Le 09/04/2012 23:27, Walter Bright a écrit :
On 4/9/2012 11:30 AM, deadalnix wrote:
In the other hand, TLS can be collected independently and only
influence the
thread that own the data. Both are every powerfull improvement, and
the design
you propose « as this » cannot provide any mean to handle that. Which
is a big
missed opportunity, and will be hard to change in the future.
I think this is an orthogonal issue.
You mean an allocator/deallocator one ?
I'm not sure. For instance, concurrent shared memory scanning will
require some magic on reference changes (it can be hooked into the
program using page protection). In such a case, you have constraint in
what the scanning function can do or can't.
If the function is scanning immutable data, such a constraint disappears.
In a similar way, when scanning TLS, you'll want to avoid going into non
TLS world. This is currently possible only of you go back to main GC
code and trigger the indirect call every single time you encounter a
pointer or a reference. This is going to be a performance killer on many
architecture.
So this code, in a way or another will need to be aware of the
qualifier. Or it will either require to pass every single
pointer/reference into an indirect function call, or forget about
optimizations that the type system has been made to allow (in the
program in general, not especially in the GC).
