Re: [PATCH 11/20] blkio: Some CFQ debugging Aid
From: Divyesh Shah
Date: Wed Nov 04 2009 - 22:10:32 EST
In the previous patchset when merged with the bio tracking patches we
had a very convenient
biocg_id we could use for debugging. If the eventual plan is to merge
the biotrack patches, do you think it makes sense to introduce the
per-blkio cgroup id here when DEBUG_BLK_CGROUP=y and use that for all
traces? The cgroup path name seems ugly to me.
-Divyesh
On Tue, Nov 3, 2009 at 3:43 PM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
> 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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