The following commit has been merged into the sched/core branch of tip: Commit-ID: 4ee4ea443a5dc3fc4d8ae338199676eae9d8ef02 Gitweb: https://git.kernel.org/tip/4ee4ea443a5dc3fc4d8ae338199676eae9d8ef02 Author: Valentin Schneider <valentin.schneider@xxxxxxx> AuthorDate: Mon, 17 Aug 2020 12:29:53 +01:00 Committer: Ingo Molnar <mingo@xxxxxxxxxx> CommitterDate: Wed, 19 Aug 2020 10:49:48 +02:00 sched/topology: Introduce SD metaflag for flags needing > 1 groups In preparation of cleaning up the sd_degenerate*() functions, mark flags used in sd_degenerate() with the new SDF_NEEDS_GROUPS flag. With this, build a compile-time mask of those SD flags. Note that sd_parent_degenerate() uses an extra flag in its mask, SD_PREFER_SIBLING, which remains singled out for now. Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Signed-off-by: Valentin Schneider <valentin.schneider@xxxxxxx> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Reviewed-by: Dietmar Eggemann <dietmar.eggemann@xxxxxxx> Acked-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> Link: https://lore.kernel.org/r/20200817113003.20802-8-valentin.schneider@xxxxxxx --- include/linux/sched/sd_flags.h | 39 +++++++++++++++++++++++---------- include/linux/sched/topology.h | 7 ++++++- 2 files changed, 35 insertions(+), 11 deletions(-) diff --git a/include/linux/sched/sd_flags.h b/include/linux/sched/sd_flags.h index c24a45b..ee5cbfc 100644 --- a/include/linux/sched/sd_flags.h +++ b/include/linux/sched/sd_flags.h @@ -8,7 +8,7 @@ #endif /* - * Expected flag uses + * 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 @@ -29,29 +29,42 @@ * 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 +#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) +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) +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) +SD_FLAG(SD_BALANCE_FORK, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) /* * Balance on wakeup @@ -69,24 +82,28 @@ SD_FLAG(SD_WAKE_AFFINE, SDF_SHARED_CHILD) /* * Domain members have different CPU capacities + * + * NEEDS_GROUPS: Per-CPU capacity is asymmetric between groups. */ -SD_FLAG(SD_ASYM_CPUCAPACITY, 0) +SD_FLAG(SD_ASYM_CPUCAPACITY, 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. + * CPU capacity. + * NEEDS_GROUPS: Capacity is shared between groups. */ -SD_FLAG(SD_SHARE_CPUCAPACITY, SDF_SHARED_CHILD) +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). + * the same cache(s). + * NEEDS_GROUPS: Caches are shared between groups. */ -SD_FLAG(SD_SHARE_PKG_RESOURCES, SDF_SHARED_CHILD) +SD_FLAG(SD_SHARE_PKG_RESOURCES, SDF_SHARED_CHILD | SDF_NEEDS_GROUPS) /* * Only a single load balancing instance diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h index 32f602f..2d59ca7 100644 --- a/include/linux/sched/topology.h +++ b/include/linux/sched/topology.h @@ -25,6 +25,13 @@ enum { }; #undef SD_FLAG +/* Generate a mask of SD flags with the SDF_NEEDS_GROUPS metaflag */ +#define SD_FLAG(name, mflags) (name * !!((mflags) & SDF_NEEDS_GROUPS)) | +static const unsigned int SD_DEGENERATE_GROUPS_MASK = +#include <linux/sched/sd_flags.h> +0; +#undef SD_FLAG + #ifdef CONFIG_SCHED_DEBUG #define SD_FLAG(_name, mflags) [__##_name] = { .meta_flags = mflags, .name = #_name }, static const struct {
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