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rcu: Add CPU-offline processing for single-node configurations

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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 <paulmck@linux.vnet.ibm.com>
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 <mingo@elte.hu>
This commit is contained in:
Paul E. McKenney 2009-08-24 09:42:01 -07:00 committed by Ingo Molnar
parent 7c614d6461
commit 33f76148ce
2 changed files with 26 additions and 0 deletions
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2
kernel/rcutree.c
View file

@ -84,6 +84,7 @@ extern long rcu_batches_completed_sched(void);
static void cpu_quiet_msk(unsigned long mask, struct rcu_state *rsp, static void cpu_quiet_msk(unsigned long mask, struct rcu_state *rsp,
struct rcu_node *rnp, unsigned long flags); struct rcu_node *rnp, unsigned long flags);
static void cpu_quiet_msk_finish(struct rcu_state *rsp, 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, static void __rcu_process_callbacks(struct rcu_state *rsp,
struct rcu_data *rdp); struct rcu_data *rdp);
static void __call_rcu(struct rcu_head *head, 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_sched_state);
__rcu_offline_cpu(cpu, &rcu_bh_state); __rcu_offline_cpu(cpu, &rcu_bh_state);
rcu_preempt_offline_cpu(cpu);
} }
#else /* #ifdef CONFIG_HOTPLUG_CPU */ #else /* #ifdef CONFIG_HOTPLUG_CPU */

24
kernel/rcutree_plugin.h
View file

@ -259,6 +259,18 @@ static int rcu_preempted_readers(struct rcu_node *rnp)
return !list_empty(&rnp->blocked_tasks[rnp->gpnum & 0x1]); 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, * 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, * 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; 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 * Because preemptable RCU does not exist, it never has any callbacks
* to check. * to check.