Re: [Xen-devel] [PATCH v3 5/6] xen/rcu: add assertions to debug build

[Julien Grall <julien@xxxxxxx>]

Hi,

On 04/03/2020 06:32, Juergen Gross wrote:
> diff --git a/xen/include/xen/rcupdate.h b/xen/include/xen/rcupdate.h
> index 31c8b86d13..9f6d420898 100644
> --- a/xen/include/xen/rcupdate.h
> +++ b/xen/include/xen/rcupdate.h
> @@ -34,10 +34,40 @@
>   #include <xen/cache.h>
>   #include <xen/spinlock.h>
>   #include <xen/cpumask.h>
> -#include <xen/preempt.h>
> +#include <xen/percpu.h>
> +#include <asm/atomic.h>
>   
>   #define __rcu
>   
> +#ifndef NDEBUG
> +DECLARE_PER_CPU(unsigned int, rcu_lock_cnt);
> +
> +static inline void rcu_quiesce_disable(void)
> +{
> +    this_cpu(rcu_lock_cnt)++;
> +    arch_lock_acquire_barrier();
I am not sure to understand the goal of this barrier. What are you 
trying to protect against?
Cheers,

--
Julien Grall

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