filterHealthy() allocated 2 slices (available + backups) per call.
filterHealthyAndExclude() allocated 3 (adds excludeSet map).
IPHash allocated fnv.New64a() object per call.
All triggered on every request's LB selection.
Changes:
- Add filterContext struct holding reusable buffers, managed by sync.Pool
- Replace filterHealthy → filterInto (writes into pooled buffers)
- Replace filterHealthyAndExclude → filterIntoExcluding (pooled buffers)
- Add inline fnvHash64a() to avoid fnv.New64a() heap allocation
- Update all 6 balancer algorithms (RoundRobin, WeightedRoundRobin,
LeastConnections, IPHash, Random, ConsistentHash) to use pooled
filterContext via acquire/release pattern
- ConsistentHash.SelectExcludingByKey also uses pool for targetSet
- Remove buildExcludeSet (merged into filterIntoExcluding)
Result: allocs/op reduced from 2-3 to 0-1 on all LB Select paths.
xfy
c6e7091089