From: Steve Sistare steven.sistare@oracle.com
maillist inclusion category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I8PIYZ CVE: NA
Reference: https://lore.kernel.org/lkml/1541767840-93588-8-git-send-email-steven.sistar...
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Define a simpler version of can_migrate_task called can_migrate_task_llc which does not require a struct lb_env argument, and judges whether a migration from one CPU to another within the same LLC should be allowed.
Signed-off-by: Steve Sistare steven.sistare@oracle.com Signed-off-by: Cheng Yu serein.chengyu@huawei.com --- kernel/sched/fair.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 79ff03288431..7df713161c9f 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -9300,6 +9300,34 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env) return 0; }
+/* + * Return true if task @p can migrate from @rq to @dst_rq in the same LLC. + * No need to test for co-locality, and no need to test task_hot(), as sharing + * LLC provides cache warmth at that level. + */ +static bool +can_migrate_task_llc(struct task_struct *p, struct rq *rq, struct rq *dst_rq) +{ + int dst_cpu = dst_rq->cpu; + + lockdep_assert_rq_held(rq); + + if (throttled_lb_pair(task_group(p), cpu_of(rq), dst_cpu)) + return false; + + if (!cpumask_test_cpu(dst_cpu, p->cpus_ptr)) { + schedstat_inc(p->stats.nr_failed_migrations_affine); + return false; + } + + if (task_on_cpu(rq, p)) { + schedstat_inc(p->stats.nr_failed_migrations_running); + return false; + } + + return true; +} + /* * detach_task() -- detach the task for the migration from @src_rq to @dst_cpu. */