DM-PCACHE is a high throughput, low-latency DAX read/write cache . This persistent memory cache can be used in front of slower block devices and according to its developer faster than the likes of BCache and DM-Writecache:
The DeviceMapper code for Linux 6.18 also includes a REQ_PREFLUSH optimization for the dm-linear target, the dm-integrity target supporting the async hash interface for better performance, and various other changes.
More details on the now-merged DM changes for Linux 6.18 via this pull request .