Meta Developing Compressed RAM "CRAM" For Linux: Better Than ZRAM & Zswap

With today's memory shortages, high prices, and ever increasing memory capacity needs, Meta engineers have been working on Compressed RAM "CRAM" for Linux. This hardware-offloaded compression still allows cacheline/byte access to compressed memory and in turn a better implementation than the likes of ZRAM and Zswap. Very promising is that there is near-native performance to raw DRAM speeds with CRAM.

Gregory Price of Meta presented yesterday at the Linux Plumbers Conference in Prague on Compressed RAM for Linux. Most of the individual pieces needed to support CRAM are already mainline. For end-users that may already be relying on the likes of Zswap or ZRAM, CRAM is offering near-native DRAM speeds.

Read-only data is shown to be as fast as the raw DRAM performance.

And for memory writes, CRAM is much faster than ZRAM or Zswap or plain swap.

Very impressive results for CRAM especially given the significant need today for maximizing Linux memory capacity. We'll see where this work leads and hopefully will all be upstreamed in the not too distant future.

Those wishing to learn more about Compressed RAM from LPC 2026 can see the session information here.