[$] How to cope with hardware-poisoned page-cache pages

"Hardware poisoning" is a mechanism for detecting and handling memoryerrors in a running system. When a particular range of memory ceases toremember correctly, it is "poisoned" and further accesses to it willgenerate errors. The kernel has had support forhardware poisoning for over a decade, but that doesn't mean it can't beimproved. At the 2022 Linux Storage,Filesystem, Memory-management and BPF Summit, Yang Shi discussed thechallenges of dealing with hardware poisoning when it affects memory usedfor the page cache.