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authorYury Norov <yury.norov@gmail.com>2022-01-23 10:38:46 -0800
committerYury Norov <yury.norov@gmail.com>2022-06-03 06:52:57 -0700
commit4aec74bccf5d047347bdfef3638e3031dd75c0a0 (patch)
tree1c47143b5015168e9c99f2cc5673b9ebd19822fc /arch
parentb6dad11d9cb105681abbfc3d57aae4b21bd0c8c4 (diff)
arch/x86: replace cpumask_weight with cpumask_empty where appropriate
In some cases, arch/x86 code calls cpumask_weight() to check if any bit of a given cpumask is set. We can do it more efficiently with cpumask_empty() because cpumask_empty() stops traversing the cpumask as soon as it finds first set bit, while cpumask_weight() counts all bits unconditionally. Signed-off-by: Yury Norov <yury.norov@gmail.com> Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/cpu/resctrl/rdtgroup.c14
-rw-r--r--arch/x86/mm/mmio-mod.c2
-rw-r--r--arch/x86/platform/uv/uv_nmi.c2
3 files changed, 9 insertions, 9 deletions
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 83f901e2c2df..f276aff521e8 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -341,14 +341,14 @@ static int cpus_mon_write(struct rdtgroup *rdtgrp, cpumask_var_t newmask,
/* Check whether cpus belong to parent ctrl group */
cpumask_andnot(tmpmask, newmask, &prgrp->cpu_mask);
- if (cpumask_weight(tmpmask)) {
+ if (!cpumask_empty(tmpmask)) {
rdt_last_cmd_puts("Can only add CPUs to mongroup that belong to parent\n");
return -EINVAL;
}
/* Check whether cpus are dropped from this group */
cpumask_andnot(tmpmask, &rdtgrp->cpu_mask, newmask);
- if (cpumask_weight(tmpmask)) {
+ if (!cpumask_empty(tmpmask)) {
/* Give any dropped cpus to parent rdtgroup */
cpumask_or(&prgrp->cpu_mask, &prgrp->cpu_mask, tmpmask);
update_closid_rmid(tmpmask, prgrp);
@@ -359,7 +359,7 @@ static int cpus_mon_write(struct rdtgroup *rdtgrp, cpumask_var_t newmask,
* and update per-cpu rmid
*/
cpumask_andnot(tmpmask, newmask, &rdtgrp->cpu_mask);
- if (cpumask_weight(tmpmask)) {
+ if (!cpumask_empty(tmpmask)) {
head = &prgrp->mon.crdtgrp_list;
list_for_each_entry(crgrp, head, mon.crdtgrp_list) {
if (crgrp == rdtgrp)
@@ -394,7 +394,7 @@ static int cpus_ctrl_write(struct rdtgroup *rdtgrp, cpumask_var_t newmask,
/* Check whether cpus are dropped from this group */
cpumask_andnot(tmpmask, &rdtgrp->cpu_mask, newmask);
- if (cpumask_weight(tmpmask)) {
+ if (!cpumask_empty(tmpmask)) {
/* Can't drop from default group */
if (rdtgrp == &rdtgroup_default) {
rdt_last_cmd_puts("Can't drop CPUs from default group\n");
@@ -413,12 +413,12 @@ static int cpus_ctrl_write(struct rdtgroup *rdtgrp, cpumask_var_t newmask,
* and update per-cpu closid/rmid.
*/
cpumask_andnot(tmpmask, newmask, &rdtgrp->cpu_mask);
- if (cpumask_weight(tmpmask)) {
+ if (!cpumask_empty(tmpmask)) {
list_for_each_entry(r, &rdt_all_groups, rdtgroup_list) {
if (r == rdtgrp)
continue;
cpumask_and(tmpmask1, &r->cpu_mask, tmpmask);
- if (cpumask_weight(tmpmask1))
+ if (!cpumask_empty(tmpmask1))
cpumask_rdtgrp_clear(r, tmpmask1);
}
update_closid_rmid(tmpmask, rdtgrp);
@@ -488,7 +488,7 @@ static ssize_t rdtgroup_cpus_write(struct kernfs_open_file *of,
/* check that user didn't specify any offline cpus */
cpumask_andnot(tmpmask, newmask, cpu_online_mask);
- if (cpumask_weight(tmpmask)) {
+ if (!cpumask_empty(tmpmask)) {
ret = -EINVAL;
rdt_last_cmd_puts("Can only assign online CPUs\n");
goto unlock;
diff --git a/arch/x86/mm/mmio-mod.c b/arch/x86/mm/mmio-mod.c
index 933a2ebad471..c3317f0650d8 100644
--- a/arch/x86/mm/mmio-mod.c
+++ b/arch/x86/mm/mmio-mod.c
@@ -400,7 +400,7 @@ static void leave_uniprocessor(void)
int cpu;
int err;
- if (!cpumask_available(downed_cpus) || cpumask_weight(downed_cpus) == 0)
+ if (!cpumask_available(downed_cpus) || cpumask_empty(downed_cpus))
return;
pr_notice("Re-enabling CPUs...\n");
for_each_cpu(cpu, downed_cpus) {
diff --git a/arch/x86/platform/uv/uv_nmi.c b/arch/x86/platform/uv/uv_nmi.c
index 1e9ff28bc2e0..ea277fc08357 100644
--- a/arch/x86/platform/uv/uv_nmi.c
+++ b/arch/x86/platform/uv/uv_nmi.c
@@ -985,7 +985,7 @@ static int uv_handle_nmi(unsigned int reason, struct pt_regs *regs)
/* Clear global flags */
if (master) {
- if (cpumask_weight(uv_nmi_cpu_mask))
+ if (!cpumask_empty(uv_nmi_cpu_mask))
uv_nmi_cleanup_mask();
atomic_set(&uv_nmi_cpus_in_nmi, -1);
atomic_set(&uv_nmi_cpu, -1);