Sean Kelly has begun to post enablement patches for CXL (Compute eXpress Link), a new interconnect layered over PCI designed for point-to-point attachment of workload accelerators, as well as expansion memories. CXL is similar to specs such as CCIX, CAPI and NV-Link. It has the weight of Intel behind it and is expected to gain traction.
Linux uses a “page cache” structure to keep copies of filesystem data in memory. When you open a file or edit a document, underlying reads and writes to and from secondary storage go via the page cache to improve performance by keeping recently used data around. Matthew Wilcox posted “Large pages in the page cache” which aims to reduce the number of “pages” that need to be tracked by not requiring specific sizes, aiming to improve performance.
Rajat Jain posted a request for comments on “Restrict the untrusted devices, to bind to only a set of ‘whitelisted’ drivers”. The idea is to respond to increasing DMA (direct memory access) attacks being enabled by USB/Thunderbolt ports that enable malicious users to attach PCI devices to laptops. The proposal was rebuffed by Greg Kroah-Hartman, who said there are already kernel interfaces that allow for automatic binding of drivers to devices to be restricted.