Problem

The eviction-disable counter mixes a non-atomic increment under a lock with a lock-free atomic decrement on the off-path. The mismatch can lose an update and leave a tree permanently eviction-disabled.

Proposed work

• Make the increment and decrement use a compatible atomicity model while preserving the lock-free decrement’s deadlock-avoidance requirement.

• Add a stress test that exercises concurrent eviction disable/enable transitions and verifies the counter returns to the expected value.