From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vivek Goyal Subject: [PATCH 10/23] io-controller: Debug hierarchical IO scheduling Date: Fri, 28 Aug 2009 17:30:59 -0400 Message-ID: <1251495072-7780-11-git-send-email-vgoyal__21683.3172984936$1251495340$gmane$org@redhat.com> References: <1251495072-7780-1-git-send-email-vgoyal@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1251495072-7780-1-git-send-email-vgoyal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, jens.axboe-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org Cc: dhaval-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org, dm-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, agk-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, balbir-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org, paolo.valente-rcYM44yAMweonA0d6jMUrA@public.gmane.org, jmarchan-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, fernando-gVGce1chcLdL9jVzuh4AOg@public.gmane.org, jmoyer-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, mingo-X9Un+BFzKDI@public.gmane.org, riel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, fchecconi-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org, akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org, righi.andrea-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org List-Id: containers.vger.kernel.org o Littile debugging aid for hierarchical IO scheduling. o Enabled under CONFIG_DEBUG_GROUP_IOSCHED o Currently it outputs more debug messages in blktrace output which helps a great deal in debugging in hierarchical setup. It also creates additional cgroup interfaces io.disk_queue and io.disk_dequeue to output some more debugging data. Signed-off-by: Gui Jianfeng Signed-off-by: Vivek Goyal --- block/Kconfig.iosched | 8 +++ block/elevator-fq.c | 168 ++++++++++++++++++++++++++++++++++++++++++++++++- block/elevator-fq.h | 29 +++++++++ 3 files changed, 202 insertions(+), 3 deletions(-) diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched index a91a807..a7d0bf8 100644 --- a/block/Kconfig.iosched +++ b/block/Kconfig.iosched @@ -90,6 +90,14 @@ config DEFAULT_IOSCHED default "cfq" if DEFAULT_CFQ default "noop" if DEFAULT_NOOP +config DEBUG_GROUP_IOSCHED + bool "Debug Hierarchical Scheduling support" + depends on CGROUPS && GROUP_IOSCHED + default n + ---help--- + Enable some debugging hooks for hierarchical scheduling support. + Currently it just outputs more information in blktrace output. + endmenu endif diff --git a/block/elevator-fq.c b/block/elevator-fq.c index 563db2d..cb348fa 100644 --- a/block/elevator-fq.c +++ b/block/elevator-fq.c @@ -251,6 +251,91 @@ init_io_entity_service_tree(struct io_entity *entity, struct io_entity *parent) entity->st = &parent_iog->sched_data.service_tree[idx]; } +#ifdef CONFIG_DEBUG_GROUP_IOSCHED +static void io_group_path(struct io_group *iog) +{ + unsigned short id = iog->iocg_id; + struct cgroup_subsys_state *css; + + rcu_read_lock(); + + if (!id) + goto out; + + css = css_lookup(&io_subsys, id); + if (!css) + goto out; + + if (!css_tryget(css)) + goto out; + + cgroup_path(css->cgroup, iog->path, sizeof(iog->path)); + + css_put(css); + + rcu_read_unlock(); + return; +out: + rcu_read_unlock(); + iog->path[0] = '\0'; + return; +} + +static inline void debug_update_stats_enqueue(struct io_entity *entity) +{ + struct io_group *iog = iog_of(entity); + + if (iog) { + struct elv_fq_data *efqd; + + /* + * Keep track of how many times a group has been added + * to active tree. + */ + iog->queue++; + + rcu_read_lock(); + efqd = rcu_dereference(iog->key); + if (efqd) + elv_log_iog(efqd, iog, "add group weight=%u", + iog->entity.weight); + rcu_read_unlock(); + } +} + +static inline void debug_update_stats_dequeue(struct io_entity *entity) +{ + struct io_group *iog = iog_of(entity); + + if (iog) { + struct elv_fq_data *efqd; + + iog->dequeue++; + rcu_read_lock(); + efqd = rcu_dereference(iog->key); + if (efqd) + elv_log_iog(efqd, iog, "del group weight=%u", + iog->entity.weight); + rcu_read_unlock(); + } +} + +static inline void print_ioq_service_stats(struct io_queue *ioq) +{ + struct io_group *iog = ioq_to_io_group(ioq); + + elv_log_ioq(ioq->efqd, ioq, "service: QTt=%lu QTs=%lu GTt=%lu GTs=%lu", + ioq->entity.total_time, ioq->entity.total_sectors, + iog->entity.total_time, iog->entity.total_sectors); +} + +#else /* DEBUG_GROUP_IOSCHED */ +static inline void io_group_path(struct io_group *iog) {} +static inline void print_ioq_service_stats(struct io_queue *ioq) {} +static inline void debug_update_stats_enqueue(struct io_entity *entity) {} +static inline void debug_update_stats_dequeue(struct io_entity *entity) {} +#endif /* DEBUG_GROUP_IOSCHED */ + static void entity_served(struct io_entity *entity, unsigned long served, unsigned long nr_sectors) @@ -338,6 +423,7 @@ static void dequeue_io_entity(struct io_entity *entity) entity->on_st = 0; st->nr_active--; sd->nr_active--; + debug_update_stats_dequeue(entity); } static void @@ -386,6 +472,7 @@ static void enqueue_io_entity(struct io_entity *entity) entity->on_st = 1; place_entity(st, entity, 0); __enqueue_io_entity(st, entity, 0); + debug_update_stats_enqueue(entity); } static struct io_entity *__lookup_next_io_entity(struct io_service_tree *st) @@ -544,6 +631,9 @@ EXPORT_SYMBOL(elv_put_ioq); static void elv_ioq_served(struct io_queue *ioq, unsigned long served) { entity_served(&ioq->entity, served, ioq->nr_sectors); + elv_log_ioq(ioq->efqd, ioq, "ioq served: QSt=%lu QSs=%lu qued=%lu", + served, ioq->nr_sectors, ioq->nr_queued); + print_ioq_service_stats(ioq); } /* @@ -797,7 +887,6 @@ io_cgroup_lookup_group(struct io_cgroup *iocg, void *key) return NULL; } - #define SHOW_FUNCTION(__VAR) \ static u64 io_cgroup_##__VAR##_read(struct cgroup *cgroup, \ struct cftype *cftype) \ @@ -917,6 +1006,64 @@ static int io_cgroup_disk_sectors_read(struct cgroup *cgroup, return 0; } +#ifdef CONFIG_DEBUG_GROUP_IOSCHED +static int io_cgroup_disk_queue_read(struct cgroup *cgroup, + struct cftype *cftype, struct seq_file *m) +{ + struct io_cgroup *iocg = NULL; + struct io_group *iog = NULL; + struct hlist_node *n; + + if (!cgroup_lock_live_group(cgroup)) + return -ENODEV; + + iocg = cgroup_to_io_cgroup(cgroup); + rcu_read_lock(); + /* Loop through all the io groups and print statistics */ + hlist_for_each_entry_rcu(iog, n, &iocg->group_data, group_node) { + /* + * There might be groups which are not functional and + * waiting to be reclaimed upon cgoup deletion. + */ + if (iog->key) + seq_printf(m, "%u:%u %lu\n", MAJOR(iog->dev), + MINOR(iog->dev), iog->queue); + } + rcu_read_unlock(); + cgroup_unlock(); + + return 0; +} + +static int io_cgroup_disk_dequeue_read(struct cgroup *cgroup, + struct cftype *cftype, struct seq_file *m) +{ + struct io_cgroup *iocg = NULL; + struct io_group *iog = NULL; + struct hlist_node *n; + + if (!cgroup_lock_live_group(cgroup)) + return -ENODEV; + + iocg = cgroup_to_io_cgroup(cgroup); + spin_lock_irq(&iocg->lock); + /* Loop through all the io groups and print statistics */ + hlist_for_each_entry_rcu(iog, n, &iocg->group_data, group_node) { + /* + * There might be groups which are not functional and + * waiting to be reclaimed upon cgoup deletion. + */ + if (iog->key) + seq_printf(m, "%u:%u %lu\n", MAJOR(iog->dev), + MINOR(iog->dev), iog->dequeue); + } + spin_unlock_irq(&iocg->lock); + cgroup_unlock(); + + return 0; +} +#endif + struct cftype io_files[] = { { .name = "weight", @@ -936,6 +1083,16 @@ struct cftype io_files[] = { .name = "disk_sectors", .read_seq_string = io_cgroup_disk_sectors_read, }, +#ifdef CONFIG_DEBUG_GROUP_IOSCHED + { + .name = "disk_queue", + .read_seq_string = io_cgroup_disk_queue_read, + }, + { + .name = "disk_dequeue", + .read_seq_string = io_cgroup_disk_dequeue_read, + }, +#endif }; static int iocg_populate(struct cgroup_subsys *subsys, struct cgroup *cgroup) @@ -1063,6 +1220,7 @@ io_group_chain_alloc(struct request_queue *q, void *key, struct cgroup *cgroup) * or cgroup deletion path depending on who is exiting first. */ elv_get_iog(iog); + io_group_path(iog); if (leaf == NULL) { leaf = iog; @@ -1237,6 +1395,7 @@ static struct io_group *io_alloc_root_group(struct request_queue *q, hlist_add_head_rcu(&iog->group_node, &iocg->group_data); iog->iocg_id = css_id(&iocg->css); spin_unlock_irq(&iocg->lock); + io_group_path(iog); return iog; } @@ -1523,6 +1682,7 @@ __elv_set_active_ioq(struct elv_fq_data *efqd, struct io_queue *ioq, int coop) efqd->busy_queues, ioq->entity.ioprio_class, ioq->entity.ioprio, ioq->entity.weight, iog_weight(iog), ioq->nr_queued); + print_ioq_service_stats(ioq); ioq->slice_start = ioq->slice_end = 0; ioq->dispatch_start = jiffies; @@ -1581,10 +1741,11 @@ static void elv_add_ioq_busy(struct elv_fq_data *efqd, struct io_queue *ioq) { BUG_ON(elv_ioq_busy(ioq)); BUG_ON(ioq == efqd->active_queue); - elv_log_ioq(efqd, ioq, "add to busy"); enqueue_ioq(ioq); elv_mark_ioq_busy(ioq); efqd->busy_queues++; + elv_log_ioq(efqd, ioq, "add to busy: qued=%d", ioq->nr_queued); + print_ioq_service_stats(ioq); } static void elv_del_ioq_busy(struct elevator_queue *e, struct io_queue *ioq) @@ -1593,7 +1754,8 @@ static void elv_del_ioq_busy(struct elevator_queue *e, struct io_queue *ioq) BUG_ON(!elv_ioq_busy(ioq)); BUG_ON(ioq->nr_queued); - elv_log_ioq(efqd, ioq, "del from busy"); + elv_log_ioq(efqd, ioq, "del from busy: qued=%d", ioq->nr_queued); + print_ioq_service_stats(ioq); elv_clear_ioq_busy(ioq); BUG_ON(efqd->busy_queues == 0); efqd->busy_queues--; diff --git a/block/elevator-fq.h b/block/elevator-fq.h index 9757e39..154014c 100644 --- a/block/elevator-fq.h +++ b/block/elevator-fq.h @@ -114,6 +114,16 @@ struct io_group { /* The device MKDEV(major, minor), this group has been created for */ dev_t dev; +#ifdef CONFIG_DEBUG_GROUP_IOSCHED + /* How many times this group has been added to active tree */ + unsigned long queue; + + /* How many times this group has been removed from active tree */ + unsigned long dequeue; + + /* Store cgroup path */ + char path[128]; +#endif }; struct io_cgroup { @@ -170,10 +180,29 @@ struct elv_fq_data { }; /* Logging facilities. */ +#ifdef CONFIG_DEBUG_GROUP_IOSCHED +#define elv_log_ioq(efqd, ioq, fmt, args...) \ +{ \ + blk_add_trace_msg((efqd)->queue, "elv%d%c %s " fmt, (ioq)->pid, \ + elv_ioq_sync(ioq) ? 'S' : 'A', \ + ioq_to_io_group(ioq)->path, ##args); \ +} + +#define elv_log_iog(efqd, iog, fmt, args...) \ +{ \ + blk_add_trace_msg((efqd)->queue, "elv %s " fmt, (iog)->path, ##args); \ +} + +#else #define elv_log_ioq(efqd, ioq, fmt, args...) \ blk_add_trace_msg((efqd)->queue, "elv%d%c " fmt, (ioq)->pid, \ elv_ioq_sync(ioq) ? 'S' : 'A', ##args) +#define elv_log_iog(efqd, iog, fmt, args...) \ + blk_add_trace_msg((efqd)->queue, "elv " fmt, ##args) + +#endif + #define elv_log(efqd, fmt, args...) \ blk_add_trace_msg((efqd)->queue, "elv " fmt, ##args) -- 1.6.0.6