On 07/14/2017 10:00 AM, Michal Hocko wrote:
> From: Michal Hocko <mhocko@xxxxxxxx>
>
> f52407ce2dea ("memory hotplug: alloc page from other node in memory
> online") has introduced N_HIGH_MEMORY checks to only use NUMA aware
> allocations when there is some memory present because the respective
> node might not have any memory yet at the time and so it could fail
> or even OOM. Things have changed since then though. Zonelists are
> now always initialized before we do any allocations even for hotplug
> (see 959ecc48fc75 ("mm/memory_hotplug.c: fix building of node hotplug
> zonelist")). Therefore these checks are not really needed. In fact
> caller of the allocator should never care about whether the node is
> populated because that might change at any time.
>
> Cc: Shaohua Li <shaohua.li@xxxxxxxxx>
> Cc: joonsoo kim <js1304@xxxxxxxxx>
> Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
> ---
> mm/page_ext.c | 5 +----
> mm/sparse-vmemmap.c | 11 +++--------
> mm/sparse.c | 10 +++-------
> 3 files changed, 7 insertions(+), 19 deletions(-)
>
> diff --git a/mm/page_ext.c b/mm/page_ext.c
> index 88ccc044b09a..714ce79256c5 100644
> --- a/mm/page_ext.c
> +++ b/mm/page_ext.c
> @@ -222,10 +222,7 @@ static void *__meminit alloc_page_ext(size_t size, int nid)
> return addr;
> }
>
> - if (node_state(nid, N_HIGH_MEMORY))
> - addr = vzalloc_node(size, nid);
> - else
> - addr = vzalloc(size);
> + addr = vzalloc_node(size, nid);
>
> return addr;
> }
> diff --git a/mm/sparse-vmemmap.c b/mm/sparse-vmemmap.c
> index c50b1a14d55e..d1a39b8051e0 100644
> --- a/mm/sparse-vmemmap.c
> +++ b/mm/sparse-vmemmap.c
> @@ -54,14 +54,9 @@ void * __meminit vmemmap_alloc_block(unsigned long size, int node)
> if (slab_is_available()) {
> struct page *page;
>
> - if (node_state(node, N_HIGH_MEMORY))
> - page = alloc_pages_node(
> - node, GFP_KERNEL | __GFP_ZERO | __GFP_RETRY_MAYFAIL,
> - get_order(size));
> - else
> - page = alloc_pages(
> - GFP_KERNEL | __GFP_ZERO | __GFP_RETRY_MAYFAIL,
> - get_order(size));
> + page = alloc_pages_node(node,
> + GFP_KERNEL | __GFP_ZERO | __GFP_RETRY_MAYFAIL,
> + get_order(size));
> if (page)
> return page_address(page);
> return NULL;
> diff --git a/mm/sparse.c b/mm/sparse.c
> index 7b4be3fd5cac..a9783acf2bb9 100644
> --- a/mm/sparse.c
> +++ b/mm/sparse.c
> @@ -65,14 +65,10 @@ static noinline struct mem_section __ref *sparse_index_alloc(int nid)
> unsigned long array_size = SECTIONS_PER_ROOT *
> sizeof(struct mem_section);
>
> - if (slab_is_available()) {
> - if (node_state(nid, N_HIGH_MEMORY))
> - section = kzalloc_node(array_size, GFP_KERNEL, nid);
> - else
> - section = kzalloc(array_size, GFP_KERNEL);
> - } else {
> + if (slab_is_available())
> + section = kzalloc_node(array_size, GFP_KERNEL, nid);
> + else
> section = memblock_virt_alloc_node(array_size, nid);
> - }
>
> return section;
> }
>
--
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