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Re: extend dl-minimal malloc implementation


On 08/17/2017 09:34 AM, H.J. Lu wrote:
> On Thu, Aug 17, 2017 at 6:10 AM, Zack Weinberg <zackw@panix.com> wrote:
>> On Thu, Aug 17, 2017 at 2:41 AM, Andreas Schwab <schwab@suse.de> wrote:
>>> On Aug 16 2017, Zack Weinberg <zackw@panix.com> wrote:
>>>
>>>> What I was trying to suggest, earlier, was that *before* either (a) or
>>>> (b) we should go through the entire of ld.so and try to *remove* as
>>>> many allocations as possible, at which point it might make sense not
>>>> to have malloc in there at all - "just" send all remaining allocations
>>>> directly to mmap (not sbrk; leave sbrk for the "real" malloc).  That
>>>> may take rearchitecting - but so may just converting alloca to malloc,
>>>> as you point out. I admit I have no idea whether this is even
>>>> feasible.
>>>
>>> You still need something on top of mmap, unless you want to waste a lot
>>> of memory.
>>
>> _Do_ we, though?  Why does ld.so need to make any allocations at all
>> above and beyond mapping in the libraries?  It's an open question as
>> far as I'm concerned.
> 
> Do we know how many calls to free within ld.so before the regular free
> takes over?
 
Yes, DJ had data on this because he tracked it with the new dl-minimal.c
changes he was working on...

DJ?

-- 
Cheers,
Carlos.


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