LSFMMBPF proposal [MM]: Lazy RCU memory reclaim

[Joel Fernandes <joel@joelfernandes.org>]

Title: Lazy RCU memory reclaim: Design, mainlining and next steps

Description:
Lazy RCU is a new technique introducing multi-second delays in RCU memory
reclaim, done to save power on Android and ChromeOS.

This talk is to describe the internals of how this works, and issues
encountered. We will also discuss the mainlining of the patches, and future
work. It is desired to also garner more interest in the -mm community and
spread awareness of this work, including future work:

 * Delaying reclaim for other flavors of RCU (such as SRCU).

 * Possible integration of delayed free'ing into the slab (FreeBSD does this
   for their equivalent of RCU, for instance).

 * Development of tooling to monitor RCU activity (BPF or otherwise).

 * Any positive or negative effects on usecases we should know about (per-VMA
   locks, BPF etc).


thanks,

 - Joel