[PATCH] x86: Add missing idle.h include to process_32.c

[PATCH] x86: Add missing idle.h include to process_32.c

[Rafael J. Wysocki]

Hi,

This fixes a very recent compilation breakage on 32-bit x86.

Please apply.

Thanks,
Rafael

---
From: Rafael J. Wysocki <rjw@sisk.pl>

x86: Add missing idle.h include to process_32.c

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
---
 arch/x86/kernel/process_32.c |    1 +
 1 file changed, 1 insertion(+)

Index: linux-2.6/arch/x86/kernel/process_32.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/process_32.c
+++ linux-2.6/arch/x86/kernel/process_32.c
@@ -55,6 +55,7 @@
 #include <asm/tlbflush.h>
 #include <asm/cpu.h>
 #include <asm/kdebug.h>
+#include <asm/idle.h>
 
 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 

Re: [PATCH] x86: Add missing idle.h include to process_32.c

[Ingo Molnar]

* Rafael J. Wysocki <rjw@sisk.pl> wrote:

> Hi,
> 
> This fixes a very recent compilation breakage on 32-bit x86.

the fix is queued up in tip/timers/urgent - sorry about that.

	Ingo

[git pull] timers fixes

[Ingo Molnar]

Linus,

Please pull the latest timers-fixes-for-linus git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git timers-fixes-for-linus

Thanks,

	Ingo

------------------>
Marc Dionne (1):
      x86: prevent stale state of c1e_mask across CPU offline/online, fix


 arch/x86/kernel/process_32.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 4b3cfdf..31f40b2 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -55,6 +55,7 @@
 #include <asm/tlbflush.h>
 #include <asm/cpu.h>
 #include <asm/kdebug.h>
+#include <asm/idle.h>
 
 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 

Re: [git pull] timers fixes

[Benjamin Herrenschmidt]

On Wed, 2008-09-24 at 09:42 +0200, Ingo Molnar wrote:
> Linus,
> 
> Please pull the latest timers-fixes-for-linus git tree from:
> 
>    git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git timers-fixes-for-linus
> 
> Thanks,
> 
> 	Ingo
> 
> ------------------>
> Marc Dionne (1):
>       x86: prevent stale state of c1e_mask across CPU offline/online, fix

Is that all the changeset comment ? Am I the only one to find that
totally useless ? Or is that the mail doesn't contain the actual
comment, only the title followed by the patch ?

Cheers,
Ben.

> 
>  arch/x86/kernel/process_32.c |    1 +
>  1 files changed, 1 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
> index 4b3cfdf..31f40b2 100644
> --- a/arch/x86/kernel/process_32.c
> +++ b/arch/x86/kernel/process_32.c
> @@ -55,6 +55,7 @@
>  #include <asm/tlbflush.h>
>  #include <asm/cpu.h>
>  #include <asm/kdebug.h>
> +#include <asm/idle.h>
>  
>  asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
>  
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/

Re: [git pull] timers fixes

[Benjamin Herrenschmidt]

On Wed, 2008-09-24 at 18:49 +1000, Benjamin Herrenschmidt wrote:
> On Wed, 2008-09-24 at 09:42 +0200, Ingo Molnar wrote:
> > Linus,
> > 
> > Please pull the latest timers-fixes-for-linus git tree from:
> > 
> >    git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git timers-fixes-for-linus
> > 
> > Thanks,
> > 
> > 	Ingo
> > 
> > ------------------>
> > Marc Dionne (1):
> >       x86: prevent stale state of c1e_mask across CPU offline/online, fix
> 
> Is that all the changeset comment ? Am I the only one to find that
> totally useless ? Or is that the mail doesn't contain the actual
> comment, only the title followed by the patch ?

Allright, so in fact, it's more like the log doesn't match
the patch in the email..

Ben.

> Cheers,
> Ben.
> 
> > 
> >  arch/x86/kernel/process_32.c |    1 +
> >  1 files changed, 1 insertions(+), 0 deletions(-)
> > 
> > diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
> > index 4b3cfdf..31f40b2 100644
> > --- a/arch/x86/kernel/process_32.c
> > +++ b/arch/x86/kernel/process_32.c
> > @@ -55,6 +55,7 @@
> >  #include <asm/tlbflush.h>
> >  #include <asm/cpu.h>
> >  #include <asm/kdebug.h>
> > +#include <asm/idle.h>
> >  
> >  asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
> >  
> > 
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at  http://vger.kernel.org/majordomo-info.html
> > Please read the FAQ at  http://www.tux.org/lkml/

Re: [git pull] timers fixes

[Ingo Molnar]

* Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:

> On Wed, 2008-09-24 at 09:42 +0200, Ingo Molnar wrote:
> > Linus,
> > 
> > Please pull the latest timers-fixes-for-linus git tree from:
> > 
> >    git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git timers-fixes-for-linus
> > 
> > Thanks,
> > 
> > 	Ingo
> > 
> > ------------------>
> > Marc Dionne (1):
> >       x86: prevent stale state of c1e_mask across CPU offline/online, fix
> 
> Is that all the changeset comment ? Am I the only one to find that 
> totally useless ? Or is that the mail doesn't contain the actual 
> comment, only the title followed by the patch ?

yeah. The build error is something like:

 arch/x86/kernel/process_32.c:78: warning: data definition has no type or storage class
 arch/x86/kernel/process_32.c:78: warning: type defaults to 'int' in declaration of 'c1e_remove_cpu'
 arch/x86/kernel/process_32.c:78: warning: parameter names (without types) in function declaration

	Ingo

Re: [git pull] timers fixes

[Ingo Molnar]

* Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:

> On Wed, 2008-09-24 at 18:49 +1000, Benjamin Herrenschmidt wrote:
> > On Wed, 2008-09-24 at 09:42 +0200, Ingo Molnar wrote:
> > > Linus,
> > > 
> > > Please pull the latest timers-fixes-for-linus git tree from:
> > > 
> > >    git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git timers-fixes-for-linus
> > > 
> > > Thanks,
> > > 
> > > 	Ingo
> > > 
> > > ------------------>
> > > Marc Dionne (1):
> > >       x86: prevent stale state of c1e_mask across CPU offline/online, fix
> > 
> > Is that all the changeset comment ? Am I the only one to find that
> > totally useless ? Or is that the mail doesn't contain the actual
> > comment, only the title followed by the patch ?
> 
> Allright, so in fact, it's more like the log doesn't match
> the patch in the email..

only because i already picked up a different submission at that time, 
and posted in this thread.

i picked up this one from lkml:

  Subject: [PATCH] Fix build error introduced by commit 4faac97d44ac27bdbb010a9c3597401a8f89341f

see the full commit log below, it has all the details.

	Ingo

------------>
>From 1eda81495a49a4ee91d8863b0a441a624375efea Mon Sep 17 00:00:00 2001
From: Marc Dionne <marc.c.dionne@gmail.com>
Date: Tue, 23 Sep 2008 22:40:02 -0400
Subject: [PATCH] x86: prevent stale state of c1e_mask across CPU offline/online, fix

Fix build error introduced by commit 4faac97d44ac27 ("x86: prevent stale
state of c1e_mask across CPU offline/online").

process_32.c needs to include idle.h to get the prototype for
c1e_remove_cpu()

Signed-off-by: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/process_32.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c
index 4b3cfdf..31f40b2 100644
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -55,6 +55,7 @@
 #include <asm/tlbflush.h>
 #include <asm/cpu.h>
 #include <asm/kdebug.h>
+#include <asm/idle.h>
 
 asmlinkage void ret_from_fork(void) __asm__("ret_from_fork");
 

[GIT PULL] timers fixes

[Frederic Weisbecker]

Thomas, Ingo,

Please pull the timers/urgent branch that can be found at:

git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
	timers/urgent

HEAD: aebacb7f6ca1926918734faae14d1f0b6fae5cb7

Thanks,
	Frederic
---

Frederic Weisbecker (1):
      posix-cpu-timers: Fix rearm racing against process tick

Nicolas Saenz Julienne (1):
      timers: Fix get_next_timer_interrupt() with no timers pending


 kernel/time/posix-cpu-timers.c | 10 +++++-----
 kernel/time/timer.c            |  8 +++++---
 2 files changed, 10 insertions(+), 8 deletions(-)

Re: [GIT PULL] timers fixes

[pr-tracker-bot]

The pull request you sent on Sat, 18 Jan 2020 19:47:46 +0100:

> git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers-urgent-for-linus

has been merged into torvalds/linux.git:
https://git.kernel.org/torvalds/c/7ff15cd0458c288afa954de843bb1903c723e5b3

Thank you!

-- 
Deet-doot-dot, I am a bot.
https://korg.wiki.kernel.org/userdoc/prtracker

[GIT PULL] timers fixes

[Ingo Molnar]

Linus,

Please pull the latest timers-urgent-for-linus git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git timers-urgent-for-linus

   # HEAD: de95a991bb72e009f47e0c4bbc90fc5f594588d5 tick/sched: Annotate lockless access to last_jiffies_update

Three fixes: fix link failure on Alpha, fix a Sparse warning and 
annotate/robustify a lockless access in the NOHZ code.

 Thanks,

	Ingo

------------------>
Arnd Bergmann (1):
      time/posix-stubs: Provide compat itimer supoprt for alpha

Eric Dumazet (1):
      tick/sched: Annotate lockless access to last_jiffies_update

Vincenzo Frascino (1):
      lib/vdso: Make __cvdso_clock_getres() static


 kernel/time/posix-stubs.c |  3 +++
 kernel/time/tick-sched.c  | 14 +++++++++-----
 lib/vdso/gettimeofday.c   |  1 +
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/kernel/time/posix-stubs.c b/kernel/time/posix-stubs.c
index 67df65f887ac..20c65a7d4e3a 100644
--- a/kernel/time/posix-stubs.c
+++ b/kernel/time/posix-stubs.c
@@ -151,6 +151,9 @@ SYSCALL_DEFINE4(clock_nanosleep, const clockid_t, which_clock, int, flags,
 
 #ifdef CONFIG_COMPAT
 COMPAT_SYS_NI(timer_create);
+#endif
+
+#if defined(CONFIG_COMPAT) || defined(CONFIG_ALPHA)
 COMPAT_SYS_NI(getitimer);
 COMPAT_SYS_NI(setitimer);
 #endif
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 8b192e67aabc..a792d21cac64 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -58,8 +58,9 @@ static void tick_do_update_jiffies64(ktime_t now)
 
 	/*
 	 * Do a quick check without holding jiffies_lock:
+	 * The READ_ONCE() pairs with two updates done later in this function.
 	 */
-	delta = ktime_sub(now, last_jiffies_update);
+	delta = ktime_sub(now, READ_ONCE(last_jiffies_update));
 	if (delta < tick_period)
 		return;
 
@@ -70,8 +71,9 @@ static void tick_do_update_jiffies64(ktime_t now)
 	if (delta >= tick_period) {
 
 		delta = ktime_sub(delta, tick_period);
-		last_jiffies_update = ktime_add(last_jiffies_update,
-						tick_period);
+		/* Pairs with the lockless read in this function. */
+		WRITE_ONCE(last_jiffies_update,
+			   ktime_add(last_jiffies_update, tick_period));
 
 		/* Slow path for long timeouts */
 		if (unlikely(delta >= tick_period)) {
@@ -79,8 +81,10 @@ static void tick_do_update_jiffies64(ktime_t now)
 
 			ticks = ktime_divns(delta, incr);
 
-			last_jiffies_update = ktime_add_ns(last_jiffies_update,
-							   incr * ticks);
+			/* Pairs with the lockless read in this function. */
+			WRITE_ONCE(last_jiffies_update,
+				   ktime_add_ns(last_jiffies_update,
+						incr * ticks));
 		}
 		do_timer(++ticks);
 
diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c
index 9ecfd3b547ba..42bd8ab955fa 100644
--- a/lib/vdso/gettimeofday.c
+++ b/lib/vdso/gettimeofday.c
@@ -221,6 +221,7 @@ int __cvdso_clock_getres_common(clockid_t clock, struct __kernel_timespec *res)
 	return 0;
 }
 
+static __maybe_unused
 int __cvdso_clock_getres(clockid_t clock, struct __kernel_timespec *res)
 {
 	int ret = __cvdso_clock_getres_common(clock, res);

[GIT PULL] timers fixes

[Ingo Molnar]

Linus,

Please pull the latest timers-fixes-for-linus git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git timers-fixes-for-linus

 Thanks,

	Ingo

------------------>
H Hartley Sweeten (1):
      timekeeping: Make local variables static

Nicolas Pitre (1):
      time: Rename misnamed minsec argument of clocks_calc_mult_shift()


 kernel/time/clocksource.c |    8 ++++----
 kernel/time/timekeeping.c |    4 ++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index c18d7ef..8588abc 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -113,7 +113,7 @@ EXPORT_SYMBOL_GPL(timecounter_cyc2time);
  * @shift:	pointer to shift variable
  * @from:	frequency to convert from
  * @to:		frequency to convert to
- * @minsec:	guaranteed runtime conversion range in seconds
+ * @maxsec:	guaranteed runtime conversion range in seconds
  *
  * The function evaluates the shift/mult pair for the scaled math
  * operations of clocksources and clockevents.
@@ -122,7 +122,7 @@ EXPORT_SYMBOL_GPL(timecounter_cyc2time);
  * NSEC_PER_SEC == 1GHz and @from is the counter frequency. For clock
  * event @to is the counter frequency and @from is NSEC_PER_SEC.
  *
- * The @minsec conversion range argument controls the time frame in
+ * The @maxsec conversion range argument controls the time frame in
  * seconds which must be covered by the runtime conversion with the
  * calculated mult and shift factors. This guarantees that no 64bit
  * overflow happens when the input value of the conversion is
@@ -131,7 +131,7 @@ EXPORT_SYMBOL_GPL(timecounter_cyc2time);
  * factors.
  */
 void
-clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec)
+clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 maxsec)
 {
 	u64 tmp;
 	u32 sft, sftacc= 32;
@@ -140,7 +140,7 @@ clocks_calc_mult_shift(u32 *mult, u32 *shift, u32 from, u32 to, u32 minsec)
 	 * Calculate the shift factor which is limiting the conversion
 	 * range:
 	 */
-	tmp = ((u64)minsec * from) >> 32;
+	tmp = ((u64)maxsec * from) >> 32;
 	while (tmp) {
 		tmp >>=1;
 		sftacc--;
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 5bb86da..eef7452 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -49,7 +49,7 @@ struct timekeeper {
 	u32	mult;
 };
 
-struct timekeeper timekeeper;
+static struct timekeeper timekeeper;
 
 /**
  * timekeeper_setup_internals - Set up internals to use clocksource clock.
@@ -164,7 +164,7 @@ static struct timespec total_sleep_time;
 /*
  * The raw monotonic time for the CLOCK_MONOTONIC_RAW posix clock.
  */
-struct timespec raw_time;
+static struct timespec raw_time;
 
 /* flag for if timekeeping is suspended */
 int __read_mostly timekeeping_suspended;

[GIT PULL] timers fixes

[Ingo Molnar]

Linus,

Please pull the latest timers-fixes-for-linus git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git timers-fixes-for-linus

 Thanks,

	Ingo

------------------>
Heiko Carstens (1):
      hrtimer: move timer stats helper functions to hrtimer.c

Thomas Gleixner (2):
      hrtimer: Tune hrtimer_interrupt hang logic
      itimer: Fix the itimer trace print format


 include/linux/hrtimer.h      |   56 +++----------------
 include/trace/events/timer.h |    8 ++--
 kernel/hrtimer.c             |  121 ++++++++++++++++++++++++++---------------
 kernel/time/timer_list.c     |    5 ++-
 4 files changed, 94 insertions(+), 96 deletions(-)

diff --git a/include/linux/hrtimer.h b/include/linux/hrtimer.h
index 9bace4b..af634e9 100644
--- a/include/linux/hrtimer.h
+++ b/include/linux/hrtimer.h
@@ -162,10 +162,11 @@ struct hrtimer_clock_base {
  * @expires_next:	absolute time of the next event which was scheduled
  *			via clock_set_next_event()
  * @hres_active:	State of high resolution mode
- * @check_clocks:	Indictator, when set evaluate time source and clock
- *			event devices whether high resolution mode can be
- *			activated.
- * @nr_events:		Total number of timer interrupt events
+ * @hang_detected:	The last hrtimer interrupt detected a hang
+ * @nr_events:		Total number of hrtimer interrupt events
+ * @nr_retries:		Total number of hrtimer interrupt retries
+ * @nr_hangs:		Total number of hrtimer interrupt hangs
+ * @max_hang_time:	Maximum time spent in hrtimer_interrupt
  */
 struct hrtimer_cpu_base {
 	spinlock_t			lock;
@@ -173,7 +174,11 @@ struct hrtimer_cpu_base {
 #ifdef CONFIG_HIGH_RES_TIMERS
 	ktime_t				expires_next;
 	int				hres_active;
+	int				hang_detected;
 	unsigned long			nr_events;
+	unsigned long			nr_retries;
+	unsigned long			nr_hangs;
+	ktime_t				max_hang_time;
 #endif
 };
 
@@ -435,47 +440,4 @@ extern u64 ktime_divns(const ktime_t kt, s64 div);
 /* Show pending timers: */
 extern void sysrq_timer_list_show(void);
 
-/*
- * Timer-statistics info:
- */
-#ifdef CONFIG_TIMER_STATS
-
-extern void timer_stats_update_stats(void *timer, pid_t pid, void *startf,
-				     void *timerf, char *comm,
-				     unsigned int timer_flag);
-
-static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
-{
-	if (likely(!timer_stats_active))
-		return;
-	timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
-				 timer->function, timer->start_comm, 0);
-}
-
-extern void __timer_stats_hrtimer_set_start_info(struct hrtimer *timer,
-						 void *addr);
-
-static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
-{
-	__timer_stats_hrtimer_set_start_info(timer, __builtin_return_address(0));
-}
-
-static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
-{
-	timer->start_site = NULL;
-}
-#else
-static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
-{
-}
-
-static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
-{
-}
-
-static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
-{
-}
-#endif
-
 #endif
diff --git a/include/trace/events/timer.h b/include/trace/events/timer.h
index e5ce87a..9496b96 100644
--- a/include/trace/events/timer.h
+++ b/include/trace/events/timer.h
@@ -301,8 +301,8 @@ TRACE_EVENT(itimer_state,
 		__entry->interval_usec	= value->it_interval.tv_usec;
 	),
 
-	TP_printk("which=%d expires=%lu it_value=%lu.%lu it_interval=%lu.%lu",
-		  __entry->which, __entry->expires,
+	TP_printk("which=%d expires=%llu it_value=%ld.%ld it_interval=%ld.%ld",
+		  __entry->which, (unsigned long long)__entry->expires,
 		  __entry->value_sec, __entry->value_usec,
 		  __entry->interval_sec, __entry->interval_usec)
 );
@@ -331,8 +331,8 @@ TRACE_EVENT(itimer_expire,
 		__entry->pid	= pid_nr(pid);
 	),
 
-	    TP_printk("which=%d pid=%d now=%lu", __entry->which,
-		      (int) __entry->pid, __entry->now)
+	TP_printk("which=%d pid=%d now=%llu", __entry->which,
+		  (int) __entry->pid, (unsigned long long)__entry->now)
 );
 
 #endif /*  _TRACE_TIMER_H */
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index ede5277..d2f9239 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -557,7 +557,7 @@ hrtimer_force_reprogram(struct hrtimer_cpu_base *cpu_base, int skip_equal)
 static int hrtimer_reprogram(struct hrtimer *timer,
 			     struct hrtimer_clock_base *base)
 {
-	ktime_t *expires_next = &__get_cpu_var(hrtimer_bases).expires_next;
+	struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
 	ktime_t expires = ktime_sub(hrtimer_get_expires(timer), base->offset);
 	int res;
 
@@ -582,7 +582,16 @@ static int hrtimer_reprogram(struct hrtimer *timer,
 	if (expires.tv64 < 0)
 		return -ETIME;
 
-	if (expires.tv64 >= expires_next->tv64)
+	if (expires.tv64 >= cpu_base->expires_next.tv64)
+		return 0;
+
+	/*
+	 * If a hang was detected in the last timer interrupt then we
+	 * do not schedule a timer which is earlier than the expiry
+	 * which we enforced in the hang detection. We want the system
+	 * to make progress.
+	 */
+	if (cpu_base->hang_detected)
 		return 0;
 
 	/*
@@ -590,7 +599,7 @@ static int hrtimer_reprogram(struct hrtimer *timer,
 	 */
 	res = tick_program_event(expires, 0);
 	if (!IS_ERR_VALUE(res))
-		*expires_next = expires;
+		cpu_base->expires_next = expires;
 	return res;
 }
 
@@ -747,17 +756,33 @@ static inline void hrtimer_init_timer_hres(struct hrtimer *timer) { }
 
 #endif /* CONFIG_HIGH_RES_TIMERS */
 
-#ifdef CONFIG_TIMER_STATS
-void __timer_stats_hrtimer_set_start_info(struct hrtimer *timer, void *addr)
+static inline void timer_stats_hrtimer_set_start_info(struct hrtimer *timer)
 {
+#ifdef CONFIG_TIMER_STATS
 	if (timer->start_site)
 		return;
-
-	timer->start_site = addr;
+	timer->start_site = __builtin_return_address(0);
 	memcpy(timer->start_comm, current->comm, TASK_COMM_LEN);
 	timer->start_pid = current->pid;
+#endif
 }
+
+static inline void timer_stats_hrtimer_clear_start_info(struct hrtimer *timer)
+{
+#ifdef CONFIG_TIMER_STATS
+	timer->start_site = NULL;
+#endif
+}
+
+static inline void timer_stats_account_hrtimer(struct hrtimer *timer)
+{
+#ifdef CONFIG_TIMER_STATS
+	if (likely(!timer_stats_active))
+		return;
+	timer_stats_update_stats(timer, timer->start_pid, timer->start_site,
+				 timer->function, timer->start_comm, 0);
 #endif
+}
 
 /*
  * Counterpart to lock_hrtimer_base above:
@@ -1217,30 +1242,6 @@ static void __run_hrtimer(struct hrtimer *timer, ktime_t *now)
 
 #ifdef CONFIG_HIGH_RES_TIMERS
 
-static int force_clock_reprogram;
-
-/*
- * After 5 iteration's attempts, we consider that hrtimer_interrupt()
- * is hanging, which could happen with something that slows the interrupt
- * such as the tracing. Then we force the clock reprogramming for each future
- * hrtimer interrupts to avoid infinite loops and use the min_delta_ns
- * threshold that we will overwrite.
- * The next tick event will be scheduled to 3 times we currently spend on
- * hrtimer_interrupt(). This gives a good compromise, the cpus will spend
- * 1/4 of their time to process the hrtimer interrupts. This is enough to
- * let it running without serious starvation.
- */
-
-static inline void
-hrtimer_interrupt_hanging(struct clock_event_device *dev,
-			ktime_t try_time)
-{
-	force_clock_reprogram = 1;
-	dev->min_delta_ns = (unsigned long)try_time.tv64 * 3;
-	printk(KERN_WARNING "hrtimer: interrupt too slow, "
-	       "forcing clock min delta to %llu ns\n",
-	       (unsigned long long) dev->min_delta_ns);
-}
 /*
  * High resolution timer interrupt
  * Called with interrupts disabled
@@ -1249,21 +1250,15 @@ void hrtimer_interrupt(struct clock_event_device *dev)
 {
 	struct hrtimer_cpu_base *cpu_base = &__get_cpu_var(hrtimer_bases);
 	struct hrtimer_clock_base *base;
-	ktime_t expires_next, now;
-	int nr_retries = 0;
-	int i;
+	ktime_t expires_next, now, entry_time, delta;
+	int i, retries = 0;
 
 	BUG_ON(!cpu_base->hres_active);
 	cpu_base->nr_events++;
 	dev->next_event.tv64 = KTIME_MAX;
 
- retry:
-	/* 5 retries is enough to notice a hang */
-	if (!(++nr_retries % 5))
-		hrtimer_interrupt_hanging(dev, ktime_sub(ktime_get(), now));
-
-	now = ktime_get();
-
+	entry_time = now = ktime_get();
+retry:
 	expires_next.tv64 = KTIME_MAX;
 
 	spin_lock(&cpu_base->lock);
@@ -1325,10 +1320,48 @@ void hrtimer_interrupt(struct clock_event_device *dev)
 	spin_unlock(&cpu_base->lock);
 
 	/* Reprogramming necessary ? */
-	if (expires_next.tv64 != KTIME_MAX) {
-		if (tick_program_event(expires_next, force_clock_reprogram))
-			goto retry;
+	if (expires_next.tv64 == KTIME_MAX ||
+	    !tick_program_event(expires_next, 0)) {
+		cpu_base->hang_detected = 0;
+		return;
 	}
+
+	/*
+	 * The next timer was already expired due to:
+	 * - tracing
+	 * - long lasting callbacks
+	 * - being scheduled away when running in a VM
+	 *
+	 * We need to prevent that we loop forever in the hrtimer
+	 * interrupt routine. We give it 3 attempts to avoid
+	 * overreacting on some spurious event.
+	 */
+	now = ktime_get();
+	cpu_base->nr_retries++;
+	if (++retries < 3)
+		goto retry;
+	/*
+	 * Give the system a chance to do something else than looping
+	 * here. We stored the entry time, so we know exactly how long
+	 * we spent here. We schedule the next event this amount of
+	 * time away.
+	 */
+	cpu_base->nr_hangs++;
+	cpu_base->hang_detected = 1;
+	delta = ktime_sub(now, entry_time);
+	if (delta.tv64 > cpu_base->max_hang_time.tv64)
+		cpu_base->max_hang_time = delta;
+	/*
+	 * Limit it to a sensible value as we enforce a longer
+	 * delay. Give the CPU at least 100ms to catch up.
+	 */
+	if (delta.tv64 > 100 * NSEC_PER_MSEC)
+		expires_next = ktime_add_ns(now, 100 * NSEC_PER_MSEC);
+	else
+		expires_next = ktime_add(now, delta);
+	tick_program_event(expires_next, 1);
+	printk_once(KERN_WARNING "hrtimer: interrupt took %llu ns\n",
+		    ktime_to_ns(delta));
 }
 
 /*
diff --git a/kernel/time/timer_list.c b/kernel/time/timer_list.c
index 665c76e..9d80db4 100644
--- a/kernel/time/timer_list.c
+++ b/kernel/time/timer_list.c
@@ -150,6 +150,9 @@ static void print_cpu(struct seq_file *m, int cpu, u64 now)
 	P_ns(expires_next);
 	P(hres_active);
 	P(nr_events);
+	P(nr_retries);
+	P(nr_hangs);
+	P_ns(max_hang_time);
 #endif
 #undef P
 #undef P_ns
@@ -254,7 +257,7 @@ static int timer_list_show(struct seq_file *m, void *v)
 	u64 now = ktime_to_ns(ktime_get());
 	int cpu;
 
-	SEQ_printf(m, "Timer List Version: v0.4\n");
+	SEQ_printf(m, "Timer List Version: v0.5\n");
 	SEQ_printf(m, "HRTIMER_MAX_CLOCK_BASES: %d\n", HRTIMER_MAX_CLOCK_BASES);
 	SEQ_printf(m, "now at %Ld nsecs\n", (unsigned long long)now);
 

[git pull] timers fixes

[Ingo Molnar]

Linus,

Please pull the latest timers-fixes-for-linus git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git timers-fixes-for-linus

 Thanks,

	Ingo

------------------>
Thomas Gleixner (1):
      clockevents: check broadcast tick device not the clock events device


 kernel/time/tick-broadcast.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index bd70345..cb01cd8 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -235,7 +235,8 @@ static void tick_do_broadcast_on_off(void *why)
 	case CLOCK_EVT_NOTIFY_BROADCAST_FORCE:
 		if (!cpu_isset(cpu, tick_broadcast_mask)) {
 			cpu_set(cpu, tick_broadcast_mask);
-			if (bc->mode == TICKDEV_MODE_PERIODIC)
+			if (tick_broadcast_device.mode ==
+			    TICKDEV_MODE_PERIODIC)
 				clockevents_shutdown(dev);
 		}
 		if (*reason == CLOCK_EVT_NOTIFY_BROADCAST_FORCE)
@@ -245,7 +246,8 @@ static void tick_do_broadcast_on_off(void *why)
 		if (!tick_broadcast_force &&
 		    cpu_isset(cpu, tick_broadcast_mask)) {
 			cpu_clear(cpu, tick_broadcast_mask);
-			if (bc->mode == TICKDEV_MODE_PERIODIC)
+			if (tick_broadcast_device.mode ==
+			    TICKDEV_MODE_PERIODIC)
 				tick_setup_periodic(dev, 0);
 		}
 		break;