title: Am I increasing shared memory correctly for GNURadio?
body: <p>I'm working with GNURadio, and working with stream tags (using stream tagging to create a burst transmitter), but my flowgraph won't run with around ~200 stream tags, citing error below.</p>
  
  <pre><code>gr::vmcircbuf_sysv_shm: shmget (1): Invalid argument
  gr::vmcircbuf_sysv_shm: shmget (1): Invalid argument
  gr::vmcircbuf_sysv_shm: shmget (1): Invalid argument
  gr::buffer::allocate_buffer: failed to allocate buffer of size 1250000 KB
  gr::vmcircbuf_sysv_shm: shmget (1): Invalid argument
  gr::vmcircbuf_sysv_shm: shmget (1): Invalid argument
  gr::vmcircbuf_sysv_shm: shmget (1): Invalid argument
  gr::buffer::allocate_buffer: failed to allocate buffer of size 1250000 KB
  terminate called after throwing an instance of 'std::bad_alloc'
    what():  std::bad_alloc
  Aborted (core dumped)
  </code></pre>
  
  <p>However, sysctl --all | grep shm outputs</p>
  
  <pre><code>kernel.shm_next_id = -1
  kernel.shm_rmid_forced = 0
  kernel.shmall = 32147483648
  kernel.shmmax = 32147483648
  kernel.shmmni = 16777216
  </code></pre>
  
  <p>This means I should have 32 GB in shared memory, correct? I set kernel.shmall and shmmax via </p>
  
  <pre><code>sudo sysctl kernel.shmall=32147483648
  sudo sysctl kernel.shmmax=32147483648
  </code></pre>
  
  <p>The only thing that concerns me is cat /proc/meminfo | grep shmem returns</p>
  
  <pre><code>Shmem:             42556 kB
  </code></pre>
  
  <p>Is there a better way to increase shared memory?</p>