Re: [PATCH v3 04/14] commit-graph: implement write_commit_graph()

> Derrick Stolee <stolee@gmail.com> writes:
>
>> +struct packed_oid_list {
>> +	struct object_id **list;
>> +	int nr;
>> +	int alloc;
>> +};
> What is the typical access pattern for this data structure?  If it
> is pretty much "allocate and grow as we find more", then a dynamic
> array of struct (rather than a dynamic array of pointers to struct)
> would be a lot more appropriate.  IOW
>
> 	struct packed_oid_list {
> 		struct object_id *list;
> 		int nr, alloc;
> 	};
>
> The version in the posted patch has to pay malloc overhead plus an
> extra pointer for each object id in the list; unless you often
> replace elements in the list randomly and/or you borrow object ID
> field in other existing data structure whose lifetime is longer than
> this list by pointing at it, I do not see how the extra indirection
> is worth it.
>