kernel_optimize_test/include/linux/task_work.h
Oleg Nesterov e91b481623 task_work: teach task_work_add() to do signal_wake_up()
So that the target task will exit the wait_event_interruptible-like
loop and call task_work_run() asap.

The patch turns "bool notify" into 0,TWA_RESUME,TWA_SIGNAL enum, the
new TWA_SIGNAL flag implies signal_wake_up().  However, it needs to
avoid the race with recalc_sigpending(), so the patch also adds the
new JOBCTL_TASK_WORK bit included in JOBCTL_PENDING_MASK.

TODO: once this patch is merged we need to change all current users
of task_work_add(notify = true) to use TWA_RESUME.

Cc: stable@vger.kernel.org # v5.7
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-06-30 12:18:08 -06:00

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C

/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_TASK_WORK_H
#define _LINUX_TASK_WORK_H
#include <linux/list.h>
#include <linux/sched.h>
typedef void (*task_work_func_t)(struct callback_head *);
static inline void
init_task_work(struct callback_head *twork, task_work_func_t func)
{
twork->func = func;
}
#define TWA_RESUME 1
#define TWA_SIGNAL 2
int task_work_add(struct task_struct *task, struct callback_head *twork, int);
struct callback_head *task_work_cancel(struct task_struct *, task_work_func_t);
void task_work_run(void);
static inline void exit_task_work(struct task_struct *task)
{
task_work_run();
}
#endif /* _LINUX_TASK_WORK_H */