Be aware, that memory obtained with MAP_UNINITIALIZED contains random
garbage, and is not zeroed out by the kernel.

If course it will not affect libast because it zeros the memory any
way, regardless whether it is zeroed already (which is IMO a bug,
memory obtained directly via mmap() are already zeroed - except if
obtained with MAP_UNINITIALIZED and a suitably configured Linux
kernel, so why memset() them with zero again?) or not.

Olga

On Wed, Aug 21, 2013 at 4:44 PM, Glenn Fowler <[email protected]> wrote:
>
> sounds reasonable
>
> On Wed, 21 Aug 2013 16:01:23 +0200 Roland Mainz wrote:
>> Hi!
>
>> ----
>
>> [More or less offtopic]
>> The Linux kernel setting "CONFIG_MMAP_ALLOW_UNINITIALIZED" is a build
>> time switch and not a runtime kernel tuneable, right ?
>
>> Background:
>> I'm looking into Linux/Android optimisations right now and AFAIK
>> libast's allocator could benefit from |mmap()|'ing anon memory using
>> |MAP_UNINITIALIZED| ...
>
>> ----
>
>> Bye,
>> Roland
>
>> --
>>   __ .  . __
>>  (o.\ \/ /.o) [email protected]
>>   \__\/\/__/  MPEG specialist, C&&JAVA&&Sun&&Unix programmer
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>>  (;O/ \/ \O;)
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-- 
      ,   _                                    _   ,
     { \/`o;====-    Olga Kryzhanovska   -====;o`\/ }
.----'-/`-/     [email protected]   \-`\-'----.
 `'-..-| /       http://twitter.com/fleyta     \ |-..-'`
      /\/\     Solaris/BSD//C/C++ programmer   /\/\
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