l = range(int(1E9))

[Cecil Westerhof]

Op Thursday 30 Apr 2015 20:59 CEST schreef Dave Angel:

> On 04/30/2015 02:48 PM, alister wrote:
>> On Thu, 30 Apr 2015 20:23:31 +0200, Gisle Vanem wrote:
>>
>>> Cecil Westerhof wrote:
>>>
>>>> If I execute:
>>>> l = range(int(1E9)
>>>>
>>>> The python process gobbles up all the memory and is killed. The
>>>> problem is that after this my swap is completely used, because
>>>> other processes have swapped to it. This make those programs more
>>>> slowly. Is there a way to circumvent Python claiming all the
>>>> memory?
>>>>
>>>> By the way: this is CPython 2.7.8.
>>>
>>> On what OS? If I try something similar on Win-8.1 and CPython
>>> 2.7.5 (32-bit):
>>>
>>> python -c "for i in range(int(1E9)): pass"
>>> Traceback (most recent call last):
>>> File "<string>", line 1, in <module>
>>> MemoryError
>>>
>>>
>>> --gv
>>
>> also MemoryError on Fedora 21 32 bit
>>
>
> That's presumably because you end up running out of address space
> before you run out of swap space. On a 64 bit system the reverse
> will be true, unless you have a really *really* large swap file
>
> ulimit is your friend if you've got a program that wants to gobble
> up all of swap space.

Yes, my system is openSUSE 64 bit. I really should look into ulimit.
The default is:
    core file size          (blocks, -c) 0
    data seg size           (kbytes, -d) unlimited
    scheduling priority             (-e) 0
    file size               (blocks, -f) unlimited
    pending signals                 (-i) 63768
    max locked memory       (kbytes, -l) 64
    max memory size         (kbytes, -m) unlimited
    open files                      (-n) 1024
    pipe size            (512 bytes, -p) 8
    POSIX message queues     (bytes, -q) 819200
    real-time priority              (-r) 0
    stack size              (kbytes, -s) 8192
    cpu time               (seconds, -t) unlimited
    max user processes              (-u) 63768
    virtual memory          (kbytes, -v) unlimited
    file locks                      (-x) unlimited

That should be fine-tuned.

-- 
Cecil Westerhof
Senior Software Engineer
LinkedIn: http://www.linkedin.com/in/cecilwesterhof