What is TLB shootdown

Question

Hello guys,

Can some one explain what is a TLB shootdown in SMPs. I am unable to find much information regarding this concept. Any good example is very much appreciated.

Answer 1

A quick example:

1. you have some memory shared by all of the processors in your system

2. one of your processors restricts access to a page of that shared memory

3. now, all of the processors have to flush their TLBs, so that the ones that aren't allowed to access that page can't do so anymore.

The actions of one processor causing the TLBs to be flushed on other processors is what is called a TLB shootdown.

Answer 2

A TLB (Translation Lookaside Buffer) is a cache of the translations from virtual memory addresses to physical memory addresses. When a processor changes the virtual-to-physical mapping of an address, it needs to tell the other processors to invalidate that mapping in their caches. That processes is called a "TLB shootdown".