Commit 1eec89a6 authored by K Prateek Nayak's avatar K Prateek Nayak Committed by Peter Zijlstra
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sched/topology: Remove sched_domain_topology_level::flags 



Support for overlapping domains added in commit e3589f6c ("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 af85596c
("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: default avatarK Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/ba4dbdf8-bc37-493d-b2e0-2efb00ea3e19@amd.com
parent f79c9aa4

include/linux/sched/sd_flags.h

+0 −8
Original line number Diff line number Diff line
@@ -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

+0 −3
Original line number Diff line number Diff line
@@ -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
Original line number Diff line number Diff line
@@ -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
Original line number Diff line number Diff line
@@ -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 {