Messages in this thread |  | | Date | Tue, 23 Jun 2009 11:48:46 +0200 | From | Ingo Molnar <> | Subject | Re: [PATCH] v4 RCU: the bloatwatch edition |
| |
* Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:
> On Mon, Jun 22, 2009 at 09:30:29AM -0700, Darren Hart wrote: > > Paul E. McKenney wrote: > >> On Mon, Jun 22, 2009 at 08:29:41AM -0700, Andrew Morton wrote: > >>> On Mon, 22 Jun 2009 14:49:51 +0200 Ingo Molnar <mingo@elte.hu> wrote: > >>> > >>>> * David Howells <dhowells@redhat.com> wrote: > >>>> > >>>>> Hi Paul, > >>>>> > >>>>> Are you going to push your RCU patch for this merge window? > >>>> Andrew needs to be convinced for that to happen. > >>>> > >>> whome? I rarely have firm opinions on anything. iirc the question > >>> here was "is it worth adding another RCU implementation to save 900 > >>> bytes"? > >>> > >>> I find it pretty hard to see how to come up with "yes" for that one but > >>> it's hardly a huge issue. If you guys feel otherwise then go wild. > >> Well, I do need to pull the "expedited" interface into the bloatwatch > >> version, and my update of rcutorture made me realize that I can cut > >> out a few more bytes, so I will submit an update. For what it is worth, > >> here are the opinions expressed on LKML: > >> + Ingo Molnar: good documentation, minimal RCU implementation. > >> ? Andi Kleen: will there be !SMP systems in the future? > >> + Lennert Buytenhek: there will be !SMP ARM for a long time. > >> + Paul Mundt: good idea for more-constrained SH platforms. > >> + David Howells: Acked-by. works on FRV board. > >> ? Andrew Morton: do we really need another RCU implementation? > >> Of course, I well remember programming systems with 4K of core memory > >> back in the 1970s, and therefore feel a bit guilty about sticking deep > >> embedded platforms with the increase in memory footprint represented > >> by Hierarchical RCU compared to Classic RCU. And Bloatwatch RCU is much > >> smaller and easier to understand/maintain than is Classic RCU. > >> So, again, I will forward port, optimize, test, and resubmit. > > > > IIRC, in previous threads on this topic, the Bloatwatch edition was > > expected to replace Classic RCU. If so, wouldn't that address Andrew's > > concern of "adding" another implementation? > > Andrew expressed a preference for dropping Classic RCU without > adding Bloatwatch RCU. ;-)
Yes. In Linux there's no forced 'tie-in' of features and we'll brutally untie them and use the most productive combination, if justified technically ;-)
Ingo
|  |