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Date: Mon, 9 Nov 2015 16:04:51 -0600 (CST)
From: Christoph Lameter <cl@linux.com>
Subject: Re: [PATCH V3 1/2] slub: fix kmem cgroup bug in
 kmem_cache_alloc_bulk
In-Reply-To: <20151109191335.GM31308@esperanza>
Message-ID: <alpine.DEB.2.20.1511091603240.26497@east.gentwo.org>
References: <20151109181604.8231.22983.stgit@firesoul> <20151109181703.8231.66384.stgit@firesoul> <20151109191335.GM31308@esperanza>
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Sender: owner-linux-mm@kvack.org
List-ID: <linux-mm.kvack.org>
To: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>, linux-mm@kvack.org, Joonsoo Kim <iamjoonsoo.kim@lge.com>, Andrew Morton <akpm@linux-foundation.org>

On Mon, 9 Nov 2015, Vladimir Davydov wrote:

> I think it must be &object
>
> BTW why is object defined as void **? I suspect we can safely drop one
> star.

See get_freepointer()

static inline void *get_freepointer(struct kmem_cache *s, void *object)
{
        return *(void **)(object + s->offset);
}

The object at some point has a freepointer and ** allows the use of the
s->offset field to get to it.


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