On Tue, 27 Oct 2009 19:41:24 -0400, dsimcha <dsim...@yahoo.com> wrote:
I'm looking at the GC implementation and starting my hacking. I noticed
that
the ends of blocks are already being used in some creative ways in the
sentinel version. This looks like a debugging feature, though I don't
understand it completely. Can one of the original implementors (Walter,
Sean)
explain to me what the heck version(SENTINEL) in gcx.d does at a high
level,
whether it conflicts with storing bit masks for precise heap scanning at
the
ends of memory blocks, and whether we still even need it?
IIRC, the sentinel byte is to prevent pointers from leaking into the next
block.
For example, if you did:
byte[] x = new byte[16]; // GC allocates 16 byte block.
x = x[$..$];
Now, if there is no sentinel byte, the pointer in x points to the *next*
memory block.
It is an interesting problem, there might be a better solution.
-Steve
