From 40b4d3dc328265c8ec6688657d74813edf785c83 Mon Sep 17 00:00:00 2001 From: Ricardo Neri Date: Thu, 6 Apr 2023 13:31:44 -0700 Subject: [PATCH] sched/topology: Check SDF_SHARED_CHILD in highest_flag_domain() 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 Signed-off-by: Ricardo Neri Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20230406203148.19182-9-ricardo.neri-calderon@linux.intel.com --- kernel/sched/sched.h | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index ec7b3e0..6784462 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -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 +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; -- 2.7.4