2015-12-02 17:11:49

by Boris Ostrovsky

Subject: [PATCH] xen: Resume PMU from non-atomic context

Resuming PMU currently triggers a warning from ___might_sleep() (assuming
CONFIG_DEBUG_ATOMIC_SLEEP is set) when xen_pmu_init() allocates GFP_KERNEL
page because we are in state resembling atomic context.

Move resuming PMU to xen_arch_resume() which is called in regular context.
For symmetry move suspending PMU to xen_arch_suspend() as well.

Signed-off-by: Boris Ostrovsky <[email protected]>
Reported-by: Konrad Rzeszutek Wilk <[email protected]>
Cc: <[email protected]> # 4.3
---
arch/x86/xen/suspend.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/arch/x86/xen/suspend.c b/arch/x86/xen/suspend.c
index feddabd..3705eab 100644
--- a/arch/x86/xen/suspend.c
+++ b/arch/x86/xen/suspend.c
@@ -68,26 +68,16 @@ static void xen_pv_post_suspend(int suspend_cancelled)

void xen_arch_pre_suspend(void)
{
- int cpu;
-
- for_each_online_cpu(cpu)
- xen_pmu_finish(cpu);
-
if (xen_pv_domain())
xen_pv_pre_suspend();
}

void xen_arch_post_suspend(int cancelled)
{
- int cpu;
-
if (xen_pv_domain())
xen_pv_post_suspend(cancelled);
else
xen_hvm_post_suspend(cancelled);
-
- for_each_online_cpu(cpu)
- xen_pmu_init(cpu);
}

static void xen_vcpu_notify_restore(void *data)
@@ -106,10 +96,20 @@ static void xen_vcpu_notify_suspend(void *data)

void xen_arch_resume(void)
{
+ int cpu;
+
on_each_cpu(xen_vcpu_notify_restore, NULL, 1);
+
+ for_each_online_cpu(cpu)
+ xen_pmu_init(cpu);
}

void xen_arch_suspend(void)
{
+ int cpu;
+
+ for_each_online_cpu(cpu)
+ xen_pmu_finish(cpu);
+
on_each_cpu(xen_vcpu_notify_suspend, NULL, 1);
}
--
1.8.1.4

2015-12-02 17:19:04

by David Vrabel

Subject: Re: [Xen-devel] [PATCH] xen: Resume PMU from non-atomic context

On 02/12/15 17:10, Boris Ostrovsky wrote:
> Resuming PMU currently triggers a warning from ___might_sleep() (assuming
> CONFIG_DEBUG_ATOMIC_SLEEP is set) when xen_pmu_init() allocates GFP_KERNEL
> page because we are in state resembling atomic context.
>
> Move resuming PMU to xen_arch_resume() which is called in regular context.
> For symmetry move suspending PMU to xen_arch_suspend() as well.

Applied to for-linus-4.4, thanks.

David