Commit 2868ef7b authored by Vivek Goyal's avatar Vivek Goyal Committed by Jens Axboe
Browse files

blkio: Some debugging aids for CFQ 



o Some debugging aids for CFQ.

Signed-off-by: default avatarVivek Goyal <vgoyal@redhat.com>
Signed-off-by: default avatarJens Axboe <jens.axboe@oracle.com>
parent b1c35769

block/Kconfig

+9 −0
Original line number Diff line number Diff line
@@ -90,6 +90,15 @@ config BLK_CGROUP 
	control disk bandwidth allocation (proportional time slice allocation)

	to such task groups.



config DEBUG_BLK_CGROUP

	bool

	depends on BLK_CGROUP

	default n

	---help---

	Enable some debugging help. Currently it stores the cgroup path

	in the blk group which can be used by cfq for tracing various

	group related activity.



endif # BLOCK



config BLOCK_COMPAT

block/Kconfig.iosched

+9 −0
Original line number Diff line number Diff line
@@ -40,6 +40,15 @@ config CFQ_GROUP_IOSCHED 
	---help---

	  Enable group IO scheduling in CFQ.



config DEBUG_CFQ_IOSCHED

	bool "Debug CFQ Scheduling"

	depends on CFQ_GROUP_IOSCHED

	select DEBUG_BLK_CGROUP

	default n

	---help---

	  Enable CFQ IO scheduling debugging in CFQ. Currently it makes

	  blktrace output more verbose.



choice

	prompt "Default I/O scheduler"

	default DEFAULT_CFQ

block/blk-cgroup.c

+4 −0
Original line number Diff line number Diff line
@@ -33,6 +33,10 @@ void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg, 
	blkg->blkcg_id = css_id(&blkcg->css);

	hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);

	spin_unlock_irqrestore(&blkcg->lock, flags);

#ifdef CONFIG_DEBUG_BLK_CGROUP

	/* Need to take css reference ? */

	cgroup_path(blkcg->css.cgroup, blkg->path, sizeof(blkg->path));

#endif

}



static void __blkiocg_del_blkio_group(struct blkio_group *blkg)

block/blk-cgroup.h

+13 −0
Original line number Diff line number Diff line
@@ -27,12 +27,25 @@ struct blkio_group { 
	void *key;

	struct hlist_node blkcg_node;

	unsigned short blkcg_id;

#ifdef CONFIG_DEBUG_BLK_CGROUP

	/* Store cgroup path */

	char path[128];

#endif

};



#define BLKIO_WEIGHT_MIN	100

#define BLKIO_WEIGHT_MAX	1000

#define BLKIO_WEIGHT_DEFAULT	500



#ifdef CONFIG_DEBUG_BLK_CGROUP

static inline char *blkg_path(struct blkio_group *blkg)

{

	return blkg->path;

}

#else

static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }

#endif



#ifdef CONFIG_BLK_CGROUP

extern struct blkio_cgroup blkio_root_cgroup;

extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);

block/cfq-iosched.c

+18 −1
Original line number Diff line number Diff line
@@ -341,8 +341,21 @@ CFQ_CFQQ_FNS(coop); 
CFQ_CFQQ_FNS(deep);

#undef CFQ_CFQQ_FNS



#ifdef CONFIG_DEBUG_CFQ_IOSCHED

#define cfq_log_cfqq(cfqd, cfqq, fmt, args...)	\

	blk_add_trace_msg((cfqd)->queue, "cfq%d%c %s " fmt, (cfqq)->pid, \

			cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \

			blkg_path(&(cfqq)->cfqg->blkg), ##args);



#define cfq_log_cfqg(cfqd, cfqg, fmt, args...)				\

	blk_add_trace_msg((cfqd)->queue, "%s " fmt,			\

				blkg_path(&(cfqg)->blkg), ##args);      \



#else

#define cfq_log_cfqq(cfqd, cfqq, fmt, args...)	\

	blk_add_trace_msg((cfqd)->queue, "cfq%d " fmt, (cfqq)->pid, ##args)

#define cfq_log_cfqg(cfqd, cfqg, fmt, args...)		do {} while (0);

#endif

#define cfq_log(cfqd, fmt, args...)	\

	blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args)
@@ -832,6 +845,7 @@ cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg) 
	if (cfqg->nr_cfqq)

		return;



	cfq_log_cfqg(cfqd, cfqg, "del_from_rr group");

	cfqg->on_st = false;

	cfqd->nr_groups--;

	st->total_weight -= cfqg->weight;
@@ -889,6 +903,9 @@ static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg, 
		cfqg->saved_serving_prio = cfqd->serving_prio;

	} else

		cfqg->saved_workload_slice = 0;



	cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime,

					st->min_vdisktime);

}



#ifdef CONFIG_CFQ_GROUP_IOSCHED
@@ -3102,7 +3119,7 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq) 
	unsigned long now;



	now = jiffies;

	cfq_log_cfqq(cfqd, cfqq, "complete");

	cfq_log_cfqq(cfqd, cfqq, "complete rqnoidle %d", !!rq_noidle(rq));



	cfq_update_hw_tag(cfqd);