Meta proposes CRAM hardware compression for Linux kernel memory management
Meta is developing CRAM, a hardware-offloaded memory compression subsystem for Linux that could offer near-DRAM read performance while outperforming zram and zswap on writes.
Summary
Meta engineers presented CRAM (Compressed RAM) at Linux Plumbers Conference 2026, a proposed Linux kernel memory-management subsystem that uses hardware offload to compress memory. Early results show read-only access approaching raw DRAM speeds, with write performance significantly exceeding zram, zswap, and traditional swap in tested workloads. Kernel development is underway but the feature is not yet upstream-ready.
How CRAM differs from existing compression
- Direct access model: CRAM provides cacheline- and byte-level access to compressed memory without full decompression, unlike zram/zswap which operate on larger blocks
- Hardware offload: Compression and decompression are handled by dedicated hardware rather than CPU-bound software algorithms
- Read performance: Demonstrated read-only access approaching raw DRAM latency and throughput
- Write performance: Substantially outperformed zram, zswap, and conventional swap in Meta's presented workloads
- Kernel status: Memory-management subsystem patches are in development; not yet merged or finalized for upstream Linux
Why it matters
If upstreamed, CRAM could reduce memory pressure in data centers and cloud environments without the latency penalties of software-based compression, though adoption depends on hardware availability beyond Meta's infrastructure.
Original reference: www.linuxtoday.com →