[LU-13909] release invalid dentries proactively on client

• Type: Bug
• Resolution: Fixed
• Priority: Minor
• Fix Version/s: Lustre 2.14.0
• Affects Version/s: Lustre 2.10.0, Lustre 2.12.0, Lustre 2.13.0
• Severity: 3
• Assignee: Lai Siyao
• Reporter: Lai Siyao

Description

When file LOOKUP lock is canceled on client, its dentry becomes invalid, but this dentry is not released immediately, and is only marked "invalid" and is left in dcache and let system to reclaim when memory is tight. And it's the same for negative dentries when parent UPDATE is canceled.

Such dentries should be released to avoid OOM on client.

Issue Links

• is related to: LU-14408 very large lustre_inode_cache
• is related to: LU-13970 add an option to disable inode cache on Lustre client
• is related to: LU-12313 Mark lustre_inode_cache as reclaimable

Comments

[Gerrit Updater]

"Etienne AUJAMES <[e-mail]>" uploaded a new patch: https://review.whamcloud.com/c/fs/lustre-release/+/55835
Subject: LU-13909 llite: prune invalid dentries
Project: fs/lustre-release
Branch: b2_12
Current Patch Set: 1
Commit: b9559275e2b23ec2f481d153c1b38be6491da93a

[Peter Jones]

Landed for 2.14

[Gerrit Updater]

Oleg Drokin ([e-mail]) merged in patch https://review.whamcloud.com/39735/
Subject: LU-13909 tests: get lustre_inode_cache count from sysfs
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: dc08f71bf98a2e126750b7d1e6d2c3dd63d1edc2

[Gerrit Updater]

Oleg Drokin ([e-mail]) merged in patch https://review.whamcloud.com/39685/
Subject: LU-13909 llite: prune invalid dentries
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: 1f0b2a0dca6a3296791584770bb0062d1b969c51

[Andreas Dilger]

I noticed that the behaviour of the lustre_inode_cache is quite different between 2.12 and master. On 2.12 it is merged with signal_cache and ptlrpc_cache and the /sys/kernel/slab/lustre_inode_cache/objects count varies widely during operation (e.g. hundreds of objects variance), but on master it gets its own slab and always shows only a small number of objects in the cache.

This seems to be a result of different flags on the slab at creation time, probably due to patch https://review.whamcloud.com/35790 "LU-12313 llite: Mark lustre_inode_cache as reclaimable".

[Gerrit Updater]

Andreas Dilger ([e-mail]) uploaded a new patch: https://review.whamcloud.com/39735
Subject: LU-13909 tests: get lustre_inode_cache count from sysfs
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: f45b51d8867acdf898ccb18dde58236476dbf74b

[Gerrit Updater]

Lai Siyao ([e-mail]) uploaded a new patch: https://review.whamcloud.com/39685
Subject: LU-13909 llite: prune invalid dentries
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: c59960cba56903ccbd3824f01c31a9cf31e66105