Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933276AbbDUT5F (ORCPT ); Tue, 21 Apr 2015 15:57:05 -0400 Received: from e33.co.us.ibm.com ([32.97.110.151]:43337 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933106AbbDUT4E (ORCPT ); Tue, 21 Apr 2015 15:56:04 -0400 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@kernel.org, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 11/12] rcu: Make RCU able to tolerate undefined CONFIG_RCU_FANOUT_LEAF Date: Tue, 21 Apr 2015 12:55:52 -0700 Message-Id: <1429646153-20677-11-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.1.5 In-Reply-To: <1429646153-20677-1-git-send-email-paulmck@linux.vnet.ibm.com> References: <20150421195529.GA17864@linux.vnet.ibm.com> <1429646153-20677-1-git-send-email-paulmck@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15042119-0009-0000-0000-00000A4456AC Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4563 Lines: 114 From: "Paul E. McKenney" 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 Signed-off-by: Paul E. McKenney --- init/Kconfig | 2 +- kernel/rcu/tree.c | 8 ++++---- kernel/rcu/tree.h | 12 +++++++++++- kernel/rcu/tree_plugin.h | 6 +++--- 4 files changed, 19 insertions(+), 9 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index efb098ac159d..17285e8e555d 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -601,7 +601,7 @@ config RCU_FANOUT_LEAF int "Tree-based hierarchical RCU leaf-level fanout value" range 2 64 if 64BIT range 2 32 if !64BIT - depends on TREE_RCU || PREEMPT_RCU + depends on (TREE_RCU || PREEMPT_RCU) && RCU_EXPERT default 64 if 64BIT default 32 if !64BIT default 16 diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 6fb8e2f0ec19..0a6d46df2194 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -120,8 +120,8 @@ 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; /* Number of rcu_nodes at specified level. */ @@ -4071,7 +4071,7 @@ 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", @@ -4097,7 +4097,7 @@ static void __init rcu_init_geometry(void) */ if (nr_cpu_ids > rcu_capacity[RCU_NUM_LVLS - 1]) panic("rcu_init_geometry: rcu_capacity[] is too small"); - else if (rcu_fanout_leaf < CONFIG_RCU_FANOUT_LEAF || + else if (rcu_fanout_leaf < RCU_FANOUT_LEAF || rcu_fanout_leaf > sizeof(unsigned long) * 8) { WARN_ON(1); return; diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index ecb259273139..da9f6adb5ff9 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -46,7 +46,17 @@ # 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 2e52502bfc95..a2f64e4fdb57 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -86,10 +86,10 @@ static void __init rcu_bootup_announce_oddness(void) pr_info("\tAdditional per-CPU info printed with stalls.\n"); if (RCU_NUM_LVLS >= 4) pr_info("\tFour(or more)-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); -- 1.8.1.5 -- 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/