mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 17:30:02 +00:00
![Valentin Schneider](/assets/img/avatar_default.png)
There would be no point in preserving a sched_domain with a single group just because it has this flag set. Add it to SD_DEGENERATE_GROUPS_MASK. Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: https://lore.kernel.org/r/20200817113003.20802-17-valentin.schneider@arm.com
156 lines
5 KiB
C
156 lines
5 KiB
C
/* 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 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)
|