abernal's blog

Objectives

• Know how to use entries in
  • /proc/sys/vm
• Decipher
  • /proc/meminfo
• Use vmstat
  • To display information about memory, paging, I/O, processor, activity, and processes memory consumption
• Understand
  • How the OOM-Killer decides when to take action and selects which processes should be exterminated to open up some memory

Memory Tuning considerations

Objectives

• Explain the importance of I/O scheduling
• Understand how Completely Fair Queue and Deadline algorithms work

I/O Scheduling

It is the interface between the generic block layer and the low-level physical device. Both Virtual Memory and Virtual File system layers submit I/O request to block devices, its the job of the I/O scheduling layer to prioritize and order these requests before they are given to the block devices.

Any I/O scheduling system has to satisfy certain conflicting requirements: