linux-stable/include/linux/sched/sd_flags.h
Ricardo Neri ca528cc501 sched/topology: Remove SHARED_CHILD from ASYM_PACKING
Only x86 and Power7 use ASYM_PACKING. They use it differently.

Power7 has cores of equal priority, but the SMT siblings of a core have
different priorities. Parent scheduling domains do not need (nor have) the
ASYM_PACKING flag. SHARED_CHILD is not needed. Using SHARED_PARENT would
cause the topology debug code to complain.

X86 has cores of different priority, but all the SMT siblings of the core
have equal priority. It needs ASYM_PACKING at the MC level, but not at the
SMT level (it also needs it at upper levels if they have scheduling groups
of different priority). Removing ASYM_PACKING from the SMT domain causes
the topology debug code to complain.

Remove SHARED_CHILD for now. We still need a topology check that satisfies
both architectures.

Suggested-by: Valentin Schneider <vschneid@redhat.com>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Zhang Rui <rui.zhang@intel.com>
Link: https://lore.kernel.org/r/20230406203148.19182-10-ricardo.neri-calderon@linux.intel.com
2023-05-08 10:58:37 +02:00

163 lines
5.2 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 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
*
* NEEDS_GROUPS: Load balancing flag.
*/
SD_FLAG(SD_ASYM_PACKING, 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)