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sched/topology: Check SDF_SHARED_CHILD in highest_flag_domain()

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Do not assume that all the children of a scheduling domain have a given
flag. Check whether it has the SDF_SHARED_CHILD meta flag.

Suggested-by: Ionela Voinescu <ionela.voinescu@arm.com>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230406203148.19182-9-ricardo.neri-calderon@linux.intel.com
This commit is contained in:
Ricardo Neri 2023-04-06 13:31:44 -07:00 committed by Peter Zijlstra
parent c9ca07886a
commit 40b4d3dc32
1 changed files with 19 additions and 3 deletions
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22
kernel/sched/sched.h
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@ -1772,6 +1772,13 @@ queue_balance_callback(struct rq *rq,
for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); \
__sd; __sd = __sd->parent)
/* A mask of all the SD flags that have the SDF_SHARED_CHILD metaflag */
#define SD_FLAG(name, mflags) (name * !!((mflags) & SDF_SHARED_CHILD)) |
static const unsigned int SD_SHARED_CHILD_MASK =
#include <linux/sched/sd_flags.h>
0;
#undef SD_FLAG
/**
* highest_flag_domain - Return highest sched_domain containing flag.
* @cpu: The CPU whose highest level of sched domain is to
@ -1779,16 +1786,25 @@ queue_balance_callback(struct rq *rq,
* @flag: The flag to check for the highest sched_domain
* for the given CPU.
*
* Returns the highest sched_domain of a CPU which contains the given flag.
* Returns the highest sched_domain of a CPU which contains @flag. If @flag has
* the SDF_SHARED_CHILD metaflag, all the children domains also have @flag.
*/
static inline struct sched_domain *highest_flag_domain(int cpu, int flag)
{
struct sched_domain *sd, *hsd = NULL;
for_each_domain(cpu, sd) {
if (!(sd->flags & flag))
if (sd->flags & flag) {
hsd = sd;
continue;
}
/*
* Stop the search if @flag is known to be shared at lower
* levels. It will not be found further up.
*/
if (flag & SD_SHARED_CHILD_MASK)
break;
hsd = sd;
}
return hsd;