[Patch V2 2/2] x86/mm/numa: remove the numa_nodemask_from_meminfo()

From: Wei Yang
Date: Mon Mar 13 2017 - 23:08:39 EST


numa_nodemask_from_meminfo() is called to set bit according to
numa_meminfo. While the only two places for this call is used to set proper
bit to a copy of numa_nodes_parsed from numa_meminfo. With current code
path, those numa node information in numa_meminfo is a subset of
numa_nodes_parsed. So it is not necessary to set the bits again.

The following is a code path analysis to prove the numa node information in
numa_meminfo is a subset of numa_nodes_parsed.

x86_numa_init()
numa_init()
Case 1
acpi_numa_init()
acpi_parse_memory_affinity()
numa_add_memblk()
node_set(numa_nodes_parsed)
acpi_parse_slit()
numa_nodemask_from_meminfo()

Case 2
amd_numa_init()
numa_add_memblk()
node_set(numa_nodes_parsed)

Case 3
dummy_numa_init()
node_set(numa_nodes_parsed)
numa_add_memblk()

numa_register_memblks()
numa_nodemask_from_meminfo()

>From the code path analysis, we can see each time a memblk is added, the
proper bit is set in numa_nodes_parsed, which means it is not necessary to
set it again in numa_nodemask_from_meminfo() for a copy of
numa_nodes_parsed.

This patch removes numa_nodemask_from_meminfo().

Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxx>
---
arch/x86/mm/numa.c | 21 +--------------------
1 file changed, 1 insertion(+), 20 deletions(-)

diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index ac632e5397aa..5ecc5a745c51 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -314,20 +314,6 @@ int __init numa_cleanup_meminfo(struct numa_meminfo *mi)
return 0;
}

-/*
- * Set nodes, which have memory in @mi, in *@nodemask.
- */
-static void __init numa_nodemask_from_meminfo(nodemask_t *nodemask,
- const struct numa_meminfo *mi)
-{
- int i;
-
- for (i = 0; i < ARRAY_SIZE(mi->blk); i++)
- if (mi->blk[i].start != mi->blk[i].end &&
- mi->blk[i].nid != NUMA_NO_NODE)
- node_set(mi->blk[i].nid, *nodemask);
-}
-
/**
* numa_reset_distance - Reset NUMA distance table
*
@@ -347,16 +333,12 @@ void __init numa_reset_distance(void)

static int __init numa_alloc_distance(void)
{
- nodemask_t nodes_parsed;
size_t size;
int i, j, cnt = 0;
u64 phys;

/* size the new table and allocate it */
- nodes_parsed = numa_nodes_parsed;
- numa_nodemask_from_meminfo(&nodes_parsed, &numa_meminfo);
-
- for_each_node_mask(i, nodes_parsed)
+ for_each_node_mask(i, numa_nodes_parsed)
cnt = i;
cnt++;
size = cnt * cnt * sizeof(numa_distance[0]);
@@ -535,7 +517,6 @@ static int __init numa_register_memblks(struct numa_meminfo *mi)

/* Account for nodes with cpus and no memory */
node_possible_map = numa_nodes_parsed;
- numa_nodemask_from_meminfo(&node_possible_map, mi);
if (WARN_ON(nodes_empty(node_possible_map)))
return -EINVAL;

--
2.11.0