[LU-238] add procfs tunable to enable/disable lockless direct I/O

• Type: Improvement
• Resolution: Won't Fix
• Priority: Minor
• Fix Version/s: Lustre 2.1.0
• Affects Version/s: Lustre 2.0.0
• Bugzilla ID: 24,201

Epic

directio lockless

• Assignee: Lai Siyao
• Reporter: Lai Siyao

Description

Currently lockless direct I/O is disabled by default, and can be enabled with mount option 'nolock'. Add procfs tunable to enable/disable lockless direct I/O.