Last year we were migrating part of YouTube's serving to a new system and we were observing unexplainable high tail latency. It was eventually attributed to mlo

Last year we were migrating part of YouTube's serving to a new system and we were observing unexplainable high tail latency. It was eventually attributed to mlock()ing some mmap()ed files, which ended up freezing the whole process for significant amounts of time. Be weary of powerful abstractions.