From: Jens Axboe Date: Wed, 7 May 2008 07:51:23 +0000 (+0200) Subject: cfq-iosched: make io priorities inherit CPU scheduling class as well as nice X-Git-Tag: v2.6.26-rc2~33^2~4 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6d63c275572d1e6f00d4fa154f16fbb0d8c2d2bf;p=linux-2.6 cfq-iosched: make io priorities inherit CPU scheduling class as well as nice We currently set all processes to the best-effort scheduling class, regardless of what CPU scheduling class they belong to. Improve that so that we correctly track idle and rt scheduling classes as well. Signed-off-by: Jens Axboe --- diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 7f909d2f48..b399c62936 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -1303,10 +1303,10 @@ static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc) printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class); case IOPRIO_CLASS_NONE: /* - * no prio set, place us in the middle of the BE classes + * no prio set, inherit CPU scheduling settings */ cfqq->ioprio = task_nice_ioprio(tsk); - cfqq->ioprio_class = IOPRIO_CLASS_BE; + cfqq->ioprio_class = task_nice_ioclass(tsk); break; case IOPRIO_CLASS_RT: cfqq->ioprio = task_ioprio(ioc); diff --git a/include/linux/ioprio.h b/include/linux/ioprio.h index 2a3bb1bb74..f98a656b17 100644 --- a/include/linux/ioprio.h +++ b/include/linux/ioprio.h @@ -67,6 +67,20 @@ static inline int task_nice_ioprio(struct task_struct *task) return (task_nice(task) + 20) / 5; } +/* + * This is for the case where the task hasn't asked for a specific IO class. + * Check for idle and rt task process, and return appropriate IO class. + */ +static inline int task_nice_ioclass(struct task_struct *task) +{ + if (task->policy == SCHED_IDLE) + return IOPRIO_CLASS_IDLE; + else if (task->policy == SCHED_FIFO || task->policy == SCHED_RR) + return IOPRIO_CLASS_RT; + else + return IOPRIO_CLASS_BE; +} + /* * For inheritance, return the highest of the two given priorities */