blkio: Changes to IO controller additional stats patches
that include some minor fixes and addresses all comments.
Changelog: (most based on Vivek Goyal's comments)
o renamed blkiocg_reset_write to blkiocg_reset_stats
o more clarification in the documentation on io_service_time and io_wait_time
o Initialize blkg->stats_lock
o rename io_add_stat to blkio_add_stat and declare it static
o use bool for direction and sync
o derive direction and sync info from existing rq methods
o use 12 for major:minor string length
o define io_service_time better to cover the NCQ case
o add a separate reset_stats interface
o make the indexed stats a 2d array to simplify macro and function pointer code
o blkio.time now exports in jiffies as before
o Added stats description in patch description and
Documentation/cgroup/blkio-controller.txt
o Prefix all stats functions with blkio and make them static as applicable
o replace IO_TYPE_MAX with IO_TYPE_TOTAL
o Moved #define constant to top of blk-cgroup.c
o Pass dev_t around instead of char *
o Add note to documentation file about resetting stats
o use BLK_CGROUP_MODULE in addition to BLK_CGROUP config option in #ifdef
statements
o Avoid struct request specific knowledge in blk-cgroup. blk-cgroup.h now has
rq_direction() and rq_sync() functions which are used by CFQ and when using
io-controller at a higher level, bio_* functions can be added.
Signed-off-by: Divyesh Shah<dpshah@google.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 9af7257..6797df5 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -18,6 +18,8 @@
#include <linux/blkdev.h>
#include "blk-cgroup.h"
+#define MAX_KEY_LEN 100
+
static DEFINE_SPINLOCK(blkio_list_lock);
static LIST_HEAD(blkio_list);
@@ -56,24 +58,27 @@
}
EXPORT_SYMBOL_GPL(cgroup_to_blkio_cgroup);
+void blkio_group_init(struct blkio_group *blkg)
+{
+ spin_lock_init(&blkg->stats_lock);
+}
+EXPORT_SYMBOL_GPL(blkio_group_init);
+
/*
* Add to the appropriate stat variable depending on the request type.
* This should be called with the blkg->stats_lock held.
*/
-void io_add_stat(uint64_t *stat, uint64_t add, unsigned int flags)
+static void blkio_add_stat(uint64_t *stat, uint64_t add, bool direction,
+ bool sync)
{
- if (flags & REQ_RW)
- stat[IO_WRITE] += add;
+ if (direction)
+ stat[BLKIO_STAT_WRITE] += add;
else
- stat[IO_READ] += add;
- /*
- * Everywhere in the block layer, an IO is treated as sync if it is a
- * read or a SYNC write. We follow the same norm.
- */
- if (!(flags & REQ_RW) || flags & REQ_RW_SYNC)
- stat[IO_SYNC] += add;
+ stat[BLKIO_STAT_READ] += add;
+ if (sync)
+ stat[BLKIO_STAT_SYNC] += add;
else
- stat[IO_ASYNC] += add;
+ stat[BLKIO_STAT_ASYNC] += add;
}
void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time)
@@ -86,23 +91,25 @@
}
EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used);
-void blkiocg_update_request_dispatch_stats(struct blkio_group *blkg,
- struct request *rq)
+void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
+ uint64_t bytes, bool direction, bool sync)
{
struct blkio_group_stats *stats;
unsigned long flags;
spin_lock_irqsave(&blkg->stats_lock, flags);
stats = &blkg->stats;
- stats->sectors += blk_rq_sectors(rq);
- io_add_stat(stats->io_serviced, 1, rq->cmd_flags);
- io_add_stat(stats->io_service_bytes, blk_rq_sectors(rq) << 9,
- rq->cmd_flags);
+ stats->sectors += bytes >> 9;
+ blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICED], 1, direction,
+ sync);
+ blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_BYTES], bytes,
+ direction, sync);
spin_unlock_irqrestore(&blkg->stats_lock, flags);
}
+EXPORT_SYMBOL_GPL(blkiocg_update_dispatch_stats);
-void blkiocg_update_request_completion_stats(struct blkio_group *blkg,
- struct request *rq)
+void blkiocg_update_completion_stats(struct blkio_group *blkg,
+ uint64_t start_time, uint64_t io_start_time, bool direction, bool sync)
{
struct blkio_group_stats *stats;
unsigned long flags;
@@ -110,16 +117,15 @@
spin_lock_irqsave(&blkg->stats_lock, flags);
stats = &blkg->stats;
- if (time_after64(now, rq->io_start_time_ns))
- io_add_stat(stats->io_service_time, now - rq->io_start_time_ns,
- rq->cmd_flags);
- if (time_after64(rq->io_start_time_ns, rq->start_time_ns))
- io_add_stat(stats->io_wait_time,
- rq->io_start_time_ns - rq->start_time_ns,
- rq->cmd_flags);
+ if (time_after64(now, io_start_time))
+ blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_TIME],
+ now - io_start_time, direction, sync);
+ if (time_after64(io_start_time, start_time))
+ blkio_add_stat(stats->stat_arr[BLKIO_STAT_WAIT_TIME],
+ io_start_time - start_time, direction, sync);
spin_unlock_irqrestore(&blkg->stats_lock, flags);
}
-EXPORT_SYMBOL_GPL(blkiocg_update_request_completion_stats);
+EXPORT_SYMBOL_GPL(blkiocg_update_completion_stats);
void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
struct blkio_group *blkg, void *key, dev_t dev)
@@ -230,7 +236,7 @@
}
static int
-blkiocg_reset_write(struct cgroup *cgroup, struct cftype *cftype, u64 val)
+blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val)
{
struct blkio_cgroup *blkcg;
struct blkio_group *blkg;
@@ -249,29 +255,32 @@
return 0;
}
-void get_key_name(int type, char *disk_id, char *str, int chars_left)
+static void blkio_get_key_name(enum stat_sub_type type, dev_t dev, char *str,
+ int chars_left, bool diskname_only)
{
- strlcpy(str, disk_id, chars_left);
+ snprintf(str, chars_left, "%d:%d", MAJOR(dev), MINOR(dev));
chars_left -= strlen(str);
if (chars_left <= 0) {
printk(KERN_WARNING
"Possibly incorrect cgroup stat display format");
return;
}
+ if (diskname_only)
+ return;
switch (type) {
- case IO_READ:
+ case BLKIO_STAT_READ:
strlcat(str, " Read", chars_left);
break;
- case IO_WRITE:
+ case BLKIO_STAT_WRITE:
strlcat(str, " Write", chars_left);
break;
- case IO_SYNC:
+ case BLKIO_STAT_SYNC:
strlcat(str, " Sync", chars_left);
break;
- case IO_ASYNC:
+ case BLKIO_STAT_ASYNC:
strlcat(str, " Async", chars_left);
break;
- case IO_TYPE_MAX:
+ case BLKIO_STAT_TOTAL:
strlcat(str, " Total", chars_left);
break;
default:
@@ -279,63 +288,47 @@
}
}
-typedef uint64_t (get_var) (struct blkio_group *, int);
+static uint64_t blkio_fill_stat(char *str, int chars_left, uint64_t val,
+ struct cgroup_map_cb *cb, dev_t dev)
+{
+ blkio_get_key_name(0, dev, str, chars_left, true);
+ cb->fill(cb, str, val);
+ return val;
+}
-#define MAX_KEY_LEN 100
-uint64_t get_typed_stat(struct blkio_group *blkg, struct cgroup_map_cb *cb,
- get_var *getvar, char *disk_id)
+/* This should be called with blkg->stats_lock held */
+static uint64_t blkio_get_stat(struct blkio_group *blkg,
+ struct cgroup_map_cb *cb, dev_t dev, enum stat_type type)
{
uint64_t disk_total;
char key_str[MAX_KEY_LEN];
- int type;
+ enum stat_sub_type sub_type;
- for (type = 0; type < IO_TYPE_MAX; type++) {
- get_key_name(type, disk_id, key_str, MAX_KEY_LEN);
- cb->fill(cb, key_str, getvar(blkg, type));
+ if (type == BLKIO_STAT_TIME)
+ return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
+ blkg->stats.time, cb, dev);
+ if (type == BLKIO_STAT_SECTORS)
+ return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
+ blkg->stats.sectors, cb, dev);
+#ifdef CONFIG_DEBUG_BLK_CGROUP
+ if (type == BLKIO_STAT_DEQUEUE)
+ return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
+ blkg->stats.dequeue, cb, dev);
+#endif
+
+ for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL;
+ sub_type++) {
+ blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false);
+ cb->fill(cb, key_str, blkg->stats.stat_arr[type][sub_type]);
}
- disk_total = getvar(blkg, IO_READ) + getvar(blkg, IO_WRITE);
- get_key_name(IO_TYPE_MAX, disk_id, key_str, MAX_KEY_LEN);
+ disk_total = blkg->stats.stat_arr[type][BLKIO_STAT_READ] +
+ blkg->stats.stat_arr[type][BLKIO_STAT_WRITE];
+ blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false);
cb->fill(cb, key_str, disk_total);
return disk_total;
}
-uint64_t get_stat(struct blkio_group *blkg, struct cgroup_map_cb *cb,
- get_var *getvar, char *disk_id)
-{
- uint64_t var = getvar(blkg, 0);
- cb->fill(cb, disk_id, var);
- return var;
-}
-
-#define GET_STAT_INDEXED(__VAR) \
-uint64_t 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, __CONV) \
-uint64_t get_##__VAR##_stat(struct blkio_group *blkg, int dummy) \
-{ \
- uint64_t data = blkg->stats.__VAR; \
- if (__CONV) \
- data = (uint64_t)jiffies_to_msecs(data) * NSEC_PER_MSEC;\
- return data; \
-}
-
-GET_STAT(time, 1);
-GET_STAT(sectors, 0);
-#ifdef CONFIG_DEBUG_BLK_CGROUP
-GET_STAT(dequeue, 0);
-#endif
-#undef GET_STAT
-
-#define SHOW_FUNCTION_PER_GROUP(__VAR, get_stats, getvar, show_total) \
+#define SHOW_FUNCTION_PER_GROUP(__VAR, type, show_total) \
static int blkiocg_##__VAR##_read(struct cgroup *cgroup, \
struct cftype *cftype, struct cgroup_map_cb *cb) \
{ \
@@ -343,7 +336,6 @@
struct blkio_group *blkg; \
struct hlist_node *n; \
uint64_t cgroup_total = 0; \
- char disk_id[10]; \
\
if (!cgroup_lock_live_group(cgroup)) \
return -ENODEV; \
@@ -353,10 +345,8 @@
hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {\
if (blkg->dev) { \
spin_lock_irq(&blkg->stats_lock); \
- snprintf(disk_id, 10, "%u:%u", MAJOR(blkg->dev),\
- MINOR(blkg->dev)); \
- cgroup_total += get_stats(blkg, cb, getvar, \
- disk_id); \
+ cgroup_total += blkio_get_stat(blkg, cb, \
+ blkg->dev, type); \
spin_unlock_irq(&blkg->stats_lock); \
} \
} \
@@ -367,16 +357,14 @@
return 0; \
}
-SHOW_FUNCTION_PER_GROUP(time, get_stat, get_time_stat, 0);
-SHOW_FUNCTION_PER_GROUP(sectors, get_stat, get_sectors_stat, 0);
-SHOW_FUNCTION_PER_GROUP(io_service_bytes, get_typed_stat,
- get_io_service_bytes_stat, 1);
-SHOW_FUNCTION_PER_GROUP(io_serviced, get_typed_stat, get_io_serviced_stat, 1);
-SHOW_FUNCTION_PER_GROUP(io_service_time, get_typed_stat,
- get_io_service_time_stat, 1);
-SHOW_FUNCTION_PER_GROUP(io_wait_time, get_typed_stat, get_io_wait_time_stat, 1);
+SHOW_FUNCTION_PER_GROUP(time, BLKIO_STAT_TIME, 0);
+SHOW_FUNCTION_PER_GROUP(sectors, BLKIO_STAT_SECTORS, 0);
+SHOW_FUNCTION_PER_GROUP(io_service_bytes, BLKIO_STAT_SERVICE_BYTES, 1);
+SHOW_FUNCTION_PER_GROUP(io_serviced, BLKIO_STAT_SERVICED, 1);
+SHOW_FUNCTION_PER_GROUP(io_service_time, BLKIO_STAT_SERVICE_TIME, 1);
+SHOW_FUNCTION_PER_GROUP(io_wait_time, BLKIO_STAT_WAIT_TIME, 1);
#ifdef CONFIG_DEBUG_BLK_CGROUP
-SHOW_FUNCTION_PER_GROUP(dequeue, get_stat, get_dequeue_stat, 0);
+SHOW_FUNCTION_PER_GROUP(dequeue, BLKIO_STAT_DEQUEUE, 0);
#endif
#undef SHOW_FUNCTION_PER_GROUP
@@ -398,32 +386,30 @@
{
.name = "time",
.read_map = blkiocg_time_read,
- .write_u64 = blkiocg_reset_write,
},
{
.name = "sectors",
.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,
+ },
+ {
+ .name = "reset_stats",
+ .write_u64 = blkiocg_reset_stats,
},
#ifdef CONFIG_DEBUG_BLK_CGROUP
{
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
index 80010ef..b22e553 100644
--- a/block/blk-cgroup.h
+++ b/block/blk-cgroup.h
@@ -23,12 +23,31 @@
#define blkio_subsys_id blkio_subsys.subsys_id
#endif
-enum io_type {
- IO_READ = 0,
- IO_WRITE,
- IO_SYNC,
- IO_ASYNC,
- IO_TYPE_MAX
+enum stat_type {
+ /* Total time spent (in ns) between request dispatch to the driver and
+ * request completion for IOs doen by this cgroup. This may not be
+ * accurate when NCQ is turned on. */
+ BLKIO_STAT_SERVICE_TIME = 0,
+ /* Total bytes transferred */
+ BLKIO_STAT_SERVICE_BYTES,
+ /* Total IOs serviced, post merge */
+ BLKIO_STAT_SERVICED,
+ /* Total time spent waiting in scheduler queue in ns */
+ BLKIO_STAT_WAIT_TIME,
+ /* All the single valued stats go below this */
+ BLKIO_STAT_TIME,
+ BLKIO_STAT_SECTORS,
+#ifdef CONFIG_DEBUG_BLK_CGROUP
+ BLKIO_STAT_DEQUEUE
+#endif
+};
+
+enum stat_sub_type {
+ BLKIO_STAT_READ = 0,
+ BLKIO_STAT_WRITE,
+ BLKIO_STAT_SYNC,
+ BLKIO_STAT_ASYNC,
+ BLKIO_STAT_TOTAL
};
struct blkio_cgroup {
@@ -42,13 +61,7 @@
/* 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_MAX];
- uint64_t io_service_bytes[IO_TYPE_MAX]; /* Total bytes transferred */
- /* Total IOs serviced, post merge */
- uint64_t io_serviced[IO_TYPE_MAX];
- /* Total time spent waiting in scheduler queue in ns */
- uint64_t io_wait_time[IO_TYPE_MAX];
+ uint64_t stat_arr[BLKIO_STAT_WAIT_TIME + 1][BLKIO_STAT_TOTAL];
#ifdef CONFIG_DEBUG_BLK_CGROUP
/* How many times this group has been removed from service tree */
unsigned long dequeue;
@@ -65,7 +78,7 @@
char path[128];
#endif
/* The device MKDEV(major, minor), this group has been created for */
- dev_t dev;
+ dev_t dev;
/* Need to serialize the stats in the case of reset/update */
spinlock_t stats_lock;
@@ -128,21 +141,21 @@
extern int blkiocg_del_blkio_group(struct blkio_group *blkg);
extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,
void *key);
+void blkio_group_init(struct blkio_group *blkg);
void blkiocg_update_timeslice_used(struct blkio_group *blkg,
unsigned long time);
-void blkiocg_update_request_dispatch_stats(struct blkio_group *blkg,
- struct request *rq);
-void blkiocg_update_request_completion_stats(struct blkio_group *blkg,
- struct request *rq);
+void blkiocg_update_dispatch_stats(struct blkio_group *blkg, uint64_t bytes,
+ bool direction, bool sync);
+void blkiocg_update_completion_stats(struct blkio_group *blkg,
+ uint64_t start_time, uint64_t io_start_time, bool direction, bool sync);
#else
struct cgroup;
static inline struct blkio_cgroup *
cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
+static inline void blkio_group_init(struct blkio_group *blkg) {}
static inline void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
- struct blkio_group *blkg, void *key, dev_t dev)
-{
-}
+ struct blkio_group *blkg, void *key, dev_t dev) {}
static inline int
blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; }
@@ -151,9 +164,10 @@
blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) { return NULL; }
static inline void blkiocg_update_timeslice_used(struct blkio_group *blkg,
unsigned long time) {}
-static inline void blkiocg_update_request_dispatch_stats(
- struct blkio_group *blkg, struct request *rq) {}
-static inline void blkiocg_update_request_completion_stats(
- struct blkio_group *blkg, struct request *rq) {}
+static inline void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
+ uint64_t bytes, bool direction, bool sync) {}
+static inline void blkiocg_update_completion_stats(struct blkio_group *blkg,
+ uint64_t start_time, uint64_t io_start_time, bool direction,
+ bool sync) {}
#endif
#endif /* _BLK_CGROUP_H */
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 42028e7..5617ae0 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -955,6 +955,7 @@
for_each_cfqg_st(cfqg, i, j, st)
*st = CFQ_RB_ROOT;
RB_CLEAR_NODE(&cfqg->rb_node);
+ blkio_group_init(&cfqg->blkg);
/*
* Take the initial reference that will be released on destroy
@@ -1865,7 +1866,8 @@
elv_dispatch_sort(q, rq);
cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]++;
- blkiocg_update_request_dispatch_stats(&cfqq->cfqg->blkg, rq);
+ blkiocg_update_dispatch_stats(&cfqq->cfqg->blkg, blk_rq_bytes(rq),
+ rq_data_dir(rq), rq_is_sync(rq));
}
/*
@@ -3286,7 +3288,9 @@
WARN_ON(!cfqq->dispatched);
cfqd->rq_in_driver--;
cfqq->dispatched--;
- blkiocg_update_request_completion_stats(&cfqq->cfqg->blkg, rq);
+ blkiocg_update_completion_stats(&cfqq->cfqg->blkg, rq_start_time_ns(rq),
+ rq_io_start_time_ns(rq), rq_data_dir(rq),
+ rq_is_sync(rq));
cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]--;