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authorIngo Molnar2012-06-11 10:30:23 +0200
committerIngo Molnar2012-06-11 10:30:23 +0200
commit4a1e001d2bb75c47a9cdbbfb66ae51daff1ddcba (patch)
tree6d6e968a087b7a26b3a04af1ef94149607b64358 /include
parenteab309494ae2b9e15f85520f00de3893162c2e43 (diff)
parentaa9b16306e3243229580ff889cc59fd66bf77973 (diff)
Merge branch 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/urgent
Merge RCU fixes from Paul E. McKenney: " This series has four patches, the major point of which is to eliminate some slowdowns (including boot-time slowdowns) resulting from some RCU_FAST_NO_HZ changes. The issue with the changes is that posting timers from the idle loop has no effect if the CPU has entered dyntick-idle mode because the CPU has already computed its wakeup time, and posting a timer does not cause it to be recomputed. The short-term fix is for RCU to precompute the timeout value so that the CPU's calculation is correct. " Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/rcutiny.h6
-rw-r--r--include/linux/rcutree.h2
-rw-r--r--include/trace/events/rcu.h1
3 files changed, 6 insertions, 3 deletions
diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
index adb5e5a38cae..854dc4c5c271 100644
--- a/include/linux/rcutiny.h
+++ b/include/linux/rcutiny.h
@@ -87,8 +87,9 @@ static inline void kfree_call_rcu(struct rcu_head *head,
#ifdef CONFIG_TINY_RCU
-static inline int rcu_needs_cpu(int cpu)
+static inline int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies)
{
+ *delta_jiffies = ULONG_MAX;
return 0;
}
@@ -96,8 +97,9 @@ static inline int rcu_needs_cpu(int cpu)
int rcu_preempt_needs_cpu(void);
-static inline int rcu_needs_cpu(int cpu)
+static inline int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies)
{
+ *delta_jiffies = ULONG_MAX;
return rcu_preempt_needs_cpu();
}
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index 3c6083cde4fc..952b79339304 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -32,7 +32,7 @@
extern void rcu_init(void);
extern void rcu_note_context_switch(int cpu);
-extern int rcu_needs_cpu(int cpu);
+extern int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies);
extern void rcu_cpu_stall_reset(void);
/*
diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h
index 1480900c511c..d274734b2aa4 100644
--- a/include/trace/events/rcu.h
+++ b/include/trace/events/rcu.h
@@ -289,6 +289,7 @@ TRACE_EVENT(rcu_dyntick,
* "In holdoff": Nothing to do, holding off after unsuccessful attempt.
* "Begin holdoff": Attempt failed, don't retry until next jiffy.
* "Dyntick with callbacks": Entering dyntick-idle despite callbacks.
+ * "Dyntick with lazy callbacks": Entering dyntick-idle w/lazy callbacks.
* "More callbacks": Still more callbacks, try again to clear them out.
* "Callbacks drained": All callbacks processed, off to dyntick idle!
* "Timer": Timer fired to cause CPU to continue processing callbacks.