[$] Faster RCUs and lockless memory allocation

Puranjay Mohan shared some of the

work he's been doing recently on improving the
performance of read-copy-update (RCU) at the 2026

Linux
Storage, Filesystem, Memory-Management, and BPF Summit; his talk would have
been nice context to have earlier in the day when Harry Yoo and Alexei
Starovoitov led a session about the

new kmalloc_nolock() function that
allows for lockless allocation from any kernel context, and which interacts with
the RCU subsystem to allow that. This article therefore covers the two sessions
together and in the reverse order, to provide that missing context.