[LU-3966] Submit quota lock improvement patches upstream

• Type: Technical task
• Resolution: Fixed
• Priority: Major
• Affects Version/s: Lustre 2.4.0, Lustre 2.5.0
• Labels: kernel
• Assignee: Niu Yawei (Inactive)
• Reporter: Andreas Dilger

Description

The quota-replace-dqptr-sem and quota-avoid-dqget-calls patches are applied to the core kernel to improve the locking of quota structures in the VFS. Since quota is enabled by default for 2.4.0 and later kernels, this has a significant performance impact on all systems (see LU-2442).

These patches should be submitted upstream so that we don't need to patch the kernel to get this improvement. Some performance tests should be run to show some benefit to a non-Lustre workload (e.g. multi-threaded IO with quota enabled, maybe dbench or iozone or fio) and these results should be included with the upstream submission.

Issue Links

• is related to: LU-2442 metadata performance degradation on current master