PLAB is promotion-local allocation buffer. TLAB is thread-local allocation buffer. I think there's just a tpyo in the post. During GC phases, threads can use

PLAB is promotion-local allocation buffer. TLAB is thread-local allocation buffer. I think there's just a tpyo in the post. During GC phases, threads can use PLABs to reduce need for synchronisation while scanning TLABs.