Re: [Xenomai-help] ENXIO error with large shared memory

["Henry Bausley" <hbausley@domain.hid>]

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ftruncate returns 0
  ----- Original Message ----- 
  From: Henry Bausley 
  To: xenomai@xenomai.org
  Sent: Monday, March 16, 2009 3:08 PM
  Subject: [Xenomai-help] ENXIO error with large shared memory


  I am trying to map a large shared memory buffer and cannot seem to map 32M.
  I get the error code ENXIO back from the posix skin mmap.

  The code works for
    ftruncate(prgshmfd, 16777216);
    pPrgShm = mmap(NULL, 16777216, PROT_READ | PROT_WRITE, MAP_SHARED, prgshmfd, 0);
  but fails if I have
    ftruncate(prgshmfd, 16777216*2);
    pPrgShm = mmap(NULL, 16777216*2, PROT_READ | PROT_WRITE, MAP_SHARED, prgshmfd, 0);


  The condition failing is mmap in xenomai/skins/posix/shm.c. 

   if (!shm->addr || off + len > shm->size) 
          {
     err = ENXIO;
     up(&shm->maplock);
     goto err_free_map;
   }


  For  16M
  len = 0x1000000 and shm->size = 0x1000000

  For 32M
  len = 0x2000000 and shm->size = 0x1FFF000

  Is there something I didn't configure correctly that is limiting my size?


  I am currently using 2.4.6 Xenomai, I-pipe 2.2-07 with kernel 2.6.26-denx on a 1Ghz PowerPC 460EX with 2G RAM


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