Module eviction 

Eviction policies for tiered cache management.

This module contains eviction logic for both L1 (in-memory) and L2 (Redis) caches, using a consistent tan-curve scoring algorithm.

Architecture

┌──────────────────────────────────────────────────────────────┐
│                    Eviction Module                           │
├──────────────────────────────────────────────────────────────┤
│  tan_curve.rs   - Core scoring algorithm                     │
│  └─ TanCurveMemoryPressure: pressure → multiplier            │
│  └─ TanCurvePolicy: recency + frequency + size → score       │
│  └─ CacheEntry: generic entry metadata for scoring           │
├──────────────────────────────────────────────────────────────┤
│  redis.rs       - Redis-specific eviction                    │
│  └─ RedisEvictionManager: proactive eviction before LRU      │
│  └─ RedisMemoryProfile: cached INFO MEMORY to avoid RTT      │
│  └─ Protected prefixes: merkle:*, idx:*                      │
└──────────────────────────────────────────────────────────────┘

L1 Memory Eviction

L1 eviction is handled directly in coordinator/mod.rs using TanCurvePolicy. The coordinator builds CacheEntry from SyncItem and calls select_victims().

L2 Redis Eviction

Redis eviction is proactive - we evict before Redis LRU kicks in to protect infrastructure keys (merkle trees, RediSearch indexes). The RedisEvictionManager tracks key metadata and uses TanCurvePolicy for consistent scoring.

Modules

redis

Proactive Redis eviction manager.

tan_curve