diff options
| author | Andrei Vagin <avagin@google.com> | 2023-03-07 23:31:58 -0800 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2023-07-17 16:08:08 -0700 |
| commit | 6f63904c8f3edb65bd85c1be01d69214ff8ca4c5 (patch) | |
| tree | 1411084a185f099140b25f05f0bbfd7104abf702 /kernel/sched/swait.c | |
| parent | ab83f455f04df5b2f7c6d4de03b6d2eaeaa27b8a (diff) | |
sched: add a few helpers to wake up tasks on the current cpu
Add complete_on_current_cpu, wake_up_poll_on_current_cpu helpers to wake
up tasks on the current CPU.
These two helpers are useful when the task needs to make a synchronous context
switch to another task. In this context, synchronous means it wakes up the
target task and falls asleep right after that.
One example of such workloads is seccomp user notifies. This mechanism allows
the supervisor process handles system calls on behalf of a target process.
While the supervisor is handling an intercepted system call, the target process
will be blocked in the kernel, waiting for a response to come back.
On-CPU context switches are much faster than regular ones.
Signed-off-by: Andrei Vagin <avagin@google.com>
Acked-by: "Peter Zijlstra (Intel)" <peterz@infradead.org>
Link: https://lore.kernel.org/r/20230308073201.3102738-4-avagin@google.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'kernel/sched/swait.c')
| -rw-r--r-- | kernel/sched/swait.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/kernel/sched/swait.c b/kernel/sched/swait.c index 76b9b796e695..72505cd3b60a 100644 --- a/kernel/sched/swait.c +++ b/kernel/sched/swait.c @@ -18,7 +18,7 @@ EXPORT_SYMBOL(__init_swait_queue_head); * If for some reason it would return 0, that means the previously waiting * task is already running, so it will observe condition true (or has already). */ -void swake_up_locked(struct swait_queue_head *q) +void swake_up_locked(struct swait_queue_head *q, int wake_flags) { struct swait_queue *curr; @@ -26,7 +26,7 @@ void swake_up_locked(struct swait_queue_head *q) return; curr = list_first_entry(&q->task_list, typeof(*curr), task_list); - wake_up_process(curr->task); + try_to_wake_up(curr->task, TASK_NORMAL, wake_flags); list_del_init(&curr->task_list); } EXPORT_SYMBOL(swake_up_locked); @@ -41,7 +41,7 @@ EXPORT_SYMBOL(swake_up_locked); void swake_up_all_locked(struct swait_queue_head *q) { while (!list_empty(&q->task_list)) - swake_up_locked(q); + swake_up_locked(q, 0); } void swake_up_one(struct swait_queue_head *q) @@ -49,7 +49,7 @@ void swake_up_one(struct swait_queue_head *q) unsigned long flags; raw_spin_lock_irqsave(&q->lock, flags); - swake_up_locked(q); + swake_up_locked(q, 0); raw_spin_unlock_irqrestore(&q->lock, flags); } EXPORT_SYMBOL(swake_up_one); |