Commit b2c18e1e authored by Jeff Moyer's avatar Jeff Moyer Committed by Jens Axboe
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cfq: calculate the seek_mean per cfq_queue not per cfq_io_context 



async cfq_queue's are already shared between processes within the same
priority, and forthcoming patches will change the mapping of cic to sync
cfq_queue from 1:1 to 1:N.  So, calculate the seekiness of a process
based on the cfq_queue instead of the cfq_io_context.

Signed-off-by: default avatarJeff Moyer <jmoyer@redhat.com>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent c30f3343

block/cfq-iosched.c

+33 −35
Original line number Diff line number Diff line
@@ -112,6 +112,11 @@ struct cfq_queue { 
	unsigned short ioprio, org_ioprio;

	unsigned short ioprio_class, org_ioprio_class;



	unsigned int seek_samples;

	u64 seek_total;

	sector_t seek_mean;

	sector_t last_request_pos;



	pid_t pid;

};
@@ -962,16 +967,16 @@ static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd, 
		return cfqd->last_position - blk_rq_pos(rq);

}



#define CIC_SEEK_THR	8 * 1024

#define CIC_SEEKY(cic)	((cic)->seek_mean > CIC_SEEK_THR)

#define CFQQ_SEEK_THR		8 * 1024

#define CFQQ_SEEKY(cfqq)	((cfqq)->seek_mean > CFQQ_SEEK_THR)



static inline int cfq_rq_close(struct cfq_data *cfqd, struct request *rq)

static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq,

			       struct request *rq)

{

	struct cfq_io_context *cic = cfqd->active_cic;

	sector_t sdist = cic->seek_mean;

	sector_t sdist = cfqq->seek_mean;



	if (!sample_valid(cic->seek_samples))

		sdist = CIC_SEEK_THR;

	if (!sample_valid(cfqq->seek_samples))

		sdist = CFQQ_SEEK_THR;



	return cfq_dist_from_last(cfqd, rq) <= sdist;

}
@@ -1000,7 +1005,7 @@ static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, 
	 * will contain the closest sector.

	 */

	__cfqq = rb_entry(parent, struct cfq_queue, p_node);

	if (cfq_rq_close(cfqd, __cfqq->next_rq))

	if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq))

		return __cfqq;



	if (blk_rq_pos(__cfqq->next_rq) < sector)
@@ -1011,7 +1016,7 @@ static struct cfq_queue *cfqq_close(struct cfq_data *cfqd, 
		return NULL;



	__cfqq = rb_entry(node, struct cfq_queue, p_node);

	if (cfq_rq_close(cfqd, __cfqq->next_rq))

	if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq))

		return __cfqq;



	return NULL;
@@ -1033,13 +1038,6 @@ static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd, 
{

	struct cfq_queue *cfqq;



	/*

	 * A valid cfq_io_context is necessary to compare requests against

	 * the seek_mean of the current cfqq.

	 */

	if (!cfqd->active_cic)

		return NULL;



	/*

	 * We should notice if some of the queues are cooperating, eg

	 * working closely on the same area of the disk. In that case,
@@ -1110,7 +1108,7 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd) 
	 * seeks. so allow a little bit of time for him to submit a new rq

	 */

	sl = cfqd->cfq_slice_idle;

	if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic))

	if (sample_valid(cfqq->seek_samples) && CFQQ_SEEKY(cfqq))

		sl = min(sl, msecs_to_jiffies(CFQ_MIN_TT));



	mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
@@ -1947,33 +1945,33 @@ cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic) 
}



static void

cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_io_context *cic,

cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq,

		       struct request *rq)

{

	sector_t sdist;

	u64 total;



	if (!cic->last_request_pos)

	if (!cfqq->last_request_pos)

		sdist = 0;

	else if (cic->last_request_pos < blk_rq_pos(rq))

		sdist = blk_rq_pos(rq) - cic->last_request_pos;

	else if (cfqq->last_request_pos < blk_rq_pos(rq))

		sdist = blk_rq_pos(rq) - cfqq->last_request_pos;

	else

		sdist = cic->last_request_pos - blk_rq_pos(rq);

		sdist = cfqq->last_request_pos - blk_rq_pos(rq);



	/*

	 * Don't allow the seek distance to get too large from the

	 * odd fragment, pagein, etc

	 */

	if (cic->seek_samples <= 60) /* second&third seek */

		sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*1024);

	if (cfqq->seek_samples <= 60) /* second&third seek */

		sdist = min(sdist, (cfqq->seek_mean * 4) + 2*1024*1024);

	else

		sdist = min(sdist, (cic->seek_mean * 4)	+ 2*1024*64);

		sdist = min(sdist, (cfqq->seek_mean * 4) + 2*1024*64);



	cic->seek_samples = (7*cic->seek_samples + 256) / 8;

	cic->seek_total = (7*cic->seek_total + (u64)256*sdist) / 8;

	total = cic->seek_total + (cic->seek_samples/2);

	do_div(total, cic->seek_samples);

	cic->seek_mean = (sector_t)total;

	cfqq->seek_samples = (7*cfqq->seek_samples + 256) / 8;

	cfqq->seek_total = (7*cfqq->seek_total + (u64)256*sdist) / 8;

	total = cfqq->seek_total + (cfqq->seek_samples/2);

	do_div(total, cfqq->seek_samples);

	cfqq->seek_mean = (sector_t)total;

}



/*
@@ -1995,11 +1993,11 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq, 
	enable_idle = old_idle = cfq_cfqq_idle_window(cfqq);



	if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle ||

	    (!cfqd->cfq_latency && cfqd->hw_tag && CIC_SEEKY(cic)))

	    (!cfqd->cfq_latency && cfqd->hw_tag && CFQQ_SEEKY(cfqq)))

		enable_idle = 0;

	else if (sample_valid(cic->ttime_samples)) {

		unsigned int slice_idle = cfqd->cfq_slice_idle;

		if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic))

		if (sample_valid(cfqq->seek_samples) && CFQQ_SEEKY(cfqq))

			slice_idle = msecs_to_jiffies(CFQ_MIN_TT);

		if (cic->ttime_mean > slice_idle)

			enable_idle = 0;
@@ -2066,7 +2064,7 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq, 
	 * if this request is as-good as one we would expect from the

	 * current cfqq, let it preempt

	 */

	if (cfq_rq_close(cfqd, rq))

	if (cfq_rq_close(cfqd, cfqq, rq))

		return true;



	return false;
@@ -2108,10 +2106,10 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq, 
		cfqq->meta_pending++;



	cfq_update_io_thinktime(cfqd, cic);

	cfq_update_io_seektime(cfqd, cic, rq);

	cfq_update_io_seektime(cfqd, cfqq, rq);

	cfq_update_idle_window(cfqd, cfqq, cic);



	cic->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq);

	cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq);



	if (cfqq == cfqd->active_queue) {

		/*

include/linux/iocontext.h

+0 −5
Original line number Diff line number Diff line
@@ -40,16 +40,11 @@ struct cfq_io_context { 
	struct io_context *ioc;



	unsigned long last_end_request;

	sector_t last_request_pos;



	unsigned long ttime_total;

	unsigned long ttime_samples;

	unsigned long ttime_mean;



	unsigned int seek_samples;

	u64 seek_total;

	sector_t seek_mean;



	struct list_head queue_list;

	struct hlist_node cic_list;

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