Hi, Ping.
Thanks, - Juri On 25/09/18 16:34, Juri Lelli wrote: > Hi Li Zefan and Tejun Heo, > > It would be great if you could please have a look at the proposed change > below (and the rest of the set of course :-). > > Another bit that I'd be more comfortable after hearing your word on it > is this one (discussed over 5/5): > > https://lore.kernel.org/lkml/20180925130750.GA25664@localhost.localdomain/ > > Best, > > - Juri > > On 03/09/18 16:27, Juri Lelli wrote: > > callback_lock grants the holder read-only access to cpusets. For fixing > > a synchronization issue between cpusets and scheduler core, it is now > > required to make callback_lock available to core scheduler code. > > > > Convert callback_lock to raw_spin_lock, so that it will be always safe > > to acquire it from atomic context. > > > > Signed-off-by: Juri Lelli <juri.le...@redhat.com> > > --- > > kernel/cgroup/cpuset.c | 66 +++++++++++++++++++++--------------------- > > 1 file changed, 33 insertions(+), 33 deletions(-) > > > > diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c > > index 266f10cb7222..5b43f482fa0f 100644 > > --- a/kernel/cgroup/cpuset.c > > +++ b/kernel/cgroup/cpuset.c > > @@ -288,7 +288,7 @@ static struct cpuset top_cpuset = { > > */ > > > > static DEFINE_MUTEX(cpuset_mutex); > > -static DEFINE_SPINLOCK(callback_lock); > > +static DEFINE_RAW_SPINLOCK(callback_lock); > > > > static struct workqueue_struct *cpuset_migrate_mm_wq; > > > > @@ -922,9 +922,9 @@ static void update_cpumasks_hier(struct cpuset *cs, > > struct cpumask *new_cpus) > > continue; > > rcu_read_unlock(); > > > > - spin_lock_irq(&callback_lock); > > + raw_spin_lock_irq(&callback_lock); > > cpumask_copy(cp->effective_cpus, new_cpus); > > - spin_unlock_irq(&callback_lock); > > + raw_spin_unlock_irq(&callback_lock); > > > > WARN_ON(!is_in_v2_mode() && > > !cpumask_equal(cp->cpus_allowed, cp->effective_cpus)); > > @@ -989,9 +989,9 @@ static int update_cpumask(struct cpuset *cs, struct > > cpuset *trialcs, > > if (retval < 0) > > return retval; > > > > - spin_lock_irq(&callback_lock); > > + raw_spin_lock_irq(&callback_lock); > > cpumask_copy(cs->cpus_allowed, trialcs->cpus_allowed); > > - spin_unlock_irq(&callback_lock); > > + raw_spin_unlock_irq(&callback_lock); > > > > /* use trialcs->cpus_allowed as a temp variable */ > > update_cpumasks_hier(cs, trialcs->cpus_allowed); > > @@ -1175,9 +1175,9 @@ static void update_nodemasks_hier(struct cpuset *cs, > > nodemask_t *new_mems) > > continue; > > rcu_read_unlock(); > > > > - spin_lock_irq(&callback_lock); > > + raw_spin_lock_irq(&callback_lock); > > cp->effective_mems = *new_mems; > > - spin_unlock_irq(&callback_lock); > > + raw_spin_unlock_irq(&callback_lock); > > > > WARN_ON(!is_in_v2_mode() && > > !nodes_equal(cp->mems_allowed, cp->effective_mems)); > > @@ -1245,9 +1245,9 @@ static int update_nodemask(struct cpuset *cs, struct > > cpuset *trialcs, > > if (retval < 0) > > goto done; > > > > - spin_lock_irq(&callback_lock); > > + raw_spin_lock_irq(&callback_lock); > > cs->mems_allowed = trialcs->mems_allowed; > > - spin_unlock_irq(&callback_lock); > > + raw_spin_unlock_irq(&callback_lock); > > > > /* use trialcs->mems_allowed as a temp variable */ > > update_nodemasks_hier(cs, &trialcs->mems_allowed); > > @@ -1338,9 +1338,9 @@ static int update_flag(cpuset_flagbits_t bit, struct > > cpuset *cs, > > spread_flag_changed = ((is_spread_slab(cs) != is_spread_slab(trialcs)) > > || (is_spread_page(cs) != is_spread_page(trialcs))); > > > > - spin_lock_irq(&callback_lock); > > + raw_spin_lock_irq(&callback_lock); > > cs->flags = trialcs->flags; > > - spin_unlock_irq(&callback_lock); > > + raw_spin_unlock_irq(&callback_lock); > > > > if (!cpumask_empty(trialcs->cpus_allowed) && balance_flag_changed) > > rebuild_sched_domains_locked(); > > @@ -1755,7 +1755,7 @@ static int cpuset_common_seq_show(struct seq_file > > *sf, void *v) > > cpuset_filetype_t type = seq_cft(sf)->private; > > int ret = 0; > > > > - spin_lock_irq(&callback_lock); > > + raw_spin_lock_irq(&callback_lock); > > > > switch (type) { > > case FILE_CPULIST: > > @@ -1774,7 +1774,7 @@ static int cpuset_common_seq_show(struct seq_file > > *sf, void *v) > > ret = -EINVAL; > > } > > > > - spin_unlock_irq(&callback_lock); > > + raw_spin_unlock_irq(&callback_lock); > > return ret; > > } > > > > @@ -1989,12 +1989,12 @@ static int cpuset_css_online(struct > > cgroup_subsys_state *css) > > > > cpuset_inc(); > > > > - spin_lock_irq(&callback_lock); > > + raw_spin_lock_irq(&callback_lock); > > if (is_in_v2_mode()) { > > cpumask_copy(cs->effective_cpus, parent->effective_cpus); > > cs->effective_mems = parent->effective_mems; > > } > > - spin_unlock_irq(&callback_lock); > > + raw_spin_unlock_irq(&callback_lock); > > > > if (!test_bit(CGRP_CPUSET_CLONE_CHILDREN, &css->cgroup->flags)) > > goto out_unlock; > > @@ -2021,12 +2021,12 @@ static int cpuset_css_online(struct > > cgroup_subsys_state *css) > > } > > rcu_read_unlock(); > > > > - spin_lock_irq(&callback_lock); > > + raw_spin_lock_irq(&callback_lock); > > cs->mems_allowed = parent->mems_allowed; > > cs->effective_mems = parent->mems_allowed; > > cpumask_copy(cs->cpus_allowed, parent->cpus_allowed); > > cpumask_copy(cs->effective_cpus, parent->cpus_allowed); > > - spin_unlock_irq(&callback_lock); > > + raw_spin_unlock_irq(&callback_lock); > > out_unlock: > > mutex_unlock(&cpuset_mutex); > > return 0; > > @@ -2065,7 +2065,7 @@ static void cpuset_css_free(struct > > cgroup_subsys_state *css) > > static void cpuset_bind(struct cgroup_subsys_state *root_css) > > { > > mutex_lock(&cpuset_mutex); > > - spin_lock_irq(&callback_lock); > > + raw_spin_lock_irq(&callback_lock); > > > > if (is_in_v2_mode()) { > > cpumask_copy(top_cpuset.cpus_allowed, cpu_possible_mask); > > @@ -2076,7 +2076,7 @@ static void cpuset_bind(struct cgroup_subsys_state > > *root_css) > > top_cpuset.mems_allowed = top_cpuset.effective_mems; > > } > > > > - spin_unlock_irq(&callback_lock); > > + raw_spin_unlock_irq(&callback_lock); > > mutex_unlock(&cpuset_mutex); > > } > > > > @@ -2174,12 +2174,12 @@ hotplug_update_tasks_legacy(struct cpuset *cs, > > { > > bool is_empty; > > > > - spin_lock_irq(&callback_lock); > > + raw_spin_lock_irq(&callback_lock); > > cpumask_copy(cs->cpus_allowed, new_cpus); > > cpumask_copy(cs->effective_cpus, new_cpus); > > cs->mems_allowed = *new_mems; > > cs->effective_mems = *new_mems; > > - spin_unlock_irq(&callback_lock); > > + raw_spin_unlock_irq(&callback_lock); > > > > /* > > * Don't call update_tasks_cpumask() if the cpuset becomes empty, > > @@ -2216,10 +2216,10 @@ hotplug_update_tasks(struct cpuset *cs, > > if (nodes_empty(*new_mems)) > > *new_mems = parent_cs(cs)->effective_mems; > > > > - spin_lock_irq(&callback_lock); > > + raw_spin_lock_irq(&callback_lock); > > cpumask_copy(cs->effective_cpus, new_cpus); > > cs->effective_mems = *new_mems; > > - spin_unlock_irq(&callback_lock); > > + raw_spin_unlock_irq(&callback_lock); > > > > if (cpus_updated) > > update_tasks_cpumask(cs); > > @@ -2312,21 +2312,21 @@ static void cpuset_hotplug_workfn(struct > > work_struct *work) > > > > /* synchronize cpus_allowed to cpu_active_mask */ > > if (cpus_updated) { > > - spin_lock_irq(&callback_lock); > > + raw_spin_lock_irq(&callback_lock); > > if (!on_dfl) > > cpumask_copy(top_cpuset.cpus_allowed, &new_cpus); > > cpumask_copy(top_cpuset.effective_cpus, &new_cpus); > > - spin_unlock_irq(&callback_lock); > > + raw_spin_unlock_irq(&callback_lock); > > /* we don't mess with cpumasks of tasks in top_cpuset */ > > } > > > > /* synchronize mems_allowed to N_MEMORY */ > > if (mems_updated) { > > - spin_lock_irq(&callback_lock); > > + raw_spin_lock_irq(&callback_lock); > > if (!on_dfl) > > top_cpuset.mems_allowed = new_mems; > > top_cpuset.effective_mems = new_mems; > > - spin_unlock_irq(&callback_lock); > > + raw_spin_unlock_irq(&callback_lock); > > update_tasks_nodemask(&top_cpuset); > > } > > > > @@ -2425,11 +2425,11 @@ void cpuset_cpus_allowed(struct task_struct *tsk, > > struct cpumask *pmask) > > { > > unsigned long flags; > > > > - spin_lock_irqsave(&callback_lock, flags); > > + raw_spin_lock_irqsave(&callback_lock, flags); > > rcu_read_lock(); > > guarantee_online_cpus(task_cs(tsk), pmask); > > rcu_read_unlock(); > > - spin_unlock_irqrestore(&callback_lock, flags); > > + raw_spin_unlock_irqrestore(&callback_lock, flags); > > } > > > > void cpuset_cpus_allowed_fallback(struct task_struct *tsk) > > @@ -2477,11 +2477,11 @@ nodemask_t cpuset_mems_allowed(struct task_struct > > *tsk) > > nodemask_t mask; > > unsigned long flags; > > > > - spin_lock_irqsave(&callback_lock, flags); > > + raw_spin_lock_irqsave(&callback_lock, flags); > > rcu_read_lock(); > > guarantee_online_mems(task_cs(tsk), &mask); > > rcu_read_unlock(); > > - spin_unlock_irqrestore(&callback_lock, flags); > > + raw_spin_unlock_irqrestore(&callback_lock, flags); > > > > return mask; > > } > > @@ -2573,14 +2573,14 @@ bool __cpuset_node_allowed(int node, gfp_t gfp_mask) > > return true; > > > > /* Not hardwall and node outside mems_allowed: scan up cpusets */ > > - spin_lock_irqsave(&callback_lock, flags); > > + raw_spin_lock_irqsave(&callback_lock, flags); > > > > rcu_read_lock(); > > cs = nearest_hardwall_ancestor(task_cs(current)); > > allowed = node_isset(node, cs->mems_allowed); > > rcu_read_unlock(); > > > > - spin_unlock_irqrestore(&callback_lock, flags); > > + raw_spin_unlock_irqrestore(&callback_lock, flags); > > return allowed; > > } > > > > -- > > 2.17.1 > >
