Messages in this thread | | | Date | Fri, 19 Jul 2013 18:29:04 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH 1/3] nohz: Kconfig: remove redundant 64-bit dependency |
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On Wed, Jul 03, 2013 at 11:36:39AM -0700, Kevin Hilman wrote: > The current 64-bit dependency is on VIRT_CPU_ACCOUNTING_GEN, which already > has its own dependency on 64-bit. Remove it from NO_HZ_FULL.
It's not exactly redundant. It's a necessary dependency inheritance. When we select NO_HZ_FULL, TICK_CPU_ACCOUNTING and VIRT_CPU_ACCOUNTING_NATIVE disappear such that only VIRT_CPU_ACCOUNTING_GEN can be selected. But if we don't have CONFIG_64bits, then VIRT_CPU_ACCOUNTING_GEN is not possible either. So we end up with nothing for the accounting (or whatever random reaction from Kconfig against that situation) and that's a bug. So we need to inherit the 64 bits dependency on NO_HZ_FULL to prevent that.
We can remove this dependency from NO_HZ_FULL, but only once we remove it from VIRT_CPU_ACCOUNTING_GEN, not the other way around otherwise this breaks bisection.
> > Cc: Frederic Weisbecker <fweisbec@gmail.com> > Signed-off-by: Kevin Hilman <khilman@linaro.org> > --- > kernel/time/Kconfig | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/kernel/time/Kconfig b/kernel/time/Kconfig > index 70f27e8..b78760f 100644 > --- a/kernel/time/Kconfig > +++ b/kernel/time/Kconfig > @@ -99,8 +99,6 @@ config NO_HZ_FULL > depends on SMP > # RCU_USER_QS dependency > depends on HAVE_CONTEXT_TRACKING > - # VIRT_CPU_ACCOUNTING_GEN dependency > - depends on 64BIT > select NO_HZ_COMMON > select RCU_USER_QS > select RCU_NOCB_CPU > -- > 1.8.3 >
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