From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com,
akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
josh@joshtriplett.org, dvhltc@us.ibm.com, niv@us.ibm.com,
tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org,
Valdis.Kletnieks@vt.edu, dhowells@redhat.com, avi@redhat.com,
mtosatti@redhat.com, torvalds@linux-foundation.org,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH RFC tip/core/rcu 2/3] rcu: Add synchronize_srcu_expedited()
Date: Fri, 9 Oct 2009 15:50:50 -0700 [thread overview]
Message-ID: <12551286514087-git-send-email-> (raw)
In-Reply-To: <20091009224954.GA26516@linux.vnet.ibm.com>
From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This patch creates a synchronize_srcu_expedited() that uses
synchronize_sched_expedited() where synchronize_srcu()
uses synchronize_sched(). The synchronize_srcu() and
synchronize_srcu_expedited() functions become one-liners that pass
synchronize_sched() or synchronize_sched_expedited(), repectively,
to a new __synchronize_srcu() function.
While in the file, move the EXPORT_SYMBOL_GPL()s to immediately
follow the corresponding functions.
Requested-by: Avi Kivity <avi@redhat.com>
Tested-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
include/linux/srcu.h | 1 +
kernel/srcu.c | 74 ++++++++++++++++++++++++++++++++++---------------
2 files changed, 52 insertions(+), 23 deletions(-)
diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index aca0eee..4765d97 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -48,6 +48,7 @@ void cleanup_srcu_struct(struct srcu_struct *sp);
int srcu_read_lock(struct srcu_struct *sp) __acquires(sp);
void srcu_read_unlock(struct srcu_struct *sp, int idx) __releases(sp);
void synchronize_srcu(struct srcu_struct *sp);
+void synchronize_srcu_expedited(struct srcu_struct *sp);
long srcu_batches_completed(struct srcu_struct *sp);
#endif
diff --git a/kernel/srcu.c b/kernel/srcu.c
index b0aeeaf..818d7d9 100644
--- a/kernel/srcu.c
+++ b/kernel/srcu.c
@@ -49,6 +49,7 @@ int init_srcu_struct(struct srcu_struct *sp)
sp->per_cpu_ref = alloc_percpu(struct srcu_struct_array);
return (sp->per_cpu_ref ? 0 : -ENOMEM);
}
+EXPORT_SYMBOL_GPL(init_srcu_struct);
/*
* srcu_readers_active_idx -- returns approximate number of readers
@@ -97,6 +98,7 @@ void cleanup_srcu_struct(struct srcu_struct *sp)
free_percpu(sp->per_cpu_ref);
sp->per_cpu_ref = NULL;
}
+EXPORT_SYMBOL_GPL(cleanup_srcu_struct);
/**
* srcu_read_lock - register a new reader for an SRCU-protected structure.
@@ -118,6 +120,7 @@ int srcu_read_lock(struct srcu_struct *sp)
preempt_enable();
return idx;
}
+EXPORT_SYMBOL_GPL(srcu_read_lock);
/**
* srcu_read_unlock - unregister a old reader from an SRCU-protected structure.
@@ -136,22 +139,12 @@ void srcu_read_unlock(struct srcu_struct *sp, int idx)
per_cpu_ptr(sp->per_cpu_ref, smp_processor_id())->c[idx]--;
preempt_enable();
}
+EXPORT_SYMBOL_GPL(srcu_read_unlock);
-/**
- * synchronize_srcu - wait for prior SRCU read-side critical-section completion
- * @sp: srcu_struct with which to synchronize.
- *
- * Flip the completed counter, and wait for the old count to drain to zero.
- * As with classic RCU, the updater must use some separate means of
- * synchronizing concurrent updates. Can block; must be called from
- * process context.
- *
- * Note that it is illegal to call synchornize_srcu() from the corresponding
- * SRCU read-side critical section; doing so will result in deadlock.
- * However, it is perfectly legal to call synchronize_srcu() on one
- * srcu_struct from some other srcu_struct's read-side critical section.
+/*
+ * Helper function for synchronize_srcu() and synchronize_srcu_expedited().
*/
-void synchronize_srcu(struct srcu_struct *sp)
+void __synchronize_srcu(struct srcu_struct *sp, void (*sync_func)(void))
{
int idx;
@@ -173,7 +166,7 @@ void synchronize_srcu(struct srcu_struct *sp)
return;
}
- synchronize_sched(); /* Force memory barrier on all CPUs. */
+ sync_func(); /* Force memory barrier on all CPUs. */
/*
* The preceding synchronize_sched() ensures that any CPU that
@@ -190,7 +183,7 @@ void synchronize_srcu(struct srcu_struct *sp)
idx = sp->completed & 0x1;
sp->completed++;
- synchronize_sched(); /* Force memory barrier on all CPUs. */
+ sync_func(); /* Force memory barrier on all CPUs. */
/*
* At this point, because of the preceding synchronize_sched(),
@@ -203,7 +196,7 @@ void synchronize_srcu(struct srcu_struct *sp)
while (srcu_readers_active_idx(sp, idx))
schedule_timeout_interruptible(1);
- synchronize_sched(); /* Force memory barrier on all CPUs. */
+ sync_func(); /* Force memory barrier on all CPUs. */
/*
* The preceding synchronize_sched() forces all srcu_read_unlock()
@@ -237,6 +230,47 @@ void synchronize_srcu(struct srcu_struct *sp)
}
/**
+ * synchronize_srcu - wait for prior SRCU read-side critical-section completion
+ * @sp: srcu_struct with which to synchronize.
+ *
+ * Flip the completed counter, and wait for the old count to drain to zero.
+ * As with classic RCU, the updater must use some separate means of
+ * synchronizing concurrent updates. Can block; must be called from
+ * process context.
+ *
+ * Note that it is illegal to call synchronize_srcu() from the corresponding
+ * SRCU read-side critical section; doing so will result in deadlock.
+ * However, it is perfectly legal to call synchronize_srcu() on one
+ * srcu_struct from some other srcu_struct's read-side critical section.
+ */
+void synchronize_srcu(struct srcu_struct *sp)
+{
+ __synchronize_srcu(sp, synchronize_sched);
+}
+EXPORT_SYMBOL_GPL(synchronize_srcu);
+
+/**
+ * synchronize_srcu_expedited - like synchronize_srcu, but less patient
+ * @sp: srcu_struct with which to synchronize.
+ *
+ * Flip the completed counter, and wait for the old count to drain to zero.
+ * As with classic RCU, the updater must use some separate means of
+ * synchronizing concurrent updates. Can block; must be called from
+ * process context.
+ *
+ * Note that it is illegal to call synchronize_srcu_expedited()
+ * from the corresponding SRCU read-side critical section; doing so
+ * will result in deadlock. However, it is perfectly legal to call
+ * synchronize_srcu_expedited() on one srcu_struct from some other
+ * srcu_struct's read-side critical section.
+ */
+void synchronize_srcu_expedited(struct srcu_struct *sp)
+{
+ __synchronize_srcu(sp, synchronize_sched_expedited);
+}
+EXPORT_SYMBOL_GPL(synchronize_srcu_expedited);
+
+/**
* srcu_batches_completed - return batches completed.
* @sp: srcu_struct on which to report batch completion.
*
@@ -248,10 +282,4 @@ long srcu_batches_completed(struct srcu_struct *sp)
{
return sp->completed;
}
-
-EXPORT_SYMBOL_GPL(init_srcu_struct);
-EXPORT_SYMBOL_GPL(cleanup_srcu_struct);
-EXPORT_SYMBOL_GPL(srcu_read_lock);
-EXPORT_SYMBOL_GPL(srcu_read_unlock);
-EXPORT_SYMBOL_GPL(synchronize_srcu);
EXPORT_SYMBOL_GPL(srcu_batches_completed);
--
1.5.2.5
next prev parent reply other threads:[~2009-10-09 22:51 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-09 22:49 [PATCH RFC tip/core/rcu 0/3] Tiny RCU and expedited SRCU Paul E. McKenney
2009-10-09 22:50 ` [PATCH RFC tip/core/rcu 1/3] rcu: The Bloatwatch Edition, v7 Paul E. McKenney
2009-10-12 9:29 ` Lai Jiangshan
2009-10-12 16:40 ` Linus Torvalds
2009-10-12 17:30 ` Paul E. McKenney
2009-10-13 6:05 ` Lai Jiangshan
2009-10-13 7:44 ` Lai Jiangshan
2009-10-13 17:00 ` Paul E. McKenney
2009-10-14 0:37 ` Lai Jiangshan
2009-10-14 1:09 ` Paul E. McKenney
2009-10-14 2:05 ` Lai Jiangshan
2009-10-14 2:49 ` Steven Rostedt
2009-10-27 7:26 ` Lai Jiangshan
2009-10-27 19:56 ` Steven Rostedt
2009-10-14 2:52 ` Paul E. McKenney
2009-10-09 22:50 ` Paul E. McKenney [this message]
2009-10-09 22:50 ` [PATCH RFC tip/core/rcu 3/3] rcu: add synchronize_srcu_expedited() to the rcutorture test suite Paul E. McKenney
2009-10-10 3:47 ` [PATCH RFC tip/core/rcu 0/3] Tiny RCU and expedited SRCU Josh Triplett
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