Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 8060c47b authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Jens Axboe
Browse files

block: rename CONFIG_DEBUG_BLK_CGROUP to CONFIG_BFQ_CGROUP_DEBUG 



This option is entirely bfq specific, give it an appropinquate name.

Also make it depend on CONFIG_BFQ_GROUP_IOSCHED in Kconfig, as all
the functionality already does so anyway.

Acked-by: default avatarTejun Heo <tj@kernel.org>
Acked-by: default avatarPaolo Valente <paolo.valente@linaro.org>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent d6258980

Documentation/block/bfq-iosched.txt

+6 −6
Original line number Diff line number Diff line
@@ -38,13 +38,13 @@ stack). To give an idea of the limits with BFQ, on slow or average 
CPUs, here are, first, the limits of BFQ for three different CPUs, on,

respectively, an average laptop, an old desktop, and a cheap embedded

system, in case full hierarchical support is enabled (i.e.,

CONFIG_BFQ_GROUP_IOSCHED is set), but CONFIG_DEBUG_BLK_CGROUP is not

CONFIG_BFQ_GROUP_IOSCHED is set), but CONFIG_BFQ_CGROUP_DEBUG is not

set (Section 4-2):

- Intel i7-4850HQ: 400 KIOPS

- AMD A8-3850: 250 KIOPS

- ARM CortexTM-A53 Octa-core: 80 KIOPS



If CONFIG_DEBUG_BLK_CGROUP is set (and of course full hierarchical

If CONFIG_BFQ_CGROUP_DEBUG is set (and of course full hierarchical

support is enabled), then the sustainable throughput with BFQ

decreases, because all blkio.bfq* statistics are created and updated

(Section 4-2). For BFQ, this leads to the following maximum
@@ -537,19 +537,19 @@ or io.bfq.weight. 


As for cgroups-v1 (blkio controller), the exact set of stat files

created, and kept up-to-date by bfq, depends on whether

CONFIG_DEBUG_BLK_CGROUP is set. If it is set, then bfq creates all

CONFIG_BFQ_CGROUP_DEBUG is set. If it is set, then bfq creates all

the stat files documented in

Documentation/cgroup-v1/blkio-controller.txt. If, instead,

CONFIG_DEBUG_BLK_CGROUP is not set, then bfq creates only the files

CONFIG_BFQ_CGROUP_DEBUG is not set, then bfq creates only the files

blkio.bfq.io_service_bytes

blkio.bfq.io_service_bytes_recursive

blkio.bfq.io_serviced

blkio.bfq.io_serviced_recursive



The value of CONFIG_DEBUG_BLK_CGROUP greatly influences the maximum

The value of CONFIG_BFQ_CGROUP_DEBUG greatly influences the maximum

throughput sustainable with bfq, because updating the blkio.bfq.*

stats is rather costly, especially for some of the stats enabled by

CONFIG_DEBUG_BLK_CGROUP.

CONFIG_BFQ_CGROUP_DEBUG.



Parameters to set

-----------------

Documentation/cgroup-v1/blkio-controller.txt

+6 −6
Original line number Diff line number Diff line
@@ -77,7 +77,7 @@ Various user visible config options 
CONFIG_BLK_CGROUP

	- Block IO controller.



CONFIG_DEBUG_BLK_CGROUP

CONFIG_BFQ_CGROUP_DEBUG

	- Debug help. Right now some additional stats file show up in cgroup

	  if this option is enabled.
@@ -193,13 +193,13 @@ Proportional weight policy files 
	  write, sync or async.



- blkio.avg_queue_size

	- Debugging aid only enabled if CONFIG_DEBUG_BLK_CGROUP=y.

	- Debugging aid only enabled if CONFIG_BFQ_CGROUP_DEBUG=y.

	  The average queue size for this cgroup over the entire time of this

	  cgroup's existence. Queue size samples are taken each time one of the

	  queues of this cgroup gets a timeslice.



- blkio.group_wait_time

	- Debugging aid only enabled if CONFIG_DEBUG_BLK_CGROUP=y.

	- Debugging aid only enabled if CONFIG_BFQ_CGROUP_DEBUG=y.

	  This is the amount of time the cgroup had to wait since it became busy

	  (i.e., went from 0 to 1 request queued) to get a timeslice for one of

	  its queues. This is different from the io_wait_time which is the
@@ -210,7 +210,7 @@ Proportional weight policy files 
	  got a timeslice and will not include the current delta.



- blkio.empty_time

	- Debugging aid only enabled if CONFIG_DEBUG_BLK_CGROUP=y.

	- Debugging aid only enabled if CONFIG_BFQ_CGROUP_DEBUG=y.

	  This is the amount of time a cgroup spends without any pending

	  requests when not being served, i.e., it does not include any time

	  spent idling for one of the queues of the cgroup. This is in
@@ -219,7 +219,7 @@ Proportional weight policy files 
	  time it had a pending request and will not include the current delta.



- blkio.idle_time

	- Debugging aid only enabled if CONFIG_DEBUG_BLK_CGROUP=y.

	- Debugging aid only enabled if CONFIG_BFQ_CGROUP_DEBUG=y.

	  This is the amount of time spent by the IO scheduler idling for a

	  given cgroup in anticipation of a better request than the existing ones

	  from other queues/cgroups. This is in nanoseconds. If this is read
@@ -228,7 +228,7 @@ Proportional weight policy files 
	  the current delta.



- blkio.dequeue

	- Debugging aid only enabled if CONFIG_DEBUG_BLK_CGROUP=y. This

	- Debugging aid only enabled if CONFIG_BFQ_CGROUP_DEBUG=y. This

	  gives the statistics about how many a times a group was dequeued

	  from service tree of the device. First two fields specify the major

	  and minor number of the device and third field specifies the number

block/Kconfig.iosched

+7 −0
Original line number Diff line number Diff line
@@ -36,6 +36,13 @@ config BFQ_GROUP_IOSCHED 
       Enable hierarchical scheduling in BFQ, using the blkio

       (cgroups-v1) or io (cgroups-v2) controller.



config BFQ_CGROUP_DEBUG

	bool "BFQ IO controller debugging"

	depends on BFQ_GROUP_IOSCHED

	---help---

	Enable some debugging help. Currently it exports additional stat

	files in a cgroup which can be useful for debugging.



endmenu



endif

block/bfq-cgroup.c

+13 −14
Original line number Diff line number Diff line
@@ -15,8 +15,7 @@ 


#include "bfq-iosched.h"



#if defined(CONFIG_BFQ_GROUP_IOSCHED) &&  defined(CONFIG_DEBUG_BLK_CGROUP)



#ifdef CONFIG_BFQ_CGROUP_DEBUG

static int bfq_stat_init(struct bfq_stat *stat, gfp_t gfp)

{

	int ret;
@@ -253,7 +252,7 @@ void bfqg_stats_update_completion(struct bfq_group *bfqg, u64 start_time_ns, 
				io_start_time_ns - start_time_ns);

}



#else /* CONFIG_BFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */

#else /* CONFIG_BFQ_CGROUP_DEBUG */



void bfqg_stats_update_io_add(struct bfq_group *bfqg, struct bfq_queue *bfqq,

			      unsigned int op) { }
@@ -267,7 +266,7 @@ void bfqg_stats_update_idle_time(struct bfq_group *bfqg) { } 
void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg) { }

void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg) { }



#endif /* CONFIG_BFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */

#endif /* CONFIG_BFQ_CGROUP_DEBUG */



#ifdef CONFIG_BFQ_GROUP_IOSCHED
@@ -351,7 +350,7 @@ void bfqg_and_blkg_put(struct bfq_group *bfqg) 
/* @stats = 0 */

static void bfqg_stats_reset(struct bfqg_stats *stats)

{

#ifdef CONFIG_DEBUG_BLK_CGROUP

#ifdef CONFIG_BFQ_CGROUP_DEBUG

	/* queued stats shouldn't be cleared */

	blkg_rwstat_reset(&stats->merged);

	blkg_rwstat_reset(&stats->service_time);
@@ -372,7 +371,7 @@ static void bfqg_stats_add_aux(struct bfqg_stats *to, struct bfqg_stats *from) 
	if (!to || !from)

		return;



#ifdef CONFIG_DEBUG_BLK_CGROUP

#ifdef CONFIG_BFQ_CGROUP_DEBUG

	/* queued stats shouldn't be cleared */

	blkg_rwstat_add_aux(&to->merged, &from->merged);

	blkg_rwstat_add_aux(&to->service_time, &from->service_time);
@@ -432,7 +431,7 @@ void bfq_init_entity(struct bfq_entity *entity, struct bfq_group *bfqg) 


static void bfqg_stats_exit(struct bfqg_stats *stats)

{

#ifdef CONFIG_DEBUG_BLK_CGROUP

#ifdef CONFIG_BFQ_CGROUP_DEBUG

	blkg_rwstat_exit(&stats->merged);

	blkg_rwstat_exit(&stats->service_time);

	blkg_rwstat_exit(&stats->wait_time);
@@ -449,7 +448,7 @@ static void bfqg_stats_exit(struct bfqg_stats *stats) 


static int bfqg_stats_init(struct bfqg_stats *stats, gfp_t gfp)

{

#ifdef CONFIG_DEBUG_BLK_CGROUP

#ifdef CONFIG_BFQ_CGROUP_DEBUG

	if (blkg_rwstat_init(&stats->merged, gfp) ||

	    blkg_rwstat_init(&stats->service_time, gfp) ||

	    blkg_rwstat_init(&stats->wait_time, gfp) ||
@@ -986,7 +985,7 @@ static ssize_t bfq_io_set_weight(struct kernfs_open_file *of, 
	return ret ?: nbytes;

}



#ifdef CONFIG_DEBUG_BLK_CGROUP

#ifdef CONFIG_BFQ_CGROUP_DEBUG

static int bfqg_print_stat(struct seq_file *sf, void *v)

{

	blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_stat,
@@ -1109,7 +1108,7 @@ static int bfqg_print_avg_queue_size(struct seq_file *sf, void *v) 
			  0, false);

	return 0;

}

#endif /* CONFIG_DEBUG_BLK_CGROUP */

#endif /* CONFIG_BFQ_CGROUP_DEBUG */



struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node)

{
@@ -1157,7 +1156,7 @@ struct cftype bfq_blkcg_legacy_files[] = { 
		.private = (unsigned long)&blkcg_policy_bfq,

		.seq_show = blkg_print_stat_ios,

	},

#ifdef CONFIG_DEBUG_BLK_CGROUP

#ifdef CONFIG_BFQ_CGROUP_DEBUG

	{

		.name = "bfq.time",

		.private = offsetof(struct bfq_group, stats.time),
@@ -1187,7 +1186,7 @@ struct cftype bfq_blkcg_legacy_files[] = { 
		.private = offsetof(struct bfq_group, stats.queued),

		.seq_show = bfqg_print_rwstat,

	},

#endif /* CONFIG_DEBUG_BLK_CGROUP */

#endif /* CONFIG_BFQ_CGROUP_DEBUG */



	/* the same statistics which cover the bfqg and its descendants */

	{
@@ -1200,7 +1199,7 @@ struct cftype bfq_blkcg_legacy_files[] = { 
		.private = (unsigned long)&blkcg_policy_bfq,

		.seq_show = blkg_print_stat_ios_recursive,

	},

#ifdef CONFIG_DEBUG_BLK_CGROUP

#ifdef CONFIG_BFQ_CGROUP_DEBUG

	{

		.name = "bfq.time_recursive",

		.private = offsetof(struct bfq_group, stats.time),
@@ -1254,7 +1253,7 @@ struct cftype bfq_blkcg_legacy_files[] = { 
		.private = offsetof(struct bfq_group, stats.dequeue),

		.seq_show = bfqg_print_stat,

	},

#endif	/* CONFIG_DEBUG_BLK_CGROUP */

#endif	/* CONFIG_BFQ_CGROUP_DEBUG */

	{ }	/* terminate */

};

block/bfq-iosched.c

+4 −4
Original line number Diff line number Diff line
@@ -4404,7 +4404,7 @@ static struct request *__bfq_dispatch_request(struct blk_mq_hw_ctx *hctx) 
	return rq;

}



#if defined(CONFIG_BFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)

#ifdef CONFIG_BFQ_CGROUP_DEBUG

static void bfq_update_dispatch_stats(struct request_queue *q,

				      struct request *rq,

				      struct bfq_queue *in_serv_queue,
@@ -4454,7 +4454,7 @@ static inline void bfq_update_dispatch_stats(struct request_queue *q, 
					     struct request *rq,

					     struct bfq_queue *in_serv_queue,

					     bool idle_timer_disabled) {}

#endif

#endif /* CONFIG_BFQ_CGROUP_DEBUG */



static struct request *bfq_dispatch_request(struct blk_mq_hw_ctx *hctx)

{
@@ -5008,7 +5008,7 @@ static bool __bfq_insert_request(struct bfq_data *bfqd, struct request *rq) 
	return idle_timer_disabled;

}



#if defined(CONFIG_BFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)

#ifdef CONFIG_BFQ_CGROUP_DEBUG

static void bfq_update_insert_stats(struct request_queue *q,

				    struct bfq_queue *bfqq,

				    bool idle_timer_disabled,
@@ -5038,7 +5038,7 @@ static inline void bfq_update_insert_stats(struct request_queue *q, 
					   struct bfq_queue *bfqq,

					   bool idle_timer_disabled,

					   unsigned int cmd_flags) {}

#endif

#endif /* CONFIG_BFQ_CGROUP_DEBUG */



static void bfq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,

			       bool at_head)