[PATCH RT 2/4] rcu: Disable RCU_FAST_NO_HZ on RT

[PATCH RT 2/4] rcu: Disable RCU_FAST_NO_HZ on RT

[Steven Rostedt]

[-- Attachment #1: 0002-rcu-Disable-RCU_FAST_NO_HZ-on-RT.patch --]
[-- Type: text/plain, Size: 727 bytes --]

From: Thomas Gleixner <tglx@linutronix.de>

This uses a timer_list timer from the irq disabled guts of the idle
code. Disable it for now to prevent wreckage.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable-rt@vger.kernel.org
---
 init/Kconfig |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/init/Kconfig b/init/Kconfig
index c06208b..87afda5 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -474,7 +474,7 @@ config RCU_FANOUT_EXACT
 
 config RCU_FAST_NO_HZ
 	bool "Accelerate last non-dyntick-idle CPU's grace periods"
-	depends on NO_HZ && SMP
+	depends on NO_HZ && SMP && !PREEMPT_RT_FULL
 	default n
 	help
 	  This option causes RCU to attempt to accelerate grace periods
-- 
1.7.10.4

[PATCH RT 0/4] [ANNOUNCE] 3.2.32-rt49-rc1 stable review

[Steven Rostedt]

Dear RT Folks,

This is the RT stable review cycle of patch 3.2.32-rt49-rc1.

Please scream at me if I messed something up. Please test the patches too.

The -rc release will be uploaded to kernel.org and will be deleted when
the final release is out. This is just a review release (or release candidate).

The pre-releases will not be pushed to the git repository, only the
final release is.

If all goes well, this patch will be converted to the next main release
on 11/2/2012.

Enjoy,

-- Steve


To build 3.2.32-rt49-rc1 directly, the following patches should be applied:

  http://www.kernel.org/pub/linux/kernel/v3.x/linux-3.2.tar.xz

  http://www.kernel.org/pub/linux/kernel/v3.x/patch-3.2.32.xz

  http://www.kernel.org/pub/linux/kernel/projects/rt/3.2/patch-3.2.32-rt49-rc1.patch.xz

You can also build from 3.2.32-rt48 by applying the incremental patch:

http://www.kernel.org/pub/linux/kernel/projects/rt/3.2/incr/patch-3.2.32-rt48-rt49-rc1.patch.xz


Changes from 3.2.32-rt48:

---


Steven Rostedt (1):
      Linux 3.2.32-rt49-rc1

Thomas Gleixner (2):
      rcu: Disable RCU_FAST_NO_HZ on RT
      net: netfilter: Serialize xt_write_recseq sections on RT

Watanabe (1):
      hrtimer: Raise softirq if hrtimer irq stalled

----
 include/linux/locallock.h          |    4 ++++
 include/linux/netfilter/x_tables.h |    7 +++++++
 init/Kconfig                       |    2 +-
 kernel/hrtimer.c                   |    9 ++++-----
 localversion-rt                    |    2 +-
 net/netfilter/core.c               |    6 ++++++
 6 files changed, 23 insertions(+), 7 deletions(-)

[PATCH RT 1/4] hrtimer: Raise softirq if hrtimer irq stalled

[Steven Rostedt]

[-- Attachment #1: 0001-hrtimer-Raise-softirq-if-hrtimer-irq-stalled.patch --]
[-- Type: text/plain, Size: 893 bytes --]

From: Watanabe <shunsuke.watanabe@tel.com>

When the hrtimer stall detection hits the softirq is not raised.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable-rt@vger.kernel.org
---
 kernel/hrtimer.c |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index bca6928..9c09d02 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -1527,11 +1527,7 @@ retry:
 	if (expires_next.tv64 == KTIME_MAX ||
 	    !tick_program_event(expires_next, 0)) {
 		cpu_base->hang_detected = 0;
-
-		if (raise)
-			raise_softirq_irqoff(HRTIMER_SOFTIRQ);
-
-		return;
+		goto out;
 	}
 
 	/*
@@ -1575,6 +1571,9 @@ retry:
 	tick_program_event(expires_next, 1);
 	printk_once(KERN_WARNING "hrtimer: interrupt took %llu ns\n",
 		    ktime_to_ns(delta));
+out:
+	if (raise)
+		raise_softirq_irqoff(HRTIMER_SOFTIRQ);
 }
 
 /*
-- 
1.7.10.4

[PATCH RT 2/4] rcu: Disable RCU_FAST_NO_HZ on RT

[Steven Rostedt]

[-- Attachment #1: 0002-rcu-Disable-RCU_FAST_NO_HZ-on-RT.patch --]
[-- Type: text/plain, Size: 751 bytes --]

From: Thomas Gleixner <tglx@linutronix.de>

This uses a timer_list timer from the irq disabled guts of the idle
code. Disable it for now to prevent wreckage.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable-rt@vger.kernel.org
---
 init/Kconfig |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/init/Kconfig b/init/Kconfig
index 720c182..aa6545f 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -469,7 +469,7 @@ config RCU_FANOUT_EXACT
 
 config RCU_FAST_NO_HZ
 	bool "Accelerate last non-dyntick-idle CPU's grace periods"
-	depends on TREE_RCU && NO_HZ && SMP
+	depends on TREE_RCU && NO_HZ && SMP && !PREEMPT_RT_FULL
 	default n
 	help
 	  This option causes RCU to attempt to accelerate grace periods
-- 
1.7.10.4

[PATCH RT 3/4] net: netfilter: Serialize xt_write_recseq sections on RT

[Steven Rostedt]

[-- Attachment #1: 0003-net-netfilter-Serialize-xt_write_recseq-sections-on-.patch --]
[-- Type: text/plain, Size: 3058 bytes --]

From: Thomas Gleixner <tglx@linutronix.de>

The netfilter code relies only on the implicit semantics of
local_bh_disable() for serializing wt_write_recseq sections. RT breaks
that and needs explicit serialization here.

Reported-by: Peter LaDow <petela@gocougs.wsu.edu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable-rt@vger.kernel.org
---
 include/linux/locallock.h          |    4 ++++
 include/linux/netfilter/x_tables.h |    7 +++++++
 net/netfilter/core.c               |    6 ++++++
 3 files changed, 17 insertions(+)

diff --git a/include/linux/locallock.h b/include/linux/locallock.h
index f1804a3..a5eea5d 100644
--- a/include/linux/locallock.h
+++ b/include/linux/locallock.h
@@ -25,6 +25,9 @@ struct local_irq_lock {
 	DEFINE_PER_CPU(struct local_irq_lock, lvar) = {			\
 		.lock = __SPIN_LOCK_UNLOCKED((lvar).lock) }
 
+#define DECLARE_LOCAL_IRQ_LOCK(lvar)					\
+	DECLARE_PER_CPU(struct local_irq_lock, lvar)
+
 #define local_irq_lock_init(lvar)					\
 	do {								\
 		int __cpu;						\
@@ -220,6 +223,7 @@ static inline int __local_unlock_irqrestore(struct local_irq_lock *lv,
 #else /* PREEMPT_RT_BASE */
 
 #define DEFINE_LOCAL_IRQ_LOCK(lvar)		__typeof__(const int) lvar
+#define DECLARE_LOCAL_IRQ_LOCK(lvar)		extern __typeof__(const int) lvar
 
 static inline void local_irq_lock_init(int lvar) { }
 
diff --git a/include/linux/netfilter/x_tables.h b/include/linux/netfilter/x_tables.h
index 32cddf7..bed90da2 100644
--- a/include/linux/netfilter/x_tables.h
+++ b/include/linux/netfilter/x_tables.h
@@ -186,6 +186,7 @@ struct xt_counters_info {
 #ifdef __KERNEL__
 
 #include <linux/netdevice.h>
+#include <linux/locallock.h>
 
 /**
  * struct xt_action_param - parameters for matches/targets
@@ -466,6 +467,8 @@ extern void xt_free_table_info(struct xt_table_info *info);
  */
 DECLARE_PER_CPU(seqcount_t, xt_recseq);
 
+DECLARE_LOCAL_IRQ_LOCK(xt_write_lock);
+
 /**
  * xt_write_recseq_begin - start of a write section
  *
@@ -480,6 +483,9 @@ static inline unsigned int xt_write_recseq_begin(void)
 {
 	unsigned int addend;
 
+	/* RT protection */
+	local_lock(xt_write_lock);
+
 	/*
 	 * Low order bit of sequence is set if we already
 	 * called xt_write_recseq_begin().
@@ -510,6 +516,7 @@ static inline void xt_write_recseq_end(unsigned int addend)
 	/* this is kind of a write_seqcount_end(), but addend is 0 or 1 */
 	smp_wmb();
 	__this_cpu_add(xt_recseq.sequence, addend);
+	local_unlock(xt_write_lock);
 }
 
 /*
diff --git a/net/netfilter/core.c b/net/netfilter/core.c
index afca6c7..aa3f87b 100644
--- a/net/netfilter/core.c
+++ b/net/netfilter/core.c
@@ -20,11 +20,17 @@
 #include <linux/proc_fs.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
+#include <linux/locallock.h>
 #include <net/net_namespace.h>
 #include <net/sock.h>
 
 #include "nf_internals.h"
 
+#ifdef CONFIG_PREEMPT_RT_BASE
+DEFINE_LOCAL_IRQ_LOCK(xt_write_lock);
+EXPORT_PER_CPU_SYMBOL(xt_write_lock);
+#endif
+
 static DEFINE_MUTEX(afinfo_mutex);
 
 const struct nf_afinfo __rcu *nf_afinfo[NFPROTO_NUMPROTO] __read_mostly;
-- 
1.7.10.4

[PATCH RT 4/4] Linux 3.2.32-rt49-rc1

[Steven Rostedt]

[-- Attachment #1: 0004-Linux-3.2.32-rt49-rc1.patch --]
[-- Type: text/plain, Size: 287 bytes --]

From: Steven Rostedt <srostedt@redhat.com>

---
 localversion-rt |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/localversion-rt b/localversion-rt
index 2470798..623b4c9 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt48
+-rt49-rc1
-- 
1.7.10.4

[PATCH RT 2/4] rcu: Disable RCU_FAST_NO_HZ on RT

[Steven Rostedt]

[-- Attachment #1: 0002-rcu-Disable-RCU_FAST_NO_HZ-on-RT.patch --]
[-- Type: text/plain, Size: 751 bytes --]

From: Thomas Gleixner <tglx@linutronix.de>

This uses a timer_list timer from the irq disabled guts of the idle
code. Disable it for now to prevent wreckage.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable-rt@vger.kernel.org
---
 init/Kconfig |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/init/Kconfig b/init/Kconfig
index 5ed453f..948350f 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -469,7 +469,7 @@ config RCU_FANOUT_EXACT
 
 config RCU_FAST_NO_HZ
 	bool "Accelerate last non-dyntick-idle CPU's grace periods"
-	depends on TREE_RCU && NO_HZ && SMP
+	depends on TREE_RCU && NO_HZ && SMP && !PREEMPT_RT_FULL
 	default n
 	help
 	  This option causes RCU to attempt to accelerate grace periods
-- 
1.7.10.4