48B ... tinySubPagePools head smallSubpagePools 480B 496B l1 16B 32B qInit,q00,q25,q50,q75,q100 ... 2K 1K head 4K ln l1 l1 l1 l2 512B q00[1%,50%) q25[25%,75%) qInit[min,25%) q50[50%,100%) q75[75%,100%) l2 q100[100%,max) PoolArena l1 l1 ... ln l1