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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2009-08-27 14:58:16 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-08-29 15:34:39 +0200 |
| commit | dd5d19bafd90d33043a4a14b2e2d98612caa293c (patch) | |
| tree | c21d547124d277f00332bdb01c75f2f4f321de8c /kernel/rcutree.c | |
| parent | 06e799764eb7c2e4640888d438c3524d756613e1 (diff) | |
| download | linux-dd5d19bafd90d33043a4a14b2e2d98612caa293c.tar.gz linux-dd5d19bafd90d33043a4a14b2e2d98612caa293c.tar.bz2 linux-dd5d19bafd90d33043a4a14b2e2d98612caa293c.zip | |
rcu: Create rcutree plugins to handle hotplug CPU for multi-level trees
When offlining CPUs from a multi-level tree, there is the
possibility of offlining the last CPU from a given node when
there are preempted RCU read-side critical sections that
started life on one of the CPUs on that node.
In this case, the corresponding tasks will be enqueued via the
task_struct's rcu_node_entry list_head onto one of the
rcu_node's blocked_tasks[] lists. These tasks need to be moved
somewhere else so that they will prevent the current grace
period from ending. That somewhere is the root rcu_node.
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: <20090827215816.GA30472@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/rcutree.c')
| -rw-r--r-- | kernel/rcutree.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c index fee6316a8673..d903e2f2b840 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -81,6 +81,7 @@ struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh_state); DEFINE_PER_CPU(struct rcu_data, rcu_bh_data); extern long rcu_batches_completed_sched(void); +static struct rcu_node *rcu_get_root(struct rcu_state *rsp); 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); @@ -876,6 +877,7 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) spin_unlock(&rnp->lock); /* irqs remain disabled. */ break; } + rcu_preempt_offline_tasks(rsp, rnp); mask = rnp->grpmask; spin_unlock(&rnp->lock); /* irqs remain disabled. */ rnp = rnp->parent; |