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| author |   Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-04-21 09:12:13 -0700 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-05-27 12:59:05 -0700 |
| commit | 47d631af58bb9b2f2dd3d0da8c98a79a5e75c738 (patch) | |
| tree | 7472330c70684ac02140d2f3796b042b53a4f6dd /kernel/rcu | |
| parent | rcu: Make RCU able to tolerate undefined CONFIG_RCU_FANOUT (diff) | |
| download | linux-dev-47d631af58bb9b2f2dd3d0da8c98a79a5e75c738.tar.xz linux-dev-47d631af58bb9b2f2dd3d0da8c98a79a5e75c738.zip | |
rcu: Make RCU able to tolerate undefined CONFIG_RCU_FANOUT_LEAF
This commit introduces an RCU_FANOUT_LEAF C-preprocessor macro so
that RCU will build even when CONFIG_RCU_FANOUT_LEAF is undefined.
The RCU_FANOUT_LEAF macro is set to the value of CONFIG_RCU_FANOUT_LEAF
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_LEAF depend
on CONFIG_RCU_EXPERT, so that Kconfig users won't be asked about
CONFIG_RCU_FANOUT_LEAF 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')
| -rw-r--r-- | kernel/rcu/tree.c | 8 | ||||
| -rw-r--r-- | kernel/rcu/tree.h | 12 | ||||
| -rw-r--r-- | kernel/rcu/tree_plugin.h | 6 |
3 files changed, 18 insertions, 8 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index ba3f8d59d948..1edd11298224 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -119,8 +119,8 @@ module_param(dump_tree, bool, 0444); /* Control rcu_node-tree auto-balancing at boot time. */ static bool rcu_fanout_exact; module_param(rcu_fanout_exact, bool, 0444); -/* Increase (but not decrease) the CONFIG_RCU_FANOUT_LEAF at boot time. */ -static int rcu_fanout_leaf = CONFIG_RCU_FANOUT_LEAF; +/* Increase (but not decrease) the RCU_FANOUT_LEAF at boot time. */ +static int rcu_fanout_leaf = RCU_FANOUT_LEAF; module_param(rcu_fanout_leaf, int, 0444); int rcu_num_lvls __read_mostly = RCU_NUM_LVLS; static int num_rcu_lvl[] = { /* Number of rcu_nodes at specified level. */ @@ -4097,7 +4097,7 @@ static void __init rcu_init_geometry(void) jiffies_till_next_fqs = d; /* If the compile-time values are accurate, just leave. */ - if (rcu_fanout_leaf == CONFIG_RCU_FANOUT_LEAF && + if (rcu_fanout_leaf == RCU_FANOUT_LEAF && nr_cpu_ids == NR_CPUS) return; pr_info("RCU: Adjusting geometry for rcu_fanout_leaf=%d, nr_cpu_ids=%d\n", @@ -4121,7 +4121,7 @@ static void __init rcu_init_geometry(void) * the configured number of CPUs. Complain and fall back to the * compile-time values if these limits are exceeded. */ - if (rcu_fanout_leaf < CONFIG_RCU_FANOUT_LEAF || + if (rcu_fanout_leaf < RCU_FANOUT_LEAF || rcu_fanout_leaf > sizeof(unsigned long) * 8 || n > rcu_capacity[MAX_RCU_LVLS]) { WARN_ON(1); diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index ac3020fff028..7d949c186302 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -48,7 +48,17 @@ # endif #endif /* #else #ifdef CONFIG_RCU_FANOUT */ -#define RCU_FANOUT_1 (CONFIG_RCU_FANOUT_LEAF) +#ifdef CONFIG_RCU_FANOUT_LEAF +#define RCU_FANOUT_LEAF CONFIG_RCU_FANOUT_LEAF +#else /* #ifdef CONFIG_RCU_FANOUT_LEAF */ +# ifdef CONFIG_64BIT +# define RCU_FANOUT_LEAF 64 +# else +# define RCU_FANOUT_LEAF 32 +# endif +#endif /* #else #ifdef CONFIG_RCU_FANOUT_LEAF */ + +#define RCU_FANOUT_1 (RCU_FANOUT_LEAF) #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) diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index d7e505970f24..713503853841 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -76,10 +76,10 @@ static void __init rcu_bootup_announce_oddness(void) pr_info("\tAdditional per-CPU info printed with stalls.\n"); if (NUM_RCU_LVL_4 != 0) pr_info("\tFour-level hierarchy is enabled.\n"); - if (CONFIG_RCU_FANOUT_LEAF != 16) + if (RCU_FANOUT_LEAF != 16) pr_info("\tBuild-time adjustment of leaf fanout to %d.\n", - CONFIG_RCU_FANOUT_LEAF); - if (rcu_fanout_leaf != CONFIG_RCU_FANOUT_LEAF) + RCU_FANOUT_LEAF); + if (rcu_fanout_leaf != RCU_FANOUT_LEAF) pr_info("\tBoot-time adjustment of leaf fanout to %d.\n", rcu_fanout_leaf); if (nr_cpu_ids != NR_CPUS) pr_info("\tRCU restricting CPUs from NR_CPUS=%d to nr_cpu_ids=%d.\n", NR_CPUS, nr_cpu_ids); |