2020-09-04 13:34:30

by Mateusz Nosek

Subject: [PATCH] mm/page_alloc.c: Clean code by removing unnecessary initialization

From: Mateusz Nosek <[email protected]>

Previously variable 'tmp' was initialized, but was not read later
before reassigning. So the initialization can be removed.

Signed-off-by: Mateusz Nosek <[email protected]>
---
mm/page_alloc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 3ae4f3651aec..77c3d2084004 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5637,7 +5637,7 @@ static int find_next_best_node(int node, nodemask_t *used_node_mask)
int n, val;
int min_val = INT_MAX;
int best_node = NUMA_NO_NODE;
- const struct cpumask *tmp = cpumask_of_node(0);
+ const struct cpumask *tmp;

/* Use the local node if we haven't already */
if (!node_isset(node, *used_node_mask)) {
--
2.20.1

2020-09-04 18:15:15

by Andrew Morton

Subject: Re: [PATCH] mm/page_alloc.c: Clean code by removing unnecessary initialization

On Fri, 4 Sep 2020 15:24:22 +0200 [email protected] wrote:

> From: Mateusz Nosek <[email protected]>
>
> Previously variable 'tmp' was initialized, but was not read later
> before reassigning. So the initialization can be removed.
>
> ...
>
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -5637,7 +5637,7 @@ static int find_next_best_node(int node, nodemask_t *used_node_mask)
> int n, val;
> int min_val = INT_MAX;
> int best_node = NUMA_NO_NODE;
> - const struct cpumask *tmp = cpumask_of_node(0);
> + const struct cpumask *tmp;
>
> /* Use the local node if we haven't already */
> if (!node_isset(node, *used_node_mask)) {

OK. But we may as well kill tmp altogether?

--- a/mm/page_alloc.c~mm-page_allocc-clean-code-by-removing-unnecessary-initialization-fix
+++ a/mm/page_alloc.c
@@ -5637,7 +5637,6 @@ static int find_next_best_node(int node,
int n, val;
int min_val = INT_MAX;
int best_node = NUMA_NO_NODE;
- const struct cpumask *tmp;

/* Use the local node if we haven't already */
if (!node_isset(node, *used_node_mask)) {
@@ -5658,8 +5657,7 @@ static int find_next_best_node(int node,
val += (n < node);

/* Give preference to headless and unused nodes */
- tmp = cpumask_of_node(n);
- if (!cpumask_empty(tmp))
+ if (!cpumask_empty(cpumask_of_node(n)))
val += PENALTY_FOR_NODE_WITH_CPUS;

/* Slight preference for less loaded node */
_