Create wrappers for sched_domains_mutex so that it can transparently be
used on both CONFIG_SMP and !CONFIG_SMP, as some function will need to
do.
Reported-by: Jon Hunter <jonathanh@nvidia.com>
Fixes: 53916d5fd3c0 ("sched/deadline: Check bandwidth overflow earlier for hotplug")
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
---
include/linux/sched.h | 2 ++
kernel/cgroup/cpuset.c | 4 ++--
kernel/sched/core.c | 4 ++--
kernel/sched/debug.c | 8 ++++----
kernel/sched/topology.c | 17 +++++++++++++++--
5 files changed, 25 insertions(+), 10 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 9632e3318e0d..d5f8c161d852 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -383,6 +383,8 @@ enum uclamp_id {
extern struct root_domain def_root_domain;
extern struct mutex sched_domains_mutex;
#endif
+extern void sched_domains_mutex_lock(void);
+extern void sched_domains_mutex_unlock(void);
struct sched_param {
int sched_priority;
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 0f910c828973..f87526edb2a4 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -994,10 +994,10 @@ static void
partition_and_rebuild_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
struct sched_domain_attr *dattr_new)
{
- mutex_lock(&sched_domains_mutex);
+ sched_domains_mutex_lock();
partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
dl_rebuild_rd_accounting();
- mutex_unlock(&sched_domains_mutex);
+ sched_domains_mutex_unlock();
}
/*
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 9aecd914ac69..7b14500d731b 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -8424,9 +8424,9 @@ void __init sched_init_smp(void)
* CPU masks are stable and all blatant races in the below code cannot
* happen.
*/
- mutex_lock(&sched_domains_mutex);
+ sched_domains_mutex_lock();
sched_init_domains(cpu_active_mask);
- mutex_unlock(&sched_domains_mutex);
+ sched_domains_mutex_unlock();
/* Move init over to a non-isolated CPU */
if (set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_TYPE_DOMAIN)) < 0)
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index ef047add7f9e..a0893a483d35 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -292,7 +292,7 @@ static ssize_t sched_verbose_write(struct file *filp, const char __user *ubuf,
bool orig;
cpus_read_lock();
- mutex_lock(&sched_domains_mutex);
+ sched_domains_mutex_lock();
orig = sched_debug_verbose;
result = debugfs_write_file_bool(filp, ubuf, cnt, ppos);
@@ -304,7 +304,7 @@ static ssize_t sched_verbose_write(struct file *filp, const char __user *ubuf,
sd_dentry = NULL;
}
- mutex_unlock(&sched_domains_mutex);
+ sched_domains_mutex_unlock();
cpus_read_unlock();
return result;
@@ -515,9 +515,9 @@ static __init int sched_init_debug(void)
debugfs_create_u32("migration_cost_ns", 0644, debugfs_sched, &sysctl_sched_migration_cost);
debugfs_create_u32("nr_migrate", 0644, debugfs_sched, &sysctl_sched_nr_migrate);
- mutex_lock(&sched_domains_mutex);
+ sched_domains_mutex_lock();
update_sched_domain_debugfs();
- mutex_unlock(&sched_domains_mutex);
+ sched_domains_mutex_unlock();
#endif
#ifdef CONFIG_NUMA_BALANCING
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index c49aea8c1025..e2b879ec9458 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -6,6 +6,19 @@
#include <linux/bsearch.h>
DEFINE_MUTEX(sched_domains_mutex);
+#ifdef CONFIG_SMP
+void sched_domains_mutex_lock(void)
+{
+ mutex_lock(&sched_domains_mutex);
+}
+void sched_domains_mutex_unlock(void)
+{
+ mutex_unlock(&sched_domains_mutex);
+}
+#else
+void sched_domains_mutex_lock(void) { }
+void sched_domains_mutex_unlock(void) { }
+#endif
/* Protected by sched_domains_mutex: */
static cpumask_var_t sched_domains_tmpmask;
@@ -2791,7 +2804,7 @@ void partition_sched_domains_locked(int ndoms_new, cpumask_var_t doms_new[],
void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
struct sched_domain_attr *dattr_new)
{
- mutex_lock(&sched_domains_mutex);
+ sched_domains_mutex_lock();
partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
- mutex_unlock(&sched_domains_mutex);
+ sched_domains_mutex_unlock();
}
--
2.48.1On 3/4/25 3:40 AM, Juri Lelli wrote:
> Create wrappers for sched_domains_mutex so that it can transparently be
> used on both CONFIG_SMP and !CONFIG_SMP, as some function will need to
> do.
>
> Reported-by: Jon Hunter <jonathanh@nvidia.com>
> Fixes: 53916d5fd3c0 ("sched/deadline: Check bandwidth overflow earlier for hotplug")
> Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
> ---
> include/linux/sched.h | 2 ++
> kernel/cgroup/cpuset.c | 4 ++--
> kernel/sched/core.c | 4 ++--
> kernel/sched/debug.c | 8 ++++----
> kernel/sched/topology.c | 17 +++++++++++++++--
> 5 files changed, 25 insertions(+), 10 deletions(-)
>
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 9632e3318e0d..d5f8c161d852 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -383,6 +383,8 @@ enum uclamp_id {
> extern struct root_domain def_root_domain;
> extern struct mutex sched_domains_mutex;
> #endif
> +extern void sched_domains_mutex_lock(void);
> +extern void sched_domains_mutex_unlock(void);
>
If all access to sched_domains_mutex is through the wrappers, we may not
need to expose sched_domains_mutex at all. Also it is more efficient for
the non-SMP case to put the wrappers inside the CONFIG_SMP block and
define the empty inline functions in the else part.
> struct sched_param {
> int sched_priority;
> diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
> index 0f910c828973..f87526edb2a4 100644
> --- a/kernel/cgroup/cpuset.c
> +++ b/kernel/cgroup/cpuset.c
> @@ -994,10 +994,10 @@ static void
> partition_and_rebuild_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
> struct sched_domain_attr *dattr_new)
> {
> - mutex_lock(&sched_domains_mutex);
> + sched_domains_mutex_lock();
> partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
> dl_rebuild_rd_accounting();
> - mutex_unlock(&sched_domains_mutex);
> + sched_domains_mutex_unlock();
> }
>
> /*
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 9aecd914ac69..7b14500d731b 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -8424,9 +8424,9 @@ void __init sched_init_smp(void)
> * CPU masks are stable and all blatant races in the below code cannot
> * happen.
> */
> - mutex_lock(&sched_domains_mutex);
> + sched_domains_mutex_lock();
> sched_init_domains(cpu_active_mask);
> - mutex_unlock(&sched_domains_mutex);
> + sched_domains_mutex_unlock();
>
> /* Move init over to a non-isolated CPU */
> if (set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_TYPE_DOMAIN)) < 0)
> diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
> index ef047add7f9e..a0893a483d35 100644
> --- a/kernel/sched/debug.c
> +++ b/kernel/sched/debug.c
> @@ -292,7 +292,7 @@ static ssize_t sched_verbose_write(struct file *filp, const char __user *ubuf,
> bool orig;
>
> cpus_read_lock();
> - mutex_lock(&sched_domains_mutex);
> + sched_domains_mutex_lock();
>
> orig = sched_debug_verbose;
> result = debugfs_write_file_bool(filp, ubuf, cnt, ppos);
> @@ -304,7 +304,7 @@ static ssize_t sched_verbose_write(struct file *filp, const char __user *ubuf,
> sd_dentry = NULL;
> }
>
> - mutex_unlock(&sched_domains_mutex);
> + sched_domains_mutex_unlock();
> cpus_read_unlock();
>
> return result;
> @@ -515,9 +515,9 @@ static __init int sched_init_debug(void)
> debugfs_create_u32("migration_cost_ns", 0644, debugfs_sched, &sysctl_sched_migration_cost);
> debugfs_create_u32("nr_migrate", 0644, debugfs_sched, &sysctl_sched_nr_migrate);
>
> - mutex_lock(&sched_domains_mutex);
> + sched_domains_mutex_lock();
> update_sched_domain_debugfs();
> - mutex_unlock(&sched_domains_mutex);
> + sched_domains_mutex_unlock();
> #endif
>
> #ifdef CONFIG_NUMA_BALANCING
> diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
> index c49aea8c1025..e2b879ec9458 100644
> --- a/kernel/sched/topology.c
> +++ b/kernel/sched/topology.c
> @@ -6,6 +6,19 @@
> #include <linux/bsearch.h>
>
> DEFINE_MUTEX(sched_domains_mutex);
> +#ifdef CONFIG_SMP
> +void sched_domains_mutex_lock(void)
> +{
> + mutex_lock(&sched_domains_mutex);
> +}
> +void sched_domains_mutex_unlock(void)
> +{
> + mutex_unlock(&sched_domains_mutex);
> +}
> +#else
> +void sched_domains_mutex_lock(void) { }
> +void sched_domains_mutex_unlock(void) { }
> +#endif
>
> /* Protected by sched_domains_mutex: */
> static cpumask_var_t sched_domains_tmpmask;
> @@ -2791,7 +2804,7 @@ void partition_sched_domains_locked(int ndoms_new, cpumask_var_t doms_new[],
> void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
> struct sched_domain_attr *dattr_new)
> {
> - mutex_lock(&sched_domains_mutex);
> + sched_domains_mutex_lock();
> partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
> - mutex_unlock(&sched_domains_mutex);
> + sched_domains_mutex_unlock();
> }
There are two "lockdep_assert_held(&sched_domains_mutex);" statements in
topology.c file and one in cpuset.c. That can be problematic in the
non-SMP case. Maybe another wrapper to do the assert?
Cheers,
Longman
On 3/4/25 10:05 AM, Waiman Long wrote:
>> --- a/kernel/sched/topology.c
>> +++ b/kernel/sched/topology.c
>> @@ -6,6 +6,19 @@
>> #include <linux/bsearch.h>
>> DEFINE_MUTEX(sched_domains_mutex);
>> +#ifdef CONFIG_SMP
>> +void sched_domains_mutex_lock(void)
>> +{
>> + mutex_lock(&sched_domains_mutex);
>> +}
>> +void sched_domains_mutex_unlock(void)
>> +{
>> + mutex_unlock(&sched_domains_mutex);
>> +}
>> +#else
>> +void sched_domains_mutex_lock(void) { }
>> +void sched_domains_mutex_unlock(void) { }
>> +#endif
>> /* Protected by sched_domains_mutex: */
>> static cpumask_var_t sched_domains_tmpmask;
>> @@ -2791,7 +2804,7 @@ void partition_sched_domains_locked(int
>> ndoms_new, cpumask_var_t doms_new[],
>> void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
>> struct sched_domain_attr *dattr_new)
>> {
>> - mutex_lock(&sched_domains_mutex);
>> + sched_domains_mutex_lock();
>> partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
>> - mutex_unlock(&sched_domains_mutex);
>> + sched_domains_mutex_unlock();
>> }
>
> There are two "lockdep_assert_held(&sched_domains_mutex);" statements
> in topology.c file and one in cpuset.c. That can be problematic in the
> non-SMP case. Maybe another wrapper to do the assert?
Ignore that as both topology.c and cpuset.c will only be compiled if
CONFIG_SMP is defined. IOW, you don't need the the "#ifdef CONFIG_SMP"
above.
Cheers,
Longman
On 04/03/25 11:01, Waiman Long wrote:
> On 3/4/25 10:05 AM, Waiman Long wrote:
> > > --- a/kernel/sched/topology.c
> > > +++ b/kernel/sched/topology.c
> > > @@ -6,6 +6,19 @@
> > > #include <linux/bsearch.h>
> > > DEFINE_MUTEX(sched_domains_mutex);
> > > +#ifdef CONFIG_SMP
> > > +void sched_domains_mutex_lock(void)
> > > +{
> > > + mutex_lock(&sched_domains_mutex);
> > > +}
> > > +void sched_domains_mutex_unlock(void)
> > > +{
> > > + mutex_unlock(&sched_domains_mutex);
> > > +}
> > > +#else
> > > +void sched_domains_mutex_lock(void) { }
> > > +void sched_domains_mutex_unlock(void) { }
> > > +#endif
> > > /* Protected by sched_domains_mutex: */
> > > static cpumask_var_t sched_domains_tmpmask;
> > > @@ -2791,7 +2804,7 @@ void partition_sched_domains_locked(int
> > > ndoms_new, cpumask_var_t doms_new[],
> > > void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
> > > struct sched_domain_attr *dattr_new)
> > > {
> > > - mutex_lock(&sched_domains_mutex);
> > > + sched_domains_mutex_lock();
> > > partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
> > > - mutex_unlock(&sched_domains_mutex);
> > > + sched_domains_mutex_unlock();
> > > }
> >
> > There are two "lockdep_assert_held(&sched_domains_mutex);" statements in
> > topology.c file and one in cpuset.c. That can be problematic in the
> > non-SMP case. Maybe another wrapper to do the assert?
>
> Ignore that as both topology.c and cpuset.c will only be compiled if
> CONFIG_SMP is defined. IOW, you don't need the the "#ifdef CONFIG_SMP"
> above.
Indeed!
Thanks,
Juri
On 05/03/25 10:52, Juri Lelli wrote:
> On 04/03/25 11:01, Waiman Long wrote:
> > On 3/4/25 10:05 AM, Waiman Long wrote:
> > > > --- a/kernel/sched/topology.c
> > > > +++ b/kernel/sched/topology.c
> > > > @@ -6,6 +6,19 @@
> > > > #include <linux/bsearch.h>
> > > > DEFINE_MUTEX(sched_domains_mutex);
> > > > +#ifdef CONFIG_SMP
> > > > +void sched_domains_mutex_lock(void)
> > > > +{
> > > > + mutex_lock(&sched_domains_mutex);
> > > > +}
> > > > +void sched_domains_mutex_unlock(void)
> > > > +{
> > > > + mutex_unlock(&sched_domains_mutex);
> > > > +}
> > > > +#else
> > > > +void sched_domains_mutex_lock(void) { }
> > > > +void sched_domains_mutex_unlock(void) { }
> > > > +#endif
> > > > /* Protected by sched_domains_mutex: */
> > > > static cpumask_var_t sched_domains_tmpmask;
> > > > @@ -2791,7 +2804,7 @@ void partition_sched_domains_locked(int
> > > > ndoms_new, cpumask_var_t doms_new[],
> > > > void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
> > > > struct sched_domain_attr *dattr_new)
> > > > {
> > > > - mutex_lock(&sched_domains_mutex);
> > > > + sched_domains_mutex_lock();
> > > > partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
> > > > - mutex_unlock(&sched_domains_mutex);
> > > > + sched_domains_mutex_unlock();
> > > > }
> > >
> > > There are two "lockdep_assert_held(&sched_domains_mutex);" statements in
> > > topology.c file and one in cpuset.c. That can be problematic in the
> > > non-SMP case. Maybe another wrapper to do the assert?
> >
> > Ignore that as both topology.c and cpuset.c will only be compiled if
> > CONFIG_SMP is defined. IOW, you don't need the the "#ifdef CONFIG_SMP"
> > above.
>
> Indeed!
Ah, actually I believe next patch (3/5) introduce usage for the !SMP
case in sched_rt_handler()
diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 4b8e33c615b1..8cebe71d2bb1 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -2910,6 +2910,7 @@ static int sched_rt_handler(const struct ctl_table *table, int write, void *buff
int ret;
mutex_lock(&mutex);
+ sched_domains_mutex_lock();
old_period = sysctl_sched_rt_period;
old_runtime = sysctl_sched_rt_runtime;
@@ -2936,6 +2937,7 @@ static int sched_rt_handler(const struct ctl_table *table, int write, void *buff
sysctl_sched_rt_period = old_period;
sysctl_sched_rt_runtime = old_runtime;
}
+ sched_domains_mutex_unlock();
mutex_unlock(&mutex);
return ret;
So, I will need to add the ifdef back I guess (I removed it on v2). Do
you agree?
Thanks,
Juri
On 3/7/25 4:32 AM, Juri Lelli wrote:
> On 05/03/25 10:52, Juri Lelli wrote:
>> On 04/03/25 11:01, Waiman Long wrote:
>>> On 3/4/25 10:05 AM, Waiman Long wrote:
>>>>> --- a/kernel/sched/topology.c
>>>>> +++ b/kernel/sched/topology.c
>>>>> @@ -6,6 +6,19 @@
>>>>> #include <linux/bsearch.h>
>>>>> DEFINE_MUTEX(sched_domains_mutex);
>>>>> +#ifdef CONFIG_SMP
>>>>> +void sched_domains_mutex_lock(void)
>>>>> +{
>>>>> + mutex_lock(&sched_domains_mutex);
>>>>> +}
>>>>> +void sched_domains_mutex_unlock(void)
>>>>> +{
>>>>> + mutex_unlock(&sched_domains_mutex);
>>>>> +}
>>>>> +#else
>>>>> +void sched_domains_mutex_lock(void) { }
>>>>> +void sched_domains_mutex_unlock(void) { }
>>>>> +#endif
>>>>> /* Protected by sched_domains_mutex: */
>>>>> static cpumask_var_t sched_domains_tmpmask;
>>>>> @@ -2791,7 +2804,7 @@ void partition_sched_domains_locked(int
>>>>> ndoms_new, cpumask_var_t doms_new[],
>>>>> void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
>>>>> struct sched_domain_attr *dattr_new)
>>>>> {
>>>>> - mutex_lock(&sched_domains_mutex);
>>>>> + sched_domains_mutex_lock();
>>>>> partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
>>>>> - mutex_unlock(&sched_domains_mutex);
>>>>> + sched_domains_mutex_unlock();
>>>>> }
>>>> There are two "lockdep_assert_held(&sched_domains_mutex);" statements in
>>>> topology.c file and one in cpuset.c. That can be problematic in the
>>>> non-SMP case. Maybe another wrapper to do the assert?
>>> Ignore that as both topology.c and cpuset.c will only be compiled if
>>> CONFIG_SMP is defined. IOW, you don't need the the "#ifdef CONFIG_SMP"
>>> above.
>> Indeed!
> Ah, actually I believe next patch (3/5) introduce usage for the !SMP
> case in sched_rt_handler()
>
> diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
> index 4b8e33c615b1..8cebe71d2bb1 100644
> --- a/kernel/sched/rt.c
> +++ b/kernel/sched/rt.c
> @@ -2910,6 +2910,7 @@ static int sched_rt_handler(const struct ctl_table *table, int write, void *buff
> int ret;
>
> mutex_lock(&mutex);
> + sched_domains_mutex_lock();
> old_period = sysctl_sched_rt_period;
> old_runtime = sysctl_sched_rt_runtime;
>
> @@ -2936,6 +2937,7 @@ static int sched_rt_handler(const struct ctl_table *table, int write, void *buff
> sysctl_sched_rt_period = old_period;
> sysctl_sched_rt_runtime = old_runtime;
> }
> + sched_domains_mutex_unlock();
> mutex_unlock(&mutex);
>
> return ret;
>
> So, I will need to add the ifdef back I guess (I removed it on v2). Do
> you agree?
You are right. That change does introduce the need to define the
!CONFIG_SMP case. I was looking the existing uses o domains_mutex when
making that suggestions.
It is a good catch.
Cheers,
Longman
Hi Waiman,
Thanks for the review!
On 04/03/25 10:05, Waiman Long wrote:
> On 3/4/25 3:40 AM, Juri Lelli wrote:
> > Create wrappers for sched_domains_mutex so that it can transparently be
> > used on both CONFIG_SMP and !CONFIG_SMP, as some function will need to
> > do.
> >
> > Reported-by: Jon Hunter <jonathanh@nvidia.com>
> > Fixes: 53916d5fd3c0 ("sched/deadline: Check bandwidth overflow earlier for hotplug")
> > Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
> > ---
> > include/linux/sched.h | 2 ++
> > kernel/cgroup/cpuset.c | 4 ++--
> > kernel/sched/core.c | 4 ++--
> > kernel/sched/debug.c | 8 ++++----
> > kernel/sched/topology.c | 17 +++++++++++++++--
> > 5 files changed, 25 insertions(+), 10 deletions(-)
> >
> > diff --git a/include/linux/sched.h b/include/linux/sched.h
> > index 9632e3318e0d..d5f8c161d852 100644
> > --- a/include/linux/sched.h
> > +++ b/include/linux/sched.h
> > @@ -383,6 +383,8 @@ enum uclamp_id {
> > extern struct root_domain def_root_domain;
> > extern struct mutex sched_domains_mutex;
> > #endif
> > +extern void sched_domains_mutex_lock(void);
> > +extern void sched_domains_mutex_unlock(void);
>
> If all access to sched_domains_mutex is through the wrappers, we may not
> need to expose sched_domains_mutex at all. Also it is more efficient for the
> non-SMP case to put the wrappers inside the CONFIG_SMP block and define the
> empty inline functions in the else part.
>
>
> > struct sched_param {
> > int sched_priority;
> > diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
> > index 0f910c828973..f87526edb2a4 100644
> > --- a/kernel/cgroup/cpuset.c
> > +++ b/kernel/cgroup/cpuset.c
> > @@ -994,10 +994,10 @@ static void
> > partition_and_rebuild_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
> > struct sched_domain_attr *dattr_new)
> > {
> > - mutex_lock(&sched_domains_mutex);
> > + sched_domains_mutex_lock();
> > partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
> > dl_rebuild_rd_accounting();
> > - mutex_unlock(&sched_domains_mutex);
> > + sched_domains_mutex_unlock();
> > }
> > /*
> > diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> > index 9aecd914ac69..7b14500d731b 100644
> > --- a/kernel/sched/core.c
> > +++ b/kernel/sched/core.c
> > @@ -8424,9 +8424,9 @@ void __init sched_init_smp(void)
> > * CPU masks are stable and all blatant races in the below code cannot
> > * happen.
> > */
> > - mutex_lock(&sched_domains_mutex);
> > + sched_domains_mutex_lock();
> > sched_init_domains(cpu_active_mask);
> > - mutex_unlock(&sched_domains_mutex);
> > + sched_domains_mutex_unlock();
> > /* Move init over to a non-isolated CPU */
> > if (set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_TYPE_DOMAIN)) < 0)
> > diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
> > index ef047add7f9e..a0893a483d35 100644
> > --- a/kernel/sched/debug.c
> > +++ b/kernel/sched/debug.c
> > @@ -292,7 +292,7 @@ static ssize_t sched_verbose_write(struct file *filp, const char __user *ubuf,
> > bool orig;
> > cpus_read_lock();
> > - mutex_lock(&sched_domains_mutex);
> > + sched_domains_mutex_lock();
> > orig = sched_debug_verbose;
> > result = debugfs_write_file_bool(filp, ubuf, cnt, ppos);
> > @@ -304,7 +304,7 @@ static ssize_t sched_verbose_write(struct file *filp, const char __user *ubuf,
> > sd_dentry = NULL;
> > }
> > - mutex_unlock(&sched_domains_mutex);
> > + sched_domains_mutex_unlock();
> > cpus_read_unlock();
> > return result;
> > @@ -515,9 +515,9 @@ static __init int sched_init_debug(void)
> > debugfs_create_u32("migration_cost_ns", 0644, debugfs_sched, &sysctl_sched_migration_cost);
> > debugfs_create_u32("nr_migrate", 0644, debugfs_sched, &sysctl_sched_nr_migrate);
> > - mutex_lock(&sched_domains_mutex);
> > + sched_domains_mutex_lock();
> > update_sched_domain_debugfs();
> > - mutex_unlock(&sched_domains_mutex);
> > + sched_domains_mutex_unlock();
> > #endif
> > #ifdef CONFIG_NUMA_BALANCING
> > diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
> > index c49aea8c1025..e2b879ec9458 100644
> > --- a/kernel/sched/topology.c
> > +++ b/kernel/sched/topology.c
> > @@ -6,6 +6,19 @@
> > #include <linux/bsearch.h>
> > DEFINE_MUTEX(sched_domains_mutex);
> > +#ifdef CONFIG_SMP
> > +void sched_domains_mutex_lock(void)
> > +{
> > + mutex_lock(&sched_domains_mutex);
> > +}
> > +void sched_domains_mutex_unlock(void)
> > +{
> > + mutex_unlock(&sched_domains_mutex);
> > +}
> > +#else
> > +void sched_domains_mutex_lock(void) { }
> > +void sched_domains_mutex_unlock(void) { }
> > +#endif
> > /* Protected by sched_domains_mutex: */
> > static cpumask_var_t sched_domains_tmpmask;
> > @@ -2791,7 +2804,7 @@ void partition_sched_domains_locked(int ndoms_new, cpumask_var_t doms_new[],
> > void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
> > struct sched_domain_attr *dattr_new)
> > {
> > - mutex_lock(&sched_domains_mutex);
> > + sched_domains_mutex_lock();
> > partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
> > - mutex_unlock(&sched_domains_mutex);
> > + sched_domains_mutex_unlock();
> > }
>
> There are two "lockdep_assert_held(&sched_domains_mutex);" statements in
> topology.c file and one in cpuset.c. That can be problematic in the non-SMP
> case. Maybe another wrapper to do the assert?
Yes, makes sense. Will modify as you suggest here and above.
Best,
Juri
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