sched/numa: Fix task_numa_free() lockdep splat
Sasha reported that lockdep claims that the following commit: made numa_group.lock interrupt unsafe:156654f491
("sched/numa: Move task_numa_free() to __put_task_struct()") While I don't see how that could be, given the commit in question moved task_numa_free() from one irq enabled region to another, the below does make both gripes and lockups upon gripe with numa=fake=4 go away. Reported-by: Sasha Levin <sasha.levin@oracle.com> Fixes:156654f491
("sched/numa: Move task_numa_free() to __put_task_struct()") Signed-off-by: Mike Galbraith <bitbucket@online.de> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: torvalds@linux-foundation.org Cc: mgorman@suse.com Cc: akpm@linux-foundation.org Cc: Dave Jones <davej@redhat.com> Link: http://lkml.kernel.org/r/1396860915.5170.5.camel@marge.simpson.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
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@ -1497,7 +1497,7 @@ static void task_numa_placement(struct task_struct *p)
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/* If the task is part of a group prevent parallel updates to group stats */
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/* If the task is part of a group prevent parallel updates to group stats */
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if (p->numa_group) {
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if (p->numa_group) {
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group_lock = &p->numa_group->lock;
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group_lock = &p->numa_group->lock;
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spin_lock(group_lock);
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spin_lock_irq(group_lock);
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}
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}
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/* Find the node with the highest number of faults */
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/* Find the node with the highest number of faults */
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@ -1572,7 +1572,7 @@ static void task_numa_placement(struct task_struct *p)
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}
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}
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}
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}
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spin_unlock(group_lock);
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spin_unlock_irq(group_lock);
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}
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}
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/* Preferred node as the node with the most faults */
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/* Preferred node as the node with the most faults */
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@ -1677,7 +1677,8 @@ static void task_numa_group(struct task_struct *p, int cpupid, int flags,
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if (!join)
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if (!join)
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return;
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return;
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double_lock(&my_grp->lock, &grp->lock);
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BUG_ON(irqs_disabled());
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double_lock_irq(&my_grp->lock, &grp->lock);
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for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++) {
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for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++) {
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my_grp->faults[i] -= p->numa_faults_memory[i];
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my_grp->faults[i] -= p->numa_faults_memory[i];
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@ -1691,7 +1692,7 @@ static void task_numa_group(struct task_struct *p, int cpupid, int flags,
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grp->nr_tasks++;
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grp->nr_tasks++;
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spin_unlock(&my_grp->lock);
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spin_unlock(&my_grp->lock);
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spin_unlock(&grp->lock);
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spin_unlock_irq(&grp->lock);
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rcu_assign_pointer(p->numa_group, grp);
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rcu_assign_pointer(p->numa_group, grp);
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@ -1710,14 +1711,14 @@ void task_numa_free(struct task_struct *p)
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void *numa_faults = p->numa_faults_memory;
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void *numa_faults = p->numa_faults_memory;
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if (grp) {
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if (grp) {
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spin_lock(&grp->lock);
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spin_lock_irq(&grp->lock);
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for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++)
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for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++)
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grp->faults[i] -= p->numa_faults_memory[i];
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grp->faults[i] -= p->numa_faults_memory[i];
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grp->total_faults -= p->total_numa_faults;
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grp->total_faults -= p->total_numa_faults;
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list_del(&p->numa_entry);
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list_del(&p->numa_entry);
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grp->nr_tasks--;
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grp->nr_tasks--;
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spin_unlock(&grp->lock);
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spin_unlock_irq(&grp->lock);
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rcu_assign_pointer(p->numa_group, NULL);
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rcu_assign_pointer(p->numa_group, NULL);
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put_numa_group(grp);
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put_numa_group(grp);
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}
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}
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@ -1385,6 +1385,15 @@ static inline void double_lock(spinlock_t *l1, spinlock_t *l2)
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spin_lock_nested(l2, SINGLE_DEPTH_NESTING);
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spin_lock_nested(l2, SINGLE_DEPTH_NESTING);
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}
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}
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static inline void double_lock_irq(spinlock_t *l1, spinlock_t *l2)
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{
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if (l1 > l2)
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swap(l1, l2);
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spin_lock_irq(l1);
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spin_lock_nested(l2, SINGLE_DEPTH_NESTING);
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}
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static inline void double_raw_lock(raw_spinlock_t *l1, raw_spinlock_t *l2)
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static inline void double_raw_lock(raw_spinlock_t *l1, raw_spinlock_t *l2)
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{
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{
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if (l1 > l2)
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if (l1 > l2)
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