[compudj]

I've been in touch with FB. They are interested in using rseq for jemalloc. They have provided prototypes of jemalloc based on rseq, along with benchmarks helping me make the case for rseq mainlining.

I don't know whether Google will ever want to swap from their in house rseq implementation to the upstream Linux rseq, use both ABIs for a transition period, or simply keep using their own in-house rseq.