diff options
Diffstat (limited to 'include/linux/sched.h')
| -rw-r--r-- | include/linux/sched.h | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 38c8654aaa9..c3ba31f210a 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -107,13 +107,25 @@ extern unsigned long nr_iowait(void); #include <asm/processor.h> +/* + * Task state bitmask. NOTE! These bits are also + * encoded in fs/proc/array.c: get_task_state(). + * + * We have two separate sets of flags: task->state + * is about runnability, while task->exit_state are + * about the task exiting. Confusing, but this way + * modifying one set can't modify the other one by + * mistake. + */ #define TASK_RUNNING 0 #define TASK_INTERRUPTIBLE 1 #define TASK_UNINTERRUPTIBLE 2 #define TASK_STOPPED 4 #define TASK_TRACED 8 +/* in tsk->exit_state */ #define EXIT_ZOMBIE 16 #define EXIT_DEAD 32 +/* in tsk->state again */ #define TASK_NONINTERACTIVE 64 #define __set_task_state(tsk, state_value) \ @@ -121,6 +133,17 @@ extern unsigned long nr_iowait(void); #define set_task_state(tsk, state_value) \ set_mb((tsk)->state, (state_value)) +/* + * set_current_state() includes a barrier so that the write of current->state + * is correctly serialised wrt the caller's subsequent test of whether to + * actually sleep: + * + * set_current_state(TASK_UNINTERRUPTIBLE); + * if (do_i_need_to_sleep()) + * schedule(); + * + * If the caller does not need such serialisation then use __set_current_state() + */ #define __set_current_state(state_value) \ do { current->state = (state_value); } while (0) #define set_current_state(state_value) \ |