install_unbound_pwq
ctx->pwq_tbl[cpu] = install_unbound_pwq(ctx->wq, cpu,
ctx->dfl_pwq = install_unbound_pwq(ctx->wq, -1, ctx->dfl_pwq);
old_pwq = install_unbound_pwq(wq, cpu, pwq);
old_pwq = install_unbound_pwq(wq, cpu, pwq);