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sched/topology: Remove sched_domain_topology_level::flags

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Support for overlapping domains added in commit e3589f6c81 ("sched:
Allow for overlapping sched_domain spans") also allowed forcefully
setting SD_OVERLAP for !NUMA domains via FORCE_SD_OVERLAP sched_feat().

Since NUMA domains had to be presumed overlapping to ensure correct
behavior, "sched_domain_topology_level::flags" was introduced. NUMA
domains added the SDTL_OVERLAP flag would ensure SD_OVERLAP was always
added during build_sched_domains() for these domains, even when
FORCE_SD_OVERLAP was off.

Condition for adding the SD_OVERLAP flag at the aforementioned commit
was as follows:

    if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP))
            sd->flags |= SD_OVERLAP;

The FORCE_SD_OVERLAP debug feature was removed in commit af85596c74
("sched/topology: Remove FORCE_SD_OVERLAP") which left the NUMA domains
as the exclusive users of SDTL_OVERLAP, SD_OVERLAP, and SD_NUMA flags.

Get rid of SDTL_OVERLAP and SD_OVERLAP as they have become redundant
and instead rely on SD_NUMA to detect the only overlapping domain
currently supported. Since SDTL_OVERLAP was the only user of
"tl->flags", get rid of "sched_domain_topology_level::flags" too.

Signed-off-by: K Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/ba4dbdf8-bc37-493d-b2e0-2efb00ea3e19@amd.com
This commit is contained in:
K Prateek Nayak
2025-07-14 10:59:35 +02:00
committed by Peter Zijlstra
parent f79c9aa446
commit 1eec89a671
4 changed files with 13 additions and 23 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/linux/sched/sd_flags.h
-8
View File
@@ -153,14 +153,6 @@ SD_FLAG(SD_ASYM_PACKING, SDF_NEEDS_GROUPS)
*/
SD_FLAG(SD_PREFER_SIBLING, SDF_NEEDS_GROUPS)
/*
* sched_groups of this level overlap
*
* SHARED_PARENT: Set for all NUMA levels above NODE.
* NEEDS_GROUPS: Overlaps can only exist with more than one group.
*/
SD_FLAG(SD_OVERLAP, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS)
/*
* Cross-node balancing
*
include/linux/sched/topology.h
-3
View File
@@ -175,8 +175,6 @@ bool cpus_share_resources(int this_cpu, int that_cpu);
typedef const struct cpumask *(*sched_domain_mask_f)(int cpu);
typedef int (*sched_domain_flags_f)(void);
#define SDTL_OVERLAP 0x01
struct sd_data {
struct sched_domain *__percpu *sd;
struct sched_domain_shared *__percpu *sds;
@@ -187,7 +185,6 @@ struct sd_data {
struct sched_domain_topology_level {
sched_domain_mask_f mask;
sched_domain_flags_f sd_flags;
int flags;
int numa_level;
struct sd_data data;
char *name;
kernel/sched/fair.c
+3 -3
View File
@@ -9926,9 +9926,9 @@ void update_group_capacity(struct sched_domain *sd, int cpu)
min_capacity = ULONG_MAX;
max_capacity = 0;
if (child->flags & SD_OVERLAP) {
if (child->flags & SD_NUMA) {
/*
* SD_OVERLAP domains cannot assume that child groups
* SD_NUMA domains cannot assume that child groups
* span the current group.
*/
@@ -9941,7 +9941,7 @@ void update_group_capacity(struct sched_domain *sd, int cpu)
}
} else {
/*
* !SD_OVERLAP domains can assume that child groups
* !SD_NUMA domains can assume that child groups
* span the current group.
*/
kernel/sched/topology.c
+10 -9
View File
@@ -89,7 +89,7 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
break;
}
if (!(sd->flags & SD_OVERLAP) &&
if (!(sd->flags & SD_NUMA) &&
cpumask_intersects(groupmask, sched_group_span(group))) {
printk(KERN_CONT "\n");
printk(KERN_ERR "ERROR: repeated CPUs\n");
@@ -102,7 +102,7 @@ static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
group->sgc->id,
cpumask_pr_args(sched_group_span(group)));
if ((sd->flags & SD_OVERLAP) &&
if ((sd->flags & SD_NUMA) &&
!cpumask_equal(group_balance_mask(group), sched_group_span(group))) {
printk(KERN_CONT " mask=%*pbl",
cpumask_pr_args(group_balance_mask(group)));
@@ -1344,7 +1344,7 @@ void sched_update_asym_prefer_cpu(int cpu, int old_prio, int new_prio)
* "sg->asym_prefer_cpu" to "sg->sgc->asym_prefer_cpu"
* which is shared by all the overlapping groups.
*/
WARN_ON_ONCE(sd->flags & SD_OVERLAP);
WARN_ON_ONCE(sd->flags & SD_NUMA);
sg = sd->groups;
if (cpu != sg->asym_prefer_cpu) {
@@ -2016,7 +2016,6 @@ void sched_init_numa(int offline_node)
for (j = 1; j < nr_levels; i++, j++) {
tl[i] = SDTL_INIT(sd_numa_mask, cpu_numa_flags, NUMA);
tl[i].numa_level = j;
tl[i].flags = SDTL_OVERLAP;
}
sched_domain_topology_saved = sched_domain_topology;
@@ -2327,7 +2326,7 @@ static void __sdt_free(const struct cpumask *cpu_map)
if (sdd->sd) {
sd = *per_cpu_ptr(sdd->sd, j);
if (sd && (sd->flags & SD_OVERLAP))
if (sd && (sd->flags & SD_NUMA))
free_sched_groups(sd->groups, 0);
kfree(*per_cpu_ptr(sdd->sd, j));
}
@@ -2393,9 +2392,13 @@ static bool topology_span_sane(const struct cpumask *cpu_map)
id_seen = sched_domains_tmpmask2;
for_each_sd_topology(tl) {
int tl_common_flags = 0;
if (tl->sd_flags)
tl_common_flags = (*tl->sd_flags)();
/* NUMA levels are allowed to overlap */
if (tl->flags & SDTL_OVERLAP)
if (tl_common_flags & SD_NUMA)
continue;
cpumask_clear(covered);
@@ -2466,8 +2469,6 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att
if (tl == sched_domain_topology)
*per_cpu_ptr(d.sd, i) = sd;
if (tl->flags & SDTL_OVERLAP)
sd->flags |= SD_OVERLAP;
if (cpumask_equal(cpu_map, sched_domain_span(sd)))
break;
}
@@ -2480,7 +2481,7 @@ build_sched_domains(const struct cpumask *cpu_map, struct sched_domain_attr *att
for_each_cpu(i, cpu_map) {
for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
sd->span_weight = cpumask_weight(sched_domain_span(sd));
if (sd->flags & SD_OVERLAP) {
if (sd->flags & SD_NUMA) {
if (build_overlap_sched_groups(sd, i))
goto error;
} else {