This document seems to be out of date for many, many years. Even it has misspelled from the first day. ARCH_HASH_SCHED_TUNE should be ARCH_HAS_SCHED_TUNE ARCH_HASH_SCHED_DOMAIN should be ARCH_HAS_SCHED_DOMAIN
Since v2.6.14, kernel completely deleted the relevant code and even arch_init_sched_domains() was deleted. Right now, kernel is asking architectures to call set_sched_topology() to override the default sched domains. Cc: Ingo Molnar <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Mel Gorman <[email protected]> Cc: Adrian Freund <[email protected]> Cc: Valentin Schneider <[email protected]> Signed-off-by: Barry Song <[email protected]> --- -v2: refine the SD_ flags description with respect to Valentin's comment Documentation/scheduler/sched-domains.rst | 18 ++++++------------ 1 file changed, 6 insertions(+), 12 deletions(-) diff --git a/Documentation/scheduler/sched-domains.rst b/Documentation/scheduler/sched-domains.rst index 5c4b7f4f0062..55983b7e1098 100644 --- a/Documentation/scheduler/sched-domains.rst +++ b/Documentation/scheduler/sched-domains.rst @@ -65,19 +65,13 @@ of the SMP domain will span the entire machine, with each group having the cpumask of a node. Or, you could do multi-level NUMA or Opteron, for example, might have just one domain covering its one NUMA level. -The implementor should read comments in include/linux/sched.h: -struct sched_domain fields, SD_FLAG_*, SD_*_INIT to get an idea of -the specifics and what to tune. +The implementor should read comments in include/linux/sched/sd_flags.h: +SD_* to get an idea of the specifics and what to tune for the SD flags +of a sched_domain. -Architectures may retain the regular override the default SD_*_INIT flags -while using the generic domain builder in kernel/sched/core.c if they wish to -retain the traditional SMT->SMP->NUMA topology (or some subset of that). This -can be done by #define'ing ARCH_HASH_SCHED_TUNE. - -Alternatively, the architecture may completely override the generic domain -builder by #define'ing ARCH_HASH_SCHED_DOMAIN, and exporting your -arch_init_sched_domains function. This function will attach domains to all -CPUs using cpu_attach_domain. +Architectures may override the generic domain builder and the default SD flags +for a given topology level by creating a sched_domain_topology_level array and +calling set_sched_topology() with this array as the parameter. The sched-domains debugging infrastructure can be enabled by enabling CONFIG_SCHED_DEBUG. This enables an error checking parse of the sched domains -- 2.25.1
