[Xen-changelog] [xen-unstable] Replace my previous patch with equivalent fix from linux-2.6.17.

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

# HG changeset patch
# User ack@xxxxxxxxxxxxxxxxxxxxx
# Node ID 18f8dde91fbd46af9eb38352ed64e48d429f95d8
# Parent  a67c1bcb5522de11bb367b5d694e66a3bea672e3
Replace my previous patch with equivalent fix from linux-2.6.17.
Might as well stay as close to that as we can...
Signed-off-by: Emmanuel Ackaouy <ack@xxxxxxxxxxxxx>
---
 patches/linux-2.6.16.13/fix-hz-suspend.patch |   15 +++------------
 1 files changed, 3 insertions(+), 12 deletions(-)

diff -r a67c1bcb5522 -r 18f8dde91fbd 
patches/linux-2.6.16.13/fix-hz-suspend.patch
--- a/patches/linux-2.6.16.13/fix-hz-suspend.patch      Thu Jun 29 14:30:41 
2006 +0100
+++ b/patches/linux-2.6.16.13/fix-hz-suspend.patch      Thu Jun 29 14:39:07 
2006 +0100
@@ -1,22 +1,26 @@ diff -pruN ../pristine-linux-2.6.16.13/k
 diff -pruN ../pristine-linux-2.6.16.13/kernel/timer.c ./kernel/timer.c
---- ../pristine-linux-2.6.16.13/kernel/timer.c 2006-05-02 14:38:44.000000000 
-0700
-+++ ./kernel/timer.c   2006-06-28 09:57:51.000000000 -0700
-@@ -555,7 +555,17 @@ found:
+--- ../pristine-linux-2.6.16.13/kernel/timer.c 2006-05-02 22:38:44.000000000 
+0100
++++ ./kernel/timer.c   2006-06-29 14:34:12.788957720 +0100
+@@ -555,6 +555,22 @@ found:
        }
        spin_unlock(&base->t_base.lock);
  
--      if (time_before(hr_expires, expires))
 +      /*
-+       * If timers are pending, "expires" will be in the recent past
-+       * of "jiffies". If there are no hr_timers registered, "hr_expires"
-+       * will be "jiffies + MAX_JIFFY_OFFSET"; this is *just* short of being
-+       * considered to be before "jiffies". This makes it very likely that
-+       * "hr_expires" *will* be considered to be before "expires".
-+       * So we must check when there are pending timers (expires <= jiffies)
-+       * to ensure that we don't accidently tell the caller that there is
-+       * nothing scheduled until half an epoch (MAX_JIFFY_OFFSET)!
++       * It can happen that other CPUs service timer IRQs and increment
++       * jiffies, but we have not yet got a local timer tick to process
++       * the timer wheels.  In that case, the expiry time can be before
++       * jiffies, but since the high-resolution timer here is relative to
++       * jiffies, the default expression when high-resolution timers are
++       * not active,
++       *
++       *   time_before(MAX_JIFFY_OFFSET + jiffies, expires)
++       *
++       * would falsely evaluate to true.  If that is the case, just
++       * return jiffies so that we can immediately fire the local timer
 +       */
-+      if (time_before(jiffies, expires) && time_before(hr_expires, expires))
++      if (time_before(expires, jiffies))
++              return jiffies;
++
+       if (time_before(hr_expires, expires))
                return hr_expires;
  
-       return expires;

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