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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-04-20 14:27:43 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-05-27 12:59:05 -0700 |
| commit | 05c5df31afd1092ca6322094d22aff6351fa67fe (patch) | |
| tree | dffce93d8da097a4701bfdafe4c23323371cd899 /kernel/rcu/tree.h | |
| parent | 8739c5cb0fb145aeed8c56ddb5ba79381c74cb97 (diff) | |
| download | linux-stable-05c5df31afd1092ca6322094d22aff6351fa67fe.tar.gz linux-stable-05c5df31afd1092ca6322094d22aff6351fa67fe.tar.bz2 linux-stable-05c5df31afd1092ca6322094d22aff6351fa67fe.zip | |
rcu: Make RCU able to tolerate undefined CONFIG_RCU_FANOUT
This commit introduces an RCU_FANOUT C-preprocessor macro so that RCU will
build even when CONFIG_RCU_FANOUT is undefined. The RCU_FANOUT macro is
set to the value of CONFIG_RCU_FANOUT when defined, otherwise it is set
to 32 for 32-bit systems and 64 for 64-bit systems. This commit then
makes CONFIG_RCU_FANOUT depend on CONFIG_RCU_EXPERT, so that Kconfig
users won't be asked about CONFIG_RCU_FANOUT unless they want to be.
Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Pranith Kumar <bobby.prani@gmail.com>
Diffstat (limited to 'kernel/rcu/tree.h')
| -rw-r--r-- | kernel/rcu/tree.h | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index a69d3dab2ec4..ac3020fff028 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -35,11 +35,23 @@ * In practice, this did work well going from three levels to four. * Of course, your mileage may vary. */ + #define MAX_RCU_LVLS 4 + +#ifdef CONFIG_RCU_FANOUT +#define RCU_FANOUT CONFIG_RCU_FANOUT +#else /* #ifdef CONFIG_RCU_FANOUT */ +# ifdef CONFIG_64BIT +# define RCU_FANOUT 64 +# else +# define RCU_FANOUT 32 +# endif +#endif /* #else #ifdef CONFIG_RCU_FANOUT */ + #define RCU_FANOUT_1 (CONFIG_RCU_FANOUT_LEAF) -#define RCU_FANOUT_2 (RCU_FANOUT_1 * CONFIG_RCU_FANOUT) -#define RCU_FANOUT_3 (RCU_FANOUT_2 * CONFIG_RCU_FANOUT) -#define RCU_FANOUT_4 (RCU_FANOUT_3 * CONFIG_RCU_FANOUT) +#define RCU_FANOUT_2 (RCU_FANOUT_1 * RCU_FANOUT) +#define RCU_FANOUT_3 (RCU_FANOUT_2 * RCU_FANOUT) +#define RCU_FANOUT_4 (RCU_FANOUT_3 * RCU_FANOUT) #if NR_CPUS <= RCU_FANOUT_1 # define RCU_NUM_LVLS 1 |