[LU-2924] shrink ldlm_poold workload

• Type: Improvement
• Resolution: Fixed
• Priority: Major
• Fix Version/s: Lustre 2.5.0
• Affects Version/s: Lustre 2.5.0
• Assignee: Oleg Drokin
• Reporter: Oleg Drokin

Description

ldlm_poold wakes every second currently and walk list of all namespaces in the system doing some bookkeeping.
On systems with a lot of servers this client list gets quite large and it makes no sense to visit every namespace in the list if some of them don't actually have any locks.

As such I think it makes sense to only get ldlm_poold to iterate over non-empty client namespaces.
Estimates from Fujitsu indicate that on a system with 2000 OSTs just the list iteration (i.e. empty namespaces) takes 2ms which is probably excessive.

Issue Links

• is related to: LU-5415 High ldlm_poold load on client
• is related to: LU-1376 ldlm_poold noise on clients significantly reduces applification performance
• is related to: LU-1128 Complete investigation of the LDLM pool shrinker and SLV handling