On Sat 23-06-12 23:52:53, Gavin Shan wrote:
> With CONFIG_SPARSEMEM_EXTREME, the two level of memory section
> descriptors are allocated from slab or bootmem. When allocating
> from slab, let slab allocator to clear the memory chunk. However,
> the memory chunk from bootmem allocator, we have to clear that
> explicitly.
I am sorry but I do not see how this optimize the current code. What is
the difference between slab doing memset and doing it explicitly for all
cases?
>
> Signed-off-by: Gavin Shan <shangw@xxxxxxxxxxxxxxxxxx>
> ---
> mm/sparse.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/mm/sparse.c b/mm/sparse.c
> index afd0998..ce50c8b 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -74,14 +74,14 @@ 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);
> - } else
> + section = kzalloc(array_size, GFP_KERNEL);
> + } else {
> section = alloc_bootmem_node(NODE_DATA(nid), array_size);
> -
> - if (section)
> - memset(section, 0, array_size);
> + if (section)
> + memset(section, 0, array_size);
> + }
>
> return section;
> }
> --
> 1.7.9.5
>
> --
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--
Michal Hocko
SUSE Labs
SUSE LINUX s.r.o.
Lihovarska 1060/12
190 00 Praha 9
Czech Republic
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