diff options
author | Jason Gunthorpe <jgg@nvidia.com> | 2023-02-21 18:11:03 +0300 |
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committer | Jason Gunthorpe <jgg@nvidia.com> | 2023-02-21 18:11:03 +0300 |
commit | 939204e4df962982cbc84acc26b29b421dd530a8 (patch) | |
tree | 753698947a28ff1f18857d198a671317352f16c8 /kernel/sched/core.c | |
parent | b4ff830eca097df51af10a9be29e8cc817327919 (diff) | |
parent | c9c3395d5e3dcc6daee66c6908354d47bf98cb0c (diff) | |
download | linux-939204e4df962982cbc84acc26b29b421dd530a8.tar.xz |
Merge tag 'v6.2' into iommufd.git for-next
Resolve conflicts from the signature change in iommu_map:
- drivers/infiniband/hw/usnic/usnic_uiom.c
Switch iommu_map_atomic() to iommu_map(.., GFP_ATOMIC)
- drivers/vfio/vfio_iommu_type1.c
Following indenting change for GFP_KERNEL
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Diffstat (limited to 'kernel/sched/core.c')
-rw-r--r-- | kernel/sched/core.c | 82 |
1 files changed, 71 insertions, 11 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 25b582b6ee5f..2a4918a1faa9 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2604,27 +2604,71 @@ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) .user_mask = NULL, .flags = SCA_USER, /* clear the user requested mask */ }; + union cpumask_rcuhead { + cpumask_t cpumask; + struct rcu_head rcu; + }; __do_set_cpus_allowed(p, &ac); - kfree(ac.user_mask); + + /* + * Because this is called with p->pi_lock held, it is not possible + * to use kfree() here (when PREEMPT_RT=y), therefore punt to using + * kfree_rcu(). + */ + kfree_rcu((union cpumask_rcuhead *)ac.user_mask, rcu); +} + +static cpumask_t *alloc_user_cpus_ptr(int node) +{ + /* + * See do_set_cpus_allowed() above for the rcu_head usage. + */ + int size = max_t(int, cpumask_size(), sizeof(struct rcu_head)); + + return kmalloc_node(size, GFP_KERNEL, node); } int dup_user_cpus_ptr(struct task_struct *dst, struct task_struct *src, int node) { + cpumask_t *user_mask; unsigned long flags; - if (!src->user_cpus_ptr) + /* + * Always clear dst->user_cpus_ptr first as their user_cpus_ptr's + * may differ by now due to racing. + */ + dst->user_cpus_ptr = NULL; + + /* + * This check is racy and losing the race is a valid situation. + * It is not worth the extra overhead of taking the pi_lock on + * every fork/clone. + */ + if (data_race(!src->user_cpus_ptr)) return 0; - dst->user_cpus_ptr = kmalloc_node(cpumask_size(), GFP_KERNEL, node); - if (!dst->user_cpus_ptr) + user_mask = alloc_user_cpus_ptr(node); + if (!user_mask) return -ENOMEM; - /* Use pi_lock to protect content of user_cpus_ptr */ + /* + * Use pi_lock to protect content of user_cpus_ptr + * + * Though unlikely, user_cpus_ptr can be reset to NULL by a concurrent + * do_set_cpus_allowed(). + */ raw_spin_lock_irqsave(&src->pi_lock, flags); - cpumask_copy(dst->user_cpus_ptr, src->user_cpus_ptr); + if (src->user_cpus_ptr) { + swap(dst->user_cpus_ptr, user_mask); + cpumask_copy(dst->user_cpus_ptr, src->user_cpus_ptr); + } raw_spin_unlock_irqrestore(&src->pi_lock, flags); + + if (unlikely(user_mask)) + kfree(user_mask); + return 0; } @@ -2907,8 +2951,11 @@ static int __set_cpus_allowed_ptr_locked(struct task_struct *p, } if (!(ctx->flags & SCA_MIGRATE_ENABLE)) { - if (cpumask_equal(&p->cpus_mask, ctx->new_mask)) + if (cpumask_equal(&p->cpus_mask, ctx->new_mask)) { + if (ctx->flags & SCA_USER) + swap(p->user_cpus_ptr, ctx->user_mask); goto out; + } if (WARN_ON_ONCE(p == current && is_migration_disabled(p) && @@ -3581,6 +3628,11 @@ static inline bool rq_has_pinned_tasks(struct rq *rq) return false; } +static inline cpumask_t *alloc_user_cpus_ptr(int node) +{ + return NULL; +} + #endif /* !CONFIG_SMP */ static void @@ -5504,7 +5556,9 @@ void scheduler_tick(void) unsigned long thermal_pressure; u64 resched_latency; - arch_scale_freq_tick(); + if (housekeeping_cpu(cpu, HK_TYPE_TICK)) + arch_scale_freq_tick(); + sched_clock_tick(); rq_lock(rq, &rf); @@ -8239,12 +8293,18 @@ long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) if (retval) goto out_put_task; - user_mask = kmalloc(cpumask_size(), GFP_KERNEL); - if (!user_mask) { + /* + * With non-SMP configs, user_cpus_ptr/user_mask isn't used and + * alloc_user_cpus_ptr() returns NULL. + */ + user_mask = alloc_user_cpus_ptr(NUMA_NO_NODE); + if (user_mask) { + cpumask_copy(user_mask, in_mask); + } else if (IS_ENABLED(CONFIG_SMP)) { retval = -ENOMEM; goto out_put_task; } - cpumask_copy(user_mask, in_mask); + ac = (struct affinity_context){ .new_mask = in_mask, .user_mask = user_mask, |