in reply to Re^2: Error: Not enough space
in thread Error: Not enough space

Check return codes from everything that can fail. In particular, see of fork is returning undef. I bet that's your problem, though it's just my intuition.

Replies are listed 'Best First'.
Re^4: Error: Not enough space
by jhazra (Novice) on Jan 05, 2005 at 22:36 UTC
    Yeah, that could be one point where its failing. I have noticed that few times as well. But sometime all forks succeed ( I see 7 processes parent + 6 child in top, which validates that all 6 forks were successful) and then error crops up later.

    Now let me give you what I have found out after doing as you guys suggested. This time I ran the program 4 times and all 4 times fork failed with ENOMEM. But as I say system staus says there is enough RAM + swap available.
    Total Memory-RAM : 8G, 1.6G free
    Swap : 10G, 2.5G free when the error occurs.
    Now parent process takes about 1.6G memory and all child processes also take up same 1.6G memory. Fork failed after 4 child processes were spawned. So logically there is no reason to get an ENOMEM in fork - right? Your thoughs please.
    Here's what I have found : If I keep allocating memory from within a process 

    perl -le 'while () {$a.="x"x(1<<26);}'

    [download]
    , after the allocated memory hits 4G for the process it terminates ( sometimes with malloc failure - Out of memory, sometimes with Segmentation fault)
    So my question is is there any process level limitations (I guess my perl is 32 bit) on how much memory can be allocated ? Also can you guys please point out if there are other things I need to check like ulimit/swap space/ram/no of processes per user/no of open file descriptors/etc/etc to track this error? Also please leave pointers on how to check also.
    Appereciate your help.
[reply]
[d/l]
      Heh :-) I think I found your problem:

      see this link on 4Gb limits /w perl5.6.1/Solaris:

      If you do want to be able to allocate more than 4GB memory inside perl, then you should use the Solaris malloc, since the perl malloc breaks when dealing with more than 2GB of memory. You can do this with

      sh Configure -Uusemymalloc

      Note that this will break binary compatibility with any version that was not compiled with -Uusemymalloc.

      You can test if your perl interpreter was compiled with usemymalloc this flag by doing 

      > perl -V|grep malloc

      [download]
      It should show "usemymalloc=n" if your perl supports more than 4 Gb. If it doesn't, you need to recompile perl or get another binary. I suggest using the most recent stable perl for this (5.8.6 at the moment).

      I'm wondering if you can't get the algorithm to work without taking up more than 4Gb, though. :-)

      "What should it profit a man, if he should win a flame war, yet lose his cool?"
[reply]
[d/l]
        Its my bad, I didnt make it clear I guess..this 4G limit was reached using a test program, NOT the actual program.
        Actual program uses 1.6G or so per process. Please see my prev post details.
[reply]

In Section Seekers of Perl Wisdom