Re: Proposal: block-based vector allocator

[Dmitry Antipov]

On 06/01/2012 01:16 AM, Stefan Monnier wrote:

> > -  return (p == m->start&&  m->type == MEM_TYPE_VECTORLIKE);
> > +  if (m->type == MEM_TYPE_VECTORLIKE)
> > +    {
> > +      if (m->end - m->start == VECTOR_BLOCK_BYTES)
>
> Please just use a new MEM_TYPE, so we don't need to worry about the
> possibility of having a non-vector-block which just happens to have the
> same size as a vector-block.

I don't understand this. Any block-allocated vector P0 has the size less than
or equal to VECTOR_BLOCK_BYTES. So, mem_find (P0) will always return mem_node
M0 where M0->end - M0->start == VECTOR_BLOCK_BYTES (IOW, such a mem_node always
corresponds to a vector block). If P1's size is greater than VECTOR_BLOCK_BYTES,
including the case when it's equal to sizeof (vector_block), mem_find (P1) will
always return it's own corresponding node M1 where P1 is equal to M1->start and
M1->end - M1->start is never equal to VECTOR_BLOCK_BYTES.

Dmitry