[YARN-9269] Minor cleanup in FpgaResourceAllocator

• Type: Sub-task
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 3.3.0
• Hadoop Flags: Reviewed
• Assignee: Peter Bacsko
• Reporter: Peter Bacsko
• Created: 01/Feb/19 12:28
• Updated: 27/Mar/19 17:34
• Resolved: 27/Mar/19 17:11

Description

Some stuff that we observed:

• addFpga() - we check for duplicate devices, but we don't print any error/warning if there's any.
• findMatchedFpga() should be called findMatchingFpga(). Also, is this method even needed? We already receive an FpgaDevice instance in updateFpga() which I believe is the same that we're looking up.
• variable IPIDpreference is confusing
• availableFpga / usedFpgaByRequestor are instances of LinkedHashMap. What's the rationale behind this? Doesn't a simple HashMap suffice?
• usedFpgaByRequestor should be renamed, naming is a bit unclear
• allowedFpgas should be an immutable list
• @VisibleForTesting methods should be package private
• get rid of * imports