From 33f76148ced0e0618062e302d2a9614efdbd4a06 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 24 Aug 2009 09:42:01 -0700 Subject: [PATCH] rcu: Add CPU-offline processing for single-node configurations Add preemptable-RCU plugin to handle the CPU-offline processing. An additional plugin is forthcoming to handle multinode RCU trees, but this current plugin works for configurations up to 32 CPUs (64 CPUs for 64-bit kernels). Signed-off-by: Paul E. McKenney Cc: laijs@cn.fujitsu.com Cc: dipankar@in.ibm.com Cc: akpm@linux-foundation.org Cc: mathieu.desnoyers@polymtl.ca Cc: josht@linux.vnet.ibm.com Cc: dvhltc@us.ibm.com Cc: niv@us.ibm.com Cc: peterz@infradead.org Cc: rostedt@goodmis.org LKML-Reference: <12511321213336-git-send-email-> Signed-off-by: Ingo Molnar --- kernel/rcutree.c | 2 ++ kernel/rcutree_plugin.h | 24 ++++++++++++++++++++++++ 2 files changed, 26 insertions(+) diff --git a/kernel/rcutree.c b/kernel/rcutree.c index cc025571407..000b0760987 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -84,6 +84,7 @@ extern long rcu_batches_completed_sched(void); static void cpu_quiet_msk(unsigned long mask, struct rcu_state *rsp, struct rcu_node *rnp, unsigned long flags); static void cpu_quiet_msk_finish(struct rcu_state *rsp, unsigned long flags); +static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp); static void __rcu_process_callbacks(struct rcu_state *rsp, struct rcu_data *rdp); static void __call_rcu(struct rcu_head *head, @@ -920,6 +921,7 @@ static void rcu_offline_cpu(int cpu) { __rcu_offline_cpu(cpu, &rcu_sched_state); __rcu_offline_cpu(cpu, &rcu_bh_state); + rcu_preempt_offline_cpu(cpu); } #else /* #ifdef CONFIG_HOTPLUG_CPU */ diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index cd2ab67400c..201334cdc20 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -259,6 +259,18 @@ static int rcu_preempted_readers(struct rcu_node *rnp) return !list_empty(&rnp->blocked_tasks[rnp->gpnum & 0x1]); } +#ifdef CONFIG_HOTPLUG_CPU + +/* + * Do CPU-offline processing for preemptable RCU. + */ +static void rcu_preempt_offline_cpu(int cpu) +{ + __rcu_offline_cpu(cpu, &rcu_preempt_state); +} + +#endif /* #ifdef CONFIG_HOTPLUG_CPU */ + /* * Check for a quiescent state from the current CPU. When a task blocks, * the task is recorded in the corresponding CPU's rcu_node structure, @@ -395,6 +407,18 @@ static int rcu_preempted_readers(struct rcu_node *rnp) return 0; } +#ifdef CONFIG_HOTPLUG_CPU + +/* + * Because preemptable RCU does not exist, it never needs CPU-offline + * processing. + */ +static void rcu_preempt_offline_cpu(int cpu) +{ +} + +#endif /* #ifdef CONFIG_HOTPLUG_CPU */ + /* * Because preemptable RCU does not exist, it never has any callbacks * to check. -- 2.39.5