sched/core: Introduce 'struct sched_domain_shared'
Since struct sched_domain is strictly per cpu; introduce a structure
that is shared between all 'identical' sched_domains.
Limit to SD_SHARE_PKG_RESOURCES domains for now, as we'll only use it
for shared cache state; if another use comes up later we can easily
relax this.
While the sched_group's are normally shared between CPUs, these are
not natural to use when we need some shared state on a domain level --
since that would require the domain to have a parent, which is not a
given.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index b99fcd1..8a878b96 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1067,6 +1067,10 @@
struct sched_group;
+struct sched_domain_shared {
+ atomic_t ref;
+};
+
struct sched_domain {
/* These fields must be setup */
struct sched_domain *parent; /* top domain must be null terminated */
@@ -1135,6 +1139,7 @@
void *private; /* used during construction */
struct rcu_head rcu; /* used during destruction */
};
+ struct sched_domain_shared *shared;
unsigned int span_weight;
/*
@@ -1168,6 +1173,7 @@
struct sd_data {
struct sched_domain **__percpu sd;
+ struct sched_domain_shared **__percpu sds;
struct sched_group **__percpu sg;
struct sched_group_capacity **__percpu sgc;
};
