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Thread exit deadlock #5

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Merged
merged 2 commits into from
Jun 1, 2020
Merged

Thread exit deadlock #5

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f5a8234
lwksched: fix CPU assignment during overcommmit (#2)
jattine May 8, 2020
2ca9a02
lwksched: Fix deadlock during thread exit
jattine May 19, 2020
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3 changes: 1 addition & 2 deletions kernel/sched/core.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2798,8 +2798,7 @@ static void __sched_fork(unsigned long clone_flags, struct task_struct *p)
p->rt.time_slice = sched_rr_timeslice;
p->rt.on_rq = 0;
p->rt.on_list = 0;
init_run_list_mos(p);
init_util_list_mos(p);
init_fork_mos(p);

#ifdef CONFIG_PREEMPT_NOTIFIERS
INIT_HLIST_HEAD(&p->preempt_notifiers);
Expand Down
22 changes: 14 additions & 8 deletions kernel/sched/mos.c
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Original file line number Diff line number Diff line change
Expand Up @@ -345,13 +345,14 @@ static void uncommit_cpu(struct task_struct *p)
struct mos_rq *mos_rq;
int cpu = p->mos.cpu_home;
int underflow = 0;
unsigned long flags;

if (cpu < 0)
return;
mos_rq = &cpu_rq(cpu)->mos;
p->mos.cpu_home = -1;

raw_spin_lock(&mos_rq->lock);
raw_spin_lock_irqsave(&mos_rq->lock, flags);
if (p->mos.thread_type == mos_thread_type_normal) {
if (mos_rq->compute_commits > 0)
mos_rq->compute_commits--;
Expand All @@ -364,7 +365,7 @@ static void uncommit_cpu(struct task_struct *p)
else
underflow = 1;
}
raw_spin_unlock(&mos_rq->lock);
raw_spin_unlock_irqrestore(&mos_rq->lock, flags);

trace_mos_cpu_uncommit(p, cpu, mos_rq->compute_commits,
mos_rq->utility_commits, underflow);
Expand All @@ -375,11 +376,12 @@ static void commit_cpu(struct task_struct *p, int cpu)
struct mos_rq *mos_rq;
unsigned int newval = 0;
int overflow = 0;
unsigned long flags;

if (cpu < 0)
return;
mos_rq = &cpu_rq(cpu)->mos;
raw_spin_lock(&mos_rq->lock);
raw_spin_lock_irqsave(&mos_rq->lock, flags);
if (p->mos.thread_type == mos_thread_type_normal) {
if (mos_rq->compute_commits < INT_MAX) {
newval = ++mos_rq->compute_commits;
Expand All @@ -395,7 +397,7 @@ static void commit_cpu(struct task_struct *p, int cpu)
} else
overflow = 1;
}
raw_spin_unlock(&mos_rq->lock);
raw_spin_unlock_irqrestore(&mos_rq->lock, flags);
p->mos.cpu_home = cpu;
trace_mos_cpu_commit(p, cpu, mos_rq->compute_commits,
mos_rq->utility_commits, overflow);
Expand Down Expand Up @@ -2991,8 +2993,13 @@ static void task_fork_mos(struct task_struct *p)

p->prio = current->prio;
p->normal_prio = current->prio;
p->mos.thread_type = mos_thread_type_normal;
p->mos.cpu_home = -1;

/* We need to remove the commit placed on the CPU that called clone.
* This occurred in core.c->sched_fork->__select_task_cpu. This needs
* to be done prior to selecting the target CPU for this new thread
* which occurs in core.c->wake_up_new_task.
*/
uncommit_cpu(p);

/*
* We need to set the cpus allowed mask appropriately. If this is
Expand Down Expand Up @@ -3054,8 +3061,7 @@ static void task_fork_mos(struct task_struct *p)

void mos_set_task_cpu(struct task_struct *p, int new_cpu)
{
if (task_cpu(p) != new_cpu &&
cpu_rq(new_cpu)->lwkcpu &&
if (cpu_rq(new_cpu)->lwkcpu &&
p->mos_process &&
new_cpu != p->mos.cpu_home) {
/* Release a previous commit if it exists */
Expand Down
11 changes: 11 additions & 0 deletions kernel/sched/mos.h
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Original file line number Diff line number Diff line change
Expand Up @@ -143,6 +143,14 @@ static inline bool is_migration_mask_valid_mos(const cpumask_t *mask,
return false;
}

static inline void init_fork_mos(struct task_struct *p)
{
p->mos.cpu_home = -1;
p->mos.thread_type = mos_thread_type_normal;
init_run_list_mos(p);
init_util_list_mos(p);
}

#else

static inline void assimilate_mos(struct rq *rq, struct task_struct *p)
Expand Down Expand Up @@ -236,6 +244,9 @@ static inline bool is_migration_mask_valid_mos(const cpumask_t *mask,
return false;
}

static inline void init_fork_mos(struct task_struct *p)
{}

#endif

#ifdef CONFIG_MOS_MOVE_SYSCALLS
Expand Down