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-rw-r--r--init/Kconfig1
-rw-r--r--kernel/rcutree.c17
-rw-r--r--kernel/rcutree.h2
3 files changed, 18 insertions, 2 deletions
diff --git a/init/Kconfig b/init/Kconfig
index 9d3a788..2d9b831 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -431,6 +431,7 @@ choice
config TREE_RCU
bool "Tree-based hierarchical RCU"
depends on !PREEMPT && SMP
+ select IRQ_WORK
help
This option selects the RCU implementation that is
designed for very large SMP system with hundreds or
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 16ea679..b61d20c 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1613,6 +1613,14 @@ static int __noreturn rcu_gp_kthread(void *arg)
}
}
+static void rsp_wakeup(struct irq_work *work)
+{
+ struct rcu_state *rsp = container_of(work, struct rcu_state, wakeup_work);
+
+ /* Wake up rcu_gp_kthread() to start the grace period. */
+ wake_up(&rsp->gp_wq);
+}
+
/*
* Start a new RCU grace period if warranted, re-initializing the hierarchy
* in preparation for detecting the next grace period. The caller must hold
@@ -1637,8 +1645,12 @@ rcu_start_gp_advanced(struct rcu_state *rsp, struct rcu_node *rnp,
}
rsp->gp_flags = RCU_GP_FLAG_INIT;
- /* Wake up rcu_gp_kthread() to start the grace period. */
- wake_up(&rsp->gp_wq);
+ /*
+ * We can't do wakeups while holding the rnp->lock, as that
+ * could cause possible deadlocks with the rq->lock. Deter
+ * the wakeup to interrupt context.
+ */
+ irq_work_queue(&rsp->wakeup_work);
}
/*
@@ -3235,6 +3247,7 @@ static void __init rcu_init_one(struct rcu_state *rsp,
rsp->rda = rda;
init_waitqueue_head(&rsp->gp_wq);
+ init_irq_work(&rsp->wakeup_work, rsp_wakeup);
rnp = rsp->level[rcu_num_lvls - 1];
for_each_possible_cpu(i) {
while (i > rnp->grphi)
diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index da77a8f..4df5034 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -27,6 +27,7 @@
#include <linux/threads.h>
#include <linux/cpumask.h>
#include <linux/seqlock.h>
+#include <linux/irq_work.h>
/*
* Define shape of hierarchy based on NR_CPUS, CONFIG_RCU_FANOUT, and
@@ -442,6 +443,7 @@ struct rcu_state {
char *name; /* Name of structure. */
char abbr; /* Abbreviated name. */
struct list_head flavors; /* List of RCU flavors. */
+ struct irq_work wakeup_work; /* Postponed wakeups */
};
/* Values for rcu_state structure's gp_flags field. */
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