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Subject[PATCH 52/54] lib/nodemask: add num_node_state_eq()
Date
Kernel code uses num_node_state() to compare number of nodes with a given
number. The underlying code calls bitmap_weight(), and we can do it more
efficiently with num_node_state_eq because conditional nodes_weight may
stop traversing the nodemask earlier, as soon as condition is met.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
---
include/linux/nodemask.h | 5 +++++
mm/page_alloc.c | 2 +-
2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h
index 197598e075e9..c5014dbf3cce 100644
--- a/include/linux/nodemask.h
+++ b/include/linux/nodemask.h
@@ -466,6 +466,11 @@ static inline int num_node_state(enum node_states state)
return nodes_weight(node_states[state]);
}

+static inline int num_node_state_eq(enum node_states state, int num)
+{
+ return nodes_weight_eq(node_states[state], num);
+}
+
#define for_each_node_state(__node, __state) \
for_each_node_mask((__node), node_states[__state])

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8dd6399bafb5..37496d764643 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -8328,7 +8328,7 @@ void __init page_alloc_init(void)
int ret;

#ifdef CONFIG_NUMA
- if (num_node_state(N_MEMORY) == 1)
+ if (num_node_state_eq(N_MEMORY, 1))
hashdist = 0;
#endif

--
2.30.2
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