Re: [PATCH 2/3][v2] blkio: Add io controller stats like
From: Divyesh Shah
Date: Fri Apr 02 2010 - 22:00:00 EST
Missed the v2 tag on this patch. Resending. Apologies for the spam.
On Fri, Apr 2, 2010 at 6:56 PM, Divyesh Shah <dpshah@xxxxxxxxxx> wrote:
> - io_service_time (the actual time in ns taken by the dis to service the IO)
> - io_wait_time (the time spent waiting in the IO shceduler queues before
> getting serviced)
> - io_serviced (number of IOs serviced from this blkio_group)
> - io_service_bytes (Number of bytes served for this cgroup)
>
> These stats are accumulated per operation type helping us to distinguish between
> read and write, and sync and async IO. This patch does not increment any of
> these stats.
>
> Signed-off-by: Divyesh Shah<dpshah@xxxxxxxxxx>
> ---
>
> Documentation/cgroups/blkio-controller.txt | 33 +++++
> block/blk-cgroup.c | 179 +++++++++++++++++++++++++---
> block/blk-cgroup.h | 41 +++++-
> block/cfq-iosched.c | 2
> 4 files changed, 229 insertions(+), 26 deletions(-)
>
> diff --git a/Documentation/cgroups/blkio-controller.txt b/Documentation/cgroups/blkio-controller.txt
> index 630879c..ededdca 100644
> --- a/Documentation/cgroups/blkio-controller.txt
> +++ b/Documentation/cgroups/blkio-controller.txt
> @@ -75,6 +75,9 @@ CONFIG_DEBUG_BLK_CGROUP
>
> Details of cgroup files
> =======================
> +Writing an int to any of the stats files (which excludes weight) will result
> +in all stats for that cgroup to be erased.
> +
> - blkio.weight
> - Specifies per cgroup weight.
>
> @@ -92,6 +95,36 @@ Details of cgroup files
> third field specifies the number of sectors transferred by the
> group to/from the device.
>
> +- blkio.io_service_bytes
> + - Number of bytes transferred to/from the disk by the group. These
> + are further divided by the type of operation - read or write, sync
> + or async. First two fields specify the major and minor number of the
> + device, third field specifies the operation type and the fourth field
> + specifies the number of bytes.
> +
> +- blkio.io_serviced
> + - Number of IOs completed to/from the disk by the group. These
> + are further divided by the type of operation - read or write, sync
> + or async. First two fields specify the major and minor number of the
> + device, third field specifies the operation type and the fourth field
> + specifies the number of IOs.
> +
> +- blkio.io_service_time
> + - Total amount of time spent by the device to service the IOs for this
> + cgroup. This is in nanoseconds to make it meaningful for flash
> + devices too. This time is further divided by the type of operation -
> + read or write, sync or async. First two fields specify the major and
> + minor number of the device, third field specifies the operation type
> + and the fourth field specifies the io_service_time in ns.
> +
> +- blkio.io_wait_time
> + - Total amount of time the IO spent waiting in the scheduler queues for
> + service. This is in nanoseconds to make it meaningful for flash
> + devices too. This time is further divided by the type of operation -
> + read or write, sync or async. First two fields specify the major and
> + minor number of the device, third field specifies the operation type
> + and the fourth field specifies the io_wait_time in ns.
> +
> - blkio.dequeue
> - Debugging aid only enabled if CONFIG_DEBUG_CFQ_IOSCHED=y. This
> gives the statistics about how many a times a group was dequeued
> diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
> index 5be3981..cac10b2 100644
> --- a/block/blk-cgroup.c
> +++ b/block/blk-cgroup.c
> @@ -17,6 +17,8 @@
> #include <linux/err.h>
> #include "blk-cgroup.h"
>
> +#define MAX_KEY_LEN 100
> +
> static DEFINE_SPINLOCK(blkio_list_lock);
> static LIST_HEAD(blkio_list);
>
> @@ -55,12 +57,15 @@ struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup)
> }
> EXPORT_SYMBOL_GPL(cgroup_to_blkio_cgroup);
>
> -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)
> {
> - blkg->time += time;
> + unsigned long flags;
> +
> + spin_lock_irqsave(&blkg->stats_lock, flags);
> + blkg->stats.time += time;
> + spin_unlock_irqrestore(&blkg->stats_lock, flags);
> }
> -EXPORT_SYMBOL_GPL(blkiocg_update_blkio_group_stats);
> +EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used);
>
> void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
> struct blkio_group *blkg, void *key, dev_t dev)
> @@ -170,13 +175,119 @@ blkiocg_weight_write(struct cgroup *cgroup, struct cftype *cftype, u64 val)
> return 0;
> }
>
> -#define SHOW_FUNCTION_PER_GROUP(__VAR) \
> +static int
> +blkiocg_reset_write(struct cgroup *cgroup, struct cftype *cftype, u64 val)
> +{
> + struct blkio_cgroup *blkcg;
> + struct blkio_group *blkg;
> + struct hlist_node *n;
> + struct blkio_group_stats *stats;
> +
> + blkcg = cgroup_to_blkio_cgroup(cgroup);
> + spin_lock_irq(&blkcg->lock);
> + hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
> + spin_lock(&blkg->stats_lock);
> + stats = &blkg->stats;
> + memset(stats, 0, sizeof(struct blkio_group_stats));
> + spin_unlock(&blkg->stats_lock);
> + }
> + spin_unlock_irq(&blkcg->lock);
> + return 0;
> +}
> +
> +static void blkio_get_key_name(int type, dev_t dev, char *str, int chars_left)
> +{
> + snprintf(str, chars_left, "%u:%u", MAJOR(dev), MINOR(dev));
> + chars_left -= strlen(str);
> + if (chars_left <= 0) {
> + printk(KERN_WARNING
> + "Possibly incorrect cgroup stat display format");
> + return;
> + }
> + switch (type) {
> + case IO_READ:
> + strlcat(str, " Read", chars_left);
> + break;
> + case IO_WRITE:
> + strlcat(str, " Write", chars_left);
> + break;
> + case IO_SYNC:
> + strlcat(str, " Sync", chars_left);
> + break;
> + case IO_ASYNC:
> + strlcat(str, " Async", chars_left);
> + break;
> + case IO_TYPE_TOTAL:
> + strlcat(str, " Total", chars_left);
> + break;
> + default:
> + strlcat(str, " Invalid", chars_left);
> + }
> +}
> +
> +typedef uint64_t (get_var) (struct blkio_group *, int);
> +
> +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));
> + 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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