Re: [PATCH 3/4] sparse: using kzalloc to clean up code

[Johannes Weiner <hannes@cmpxchg.org>]

On Thu, Aug 04, 2011 at 02:55:17PM +0800, Bob Liu wrote:
> On Thu, Aug 4, 2011 at 2:10 PM, Pekka Enberg <penberg@kernel.org> wrote:
> > On Thu, Aug 4, 2011 at 6:09 AM, Bob Liu <lliubbo@gmail.com> wrote:
> >> This patch using kzalloc to clean up sparse_index_alloc() and
> >> __GFP_ZERO to clean up __kmalloc_section_memmap().
> >>
> >> Signed-off-by: Bob Liu <lliubbo@gmail.com>
> >> ---
> >>  mm/sparse.c |   24 +++++++-----------------
> >>  1 files changed, 7 insertions(+), 17 deletions(-)
> >>
> >> diff --git a/mm/sparse.c b/mm/sparse.c
> >> index 858e1df..9596635 100644
> >> --- a/mm/sparse.c
> >> +++ b/mm/sparse.c
> >> @@ -65,15 +65,12 @@ static struct mem_section noinline __init_refok *sparse_index_alloc(int nid)
> >>
> >>        if (slab_is_available()) {
> >>                if (node_state(nid, N_HIGH_MEMORY))
> >> -                       section = kmalloc_node(array_size, GFP_KERNEL, nid);
> >> +                       section = kzalloc_node(array_size, GFP_KERNEL, nid);
> >>                else
> >> -                       section = kmalloc(array_size, GFP_KERNEL);
> >> +                       section = kzalloc(array_size, GFP_KERNEL);
> >>        } else
> >>                section = alloc_bootmem_node(NODE_DATA(nid), array_size);
> >>
> >> -       if (section)
> >> -               memset(section, 0, array_size);
> >> -
> >
> > You now broke the alloc_bootmem_node() path.
> >
> 
> Yes.
> But In my opinion, the alloc_bootmem_node() will also return zeroed memory.
> I saw it has used kzalloc or memset() but i'm not pretty sure.
> CC'd yinghai@kernel.org,hpa@zytor.com

You are right, bootmem always returns zeroed memory.  But it deserves
mentioning in the changelog.

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