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Commit 817e5000 authored by Sebastian Ott's avatar Sebastian Ott Committed by Martin Schwidefsky
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[S390] hibernate: directly trigger subchannel evaluation 



Using the generic css_schedule_eval to evaluate subchannels
while resuming from hibernation is very slow when used with
many devices. Provide a new evaluation trigger which exploits
css_sched_sch_todo and use this in the resume callback for
ccw devices.

Signed-off-by: default avatarSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent cfc9066b

drivers/s390/cio/cio.h

+5 −0
Original line number Diff line number Diff line
@@ -68,8 +68,13 @@ struct schib { 
	__u8 mda[4];		 /* model dependent area */

} __attribute__ ((packed,aligned(4)));



/*

 * When rescheduled, todo's with higher values will overwrite those

 * with lower values.

 */

enum sch_todo {

	SCH_TODO_NOTHING,

	SCH_TODO_EVAL,

	SCH_TODO_UNREG,

};

drivers/s390/cio/css.c

+59 −45
Original line number Diff line number Diff line
@@ -195,51 +195,6 @@ void css_sch_device_unregister(struct subchannel *sch) 
}

EXPORT_SYMBOL_GPL(css_sch_device_unregister);



static void css_sch_todo(struct work_struct *work)

{

	struct subchannel *sch;

	enum sch_todo todo;



	sch = container_of(work, struct subchannel, todo_work);

	/* Find out todo. */

	spin_lock_irq(sch->lock);

	todo = sch->todo;

	CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid,

		      sch->schid.sch_no, todo);

	sch->todo = SCH_TODO_NOTHING;

	spin_unlock_irq(sch->lock);

	/* Perform todo. */

	if (todo == SCH_TODO_UNREG)

		css_sch_device_unregister(sch);

	/* Release workqueue ref. */

	put_device(&sch->dev);

}



/**

 * css_sched_sch_todo - schedule a subchannel operation

 * @sch: subchannel

 * @todo: todo

 *

 * Schedule the operation identified by @todo to be performed on the slow path

 * workqueue. Do nothing if another operation with higher priority is already

 * scheduled. Needs to be called with subchannel lock held.

 */

void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)

{

	CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n",

		      sch->schid.ssid, sch->schid.sch_no, todo);

	if (sch->todo >= todo)

		return;

	/* Get workqueue ref. */

	if (!get_device(&sch->dev))

		return;

	sch->todo = todo;

	if (!queue_work(cio_work_q, &sch->todo_work)) {

		/* Already queued, release workqueue ref. */

		put_device(&sch->dev);

	}

}



static void ssd_from_pmcw(struct chsc_ssd_info *ssd, struct pmcw *pmcw)

{

	int i;
@@ -466,6 +421,65 @@ static void css_evaluate_subchannel(struct subchannel_id schid, int slow) 
		css_schedule_eval(schid);

}



/**

 * css_sched_sch_todo - schedule a subchannel operation

 * @sch: subchannel

 * @todo: todo

 *

 * Schedule the operation identified by @todo to be performed on the slow path

 * workqueue. Do nothing if another operation with higher priority is already

 * scheduled. Needs to be called with subchannel lock held.

 */

void css_sched_sch_todo(struct subchannel *sch, enum sch_todo todo)

{

	CIO_MSG_EVENT(4, "sch_todo: sched sch=0.%x.%04x todo=%d\n",

		      sch->schid.ssid, sch->schid.sch_no, todo);

	if (sch->todo >= todo)

		return;

	/* Get workqueue ref. */

	if (!get_device(&sch->dev))

		return;

	sch->todo = todo;

	if (!queue_work(cio_work_q, &sch->todo_work)) {

		/* Already queued, release workqueue ref. */

		put_device(&sch->dev);

	}

}



static void css_sch_todo(struct work_struct *work)

{

	struct subchannel *sch;

	enum sch_todo todo;

	int ret;



	sch = container_of(work, struct subchannel, todo_work);

	/* Find out todo. */

	spin_lock_irq(sch->lock);

	todo = sch->todo;

	CIO_MSG_EVENT(4, "sch_todo: sch=0.%x.%04x, todo=%d\n", sch->schid.ssid,

		      sch->schid.sch_no, todo);

	sch->todo = SCH_TODO_NOTHING;

	spin_unlock_irq(sch->lock);

	/* Perform todo. */

	switch (todo) {

	case SCH_TODO_NOTHING:

		break;

	case SCH_TODO_EVAL:

		ret = css_evaluate_known_subchannel(sch, 1);

		if (ret == -EAGAIN) {

			spin_lock_irq(sch->lock);

			css_sched_sch_todo(sch, todo);

			spin_unlock_irq(sch->lock);

		}

		break;

	case SCH_TODO_UNREG:

		css_sch_device_unregister(sch);

		break;

	}

	/* Release workqueue ref. */

	put_device(&sch->dev);

}



static struct idset *slow_subchannel_set;

static spinlock_t slow_subchannel_lock;

static wait_queue_head_t css_eval_wq;

drivers/s390/cio/device.c

+2 −2
Original line number Diff line number Diff line
@@ -1868,9 +1868,9 @@ static void __ccw_device_pm_restore(struct ccw_device *cdev) 
	 */

	cdev->private->flags.resuming = 1;

	cdev->private->path_new_mask = LPM_ANYPATH;

	css_schedule_eval(sch->schid);

	css_sched_sch_todo(sch, SCH_TODO_EVAL);

	spin_unlock_irq(sch->lock);

	css_complete_work();

	css_wait_for_slow_path();



	/* cdev may have been moved to a different subchannel. */

	sch = to_subchannel(cdev->dev.parent);