linux-loongson/include/linux/sched/sd_flags.h
K Prateek Nayak 1eec89a671 sched/topology: Remove sched_domain_topology_level::flags
Support for overlapping domains added in commit e3589f6c81 ("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 af85596c74
("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: K Prateek Nayak <kprateek.nayak@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/ba4dbdf8-bc37-493d-b2e0-2efb00ea3e19@amd.com
2025-07-14 10:59:35 +02:00

163 lines
5.1 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 cluster (LLC tags or L2 cache)
*
* NEEDS_GROUPS: Clusters are shared between groups.
*/
SD_FLAG(SD_CLUSTER, SDF_NEEDS_GROUPS)
/*
* Domain members share CPU Last Level 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_LLC, 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)
/*
* 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)