Re: [PATCH] mm: Support memblock alloc on the exact node for sparse_buffer_init()

[Wei Yang <richardw.yang@linux.intel.com>]

On Wed, Sep 18, 2019 at 12:22:29PM +0800, Yunfeng Ye wrote:
>Currently, when memblock_find_in_range_node() fail on the exact node, it
>will use %NUMA_NO_NODE to find memblock from other nodes. At present,
>the work is good, but when the large memory is insufficient and the
>small memory is enough, we want to allocate the small memory of this
>node first, and do not need to allocate large memory from other nodes.
>
>In sparse_buffer_init(), it will prepare large chunks of memory for page
>structure. The page management structure requires a lot of memory, but
>if the node does not have enough memory, it can be converted to a small
>memory allocation without having to allocate it from other nodes.
>
>Add %MEMBLOCK_ALLOC_EXACT_NODE flag for this situation. Normally, the
>behavior is the same with %MEMBLOCK_ALLOC_ACCESSIBLE, only that it will
>not allocate from other nodes when a single node fails to allocate.
>
>If large contiguous block memory allocated fail in sparse_buffer_init(),
>it will allocates small block memmory section by section later.
>

Looks this changes current behavior even it fall back to section based
allocation.

>Signed-off-by: Yunfeng Ye <yeyunfeng@huawei.com>
>---
> include/linux/memblock.h | 1 +
> mm/memblock.c            | 3 ++-
> mm/sparse.c              | 2 +-
> 3 files changed, 4 insertions(+), 2 deletions(-)
>
>diff --git a/include/linux/memblock.h b/include/linux/memblock.h
>index f491690..9a81d9c 100644
>--- a/include/linux/memblock.h
>+++ b/include/linux/memblock.h
>@@ -339,6 +339,7 @@ static inline int memblock_get_region_node(const struct memblock_region *r)
> #define MEMBLOCK_ALLOC_ANYWHERE	(~(phys_addr_t)0)
> #define MEMBLOCK_ALLOC_ACCESSIBLE	0
> #define MEMBLOCK_ALLOC_KASAN		1
>+#define MEMBLOCK_ALLOC_EXACT_NODE	2
>
> /* We are using top down, so it is safe to use 0 here */
> #define MEMBLOCK_LOW_LIMIT 0
>diff --git a/mm/memblock.c b/mm/memblock.c
>index 7d4f61a..dbd52c3c 100644
>--- a/mm/memblock.c
>+++ b/mm/memblock.c
>@@ -277,6 +277,7 @@ static phys_addr_t __init_memblock memblock_find_in_range_node(phys_addr_t size,
>
> 	/* pump up @end */
> 	if (end == MEMBLOCK_ALLOC_ACCESSIBLE ||
>+	    end == MEMBLOCK_ALLOC_EXACT_NODE ||
> 	    end == MEMBLOCK_ALLOC_KASAN)
> 		end = memblock.current_limit;
>
>@@ -1365,7 +1366,7 @@ static phys_addr_t __init memblock_alloc_range_nid(phys_addr_t size,
> 	if (found && !memblock_reserve(found, size))
> 		goto done;
>
>-	if (nid != NUMA_NO_NODE) {
>+	if (end != MEMBLOCK_ALLOC_EXACT_NODE && nid != NUMA_NO_NODE) {
> 		found = memblock_find_in_range_node(size, align, start,
> 						    end, NUMA_NO_NODE,
> 						    flags);
>diff --git a/mm/sparse.c b/mm/sparse.c
>index 72f010d..828db46 100644
>--- a/mm/sparse.c
>+++ b/mm/sparse.c
>@@ -477,7 +477,7 @@ static void __init sparse_buffer_init(unsigned long size, int nid)
> 	sparsemap_buf =
> 		memblock_alloc_try_nid_raw(size, PAGE_SIZE,
> 						addr,
>-						MEMBLOCK_ALLOC_ACCESSIBLE, nid);
>+						MEMBLOCK_ALLOC_EXACT_NODE, nid);
> 	sparsemap_buf_end = sparsemap_buf + size;
> }
>
>-- 
>2.7.4.huawei.3
>

-- 
Wei Yang
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