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e788be95a5
Some use cases don't always need an IPI when sending a TWA_SIGNAL notification. Add TWA_SIGNAL_NO_IPI, which is just like TWA_SIGNAL, except it doesn't send an IPI to the target task. It merely sets TIF_NOTIFY_SIGNAL and wakes up the task. This can be useful in avoiding a forceful transition to the kernel if the task is running in userspace. Depending on the task_work in question, it may be quite fine waiting for the next reschedule or kernel enter anyway, or the use case may even have other mechanisms for hinting to the task that a transition may be useful. This can drive more cooperative scheduling of task_work. Reviewed-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/821f42b6-7d91-8074-8212-d34998097de4@kernel.dk Signed-off-by: Jens Axboe <axboe@kernel.dk>
41 lines
979 B
C
41 lines
979 B
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_TASK_WORK_H
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#define _LINUX_TASK_WORK_H
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#include <linux/list.h>
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#include <linux/sched.h>
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typedef void (*task_work_func_t)(struct callback_head *);
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static inline void
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init_task_work(struct callback_head *twork, task_work_func_t func)
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{
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twork->func = func;
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}
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enum task_work_notify_mode {
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TWA_NONE,
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TWA_RESUME,
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TWA_SIGNAL,
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TWA_SIGNAL_NO_IPI,
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};
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static inline bool task_work_pending(struct task_struct *task)
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{
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return READ_ONCE(task->task_works);
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}
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int task_work_add(struct task_struct *task, struct callback_head *twork,
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enum task_work_notify_mode mode);
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struct callback_head *task_work_cancel_match(struct task_struct *task,
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bool (*match)(struct callback_head *, void *data), void *data);
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struct callback_head *task_work_cancel(struct task_struct *, task_work_func_t);
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void task_work_run(void);
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static inline void exit_task_work(struct task_struct *task)
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{
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task_work_run();
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}
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#endif /* _LINUX_TASK_WORK_H */
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