diff options
| author | Yury Norov [NVIDIA] <yury.norov@gmail.com> | 2025-05-09 12:20:08 -0400 |
|---|---|---|
| committer | Yury Norov <yury.norov@gmail.com> | 2025-05-13 11:40:04 -0400 |
| commit | 895ee6a22e3195b7c1fee140c842bdeedb89ed33 (patch) | |
| tree | ff3267bf545568210ea89b4880652979e50ad08f | |
| parent | a256ae22570ee4c3427fdc703a58a89afee6a332 (diff) | |
topology: make for_each_node_with_cpus() O(N)
for_each_node_with_cpus() calls nr_cpus_node() at every iteration, which
makes it O(N^2). Kernel tracks such nodes with N_CPU record in node_states
array. Switching to it makes for_each_node_with_cpus() O(N).
Andrea:
Now we can include also offline nodes with CPUs assigned (assuming it's
possible). If checking the online state is required, the user must use
node_online() within the loop.
CC: Andrea Righi <arighi@nvidia.com>
CC:Tejun Heo <tj@kernel.org>
Signed-off-by: Yury Norov [NVIDIA] <yury.norov@gmail.com>
| -rw-r--r-- | include/linux/nodemask.h | 1 | ||||
| -rw-r--r-- | include/linux/topology.h | 5 |
2 files changed, 2 insertions, 4 deletions
diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h index 0aa6b63aa747..f08ae71585fa 100644 --- a/include/linux/nodemask.h +++ b/include/linux/nodemask.h @@ -522,6 +522,7 @@ static __always_inline int node_random(const nodemask_t *maskp) #define for_each_node(node) for_each_node_state(node, N_POSSIBLE) #define for_each_online_node(node) for_each_node_state(node, N_ONLINE) +#define for_each_node_with_cpus(node) for_each_node_state(node, N_CPU) /* * For nodemask scratch area. diff --git a/include/linux/topology.h b/include/linux/topology.h index 24e715f0f6d2..ffee6b4a071a 100644 --- a/include/linux/topology.h +++ b/include/linux/topology.h @@ -29,6 +29,7 @@ #include <linux/arch_topology.h> #include <linux/cpumask.h> +#include <linux/nodemask.h> #include <linux/bitops.h> #include <linux/mmzone.h> #include <linux/smp.h> @@ -39,10 +40,6 @@ #define nr_cpus_node(node) cpumask_weight(cpumask_of_node(node)) #endif -#define for_each_node_with_cpus(node) \ - for_each_online_node(node) \ - if (nr_cpus_node(node)) - int arch_update_cpu_topology(void); /* Conform to ACPI 2.0 SLIT distance definitions */ |