[PATCH v3 6/7] lib/group_cpus: drop unneeded cpumask_empty() call in __group_cpus_evenly()

Yury Norov
2023-12-12T04:21:40Z

The function is called twice. First time it's called with
cpumask_present as a parameter, which can't be empty. Second time it's
called with a mask created with cpumask_andnot(), which returns false if
the result is an empty mask.

We can safely drop redundand cpumask_empty() call from the
__group_cpus_evenly() and save few cycles.

Signed-off-by: Yury Norov <yury.norov@gmail.com>
---
lib/group_cpus.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/lib/group_cpus.c b/lib/group_cpus.c
index c7fcd04c87bf..664a56171a1b 100644
--- a/lib/group_cpus.c
+++ b/lib/group_cpus.c
@@ -252,9 +252,6 @@ static int __group_cpus_evenly(unsigned int startgrp, unsigned int numgrps,
nodemask_t nodemsk = NODE_MASK_NONE;
struct node_groups *node_groups;

- if (cpumask_empty(cpu_mask))
- return 0;
-
nodes = get_nodes_in_cpumask(node_to_cpumask, cpu_mask, &nodemsk);

/*
@@ -394,9 +391,14 @@ struct cpumask *group_cpus_evenly(unsigned int numgrps)
curgrp = 0;
else
curgrp = nr_present;
- cpumask_andnot(npresmsk, cpu_possible_mask, npresmsk);
- ret = __group_cpus_evenly(curgrp, numgrps, node_to_cpumask,
- npresmsk, nmsk, masks);
+
+ if (cpumask_andnot(npresmsk, cpu_possible_mask, npresmsk))
+ /* If npresmsk is not empty */
+ ret = __group_cpus_evenly(curgrp, numgrps, node_to_cpumask,
+ npresmsk, nmsk, masks);
+ else
+ ret = 0;
+
if (ret >= 0)
nr_others = ret;

--
2.40.1