diff options
| author | Will Deacon <will@kernel.org> | 2021-07-30 12:24:33 +0100 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-08-20 12:33:00 +0200 |
| commit | b90ca8badbd11488e5f762346b028666808164e7 (patch) | |
| tree | 38cf3f80ceb6e2ae051c85fbb7b4696fecc90ed6 | |
| parent | 234a503e670be01f72841be9fcf68dfb89a1fa8b (diff) | |
sched: Introduce task_struct::user_cpus_ptr to track requested affinity
In preparation for saving and restoring the user-requested CPU affinity
mask of a task, add a new cpumask_t pointer to 'struct task_struct'.
If the pointer is non-NULL, then the mask is copied across fork() and
freed on task exit.
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <Valentin.Schneider@arm.com>
Link: https://lore.kernel.org/r/20210730112443.23245-7-will@kernel.org
| -rw-r--r-- | include/linux/sched.h | 13 | ||||
| -rw-r--r-- | init/init_task.c | 1 | ||||
| -rw-r--r-- | kernel/fork.c | 2 | ||||
| -rw-r--r-- | kernel/sched/core.c | 20 |
4 files changed, 36 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 50db9496c99d..2c5d638daaad 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -748,6 +748,7 @@ struct task_struct { unsigned int policy; int nr_cpus_allowed; const cpumask_t *cpus_ptr; + cpumask_t *user_cpus_ptr; cpumask_t cpus_mask; void *migration_pending; #ifdef CONFIG_SMP @@ -1706,6 +1707,8 @@ extern int task_can_attach(struct task_struct *p, const struct cpumask *cs_cpus_ #ifdef CONFIG_SMP extern void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask); extern int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask); +extern int dup_user_cpus_ptr(struct task_struct *dst, struct task_struct *src, int node); +extern void release_user_cpus_ptr(struct task_struct *p); #else static inline void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) { @@ -1716,6 +1719,16 @@ static inline int set_cpus_allowed_ptr(struct task_struct *p, const struct cpuma return -EINVAL; return 0; } +static inline int dup_user_cpus_ptr(struct task_struct *dst, struct task_struct *src, int node) +{ + if (src->user_cpus_ptr) + return -EINVAL; + return 0; +} +static inline void release_user_cpus_ptr(struct task_struct *p) +{ + WARN_ON(p->user_cpus_ptr); +} #endif extern int yield_to(struct task_struct *p, bool preempt); diff --git a/init/init_task.c b/init/init_task.c index 562f2ef8d157..2d024066e27b 100644 --- a/init/init_task.c +++ b/init/init_task.c @@ -80,6 +80,7 @@ struct task_struct init_task .normal_prio = MAX_PRIO - 20, .policy = SCHED_NORMAL, .cpus_ptr = &init_task.cpus_mask, + .user_cpus_ptr = NULL, .cpus_mask = CPU_MASK_ALL, .nr_cpus_allowed= NR_CPUS, .mm = NULL, diff --git a/kernel/fork.c b/kernel/fork.c index 1a9af73b47c1..5d7addf0c41a 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -446,6 +446,7 @@ void put_task_stack(struct task_struct *tsk) void free_task(struct task_struct *tsk) { + release_user_cpus_ptr(tsk); scs_release(tsk); #ifndef CONFIG_THREAD_INFO_IN_TASK @@ -919,6 +920,7 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node) #endif if (orig->cpus_ptr == &orig->cpus_mask) tsk->cpus_ptr = &tsk->cpus_mask; + dup_user_cpus_ptr(tsk, orig, node); /* * One for the user space visible state that goes away when reaped. diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 8cec0d24c88c..360a3ec6d03b 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2480,6 +2480,26 @@ void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) __do_set_cpus_allowed(p, new_mask, 0); } +int dup_user_cpus_ptr(struct task_struct *dst, struct task_struct *src, + int node) +{ + if (!src->user_cpus_ptr) + return 0; + + dst->user_cpus_ptr = kmalloc_node(cpumask_size(), GFP_KERNEL, node); + if (!dst->user_cpus_ptr) + return -ENOMEM; + + cpumask_copy(dst->user_cpus_ptr, src->user_cpus_ptr); + return 0; +} + +void release_user_cpus_ptr(struct task_struct *p) +{ + kfree(p->user_cpus_ptr); + p->user_cpus_ptr = NULL; +} + /* * This function is wildly self concurrent; here be dragons. * |