diff options
| author | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2011-11-21 18:02:02 -0500 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-12-03 10:49:58 -0800 |
| commit | e5fd47bfab2df0c2184cc0bf4245d8e1bb7724fb (patch) | |
| tree | 7651116728e2d69a7a8362cf88c80761919b971b /arch/x86/xen | |
| parent | af968e29acd91ebeb4224e899202c46c93171ecd (diff) | |
xen/pm_idle: Make pm_idle be default_idle under Xen.
The idea behind commit d91ee5863b71 ("cpuidle: replace xen access to x86
pm_idle and default_idle") was to have one call - disable_cpuidle()
which would make pm_idle not be molested by other code. It disallows
cpuidle_idle_call to be set to pm_idle (which is excellent).
But in the select_idle_routine() and idle_setup(), the pm_idle can still
be set to either: amd_e400_idle, mwait_idle or default_idle. This
depends on some CPU flags (MWAIT) and in AMD case on the type of CPU.
In case of mwait_idle we can hit some instances where the hypervisor
(Amazon EC2 specifically) sets the MWAIT and we get:
Brought up 2 CPUs
invalid opcode: 0000 [#1] SMP
Pid: 0, comm: swapper Not tainted 3.1.0-0.rc6.git0.3.fc16.x86_64 #1
RIP: e030:[<ffffffff81015d1d>] [<ffffffff81015d1d>] mwait_idle+0x6f/0xb4
...
Call Trace:
[<ffffffff8100e2ed>] cpu_idle+0xae/0xe8
[<ffffffff8149ee78>] cpu_bringup_and_idle+0xe/0x10
RIP [<ffffffff81015d1d>] mwait_idle+0x6f/0xb4
RSP <ffff8801d28ddf10>
In the case of amd_e400_idle we don't get so spectacular crashes, but we
do end up making an MSR which is trapped in the hypervisor, and then
follow it up with a yield hypercall. Meaning we end up going to
hypervisor twice instead of just once.
The previous behavior before v3.0 was that pm_idle was set to
default_idle regardless of select_idle_routine/idle_setup.
We want to do that, but only for one specific case: Xen. This patch
does that.
Fixes RH BZ #739499 and Ubuntu #881076
Reported-by: Stefan Bader <stefan.bader@canonical.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86/xen')
| -rw-r--r-- | arch/x86/xen/setup.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c index 38d0af4fefe..1093f80c162 100644 --- a/arch/x86/xen/setup.c +++ b/arch/x86/xen/setup.c @@ -410,6 +410,6 @@ void __init xen_arch_setup(void) #endif disable_cpuidle(); boot_option_idle_override = IDLE_HALT; - + WARN_ON(set_pm_idle_to_default()); fiddle_vdso(); } |