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| 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 /kernel | |
| parent | sched: Reject CPU affinity changes based on task_cpu_possible_mask() (diff) | |
| download | linux-b90ca8badbd11488e5f762346b028666808164e7.tar.gz linux-b90ca8badbd11488e5f762346b028666808164e7.tar.bz2 linux-b90ca8badbd11488e5f762346b028666808164e7.zip | |
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
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/fork.c | 2 | ||||
| -rw-r--r-- | kernel/sched/core.c | 20 |
2 files changed, 22 insertions, 0 deletions
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. * |