[ANNOUNCE] 3.4.42-rt57

From: Steven Rostedt
Date: Tue May 07 2013 - 10:37:19 EST



Dear RT Folks,

I'm pleased to announce the 3.4.42-rt57 stable release.


You can get this release via the git tree at:

git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git

branch: v3.4-rt
Head SHA1: 3586f2835e04bc4e07a7d521323854fad1778ec7


Or to build 3.4.42-rt57 directly, the following patches should be applied:

http://www.kernel.org/pub/linux/kernel/v3.x/linux-3.4.tar.xz

http://www.kernel.org/pub/linux/kernel/v3.x/patch-3.4.42.xz

http://www.kernel.org/pub/linux/kernel/projects/rt/3.4/patch-3.4.42-rt57.patch.xz



You can also build from 3.4.42-rt56 by applying the incremental patch:

http://www.kernel.org/pub/linux/kernel/projects/rt/3.4/incr/patch-3.4.42-rt56-rt57.patch.xz



Enjoy,

-- Steve


Changes from v3.4.42-rt56:

---

Eric Dumazet (1):
tcp: force a dst refcount when prequeue packet

Steven Rostedt (2):
x86/mce: Defer mce wakeups to threads for PREEMPT_RT
swap: Use unique local lock name for swap_lock

Steven Rostedt (Red Hat) (1):
Linux 3.4.42-rt57

----
arch/x86/kernel/cpu/mcheck/mce.c | 78 +++++++++++++++++++++++++++++---------
include/net/tcp.h | 1 +
localversion-rt | 2 +-
mm/swap.c | 20 +++++-----
4 files changed, 73 insertions(+), 28 deletions(-)
---------------------------
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 91466f5..63c96f9 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -15,6 +15,7 @@
#include <linux/rcupdate.h>
#include <linux/kobject.h>
#include <linux/uaccess.h>
+#include <linux/kthread.h>
#include <linux/kdebug.h>
#include <linux/kernel.h>
#include <linux/percpu.h>
@@ -1293,6 +1294,63 @@ static void mce_do_trigger(struct work_struct *work)

static DECLARE_WORK(mce_trigger_work, mce_do_trigger);

+static void __mce_notify_work(void)
+{
+ /* Not more than two messages every minute */
+ static DEFINE_RATELIMIT_STATE(ratelimit, 60*HZ, 2);
+
+ /* wake processes polling /dev/mcelog */
+ wake_up_interruptible(&mce_chrdev_wait);
+
+ /*
+ * There is no risk of missing notifications because
+ * work_pending is always cleared before the function is
+ * executed.
+ */
+ if (mce_helper[0] && !work_pending(&mce_trigger_work))
+ schedule_work(&mce_trigger_work);
+
+ if (__ratelimit(&ratelimit))
+ pr_info(HW_ERR "Machine check events logged\n");
+}
+
+#ifdef CONFIG_PREEMPT_RT_FULL
+struct task_struct *mce_notify_helper;
+
+static int mce_notify_helper_thread(void *unused)
+{
+ while (1) {
+ set_current_state(TASK_INTERRUPTIBLE);
+ schedule();
+ if (kthread_should_stop())
+ break;
+ __mce_notify_work();
+ }
+ return 0;
+}
+
+static int mce_notify_work_init(void)
+{
+ mce_notify_helper = kthread_run(mce_notify_helper_thread, NULL,
+ "mce-notify");
+ if (!mce_notify_helper)
+ return -ENOMEM;
+
+ return 0;
+}
+
+static void mce_notify_work(void)
+{
+ wake_up_process(mce_notify_helper);
+}
+#else
+static void mce_notify_work(void)
+{
+ __mce_notify_work();
+}
+static inline int mce_notify_work_init(void) { return 0; }
+#endif
+
/*
* Notify the user(s) about new machine check events.
* Can be called from interrupt context, but not from machine check/NMI
@@ -1300,24 +1358,8 @@ static DECLARE_WORK(mce_trigger_work, mce_do_trigger);
*/
int mce_notify_irq(void)
{
- /* Not more than two messages every minute */
- static DEFINE_RATELIMIT_STATE(ratelimit, 60*HZ, 2);
-
if (test_and_clear_bit(0, &mce_need_notify)) {
- /* wake processes polling /dev/mcelog */
- wake_up_interruptible(&mce_chrdev_wait);
-
- /*
- * There is no risk of missing notifications because
- * work_pending is always cleared before the function is
- * executed.
- */
- if (mce_helper[0] && !work_pending(&mce_trigger_work))
- schedule_work(&mce_trigger_work);
-
- if (__ratelimit(&ratelimit))
- pr_info(HW_ERR "Machine check events logged\n");
-
+ mce_notify_work();
return 1;
}
return 0;
@@ -2295,6 +2337,8 @@ static __init int mcheck_init_device(void)
/* register character device /dev/mcelog */
misc_register(&mce_chrdev_device);

+ err = mce_notify_work_init();
+
return err;
}
device_initcall(mcheck_init_device);
diff --git a/include/net/tcp.h b/include/net/tcp.h
index 2757a11..8376a6a 100644
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -948,6 +948,7 @@ static inline int tcp_prequeue(struct sock *sk, struct sk_buff *skb)
if (sysctl_tcp_low_latency || !tp->ucopy.task)
return 0;

+ skb_dst_force(skb);
__skb_queue_tail(&tp->ucopy.prequeue, skb);
tp->ucopy.memory += skb->truesize;
if (tp->ucopy.memory > sk->sk_rcvbuf) {
diff --git a/localversion-rt b/localversion-rt
index fdb0f88..c06cc435 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt56
+-rt57
diff --git a/mm/swap.c b/mm/swap.c
index 62dc70c..15c1c53 100644
--- a/mm/swap.c
+++ b/mm/swap.c
@@ -42,7 +42,7 @@ static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs);
static DEFINE_PER_CPU(struct pagevec, lru_deactivate_pvecs);

static DEFINE_LOCAL_IRQ_LOCK(rotate_lock);
-static DEFINE_LOCAL_IRQ_LOCK(swap_lock);
+static DEFINE_LOCAL_IRQ_LOCK(swapvec_lock);

/*
* This path almost never happens for VM activity - pages are normally
@@ -332,13 +332,13 @@ static void activate_page_drain(int cpu)
void activate_page(struct page *page)
{
if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
- struct pagevec *pvec = &get_locked_var(swap_lock,
+ struct pagevec *pvec = &get_locked_var(swapvec_lock,
activate_page_pvecs);

page_cache_get(page);
if (!pagevec_add(pvec, page))
pagevec_lru_move_fn(pvec, __activate_page, NULL);
- put_locked_var(swap_lock, activate_page_pvecs);
+ put_locked_var(swapvec_lock, activate_page_pvecs);
}
}

@@ -378,12 +378,12 @@ EXPORT_SYMBOL(mark_page_accessed);

void __lru_cache_add(struct page *page, enum lru_list lru)
{
- struct pagevec *pvec = &get_locked_var(swap_lock, lru_add_pvecs)[lru];
+ struct pagevec *pvec = &get_locked_var(swapvec_lock, lru_add_pvecs)[lru];

page_cache_get(page);
if (!pagevec_add(pvec, page))
__pagevec_lru_add(pvec, lru);
- put_locked_var(swap_lock, lru_add_pvecs);
+ put_locked_var(swapvec_lock, lru_add_pvecs);
}
EXPORT_SYMBOL(__lru_cache_add);

@@ -548,19 +548,19 @@ void deactivate_page(struct page *page)
return;

if (likely(get_page_unless_zero(page))) {
- struct pagevec *pvec = &get_locked_var(swap_lock,
+ struct pagevec *pvec = &get_locked_var(swapvec_lock,
lru_deactivate_pvecs);

if (!pagevec_add(pvec, page))
pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL);
- put_locked_var(swap_lock, lru_deactivate_pvecs);
+ put_locked_var(swapvec_lock, lru_deactivate_pvecs);
}
}

void lru_add_drain(void)
{
- lru_add_drain_cpu(local_lock_cpu(swap_lock));
- local_unlock_cpu(swap_lock);
+ lru_add_drain_cpu(local_lock_cpu(swapvec_lock));
+ local_unlock_cpu(swapvec_lock);
}

static void lru_add_drain_per_cpu(struct work_struct *dummy)
@@ -771,7 +771,7 @@ EXPORT_SYMBOL(pagevec_lookup_tag);
static int __init swap_init_locks(void)
{
local_irq_lock_init(rotate_lock);
- local_irq_lock_init(swap_lock);
+ local_irq_lock_init(swapvec_lock);
return 1;
}
early_initcall(swap_init_locks);


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