std.experimental.allocator.make should throw on out-of-memory

Alex Parrill via Digitalmars-d digitalmars-d at puremagic.com
Thu Apr 21 07:39:30 PDT 2016


On Thursday, 21 April 2016 at 13:42:50 UTC, Era Scarecrow wrote:
> On Thursday, 21 April 2016 at 09:15:05 UTC, Thiez wrote:
>> On Thursday, 21 April 2016 at 04:07:52 UTC, Era Scarecrow 
>> wrote:
>>>  I'd say either you specify the amount of retries, or give 
>>> some amount that would be acceptable for some background 
>>> program to retry for. Say, 30 seconds.
>>
>> Would that actually be more helpful than simply printing an 
>> OOM message and shutting down / crashing? Because if the limit 
>> is 30 seconds *per allocation* then successfully allocating, 
>> say, 20 individual objects might take anywhere between 0 
>> seconds and almost (but not *quite*) 10 minutes. In the latter 
>> case the program is still making progress but for the user it 
>> would appear frozen.
>
>  Good point. Maybe having a global threshold of 30 seconds 
> while it waits and retries every 1/2 second.
>
>  In 30 seconds a lot can change. You can get gigabytes of 
> memory freed from other processes and jobs. In the end it 
> really depends on the application. A backup utility that you 
> run overnight gives you 8+ hours to do the backup that probably 
> takes up to 2 hours to actually do. On the other hand no one 
> (sane anyways) wants to wait if they are actively using the 
> application and would prefer it to die quickly and restart it 
> when there's fewer demands on the system.

I'm proposing that make throws an exception if the allocator 
cannot satisfy a request (ie allocate returns null). How the 
allocator tries to allocate is it's own business; if it wants to 
sleep (which I don't believe would be helpful outside of 
specialized cases), make doesn't need to care.

Sleeping would be very bad for certain workloads (you mentioned 
games), so having make itself sleep would be inappropriate.


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