3D die-stacking has enabled energy-efficient solutions for near data processing by integrating multiple dice of high-density memory layers and processor cores within the same package. One promising approach is to employ the in-package memory as a gigascale last-level cache for data-intensive computing. Most existing in-package cache controllers rely on the command scheduling policies borrowed from the off-chip DRAM system. Regrettably, these control policies are not specifically tailored for in-package cache traffics, which results in a limited bandwidth efficiency. This paper proposes ReTagger, a DRAM cache controller that employs repeated tags to alleviate the cost of DRAM row buffer misses. Our simulation results on a set of ten data-intensive applications indicate an average of 20% performance improvement for the proposed controller over the state-of-the-art DRAM caches.