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Message-Id: <1435700910-9104-1-git-send-email-paulmck@linux.vnet.ibm.com>
Date: Tue, 30 Jun 2015 14:48:26 -0700
From: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To: linux-kernel@...r.kernel.org
Cc: mingo@...nel.org, laijs@...fujitsu.com, dipankar@...ibm.com,
akpm@...ux-foundation.org, mathieu.desnoyers@...icios.com,
josh@...htriplett.org, tglx@...utronix.de, peterz@...radead.org,
rostedt@...dmis.org, dhowells@...hat.com, edumazet@...gle.com,
dvhart@...ux.intel.com, fweisbec@...il.com, oleg@...hat.com,
bobby.prani@...il.com,
"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: [PATCH RFC tip/core/rcu 1/5] rcu: Prepare for expedited GP driving normal GP
From: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
This is a pure code-movement commit in preparation for changes that
allow short-circuiting of normal grace-period processing due to
concurrent execution of an expedited grace period.
Signed-off-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
---
kernel/rcu/tree.c | 108 +++++++++++++++++++++++++++---------------------------
1 file changed, 54 insertions(+), 54 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 041968e3b7ce..bea9b9c80d91 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1393,6 +1393,60 @@ void rcu_cpu_stall_reset(void)
WRITE_ONCE(rsp->jiffies_stall, jiffies + ULONG_MAX / 2);
}
+/* Adjust sequence number for start of update-side operation. */
+static void rcu_seq_start(unsigned long *sp)
+{
+ WRITE_ONCE(*sp, *sp + 1);
+ smp_mb(); /* Ensure update-side operation after counter increment. */
+ WARN_ON_ONCE(!(*sp & 0x1));
+}
+
+/* Adjust sequence number for end of update-side operation. */
+static void rcu_seq_end(unsigned long *sp)
+{
+ smp_mb(); /* Ensure update-side operation before counter increment. */
+ WRITE_ONCE(*sp, *sp + 1);
+ WARN_ON_ONCE(*sp & 0x1);
+}
+
+/* Take a snapshot of the update side's sequence number. */
+static unsigned long rcu_seq_snap(unsigned long *sp)
+{
+ unsigned long s;
+
+ smp_mb(); /* Caller's modifications seen first by other CPUs. */
+ s = (READ_ONCE(*sp) + 3) & ~0x1;
+ smp_mb(); /* Above access must not bleed into critical section. */
+ return s;
+}
+
+/*
+ * Given a snapshot from rcu_seq_snap(), determine whether or not a
+ * full update-side operation has occurred.
+ */
+static bool rcu_seq_done(unsigned long *sp, unsigned long s)
+{
+ return ULONG_CMP_GE(READ_ONCE(*sp), s);
+}
+
+/* Wrapper functions for expedited grace periods. */
+static void rcu_exp_gp_seq_start(struct rcu_state *rsp)
+{
+ rcu_seq_start(&rsp->expedited_sequence);
+}
+static void rcu_exp_gp_seq_end(struct rcu_state *rsp)
+{
+ rcu_seq_end(&rsp->expedited_sequence);
+}
+static unsigned long rcu_exp_gp_seq_snap(struct rcu_state *rsp)
+{
+ return rcu_seq_snap(&rsp->expedited_sequence);
+}
+static bool rcu_exp_gp_seq_done(struct rcu_state *rsp, unsigned long s)
+{
+ return rcu_seq_done(&rsp->expedited_sequence, s);
+}
+
/*
* Initialize the specified rcu_data structure's default callback list
* to empty. The default callback list is the one that is not used by
@@ -3307,60 +3361,6 @@ void cond_synchronize_sched(unsigned long oldstate)
}
EXPORT_SYMBOL_GPL(cond_synchronize_sched);
-/* Adjust sequence number for start of update-side operation. */
-static void rcu_seq_start(unsigned long *sp)
-{
- WRITE_ONCE(*sp, *sp + 1);
- smp_mb(); /* Ensure update-side operation after counter increment. */
- WARN_ON_ONCE(!(*sp & 0x1));
-}
-
-/* Adjust sequence number for end of update-side operation. */
-static void rcu_seq_end(unsigned long *sp)
-{
- smp_mb(); /* Ensure update-side operation before counter increment. */
- WRITE_ONCE(*sp, *sp + 1);
- WARN_ON_ONCE(*sp & 0x1);
-}
-
-/* Take a snapshot of the update side's sequence number. */
-static unsigned long rcu_seq_snap(unsigned long *sp)
-{
- unsigned long s;
-
- smp_mb(); /* Caller's modifications seen first by other CPUs. */
- s = (READ_ONCE(*sp) + 3) & ~0x1;
- smp_mb(); /* Above access must not bleed into critical section. */
- return s;
-}
-
-/*
- * Given a snapshot from rcu_seq_snap(), determine whether or not a
- * full update-side operation has occurred.
- */
-static bool rcu_seq_done(unsigned long *sp, unsigned long s)
-{
- return ULONG_CMP_GE(READ_ONCE(*sp), s);
-}
-
-/* Wrapper functions for expedited grace periods. */
-static void rcu_exp_gp_seq_start(struct rcu_state *rsp)
-{
- rcu_seq_start(&rsp->expedited_sequence);
-}
-static void rcu_exp_gp_seq_end(struct rcu_state *rsp)
-{
- rcu_seq_end(&rsp->expedited_sequence);
-}
-static unsigned long rcu_exp_gp_seq_snap(struct rcu_state *rsp)
-{
- return rcu_seq_snap(&rsp->expedited_sequence);
-}
-static bool rcu_exp_gp_seq_done(struct rcu_state *rsp, unsigned long s)
-{
- return rcu_seq_done(&rsp->expedited_sequence, s);
-}
-
/* Common code for synchronize_{rcu,sched}_expedited() work-done checking. */
static bool sync_exp_work_done(struct rcu_state *rsp, struct rcu_node *rnp,
atomic_long_t *stat, unsigned long s)
--
1.8.1.5
--
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