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    rcu: move PREEMPT_RCU config option back under PREEMPT · 21bbb39c
    Paul E. McKenney 提交于
    The original preemptible-RCU patch put the choice between classic and
    preemptible RCU into kernel/Kconfig.preempt, which resulted in build failures
    on machines not supporting CONFIG_PREEMPT.  This choice was therefore moved to
    init/Kconfig, which worked, but placed the choice between classic and
    preemptible RCU at the top level, a very obtuse choice indeed.
    
    This patch changes from the Kconfig "choice" mechanism to a pair of booleans,
    only one of which (CONFIG_PREEMPT_RCU) is user-visible, and is located in
    kernel/Kconfig.preempt, where one would expect it to be.  The other
    (CONFIG_CLASSIC_RCU) is in init/Kconfig so that it is available to all
    architectures, hopefully avoiding build breakage.  Thanks to Roman Zippel for
    suggesting this approach.
    Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>
    Cc: Ingo Molnar <mingo@elte.hu>
    Acked-by: NSteven Rostedt <rostedt@goodmis.org>
    Cc: Dipankar Sarma <dipankar@in.ibm.com>
    Cc: Josh Triplett <josh@freedesktop.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
    Cc: Roman Zippel <zippel@linux-m68k.org>
    Cc: Sam Ravnborg <sam@ravnborg.org>
    Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
    21bbb39c
Kconfig 27.8 KB