[PATCH 11/20] blkio: Some CFQ debugging Aid
From: Vivek Goyal
Date: Tue Nov 03 2009 - 18:46:03 EST
o Some CFQ debugging Aid.
Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
---
block/Kconfig | 9 +++++++++
block/Kconfig.iosched | 9 +++++++++
block/blk-cgroup.c | 4 ++++
block/blk-cgroup.h | 13 +++++++++++++
block/cfq-iosched.c | 33 +++++++++++++++++++++++++++++++++
5 files changed, 68 insertions(+), 0 deletions(-)
diff --git a/block/Kconfig b/block/Kconfig
index 6ba1a8e..e20fbde 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -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
diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched
index a521c69..9c5f0b5 100644
--- a/block/Kconfig.iosched
+++ b/block/Kconfig.iosched
@@ -48,6 +48,15 @@ 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
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index a62b8a3..4c68682 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -39,6 +39,10 @@ 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)
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index 2bf736b..cb72c35 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -26,12 +26,25 @@ 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
+
extern struct blkio_cgroup blkio_root_cgroup;
struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index b9a052b..2fde3c4 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -258,8 +258,29 @@ CFQ_CFQQ_FNS(sync);
CFQ_CFQQ_FNS(coop);
#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_to_cfqg((cfqq))->blkg), ##args);
+
+#define cfq_log_cfqe(cfqd, cfqe, fmt, args...) \
+ if (cfqq_of(cfqe)) { \
+ struct cfq_queue *cfqq = cfqq_of(cfqe); \
+ blk_add_trace_msg((cfqd)->queue, "cfq%d%c %s " fmt, \
+ (cfqq)->pid, cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \
+ blkg_path(&cfqq_to_cfqg((cfqq))->blkg), ##args);\
+ } else { \
+ struct cfq_group *cfqg = cfqg_of(cfqe); \
+ 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_cfqe(cfqd, cfqe, fmt, args...)
+#endif
+
#define cfq_log(cfqd, fmt, args...) \
blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args)
@@ -400,6 +421,8 @@ cfq_init_cfqe_parent(struct cfq_entity *cfqe, struct cfq_entity *p_cfqe)
#define for_each_entity(entity) \
for (; entity && entity->parent; entity = entity->parent)
+#define cfqe_is_cfqq(cfqe) (!(cfqe)->my_sd)
+
static inline struct cfq_group *cfqg_of_blkg(struct blkio_group *blkg)
{
if (blkg)
@@ -588,6 +611,8 @@ void cfq_delink_blkio_group(void *key, struct blkio_group *blkg)
#define for_each_entity(entity) \
for (; entity != NULL; entity = NULL)
+#define cfqe_is_cfqq(cfqe) 1
+
static void cfq_release_cfq_groups(struct cfq_data *cfqd) {}
static inline void cfq_get_cfqg_ref(struct cfq_group *cfqg) {}
static inline void cfq_put_cfqg(struct cfq_group *cfqg) {}
@@ -885,6 +910,10 @@ static void dequeue_cfqq(struct cfq_queue *cfqq)
struct cfq_sched_data *sd = cfq_entity_sched_data(cfqe);
dequeue_cfqe(cfqe);
+ if (!cfqe_is_cfqq(cfqe)) {
+ cfq_log_cfqe(cfqq->cfqd, cfqe, "del_from_rr group");
+ }
+
/* Do not dequeue parent if it has other entities under it */
if (sd->nr_active)
break;
@@ -970,6 +999,8 @@ static void requeue_cfqq(struct cfq_queue *cfqq, int add_front)
static void cfqe_served(struct cfq_entity *cfqe, unsigned long served)
{
+ struct cfq_data *cfqd = cfqq_of(cfqe)->cfqd;
+
for_each_entity(cfqe) {
/*
* Can't update entity disk time while it is on sorted rb-tree
@@ -979,6 +1010,8 @@ static void cfqe_served(struct cfq_entity *cfqe, unsigned long served)
cfqe->vdisktime += cfq_delta_fair(served, cfqe);
update_min_vdisktime(cfqe->st);
__enqueue_cfqe(cfqe->st, cfqe, 0);
+ cfq_log_cfqe(cfqd, cfqe, "served: vt=%llx min_vt=%llx",
+ cfqe->vdisktime, cfqe->st->min_vdisktime);
/* If entity prio class has changed, take that into account */
if (unlikely(cfqe->ioprio_class_changed)) {
--
1.6.2.5
--
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