On 9/23/13 10:01 AM, deadalnix wrote:
On Sunday, 22 September 2013 at 23:49:56 UTC, Andrei Alexandrescu wrote:
Hello,
First of all, awesome !
Now the meeeeh part.
I really think the it thing is not good. I don't think it is desirable
or necessary. We should get rid of it.
The singleton allocator "it" is instrumental for supporting stateful and
stateless allocators with ease. It took me a few iterations to get to
that, and I'm very pleased with the results. I think it would be
difficult to improve on it without making other parts more difficult.
You can't deal with ubyte[] like that, that is incorrect in regard to -
unimplemented - aliasing rules. Allocator should deal with void[] .
I think I'll do that.
What you call safe really isn't. Allocate something on the GC, store a
pointer on a custom allocated location, collect, enjoy the memory
corruption.
I don't understand this. There are no pointers at this level, only
untyped memory. The main chance of corruption is to access something
after it's been freed.
All operation are safe according to your proposal.
No, for most allocators freeing and reallocating are unsafe.
Allocation can only be safe if the GRAND MASTER GC is aware of it.
I don't think so.
You proposal allocate shared memory.
No. It allocates unshared memory off of a shared or unshared allocator.
The memory just allocated is as of yet unshared for the simple reason
that only one thread has as of yet access to it.
This is common in C/C++ world as
memory is shared by default, but shouldn't be in D. It is highly
desirable to allocate with different methods for different type
qualifier. How does your design adapt to that ?
The typed allocators will have distinct methods for shared and unshared
allocation. Even at this level it's possible to design an allocator that
allocates in different ways with a shared vs. an unshared allocator
object (overload on shared). So far I've only designed non-shared
allocators, or wrap those that are already shared (malloc and new).
Finally, we got to decide how these basics block are used to form typed
allocators, and interact with language constructs.
Sure. Again: I describe the Otto cycle and you discuss how to paint the
road.
Andrei
