Re: [RFD PATCH 0/3] Use "object index" rather than pointers in the object hashing

On Mon, 16 Apr 2007, Junio C Hamano wrote:

I was thinking about revamping that "keeping track of all
objects" stuff for some time, too, but in a different direction.
Glad I have not touched that area ;-).

Well, I obviously shouldn't have touched it either. I introduced a bug in 
the first patch of the series (and the bug got removed by the third patch, 
but since the third patch was not worth applying yet, it means that 
patches 1 and 2 shouldn't be applied either, because of the bug).

The bug was that when I modified the generic object allocator framework to 
work with "union any_object", it would still do

	static struct name *block;		/* where "name" was "object" */
	...
	return block++;

so while we *allocated* a block of "union any_objects", the patch would 
then end up doling them out as "struct object" (which is *wrong* - we 
don't know which kind of object it is yet, so we need to allocate the 
maximum size!).

So it *should* have been

	static type *block;
	...
	return block++;

but it actually turns out that my timings seem to say that it's better to 
do the memset of the object just before returning it, so I changed it to 
use "xmalloc()" instead of "xcalloc()" for the block allocation, and then 
use

	static type *block;
	void *ret;
	...
	ret = block++;
	memset(ret, 0, sizeof(type));
	return ret;

instead.

I think this makes sense, although the numbers are somewhat
dissapointing.

Well, with just patches 1&2, the numbers don't go down, and the code looks 
cleaner (and it removes more lines than it adds). So let me re-send the 
series, and while I will re-send the final patch#3, only #1/#2 are 
actually meant to be considered for actual inclusion at this point.

		Linus