diff options
Diffstat (limited to 'include/linux/sched/sd_flags.h')
| -rw-r--r-- | include/linux/sched/sd_flags.h | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/include/linux/sched/sd_flags.h b/include/linux/sched/sd_flags.h new file mode 100644 index 000000000000..57bde66d95f7 --- /dev/null +++ b/include/linux/sched/sd_flags.h @@ -0,0 +1,166 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * sched-domains (multiprocessor balancing) flag declarations. + */ + +#ifndef SD_FLAG +# error "Incorrect import of SD flags definitions" +#endif + +/* + * Hierarchical metaflags + * + * SHARED_CHILD: These flags are meant to be set from the base domain upwards. + * If a domain has this flag set, all of its children should have it set. This + * is usually because the flag describes some shared resource (all CPUs in that + * domain share the same resource), or because they are tied to a scheduling + * behaviour that we want to disable at some point in the hierarchy for + * scalability reasons. + * + * In those cases it doesn't make sense to have the flag set for a domain but + * not have it in (some of) its children: sched domains ALWAYS span their child + * domains, so operations done with parent domains will cover CPUs in the lower + * child domains. + * + * + * SHARED_PARENT: These flags are meant to be set from the highest domain + * downwards. If a domain has this flag set, all of its parents should have it + * set. This is usually for topology properties that start to appear above a + * certain level (e.g. domain starts spanning CPUs outside of the base CPU's + * socket). + */ +#define SDF_SHARED_CHILD 0x1 +#define SDF_SHARED_PARENT 0x2 + +/* + * Behavioural metaflags + * + * NEEDS_GROUPS: These flags are only relevant if the domain they are set on has + * more than one group. This is usually for balancing flags (load balancing + * involves equalizing a metric between groups), or for flags describing some + * shared resource (which would be shared between groups). + */ +#define SDF_NEEDS_GROUPS 0x4 + +/* + * Balance when about to become idle + * + * SHARED_CHILD: Set from the base domain up to cpuset.sched_relax_domain_level. + * NEEDS_GROUPS: Load balancing flag. + */ +SD_FLAG(SD_BALANCE_NEWIDLE, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) + +/* + * Balance on exec + * + * SHARED_CHILD: Set from the base domain up to the NUMA reclaim level. + * NEEDS_GROUPS: Load balancing flag. + */ +SD_FLAG(SD_BALANCE_EXEC, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) + +/* + * Balance on fork, clone + * + * SHARED_CHILD: Set from the base domain up to the NUMA reclaim level. + * NEEDS_GROUPS: Load balancing flag. + */ +SD_FLAG(SD_BALANCE_FORK, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) + +/* + * Balance on wakeup + * + * SHARED_CHILD: Set from the base domain up to cpuset.sched_relax_domain_level. + * NEEDS_GROUPS: Load balancing flag. + */ +SD_FLAG(SD_BALANCE_WAKE, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) + +/* + * Consider waking task on waking CPU. + * + * SHARED_CHILD: Set from the base domain up to the NUMA reclaim level. + */ +SD_FLAG(SD_WAKE_AFFINE, SDF_SHARED_CHILD) + +/* + * Domain members have different CPU capacities + * + * SHARED_PARENT: Set from the topmost domain down to the first domain where + * asymmetry is detected. + * NEEDS_GROUPS: Per-CPU capacity is asymmetric between groups. + */ +SD_FLAG(SD_ASYM_CPUCAPACITY, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS) + +/* + * Domain members have different CPU capacities spanning all unique CPU + * capacity values. + * + * SHARED_PARENT: Set from the topmost domain down to the first domain where + * all available CPU capacities are visible + * NEEDS_GROUPS: Per-CPU capacity is asymmetric between groups. + */ +SD_FLAG(SD_ASYM_CPUCAPACITY_FULL, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS) + +/* + * Domain members share CPU capacity (i.e. SMT) + * + * SHARED_CHILD: Set from the base domain up until spanned CPUs no longer share + * CPU capacity. + * NEEDS_GROUPS: Capacity is shared between groups. + */ +SD_FLAG(SD_SHARE_CPUCAPACITY, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) + +/* + * Domain members share CPU package resources (i.e. caches) + * + * SHARED_CHILD: Set from the base domain up until spanned CPUs no longer share + * the same cache(s). + * NEEDS_GROUPS: Caches are shared between groups. + */ +SD_FLAG(SD_SHARE_PKG_RESOURCES, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) + +/* + * Only a single load balancing instance + * + * SHARED_PARENT: Set for all NUMA levels above NODE. Could be set from a + * different level upwards, but it doesn't change that if a + * domain has this flag set, then all of its parents need to have + * it too (otherwise the serialization doesn't make sense). + * NEEDS_GROUPS: No point in preserving domain if it has a single group. + */ +SD_FLAG(SD_SERIALIZE, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS) + +/* + * Place busy tasks earlier in the domain + * + * SHARED_CHILD: Usually set on the SMT level. Technically could be set further + * up, but currently assumed to be set from the base domain + * upwards (see update_top_cache_domain()). + * NEEDS_GROUPS: Load balancing flag. + */ +SD_FLAG(SD_ASYM_PACKING, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) + +/* + * Prefer to place tasks in a sibling domain + * + * Set up until domains start spanning NUMA nodes. Close to being a SHARED_CHILD + * flag, but cleared below domains with SD_ASYM_CPUCAPACITY. + * + * NEEDS_GROUPS: Load balancing flag. + */ +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 + * + * SHARED_PARENT: Set for all NUMA levels above NODE. + * NEEDS_GROUPS: No point in preserving domain if it has a single group. + */ +SD_FLAG(SD_NUMA, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS) |