[$] The problem of unnecessary readahead

The final session in the memory-management track of the 2025 Linux Storage,
Filesystem, Memory-Management, and BPF Summit was a brief, last-minute
addition run by Kalesh Singh. The kernel's readahead mechanism is
generally good for performance; it ensures that data is present by the time
an application gets around to asking for it. Sometimes, though, readahead
can go a little too far.