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

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
......@@ -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
......
......@@ -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
......
......@@ -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)
......
......@@ -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);
......
......@@ -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);
......
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