Re: [Bisected] qemu hangs on current git

From: Peter Zijlstra
Date: Wed Jan 22 2014 - 05:25:15 EST


On Wed, Jan 22, 2014 at 10:37:55AM +0100, Markus Trippelsdorf wrote:
> git bisect points to:
>
> commit 8cb75e0c4ec9786b81439761eac1d18d4a931af3
> Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Date: Wed Nov 20 12:22:37 2013 +0100
>
> sched/preempt: Fix up missed PREEMPT_NEED_RESCHED folding
>

No idea why kvm would go funny on that, real hardware runs fine.

You're running a !PREEMPT kernel, right? Does the below make any
difference?

---
include/linux/preempt.h | 5 -----
1 file changed, 5 deletions(-)

diff --git a/include/linux/preempt.h b/include/linux/preempt.h
index 59749fc48328..de83b4eb1642 100644
--- a/include/linux/preempt.h
+++ b/include/linux/preempt.h
@@ -134,7 +134,6 @@ do { \
#undef preempt_check_resched
#endif

-#ifdef CONFIG_PREEMPT
#define preempt_set_need_resched() \
do { \
set_preempt_need_resched(); \
@@ -144,10 +143,6 @@ do { \
if (tif_need_resched()) \
set_preempt_need_resched(); \
} while (0)
-#else
-#define preempt_set_need_resched() do { } while (0)
-#define preempt_fold_need_resched() do { } while (0)
-#endif

#ifdef CONFIG_PREEMPT_NOTIFIERS

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