From: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
The current rebuild_sched_domains will only rebuild the sched domains
unless the cpumask changes. However, in some scenarios when the
topology flag value changes, it will not rebuild the sched domain.
We create a regenerate_sched_domains function that will always
rebuild all the sched domains to take care of this scenario.
Signed-off-by: Tim Chen <tim.c.chen@xxxxxxxxxxxxxxx>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@xxxxxxxxxxxxxxx>
---
include/linux/cpuset.h | 2 ++
include/linux/sched.h | 3 +++
kernel/cpuset.c | 32 +++++++++++++++++++++++++-------
kernel/sched/core.c | 25 ++++++++++++++++++++++---
4 files changed, 52 insertions(+), 10 deletions(-)
diff --git a/include/linux/cpuset.h b/include/linux/cpuset.h
index bfc204e..9f948fa 100644
--- a/include/linux/cpuset.h
+++ b/include/linux/cpuset.h
@@ -102,6 +102,8 @@ extern int current_cpuset_is_being_rebound(void);
extern void rebuild_sched_domains(void);
+extern void regenerate_sched_domains(void);
+
extern void cpuset_print_current_mems_allowed(void);
/*
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 62c68e5..3301959 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1152,6 +1152,9 @@ static inline struct cpumask *sched_domain_span(struct sched_domain *sd)
extern void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
struct sched_domain_attr *dattr_new);
+extern void regen_partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
+ struct sched_domain_attr *dattr_new);
+
/* Allocate an array of sched domains, for partition_sched_domains(). */
cpumask_var_t *alloc_sched_domains(unsigned int ndoms);
void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms);
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index c7fd277..f6f7c17 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -794,10 +794,12 @@ done:
* which has that flag enabled, or if any cpuset with a non-empty
* 'cpus' is removed, then call this routine to rebuild the
* scheduler's dynamic sched domains.
+ * If forced flag is set, then we will always regenerate all new
+ * sched domains.
*
* Call with cpuset_mutex held. Takes get_online_cpus().
*/
-static void rebuild_sched_domains_locked(void)
+static void rebuild_sched_domains_locked(bool rebuild_all)
{
struct sched_domain_attr *attr;
cpumask_var_t *doms;
@@ -818,12 +820,17 @@ static void rebuild_sched_domains_locked(void)
ndoms = generate_sched_domains(&doms, &attr);
/* Have scheduler rebuild the domains */
- partition_sched_domains(ndoms, doms, attr);
+ if (rebuild_all)
+ /* Will rebuild a complete set of all sched domains */
+ regen_partition_sched_domains(ndoms, doms, attr);
+ else
+ /* Rebuild only sched domains with changed cpu masks */
+ partition_sched_domains(ndoms, doms, attr);
out:
put_online_cpus();
}
#else /* !CONFIG_SMP */
-static void rebuild_sched_domains_locked(void)
+static void rebuild_sched_domains_locked(bool forced)
{
}
#endif /* CONFIG_SMP */
@@ -831,7 +838,18 @@ static void rebuild_sched_domains_locked(void)
void rebuild_sched_domains(void)
{
mutex_lock(&cpuset_mutex);
- rebuild_sched_domains_locked();
+ rebuild_sched_domains_locked(false);
+ mutex_unlock(&cpuset_mutex);
+}
+
+/*
+ * Similar to rebuild_sched domains, but will force
+ * all sched domains to be always rebuilt.
+ */
+void regenerate_sched_domains(void)
+{
+ mutex_lock(&cpuset_mutex);
+ rebuild_sched_domains_locked(true);
mutex_unlock(&cpuset_mutex);
}
@@ -919,7 +937,7 @@ static void update_cpumasks_hier(struct cpuset *cs, struct cpumask *new_cpus)
rcu_read_unlock();
if (need_rebuild_sched_domains)
- rebuild_sched_domains_locked();
+ rebuild_sched_domains_locked(false);
}
/**
@@ -1267,7 +1285,7 @@ static int update_relax_domain_level(struct cpuset *cs, s64 val)
cs->relax_domain_level = val;
if (!cpumask_empty(cs->cpus_allowed) &&
is_sched_load_balance(cs))
- rebuild_sched_domains_locked();
+ rebuild_sched_domains_locked(true);
}
return 0;
@@ -1333,7 +1351,7 @@ static int update_flag(cpuset_flagbits_t bit, struct cpuset *cs,
spin_unlock_irq(&callback_lock);
if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed)
- rebuild_sched_domains_locked();
+ rebuild_sched_domains_locked(false);
if (spread_flag_changed)
update_tasks_flags(cs);
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 2a906f2..ec752da 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -7069,8 +7069,9 @@ static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
*
* Call with hotplug lock held
*/
-void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
- struct sched_domain_attr *dattr_new)
+static void __partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
+ struct sched_domain_attr *dattr_new,
+ int need_domain_rebuild)
{
int i, j, n;
int new_topology;
@@ -7081,7 +7082,7 @@ void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
unregister_sched_domain_sysctl();
/* Let architecture update cpu core mappings. */
- new_topology = arch_update_cpu_topology();
+ new_topology = arch_update_cpu_topology() | need_domain_rebuild;
n = doms_new ? ndoms_new : 0;
@@ -7132,6 +7133,24 @@ match2:
mutex_unlock(&sched_domains_mutex);
}
+/*
+ * Generate sched domains only when the cpumask or domain attr changes
+ */
+void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
+ struct sched_domain_attr *dattr_new)
+{
+ __partition_sched_domains(ndoms_new, doms_new, dattr_new, 0);
+}
+
+/*
+ * Generate new sched domains always
+ */
+void regen_partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
+ struct sched_domain_attr *dattr_new)
+{
+ __partition_sched_domains(ndoms_new, doms_new, dattr_new, 1);
+}
+
static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */
/*
--
2.7.4
--
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