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Subject: Re: [PATCH -mm 5/6] slqb: introduce __kfree_rcu
From: Pekka Enberg <penberg@cs.helsinki.fi>
To: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
       Christoph Lameter <cl@linux-foundation.org>,
       Nick Piggin <npiggin@suse.de>,
       "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
       Manfred Spraul <manfred@colorfullife.com>, Ingo Molnar <mingo@elte.hu>,
       Peter Zijlstra <peterz@infradead.org>, linux-kernel@vger.kernel.org
In-Reply-To: <49AD3448.6050105@cn.fujitsu.com>
References: <49AD3448.6050105@cn.fujitsu.com>
Date: Mon, 23 Mar 2009 09:54:59 +0200
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On Tue, 2009-03-03 at 21:44 +0800, Lai Jiangshan wrote:
> Introduce __kfree_rcu() for kfree_rcu()
> 
> It like __kfree_rcu() in slab.c, slub.c
> We can calculate the object poiter from a poiter inside this
> object in slqb.c, so we can use it for rcu callback and free
> the object.
> 
> Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
> ---
> diff --git a/mm/slqb.c b/mm/slqb.c
> index 48bdf3b..c258ddc 100644
> --- a/mm/slqb.c
> +++ b/mm/slqb.c
> @@ -2482,6 +2484,23 @@ void kfree(const void *object)
>  }
>  EXPORT_SYMBOL(kfree);
>  
> +static void kfree_rcu_callback(struct rcu_head *rcu)
> +{
> +	void *portion = rcu;
> +	struct slqb_page *page = virt_to_head_slqb_page(portion);
> +	struct kmem_cache *s = page->list->cache;
> +	unsigned int index = (portion - page->s_mem) / s->size;
> +	void *object = page->s_mem + s->size * index;

Basically the same nit as with the other patches as well: please
separate variable declarations from the initializations for readability.

> +
> +	slab_free(s, page, object);
> +}
> +
> +void __kfree_rcu(const void *objp, struct rcu_head *rcu)
> +{
> +	call_rcu(rcu, kfree_rcu_callback);
> +}
> +EXPORT_SYMBOL(__kfree_rcu);
> +
>  static void kmem_cache_trim_percpu(void *arg)
>  {
>  	int cpu = smp_processor_id();
> 
> 
> 
> 
>