Re: StringNg review: MemBlob

On Tue, Oct 19, 2010 at 4:35 PM, Alex Rousskov
<rousskov_at_measurement-factory.com> wrote:
> On 10/19/2010 08:08 AM, Kinkie wrote:
>>
>> On Mon, Oct 18, 2010 at 7:56 PM, Alex Rousskov wrote:
>>
>>> Once MemBlob is committed, please consider re-integrating it with memory
>>> pools. This is the biggest remaining XXX, IMO.
>>
>> I've checked and confirmed why MemPools integration was disabled: it's
>> due to an inherent asymmetry in memAllocString/memFreeString: if
>> mempools are not initialized, memAllocString will happily allocate the
>> string using xcalloc. When the time comes to deallocate such strings,
>> it will fail to find a pool to dealloc from and fail an assertion.
>>
>> The only way I can think of to cleanly resolve this is quite
>> disruptive, as it means making MemPools a proper singleton obect to
>> make sure they are initialized before being used: it's a complex
>> project on its own which I'd list as a dependency before integrating
>> MemPools back in.
>
> What happens if you call Mem::Init() from memAllocString()? I am sure a few
> things will need to be fixed (e.g., Mem::Init() should exit if called
> twice), but it does not sound disruptive to me.

Tried that, using a string-pool as singleton-like initialization
indicator. There are some prerequisites to be called in turn. I have
not investigated further; I can investigate further if you wish.

>
>
>> IMVHO body pipelining should go through SBuf, not MemBlob, but that's
>> for body pipelining to work out.
>
> Currently, MemBlob's append-only design prevents efficient message body
> pipelining. Since SBuf relies on MemBlob, SBuf inherits the same problem
> (and adds more problems due to poor used area tracking). We will need to
> decide whether to enhance MemBlob/SBuf to improve pipelining support or
> switch to a pipeline that uses a "bunch of buffers" instead of a single one.
> This is a topic for another thread though.

Yes. Unfortunately I don't understand what is the use case you have in mind :(
My original thought was to use SBuf's append/consume pair for this.

Thanks again!

-- 
    /kinkie