|
* we were basing the glib allocators on throwing std::bad_alloc just like
the C++ operators. However, this always was unsafe since we were throwing
exceptions across plain-C frames (Glib).
Also, the memory vtable has been deprecated in Glib, resulting in
ugly warnings.
* Instead, we now let the C++ new/delete operators work like Glib
by basing them on g_malloc/g_slice.
This means they will assert and the application will terminate
abnormally in case of OOM. OOMs cannot be handled properly anyway, so it is
more important to have a good memory limiting mechanism.
* Memory limiting has been completely revised.
Instead of approximating undo stack sizes using virtual methods
(which is unprecise and comes with a performance penalty),
we now use a common base class SciTECO::Object to count the memory
required by all objects allocated within SciTECO.
This is less precise than using global replacement new/deletes
which would allow us to control allocations in all C++ code including
Scintilla, but they are only supported as of C++14 (GCC 5) and adding compile-time
checks would be cumbersome.
In any case, we're missing Glib allocations (esp. strings).
* As a platform-specific extension, on Linux/glibc we use mallinfo()
to count the exact memory usage of the process.
On Windows, we use GetProcessMemoryInfo() -- the latter implementation
is currently UNTESTED.
* We use g_malloc() for new/delete operators when there is
malloc_trim() since g_slice does not free heap chunks properly
(probably does its own mmap()ing), rendering malloc_trim() ineffective.
We've also benchmarked g_slice on Linux/glib (malloc_trim() shouldn't
be available elsewhere) and found that it brings no significant
performance benefit.
On all other platforms, we use g_slice since it is assumed
that it at least does not hurt.
The new g_slice based allocators should be tested on MSVCRT
since I assume that they bring a significant performance benefit
on Windows.
* Memory limiting does now work in batch mode as well and is still
enabled by default.
* The old UndoTokenWithSize CRTP hack could be removed.
UndoStack operations should be a bit faster now.
But on the other hand, there will be an overhead due to repeated
memory limit checking on every processed character.
|
