf89c11c5e69accf336082033632a812c0f56506be0d86427a3219 .
The reason for the revert is that we observe ABA problem around
inline method cache. When a cache misshits, we search for a
method entry. And if the entry is identical to what was cached
before, we reuse the cache. But the commits we are reverting here
introduced situations where a method entry is freed, then the
identical memory region is used for another method entry. An
inline method cache cannot detect that ABA.
Here is a code that reproduce such situation:
```ruby
require 'prime'
class << Integer
alias org_sqrt sqrt
def sqrt(n)
raise
end
GC.stress = true
Prime.each(7*37){} rescue nil # <- Here we populate CC
class << Object.new; end
# These adjacent remove-then-alias maneuver
# frees a method entry, then immediately
# reuses it for another.
remove_method :sqrt
alias sqrt org_sqrt
end
Prime.each(7*37).to_a # <- SEGV
```
For some reason symbols (or classes) are being overridden in trunk
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67598 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit adds the new method `GC.compact` and compacting GC support.
Please see this issue for caveats:
https://bugs.ruby-lang.org/issues/15626
[Feature #15626]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67576 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Because hard to specify commits related to r67479 only.
So please commit again.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67499 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit adds the new method `GC.compact` and compacting GC support.
Please see this issue for caveats:
https://bugs.ruby-lang.org/issues/15626
[Feature #15626]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67479 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* id_table.h (rb_id_table_iterator_result): add dummy sentinel
member because C standard prohibits a trailing comma.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55821 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This allows us to swap in rb_id_table_memsize for st_memsize
(which takes a "const st_table *") more easily.
It also makes sense to do the same for rb_id_table_size,
too; as the table cannot be altered when accessing size.
* id_table.h (rb_id_table_size): const arg
(rb_id_table_memsize): ditto
* id_table.c (st_id_table_size): ditto
(st_id_table_memsize): ditto
(list_id_table_size): ditto
(list_id_table_memsize): ditto
(hash_id_table_size): ditto
(hash_id_table_memsize): ditto
(mix_id_table_size): ditto
(mix_id_table_memsize): ditto
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@52428 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
* id_table.h (rb_id_table_foreach_func_t): define callback
function type for rb_id_table_foreach().
* id_table.h (rb_id_table_foreach_values_func_t): ditto for
rb_id_table_foreach_values().
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51682 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
[Feature #11420]
This table only manage ID->VALUE table to reduce overhead of st.
Some functions prefixed rb_id_table_* are provided.
* id_table.c: implement rb_id_table_*.
There are several algorithms to implement it.
Now, there are roughly 4 types:
* st
* array
* hash (implemented by Yura Sokolov)
* mix of array and hash
The macro ID_TABLE_IMPL can choose implementation.
You can see detailes about them at the head of id_table.c.
At the default, I choose 34 (mix of list and hash).
This is not final decision.
Please report your suitable parameters or
your data structure.
* symbol.c: introduce rb_id_serial_t and rb_id_to_serial()
to represent ID by serial number.
* internal.h: use id_table for method tables.
* class.c, gc.c, marshal.c, vm.c, vm_method.c: ditto.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@51541 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
Jemma Issroff
Peter Zhu
卜部昌平
tenderlove
kazu
nobu
normal
ko1