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2309a05d2a
Introducing new, complementary to SD_ASYM_CPUCAPACITY, sched_domain topology flag, to distinguish between shed_domains where any CPU capacity asymmetry is detected (SD_ASYM_CPUCAPACITY) and ones where a full set of CPU capacities is visible to all domain members (SD_ASYM_CPUCAPACITY_FULL). With the distinction between full and partial CPU capacity asymmetry, brought in by the newly introduced flag, the scope of the original SD_ASYM_CPUCAPACITY flag gets shifted, still maintaining the existing behaviour when one is detected on a given sched domain, allowing misfit migrations within sched domains that do not observe full range of CPU capacities but still do have members with different capacity values. It loses though it's meaning when it comes to the lowest CPU asymmetry sched_domain level per-cpu pointer, which is to be now denoted by SD_ASYM_CPUCAPACITY_FULL flag. Signed-off-by: Beata Michalska <beata.michalska@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Valentin Schneider <valentin.schneider@arm.com> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Link: https://lore.kernel.org/r/20210603140627.8409-2-beata.michalska@arm.com
166 lines
5.4 KiB
C
166 lines
5.4 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* sched-domains (multiprocessor balancing) flag declarations.
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*/
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#ifndef SD_FLAG
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# error "Incorrect import of SD flags definitions"
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#endif
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/*
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* Hierarchical metaflags
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*
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* SHARED_CHILD: These flags are meant to be set from the base domain upwards.
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* If a domain has this flag set, all of its children should have it set. This
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* is usually because the flag describes some shared resource (all CPUs in that
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* domain share the same resource), or because they are tied to a scheduling
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* behaviour that we want to disable at some point in the hierarchy for
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* scalability reasons.
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*
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* In those cases it doesn't make sense to have the flag set for a domain but
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* not have it in (some of) its children: sched domains ALWAYS span their child
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* domains, so operations done with parent domains will cover CPUs in the lower
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* child domains.
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*
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*
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* SHARED_PARENT: These flags are meant to be set from the highest domain
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* downwards. If a domain has this flag set, all of its parents should have it
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* set. This is usually for topology properties that start to appear above a
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* certain level (e.g. domain starts spanning CPUs outside of the base CPU's
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* socket).
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*/
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#define SDF_SHARED_CHILD 0x1
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#define SDF_SHARED_PARENT 0x2
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/*
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* Behavioural metaflags
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*
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* NEEDS_GROUPS: These flags are only relevant if the domain they are set on has
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* more than one group. This is usually for balancing flags (load balancing
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* involves equalizing a metric between groups), or for flags describing some
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* shared resource (which would be shared between groups).
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*/
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#define SDF_NEEDS_GROUPS 0x4
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/*
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* Balance when about to become idle
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*
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* SHARED_CHILD: Set from the base domain up to cpuset.sched_relax_domain_level.
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* NEEDS_GROUPS: Load balancing flag.
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*/
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SD_FLAG(SD_BALANCE_NEWIDLE, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS)
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/*
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* Balance on exec
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*
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* SHARED_CHILD: Set from the base domain up to the NUMA reclaim level.
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* NEEDS_GROUPS: Load balancing flag.
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*/
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SD_FLAG(SD_BALANCE_EXEC, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS)
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/*
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* Balance on fork, clone
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*
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* SHARED_CHILD: Set from the base domain up to the NUMA reclaim level.
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* NEEDS_GROUPS: Load balancing flag.
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*/
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SD_FLAG(SD_BALANCE_FORK, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS)
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/*
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* Balance on wakeup
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*
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* SHARED_CHILD: Set from the base domain up to cpuset.sched_relax_domain_level.
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* NEEDS_GROUPS: Load balancing flag.
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*/
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SD_FLAG(SD_BALANCE_WAKE, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS)
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/*
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* Consider waking task on waking CPU.
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*
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* SHARED_CHILD: Set from the base domain up to the NUMA reclaim level.
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*/
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SD_FLAG(SD_WAKE_AFFINE, SDF_SHARED_CHILD)
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/*
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* Domain members have different CPU capacities
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*
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* SHARED_PARENT: Set from the topmost domain down to the first domain where
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* asymmetry is detected.
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* NEEDS_GROUPS: Per-CPU capacity is asymmetric between groups.
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*/
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SD_FLAG(SD_ASYM_CPUCAPACITY, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS)
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/*
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* Domain members have different CPU capacities spanning all unique CPU
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* capacity values.
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*
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* SHARED_PARENT: Set from the topmost domain down to the first domain where
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* all available CPU capacities are visible
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* NEEDS_GROUPS: Per-CPU capacity is asymmetric between groups.
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*/
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SD_FLAG(SD_ASYM_CPUCAPACITY_FULL, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS)
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/*
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* Domain members share CPU capacity (i.e. SMT)
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*
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* SHARED_CHILD: Set from the base domain up until spanned CPUs no longer share
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* CPU capacity.
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* NEEDS_GROUPS: Capacity is shared between groups.
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*/
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SD_FLAG(SD_SHARE_CPUCAPACITY, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS)
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/*
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* Domain members share CPU package resources (i.e. caches)
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*
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* SHARED_CHILD: Set from the base domain up until spanned CPUs no longer share
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* the same cache(s).
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* NEEDS_GROUPS: Caches are shared between groups.
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*/
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SD_FLAG(SD_SHARE_PKG_RESOURCES, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS)
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/*
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* Only a single load balancing instance
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*
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* SHARED_PARENT: Set for all NUMA levels above NODE. Could be set from a
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* different level upwards, but it doesn't change that if a
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* domain has this flag set, then all of its parents need to have
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* it too (otherwise the serialization doesn't make sense).
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* NEEDS_GROUPS: No point in preserving domain if it has a single group.
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*/
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SD_FLAG(SD_SERIALIZE, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS)
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/*
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* Place busy tasks earlier in the domain
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*
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* SHARED_CHILD: Usually set on the SMT level. Technically could be set further
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* up, but currently assumed to be set from the base domain
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* upwards (see update_top_cache_domain()).
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* NEEDS_GROUPS: Load balancing flag.
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*/
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SD_FLAG(SD_ASYM_PACKING, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS)
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/*
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* Prefer to place tasks in a sibling domain
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*
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* Set up until domains start spanning NUMA nodes. Close to being a SHARED_CHILD
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* flag, but cleared below domains with SD_ASYM_CPUCAPACITY.
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*
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* NEEDS_GROUPS: Load balancing flag.
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*/
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SD_FLAG(SD_PREFER_SIBLING, SDF_NEEDS_GROUPS)
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/*
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* sched_groups of this level overlap
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*
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* SHARED_PARENT: Set for all NUMA levels above NODE.
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* NEEDS_GROUPS: Overlaps can only exist with more than one group.
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*/
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SD_FLAG(SD_OVERLAP, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS)
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/*
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* Cross-node balancing
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*
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* SHARED_PARENT: Set for all NUMA levels above NODE.
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* NEEDS_GROUPS: No point in preserving domain if it has a single group.
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*/
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SD_FLAG(SD_NUMA, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS)
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