Excerpts from Nicholas Piggin's message of July 13, 2020 2:45 pm: > Excerpts from Andy Lutomirski's message of July 11, 2020 3:04 am: >> Also, as it stands, I can easily see in_irq() ceasing to promise to >> serialize. There are older kernels for which it does not promise to >> serialize. And I have plans to make it stop serializing in the >> nearish future. > > You mean x86's return from interrupt? Sounds fun... you'll konw where to > update the membarrier sync code, at least :) Oh, I should actually say Mathieu recently clarified a return from interrupt doesn't fundamentally need to serialize in order to support membarrier sync core. https://lists.ozlabs.org/pipermail/linuxppc-dev/2020-July/214171.html So you may not need to do anything more if you relaxed it. Thanks, Nick