Just some background - the solution/benchmark spawned from an index lookup latency issue. In our search engine, we generate enormous b-tree indexes and store th

Just some background - the solution/benchmark spawned from an index lookup latency issue. In our search engine, we generate enormous b-tree indexes and store them in memory (rsync from master then mmap). After adding more logic, intersects, and unions the search engine started to miss SLA. Eventually, we traced the problem back to the additional latency in the vmalloc code path. The get_free_page* API code path had much lower latency and llds was born (llds uses k*alloc which is a wrapper around GFP). Additional use cases where llds is being used is in low-energy compute environments (like SeaMicro machines) where every CPU cycle is expensive due to increased hardware latency.