Messages in this thread | | | Date | Tue, 3 May 2022 14:33:22 +0100 | From | Mark Rutland <> | Subject | Re: [PATCH 10/21] context_tracking: Take idle eqs entrypoints over RCU |
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On Tue, May 03, 2022 at 01:42:25PM +0200, Frederic Weisbecker wrote: > On Tue, May 03, 2022 at 12:02:51PM +0100, Mark Rutland wrote: > > Hi Frederic, > > > > On Tue, May 03, 2022 at 12:00:40PM +0200, Frederic Weisbecker wrote: > > > The RCU dynticks counter is going to be merged into the context tracking > > > subsystem. Start with moving the idle extended quiescent states > > > entrypoints to context tracking. For now those are dumb redirections to > > > existing RCU calls. > > > > I was a bit confused looking at this, because that redirection only exists for > > CONFIG_CONTEXT_TRACKING, and is empty otherwise. > > > > I see this patch makes TREE_RCU select CONTEXT_TRACKING, which means that > > works. Since that also means building the rest of the context tracking code, I > > think it'd be worth mentioning that in the commit message. > > Not exactly, it only builds a minimal version of CONTEXT_TRACKING, which maps > to roughly the vanilla RCU-idle code. > > The user tracking part (which is the vanilla CONTEXT_TRACKING) now becomes > CONFIG_CONTEXT_TRACKING_USER
Ah, sorry. That makes sense to me now!
> > Do all architectures which can use TREE_RCU today already support context > > tracking? If not, do those work by default? > > No need to, the old context tracking becomes CONFIG_CONTEXT_TRACKING_USER > which is not needed by TREE_RCU. > > Ok you're right, this is all very confusing :o) > > Let's clarify this, I'm going to do the following on the next version: > > * The current CONFIG_CONTEXT_TRACKING becomes CONFIG_CONTEXT_TRACKING_USER. > This part needs support from the architecture. > > * The RCU-idle functions that have been moved to context tracking will become > CONFIG_CONTEXT_TRACKING_IDLE. This part doesn't need support from the > architecture and will be set by TREE_RCU. > > Would that look clearer?
I think so, yes!
It would also help if the prior commit message could be explicit about the end result: After the Kconfig rework both CONFIG_CONTEXT_TRACKING_USER and CONFIG_CONTEXT_TRACKING exist, but CONFIG_CONTEXT_TRACKING will only used to decide whether to build object files with common context tracking logic.
Thanks, Mark.
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