Re: PATCH: two slab-like memory allocators

On Thu, Dec 1, 2016 at 1:26 PM, Tomas Vondra <tomas(dot)vondra(at)2ndquadrant(dot)com>
wrote:

>
>
> Dne 11/27/2016 v 11:02 PM Andres Freund napsal(a):
>
>> On 2016-11-27 22:21:49 +0100, Petr Jelinek wrote:
>>
>>> On 27/11/16 21:47, Andres Freund wrote:
>>>
>>>> Hi,
>>>>
>>>> +typedef struct SlabBlockData *SlabBlock; /* forward
>>>>>> reference */
>>>>>> +typedef struct SlabChunkData *SlabChunk;
>>>>>>
>>>>>> Can we please not continue hiding pointers behind typedefs? It's a bad
>>>>>> pattern, and that it's fairly widely used isn't a good excuse to
>>>>>> introduce further usages of it.
>>>>>>
>>>>>>
>>>>> Why is it a bad pattern?
>>>>>
>>>>
>>>> It hides what is passed by reference, and what by value, and it makes it
>>>> a guessing game whether you need -> or . since you don't know whether
>>>> it's a pointer or the actual object. All to save a * in parameter and
>>>> variable declaration?...
>>>>
>>>>
>>> FWIW I don't like that pattern either although it's used in many
>>> parts of our code-base.
>>>
>>
>> But relatively few new ones, most of it is pretty old.
>>
>>
> I do agree it's not particularly pretty pattern, but in this case it's
> fairly isolated in the mmgr sources, and I quite value the consistency in
> this part of the code (i.e. that aset.c, slab.c and generation.c all use
> the same approach). So I haven't changed this.
>
> The attached v7 fixes the off-by-one error in slab.c, causing failures in
> test_decoding isolation tests, and renames Gen to Generation, as proposed
> by Petr.
>

Moved to next CF with same status (needs review).

Regards,
Hari Babu
Fujitsu Australia