Re: [PATCH 1/1] rcu/tree: Drop the lock before entering to page allocator

[Sebastian Andrzej Siewior]

On 2020-07-15 20:35:37 [+0200], Uladzislau Rezki (Sony) wrote:
> @@ -3306,6 +3307,9 @@ kvfree_call_rcu_add_ptr_to_bulk(struct kfree_rcu_cpu 
> *krcp, void *ptr)
>                       if (IS_ENABLED(CONFIG_PREEMPT_RT))
>                               return false;
>  
> +                     preempt_disable();
> +                     krc_this_cpu_unlock(*krcp, *flags);

Now you enter memory allocator with disabled preemption. This isn't any
better but we don't have a warning for this yet.
What happened to the part where I asked for a spinlock_t?

> +
>                       /*
>                        * NOTE: For one argument of kvfree_rcu() we can
>                        * drop the lock and get the page in sleepable

Sebastian