/proc in Linux

I love /proc directory. because you can find almost work inside a Linux Operating system.
  • nubmer is process_id -> in that directory, you can check process status.
  • ex) How many files opened in specific process (with process-id) ? ‘fd’
  • ex) memory usage detailed ‘mem’ and…

Too many, so find it by yourself via googling 🙂

interrupt and ksoftirqd

In linux, The procedure of interrupts is divided by  The Top half and The Bottom half.

  • Top half
    • mainly transfer data to repository for processing data like calling API with parameter in the programming.
    • on example, network card received packet , and then will trigger proper interrupt after storing packet data at memory somewhere in the NIC.
    • Uninterruptible by OS.
  • Bottom half
    • working .. working ..
    • can be interruptible.
      • ksoftirq calls when bottom half is too long to process queued other interrupts(the top half).
      • You can see that ksoftirqd keep CPU high when the bottom half which run too long time is working .

 

(further) need to explain with kernel source.