[v25.3.x] cluster/namespaced_cache: stop eviction loop when no entries are evictable#30015
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piyushredpanda merged 1 commit intoMar 31, 2026
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…table When all entries in the cache are pinned (unevictable), the eviction loop in insert() would repeatedly scan the entire LRU list up to _size times, resulting in O(n^2) behavior. With 9000+ producers this causes reactor stalls of 400ms+. Fix by checking the return value of evict() in the loop condition so the loop exits immediately when no evictable entry is found. CORE-15947 (cherry picked from commit 4a4cc90)
piyushredpanda
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Mar 31, 2026
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Backport of PR #29991