[Xen-changelog] [xen-unstable] linux: Fix softlockup interaction with noidlehz.

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User kfraser@xxxxxxxxxxxxxxxxxxxxx
# Date 1170814616 0
# Node ID 1a411820230bdcc0edb5cdf0d6fa97b87eea01d8
# Parent  f28b144fb5cd61d02743b37dc79ac9277de5a2e3
linux: Fix softlockup interaction with noidlehz.

next_timer_interrupt() must check for when timer ISR is due to wake up
the softlockup thread.

Signed-off-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
---
 patches/linux-2.6.18/series                      |    1 
 patches/linux-2.6.18/softlockup-no-idle-hz.patch |   32 +++++++++++++++++++++++
 2 files changed, 33 insertions(+)

diff -r f28b144fb5cd -r 1a411820230b patches/linux-2.6.18/series
--- a/patches/linux-2.6.18/series       Wed Feb 07 00:51:26 2007 +0000
+++ b/patches/linux-2.6.18/series       Wed Feb 07 02:16:56 2007 +0000
@@ -18,3 +18,4 @@ x86-elfnote-as-preprocessor-macro.patch
 x86-elfnote-as-preprocessor-macro.patch
 fixaddr-top.patch
 git-c06cb8b1c4d25e5b4d7a2d7c2462619de1e0dbc4.patch
+softlockup-no-idle-hz.patch
diff -r f28b144fb5cd -r 1a411820230b 
patches/linux-2.6.18/softlockup-no-idle-hz.patch
--- /dev/null   Thu Jan 01 00:00:00 1970 +0000
+++ b/patches/linux-2.6.18/softlockup-no-idle-hz.patch  Wed Feb 07 02:16:56 
2007 +0000
@@ -0,0 +1,56 @@
+diff -pruN ../orig-linux-2.6.18/include/linux/sched.h ./include/linux/sched.h
+--- ../orig-linux-2.6.18/include/linux/sched.h 2006-09-20 04:42:06.000000000 
+0100
++++ ./include/linux/sched.h    2007-02-07 01:10:24.000000000 +0000
+@@ -211,10 +211,15 @@ extern void update_process_times(int use
+ extern void scheduler_tick(void);
+ 
+ #ifdef CONFIG_DETECT_SOFTLOCKUP
++extern unsigned long softlockup_get_next_event(void);
+ extern void softlockup_tick(void);
+ extern void spawn_softlockup_task(void);
+ extern void touch_softlockup_watchdog(void);
+ #else
++static inline unsigned long softlockup_get_next_event(void)
++{
++      return MAX_JIFFY_OFFSET;
++}
+ static inline void softlockup_tick(void)
+ {
+ }
+diff -pruN ../orig-linux-2.6.18/kernel/softlockup.c ./kernel/softlockup.c
+--- ../orig-linux-2.6.18/kernel/softlockup.c   2006-09-20 04:42:06.000000000 
+0100
++++ ./kernel/softlockup.c      2007-02-07 01:53:22.000000000 +0000
+@@ -40,6 +40,19 @@ void touch_softlockup_watchdog(void)
+ }
+ EXPORT_SYMBOL(touch_softlockup_watchdog);
+ 
++unsigned long softlockup_get_next_event(void)
++{
++      int this_cpu = smp_processor_id();
++      unsigned long touch_timestamp = per_cpu(touch_timestamp, this_cpu);
++
++      if (per_cpu(print_timestamp, this_cpu) == touch_timestamp ||
++              did_panic ||
++                      !per_cpu(watchdog_task, this_cpu))
++              return MAX_JIFFY_OFFSET;
++
++      return min_t(long, 0, touch_timestamp + HZ - jiffies);
++}
++
+ /*
+  * This callback runs from the timer interrupt, and checks
+  * whether the watchdog thread has hung or not:
+diff -pruN ../orig-linux-2.6.18/kernel/timer.c ./kernel/timer.c
+--- ../orig-linux-2.6.18/kernel/timer.c        2006-09-20 04:42:06.000000000 
+0100
++++ ./kernel/timer.c   2007-02-07 01:29:34.000000000 +0000
+@@ -485,7 +485,9 @@ unsigned long next_timer_interrupt(void)
+               if (hr_expires < 3)
+                       return hr_expires + jiffies;
+       }
+-      hr_expires += jiffies;
++      hr_expires = min_t(unsigned long,
++                         softlockup_get_next_event(),
++                         hr_expires) + jiffies;
+ 
+       base = __get_cpu_var(tvec_bases);
+       spin_lock(&base->lock);

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