Messages in this thread | | | Date | Thu, 12 Jan 2012 17:08:21 +0100 (CET) | From | Jan Engelhardt <> | Subject | Re: [PATCH] rcu: avoid checking for constant |
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On Thursday 2012-01-12 16:29, Paul E. McKenney wrote:
>On Thu, Jan 12, 2012 at 11:57:10AM +0100, Jan Engelhardt wrote: >> On Thursday 2012-01-12 11:54, Eric Dumazet wrote: >> >> >Le jeudi 12 janvier 2012 à 11:34 +0100, Jan Engelhardt a écrit : >> > >> >> When compiling kernel or module code with -O0, "offset" is no longer >> >> considered a constant, and therefore always triggers the build error >> >> that BUILD_BUG_ON is defined to yield. >> > >> >Why compiling kernel with -O0 is even considered ? >> >> The compile error was observed when trying to compile an out-of-tree >> module with -O0. > >Hmmm... Why not have a glue .c file in your out-of-tree module >that contains function like[...]
Maybe, maybe naah. The kernel relying on gcc's -O2 mode to do constant value analysis through and into inline functions does not sound too great. The compiler could change on the next moonphase. In fact, one can't use clang -O2 because of this. With my patch, one can again use clang -O2 [with respect to kfree_rcu]. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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