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sched/topology: Remove SHARED_CHILD from ASYM_PACKING

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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
This commit is contained in:
Ricardo Neri 2023-04-06 13:31:45 -07:00 committed by Peter Zijlstra
parent 40b4d3dc32
commit ca528cc501
1 changed files with 1 additions and 4 deletions
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5
include/linux/sched/sd_flags.h
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@ -132,12 +132,9 @@ 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)
SD_FLAG(SD_ASYM_PACKING, SDF_NEEDS_GROUPS)
/*
* Prefer to place tasks in a sibling domain