glib/gobject
Thomas Haller d8e4f39aa8 gobject: track GWeakRef in object's WeakRefData with an array
GSList doesn't seem the best choice here. It's benefits are that it's
relatively convenient to use (albeit not very efficient) and that an
empty list requires only the pointer to the list's head.

But for non-empty list, we need to allocate GSList elements. We can do
better, by writing more code.

I think it's worth optimizing GObject, at the expense of a bit(?) more
complicated code. The complicated code is still entirely self-contained,
so unless you review WeakRefData usage, it doesn't need to bother you.
Note that this can be easily measure to be a bit faster. But I think the
more important part is to safe some allocations. Often objects are
long-lived, and the GWeakRef will be tracked for a long time. It is
interesting, to optimize the memory usage of that.

- if the list only contains one weak reference, it's interned/embedded in
  WeakRefData.list.one. Otherwise, an array is allocated and tracked
  at WeakRefData.list.many.

- when the buffer grows, we double the size. When the buffer shrinks,
  we reallocate to 50% when 75% are empty. When the buffer shrinks to
  length 1, we free it (so that "list.one" is always used with a length
  of 1).
  That means, at worst case we waste 75% of the allocated buffer,
  which is a choice in the hope that future weak references will be
  registered, and that this is a suitable strategy.

- on architectures like x86_68, does this not increase the size of
  WeakRefData.

Also, the number of weak-refs is now limited to 65535, and now an
assertion fails when you try to register more than that. But note that
the internal tracking just uses a linear search, so you really don't
want to register thousands of weak references on an object. If you do
that, the current implementation is not suitable anyway and you must
rethink your approach. Nor does it make sense to optimize the
implementation for such a use case. Instead, the implementation is
optimized for a few (one!) weak reference per object.
2024-02-02 14:49:09 +01:00
..
tests gobject: track GWeakRef in object's WeakRefData with an array 2024-02-02 14:49:09 +01:00
gatomicarray.c GAtomicArray: Ensure metadata does not misalign the payload 2023-01-29 12:36:06 +00:00
gatomicarray.h GAtomicArray: Ensure metadata does not misalign the payload 2023-01-29 12:36:06 +00:00
gbinding.c Remove all nicks and blurbs from param specs 2023-11-29 13:41:34 +00:00
gbinding.h docs: Move the GBinding SECTION 2023-10-16 23:34:04 +01:00
gbindinggroup.c Remove all nicks and blurbs from param specs 2023-11-29 13:41:34 +00:00
gbindinggroup.h docs: Move the GBindingGroup SECTION 2023-10-16 23:34:20 +01:00
gboxed.c Add boxed GType for GRand 2023-12-31 09:09:48 +00:00
gboxed.h Rename all visibility macros 2022-10-13 20:53:56 -04:00
gclosure.c GType: introduce GTYPE_TO_POINTER/GPOINTER_TO_TYPE 2023-10-25 12:01:02 +01:00
gclosure.h docs: Move the GClosure SECTION 2023-10-16 23:35:05 +01:00
genums.c docs: Move enum type documentation to Markdown 2023-10-11 14:01:29 +01:00
genums.h genums: use g_once_init_enter_pointer for GType initializers 2024-01-15 17:32:11 -08:00
glib-enumtypes.c.template gobject: use g_once_init_enter_pointer for GType initializers 2023-10-04 14:50:54 +01:00
glib-enumtypes.h.template Revert "meson: Use gnome.mkenum_simple()" 2022-11-24 12:06:10 +00:00
glib-genmarshal.in Replace all uses of G_VA_COPY with Standard C va_copy 2022-10-26 18:07:55 +01:00
glib-mkenums.in mkenums: Allow , in a character literal 2023-11-21 11:54:42 +00:00
glib-types.h Add boxed GType for GRand 2023-12-31 09:09:48 +00:00
gmarshal.c Replace all uses of G_VA_COPY with Standard C va_copy 2022-10-26 18:07:55 +01:00
gmarshal.h Rename all visibility macros 2022-10-13 20:53:56 -04:00
gobject_gdb.py gobject_gdb.py: Do not break bt on optimized build 2023-12-12 17:30:01 +00:00
gobject_probes.d Add missing semicolons to gobject_probes.d 2012-10-15 19:48:44 -04:00
gobject_trace.h Add SPDX license headers for LGPL-2.1-or-later to various files 2022-06-01 12:44:23 +01:00
gobject-autocleanups.h Ignore autocleanups when generating introspection data 2023-10-23 10:25:30 +01:00
gobject-query.c Merge branch 'more-spdx' into 'main' 2022-07-05 11:06:49 +00:00
gobject.c gobject: track GWeakRef in object's WeakRefData with an array 2024-02-02 14:49:09 +01:00
gobject.h docs: Move the GObject SECTION 2023-10-16 23:34:24 +01:00
gobject.rc.in meson: build Windows resource files 2018-01-04 22:19:30 +01:00
gobject.stp.in stp: add code comment to gobject.object_unref about object being dangling 2023-12-30 00:20:17 +01:00
gobjectnotifyqueue.c Replace most GObject warnings with criticals 2022-08-09 13:18:47 -05:00
gparam.c Add destructor for GParamSpecPool 2023-12-19 18:41:02 +00:00
gparam.h Add destructor for GParamSpecPool 2023-12-19 18:41:02 +00:00
gparamspecs.c GType: introduce GTYPE_TO_POINTER/GPOINTER_TO_TYPE 2023-10-25 12:01:02 +01:00
gparamspecs.h Rename all visibility macros 2022-10-13 20:53:56 -04:00
gsignal.c gsignal.c: drop an optimization that is undefined behaviour 2024-01-05 16:46:29 -08:00
gsignal.h gsignal: fix reference to signals documentation page 2023-12-15 21:03:42 +01:00
gsignalgroup.c Remove all nicks and blurbs from param specs 2023-11-29 13:41:34 +00:00
gsignalgroup.h docs: Move the GSignalGroup SECTION 2023-10-16 23:34:44 +01:00
gsourceclosure.c gobject: use g_once_init_enter_pointer for GType initializers 2023-10-04 14:50:54 +01:00
gsourceclosure.h Rename all visibility macros 2022-10-13 20:53:56 -04:00
gtype-private.h Merge branch 'more-spdx' into 'main' 2022-07-05 11:06:49 +00:00
gtype.c Change GType print placeholders to G_GUINTPTR_FORMAT 2023-10-25 12:01:02 +01:00
gtype.h GType: introduce GTYPE_TO_POINTER/GPOINTER_TO_TYPE 2023-10-25 12:01:02 +01:00
gtypemodule.c gtypemodule: Add assertions in finalize() 2023-12-21 18:25:36 +01:00
gtypemodule.h docs: Move the GTypeModule SECTION 2023-10-16 23:34:59 +01:00
gtypeplugin.c gobject: Fix invalid doc links 2023-10-23 11:26:53 +01:00
gtypeplugin.h docs: Move the GTypePlugin SECTION 2023-10-16 23:34:53 +01:00
gvalue.c docs: Move GValue documentation to Markdown 2023-10-11 14:01:29 +01:00
gvalue.h Rename all visibility macros 2022-10-13 20:53:56 -04:00
gvaluearray.c gobject: Fix invalid doc links 2023-10-23 11:26:53 +01:00
gvaluearray.h docs: Move the GValueArray SECTION 2023-10-16 23:34:39 +01:00
gvaluecollector.h docs: Move the value collection documentation to Markdown 2023-10-23 13:18:13 +01:00
gvaluetransform.c Add SPDX license headers for LGPL-2.1-or-later to various files 2022-06-01 12:44:23 +01:00
gvaluetypes.c gvalue: add g_value_steal_string() 2023-11-04 10:40:30 +00:00
gvaluetypes.h gvalue: add g_value_steal_string() 2023-11-04 10:40:30 +00:00
libgobject-gdb.py.in Rename gdb macros with _gdb suffix to avoid ns clashes 2016-05-23 10:52:10 -04:00
meson.build build: Move gir generation to an introspection folder 2023-12-20 21:35:53 +01:00