[LU-16696] Lustre memcg oom workaround for unpatched kernels

• Type: Improvement
• Resolution: Duplicate
• Priority: Minor
• Assignee: Shaun Tancheff
• Reporter: Shaun Tancheff

Description

Lustre buffered I/O does not work well with restrictive memcg memory settings.

This is partially to do unstable_page_accounting() not providing the expected counts and
balance_dirty_pages_ratelimited() not throttling.

However the memcg also needs to be adjusted when min, low and high are left to the defaults (0, 0, and PAGE_COUNTER_MAX respectively). min and low at 0 disables too much of the memcg reclaim that also would provided the throttling needed.

NOTE: This not a lustre specific issue.

Issue Links

• duplicates: LU-16680 add lowmem sync feature
• is related to: LU-16697 Lustre should set appropriate BDI_CAP_* and s_iflags for writeback and cgroup wb
• is related to: LU-16713 Writeback and commit pages under memory pressure to avoid OOM