Re: [PATCH 2/3][v2] blkio: Add io controller stats like
From: Divyesh Shah
Date: Mon Apr 05 2010 - 18:18:19 EST
On Mon, Apr 5, 2010 at 11:58 AM, Vivek Goyal <vgoyal@xxxxxxxxxx> wrote:
> On Fri, Apr 02, 2010 at 06:56:35PM -0700, Divyesh Shah wrote:
>
> [..]
>> +static uint64_t blkio_get_typed_stat(struct blkio_group *blkg,
>> + struct cgroup_map_cb *cb, get_var *getvar, dev_t dev)
>> +{
>> + uint64_t disk_total;
>> + char key_str[MAX_KEY_LEN];
>> + int type;
>> +
>> + for (type = 0; type < IO_TYPE_TOTAL; type++) {
>> + blkio_get_key_name(type, dev, key_str, MAX_KEY_LEN);
>> + cb->fill(cb, key_str, getvar(blkg, type));
>> + }
>> + disk_total = getvar(blkg, IO_READ) + getvar(blkg, IO_WRITE);
>> + blkio_get_key_name(IO_TYPE_TOTAL, dev, key_str, MAX_KEY_LEN);
>> + cb->fill(cb, key_str, disk_total);
>> + return disk_total;
>> +}
>> +
>> +static uint64_t blkio_get_stat(struct blkio_group *blkg,
>> + struct cgroup_map_cb *cb, get_var *getvar, dev_t dev)
>> +{
>> + uint64_t var = getvar(blkg, 0);
>> + char str[10];
>> +
>> + snprintf(str, 10, "%u:%u", MAJOR(dev), MINOR(dev));
>
> What is the significance of limiting major:minor string to 10 characters?
> I see BDEVT_SIZE being used in genhd.c. But it looks like it is valid
> only if we printing numbers in hex.
>
> In genhd.c:diskstats_show(), we seem to be using %4d and %7d for major
> minor numbers. In extended minor allocation scheme, we seem to be having
> 20 bits for minor numbers, so 7 decimal places for representing max minor
> number will make sense. Not sure about major number though.
>
> So it might be safe to just to follow diskstats_show convention and at
> least keep the buffer size as 12 (4:7).
Will do in V3
>
> Vivek
>
>> + cb->fill(cb, str, var);
>> + return var;
>> +}
>> +
>> +#define GET_STAT_INDEXED(__VAR) \
>> +uint64_t blkio_get_##__VAR##_stat(struct blkio_group *blkg, int type) \
>> +{ \
>> + return blkg->stats.__VAR[type]; \
>> +} \
>> +
>> +GET_STAT_INDEXED(io_service_bytes);
>> +GET_STAT_INDEXED(io_serviced);
>> +GET_STAT_INDEXED(io_service_time);
>> +GET_STAT_INDEXED(io_wait_time);
>> +#undef GET_STAT_INDEXED
>> +
>> +#define GET_STAT(__VAR) \
>> +uint64_t blkio_get_##__VAR##_stat(struct blkio_group *blkg, int dummy) \
>> +{ \
>> + return blkg->stats.__VAR; \
>> +}
>> +
>> +GET_STAT(time);
>> +GET_STAT(sectors);
>> +#ifdef CONFIG_DEBUG_BLK_CGROUP
>> +GET_STAT(dequeue);
>> +#endif
>> +#undef GET_STAT
>> +
>> +#define SHOW_FUNCTION_PER_GROUP(__VAR, get_stats, getvar, show_total) \
>> static int blkiocg_##__VAR##_read(struct cgroup *cgroup, \
>> - struct cftype *cftype, struct seq_file *m) \
>> + struct cftype *cftype, struct cgroup_map_cb *cb) \
>> { \
>> struct blkio_cgroup *blkcg; \
>> struct blkio_group *blkg; \
>> struct hlist_node *n; \
>> + uint64_t cgroup_total = 0; \
>> \
>> if (!cgroup_lock_live_group(cgroup)) \
>> return -ENODEV; \
>> @@ -184,19 +295,32 @@ static int blkiocg_##__VAR##_read(struct cgroup *cgroup, \
>> blkcg = cgroup_to_blkio_cgroup(cgroup); \
>> rcu_read_lock(); \
>> hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {\
>> - if (blkg->dev) \
>> - seq_printf(m, "%u:%u %lu\n", MAJOR(blkg->dev), \
>> - MINOR(blkg->dev), blkg->__VAR); \
>> + if (blkg->dev) { \
>> + spin_lock_irq(&blkg->stats_lock); \
>> + cgroup_total += get_stats(blkg, cb, getvar, \
>> + blkg->dev); \
>> + spin_unlock_irq(&blkg->stats_lock); \
>> + } \
>> } \
>> + if (show_total) \
>> + cb->fill(cb, "Total", cgroup_total); \
>> rcu_read_unlock(); \
>> cgroup_unlock(); \
>> return 0; \
>> }
>>
>> -SHOW_FUNCTION_PER_GROUP(time);
>> -SHOW_FUNCTION_PER_GROUP(sectors);
>> +SHOW_FUNCTION_PER_GROUP(time, blkio_get_stat, blkio_get_time_stat, 0);
>> +SHOW_FUNCTION_PER_GROUP(sectors, blkio_get_stat, blkio_get_sectors_stat, 0);
>> +SHOW_FUNCTION_PER_GROUP(io_service_bytes, blkio_get_typed_stat,
>> + blkio_get_io_service_bytes_stat, 1);
>> +SHOW_FUNCTION_PER_GROUP(io_serviced, blkio_get_typed_stat,
>> + blkio_get_io_serviced_stat, 1);
>> +SHOW_FUNCTION_PER_GROUP(io_service_time, blkio_get_typed_stat,
>> + blkio_get_io_service_time_stat, 1);
>> +SHOW_FUNCTION_PER_GROUP(io_wait_time, blkio_get_typed_stat,
>> + blkio_get_io_wait_time_stat, 1);
>> #ifdef CONFIG_DEBUG_BLK_CGROUP
>> -SHOW_FUNCTION_PER_GROUP(dequeue);
>> +SHOW_FUNCTION_PER_GROUP(dequeue, blkio_get_stat, blkio_get_dequeue_stat, 0);
>> #endif
>> #undef SHOW_FUNCTION_PER_GROUP
>>
>> @@ -204,7 +328,7 @@ SHOW_FUNCTION_PER_GROUP(dequeue);
>> void blkiocg_update_blkio_group_dequeue_stats(struct blkio_group *blkg,
>> unsigned long dequeue)
>> {
>> - blkg->dequeue += dequeue;
>> + blkg->stats.dequeue += dequeue;
>> }
>> EXPORT_SYMBOL_GPL(blkiocg_update_blkio_group_dequeue_stats);
>> #endif
>> @@ -217,16 +341,39 @@ struct cftype blkio_files[] = {
>> },
>> {
>> .name = "time",
>> - .read_seq_string = blkiocg_time_read,
>> + .read_map = blkiocg_time_read,
>> + .write_u64 = blkiocg_reset_write,
>> },
>> {
>> .name = "sectors",
>> - .read_seq_string = blkiocg_sectors_read,
>> + .read_map = blkiocg_sectors_read,
>> + .write_u64 = blkiocg_reset_write,
>> + },
>> + {
>> + .name = "io_service_bytes",
>> + .read_map = blkiocg_io_service_bytes_read,
>> + .write_u64 = blkiocg_reset_write,
>> + },
>> + {
>> + .name = "io_serviced",
>> + .read_map = blkiocg_io_serviced_read,
>> + .write_u64 = blkiocg_reset_write,
>> + },
>> + {
>> + .name = "io_service_time",
>> + .read_map = blkiocg_io_service_time_read,
>> + .write_u64 = blkiocg_reset_write,
>> + },
>> + {
>> + .name = "io_wait_time",
>> + .read_map = blkiocg_io_wait_time_read,
>> + .write_u64 = blkiocg_reset_write,
>> },
>> #ifdef CONFIG_DEBUG_BLK_CGROUP
>> {
>> .name = "dequeue",
>> - .read_seq_string = blkiocg_dequeue_read,
>> + .read_map = blkiocg_dequeue_read,
>> + .write_u64 = blkiocg_reset_write,
>> },
>> #endif
>> };
>> diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
>> index fe44517..e8600b0 100644
>> --- a/block/blk-cgroup.h
>> +++ b/block/blk-cgroup.h
>> @@ -23,6 +23,14 @@ extern struct cgroup_subsys blkio_subsys;
>> #define blkio_subsys_id blkio_subsys.subsys_id
>> #endif
>>
>> +enum io_type {
>> + IO_READ = 0,
>> + IO_WRITE,
>> + IO_SYNC,
>> + IO_ASYNC,
>> + IO_TYPE_TOTAL
>> +};
>> +
>> struct blkio_cgroup {
>> struct cgroup_subsys_state css;
>> unsigned int weight;
>> @@ -30,6 +38,23 @@ struct blkio_cgroup {
>> struct hlist_head blkg_list;
>> };
>>
>> +struct blkio_group_stats {
>> + /* total disk time and nr sectors dispatched by this group */
>> + uint64_t time;
>> + uint64_t sectors;
>> + /* Total disk time used by IOs in ns */
>> + uint64_t io_service_time[IO_TYPE_TOTAL];
>> + uint64_t io_service_bytes[IO_TYPE_TOTAL]; /* Total bytes transferred */
>> + /* Total IOs serviced, post merge */
>> + uint64_t io_serviced[IO_TYPE_TOTAL];
>> + /* Total time spent waiting in scheduler queue in ns */
>> + uint64_t io_wait_time[IO_TYPE_TOTAL];
>> +#ifdef CONFIG_DEBUG_BLK_CGROUP
>> + /* How many times this group has been removed from service tree */
>> + unsigned long dequeue;
>> +#endif
>> +};
>> +
>> struct blkio_group {
>> /* An rcu protected unique identifier for the group */
>> void *key;
>> @@ -38,15 +63,13 @@ struct blkio_group {
>> #ifdef CONFIG_DEBUG_BLK_CGROUP
>> /* Store cgroup path */
>> char path[128];
>> - /* How many times this group has been removed from service tree */
>> - unsigned long dequeue;
>> #endif
>> /* The device MKDEV(major, minor), this group has been created for */
>> - dev_t dev;
>> + dev_t dev;
>>
>> - /* total disk time and nr sectors dispatched by this group */
>> - unsigned long time;
>> - unsigned long sectors;
>> + /* Need to serialize the stats in the case of reset/update */
>> + spinlock_t stats_lock;
>> + struct blkio_group_stats stats;
>> };
>>
>> typedef void (blkio_unlink_group_fn) (void *key, struct blkio_group *blkg);
>> @@ -105,8 +128,8 @@ extern void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
>> extern int blkiocg_del_blkio_group(struct blkio_group *blkg);
>> extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,
>> void *key);
>> -void blkiocg_update_blkio_group_stats(struct blkio_group *blkg,
>> - unsigned long time);
>> +void blkiocg_update_timeslice_used(struct blkio_group *blkg,
>> + unsigned long time);
>> #else
>> struct cgroup;
>> static inline struct blkio_cgroup *
>> @@ -122,7 +145,7 @@ blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; }
>>
>> static inline struct blkio_group *
>> blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) { return NULL; }
>> -static inline void blkiocg_update_blkio_group_stats(struct blkio_group *blkg,
>> +static inline void blkiocg_update_timeslice_used(struct blkio_group *blkg,
>> unsigned long time) {}
>> #endif
>> #endif /* _BLK_CGROUP_H */
>> diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
>> index c18e348..d91df9f 100644
>> --- a/block/cfq-iosched.c
>> +++ b/block/cfq-iosched.c
>> @@ -914,7 +914,7 @@ static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg,
>>
>> cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime,
>> st->min_vdisktime);
>> - blkiocg_update_blkio_group_stats(&cfqg->blkg, used_sl);
>> + blkiocg_update_timeslice_used(&cfqg->blkg, used_sl);
>> }
>>
>> #ifdef CONFIG_CFQ_GROUP_IOSCHED
>
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