From d79fc0fc6645b0cf5cd980da76942ca6d6300fa4 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Sat, 10 Sep 2005 00:26:12 -0700 Subject: [PATCH] [PATCH] sched: TASK_NONINTERACTIVE This patch implements a task state bit (TASK_NONINTERACTIVE), which can be used by blocking points to mark the task's wait as "non-interactive". This does not mean the task will be considered a CPU-hog - the wait will simply not have an effect on the waiting task's priority - positive or negative alike. Right now only pipe_wait() will make use of it, because it's a common source of not-so-interactive waits (kernel compilation jobs, etc.). Signed-off-by: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/pipe.c | 6 +++++- include/linux/sched.h | 1 + kernel/sched.c | 11 ++++++++++- 3 files changed, 16 insertions(+), 2 deletions(-) diff --git a/fs/pipe.c b/fs/pipe.c index 2c7a23dde2d..66aa0b938d6 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -39,7 +39,11 @@ void pipe_wait(struct inode * inode) { DEFINE_WAIT(wait); - prepare_to_wait(PIPE_WAIT(*inode), &wait, TASK_INTERRUPTIBLE); + /* + * Pipes are system-local resources, so sleeping on them + * is considered a noninteractive wait: + */ + prepare_to_wait(PIPE_WAIT(*inode), &wait, TASK_INTERRUPTIBLE|TASK_NONINTERACTIVE); up(PIPE_SEM(*inode)); schedule(); finish_wait(PIPE_WAIT(*inode), &wait); diff --git a/include/linux/sched.h b/include/linux/sched.h index 8a1fcfe80fc..ac70f845b5b 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -114,6 +114,7 @@ extern unsigned long nr_iowait(void); #define TASK_TRACED 8 #define EXIT_ZOMBIE 16 #define EXIT_DEAD 32 +#define TASK_NONINTERACTIVE 64 #define __set_task_state(tsk, state_value) \ do { (tsk)->state = (state_value); } while (0) diff --git a/kernel/sched.c b/kernel/sched.c index 24eed372d28..6da13bba3e2 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -1260,6 +1260,16 @@ out_activate: p->activated = -1; } + /* + * Tasks that have marked their sleep as noninteractive get + * woken up without updating their sleep average. (i.e. their + * sleep is handled in a priority-neutral manner, no priority + * boost and no penalty.) + */ + if (old_state & TASK_NONINTERACTIVE) + __activate_task(p, rq); + else + activate_task(p, rq, cpu == this_cpu); /* * Sync wakeups (i.e. those types of wakeups where the waker * has indicated that it will leave the CPU in short order) @@ -1268,7 +1278,6 @@ out_activate: * the waker guarantees that the freshly woken up task is going * to be considered on this CPU.) */ - activate_task(p, rq, cpu == this_cpu); if (!sync || cpu != this_cpu) { if (TASK_PREEMPTS_CURR(p, rq)) resched_task(rq->curr);