Add support for configuring I/O priority per block cgroup. Assign the lowest
of the following two priorities to a request: rq->ioprio and blkcg->ioprio.
Maintain statistics per cgroup and make these available in sysfs.
This patch has been tested as follows:
SHELL 1
modprobe scsi_debug ndelay=1000000 max_queue=16 &&
while [ -z "$sd" ]; do sd=/dev/$(basename /sys/bus/pseudo/drivers/scsi_debug/adapter*/host*/target*/*/block/*); done &&
cd /sys/fs/cgroup/blkio/ &&
echo 2 >blkio.dd.prio &&
mkdir -p hipri &&
cd hipri &&
echo 1 >blkio.dd.prio &&
echo $$ >cgroup.procs &&
max-iops -a1 -d32 -j1 -e mq-deadline $sd
SHELL 2
sd=/dev/$(basename /sys/bus/pseudo/drivers/scsi_debug/adapter*/host*/target*/*/block/*) &&
max-iops -a1 -d32 -j1 -e mq-deadline $sd
Result:
* 12000 IOPS in shell 1
* 2000 IOPS in shell 2
The max-iops script is a script that runs fio with the following arguments:
--bs=4K --gtod_reduce=1 --ioengine=libaio --ioscheduler=${arg_e} --runtime=60
--norandommap --rw=read --thread --buffered=0 --numjobs=${arg_j}
--iodepth=${arg_d}
--iodepth_batch_submit=${arg_a} --iodepth_batch_complete=$((arg_d / 2))
--name=${positional_argument_1} --filename=${positional_argument_1}
Cc: Damien Le Moal <damien.lemoal@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Ming Lei <ming.lei@xxxxxxxxxx>
Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx>
---
block/Kconfig.iosched | 6 ++
block/Makefile | 1 +
block/mq-deadline-cgroup.c | 206 +++++++++++++++++++++++++++++++++++++
block/mq-deadline-cgroup.h | 73 +++++++++++++
block/mq-deadline.c | 96 ++++++++++++++---
5 files changed, 370 insertions(+), 12 deletions(-)
create mode 100644 block/mq-deadline-cgroup.c
create mode 100644 block/mq-deadline-cgroup.h
diff --git a/block/Kconfig.iosched b/block/Kconfig.iosched
index 2f2158e05a91..64053d67a97b 100644
--- a/block/Kconfig.iosched
+++ b/block/Kconfig.iosched
@@ -9,6 +9,12 @@ config MQ_IOSCHED_DEADLINE
help
MQ version of the deadline IO scheduler.
+config MQ_IOSCHED_DEADLINE_CGROUP
+ tristate
+ default y
+ depends on MQ_IOSCHED_DEADLINE
+ depends on BLK_CGROUP
+
config MQ_IOSCHED_KYBER
tristate "Kyber I/O scheduler"
default y
diff --git a/block/Makefile b/block/Makefile
index 8d841f5f986f..7d5763d5f988 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_BLK_DEV_THROTTLING) += blk-throttle.o
obj-$(CONFIG_BLK_CGROUP_IOLATENCY) += blk-iolatency.o
obj-$(CONFIG_BLK_CGROUP_IOCOST) += blk-iocost.o
obj-$(CONFIG_MQ_IOSCHED_DEADLINE) += mq-deadline.o
+obj-$(CONFIG_MQ_IOSCHED_DEADLINE_CGROUP)+= mq-deadline-cgroup.o
obj-$(CONFIG_MQ_IOSCHED_KYBER) += kyber-iosched.o
bfq-y := bfq-iosched.o bfq-wf2q.o bfq-cgroup.o
obj-$(CONFIG_IOSCHED_BFQ) += bfq.o
diff --git a/block/mq-deadline-cgroup.c b/block/mq-deadline-cgroup.c
new file mode 100644
index 000000000000..3983795dda60
--- /dev/null
+++ b/block/mq-deadline-cgroup.c
@@ -0,0 +1,206 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/blk-cgroup.h>
+#include <linux/ioprio.h>
+
+#include "mq-deadline-cgroup.h"
+
+static struct blkcg_policy dd_blkcg_policy;
+
+static struct dd_blkcg *dd_blkcg_from_css(struct cgroup_subsys_state *css)
+{
+ struct blkcg *blkcg = css_to_blkcg(css);
+ struct blkcg_policy_data *cpd = blkcg_to_cpd(blkcg, &dd_blkcg_policy);
+
+ return container_of(cpd, struct dd_blkcg, cpd);
+}
+
+static u64 dd_show_prio(struct cgroup_subsys_state *css, struct cftype *cft)
+{
+ return dd_blkcg_from_css(css)->prio;
+}
+
+static int dd_set_prio(struct cgroup_subsys_state *css, struct cftype *cft,
+ u64 val)
+{
+ struct dd_blkcg *dd_blkcg = dd_blkcg_from_css(css);
+
+ if (val < 0 || val > 3)
+ return -EINVAL;
+ dd_blkcg->prio = val;
+ return 0;
+}
+
+/*
+ * Total number of inserted requests not associated with any cgroup and
+ * with I/O priority cft->private.
+ */
+static u64 dd_show_nocg(struct cgroup_subsys_state *css,
+ struct cftype *cft)
+{
+ const u8 prio = cft->private;
+
+ return atomic_read(&nocg_inserted[prio]);
+}
+
+/* Number of inserted but not completed requests for priority cft->private. */
+static u64 dd_show_inserted(struct cgroup_subsys_state *css,
+ struct cftype *cft)
+{
+ struct dd_blkcg *blkcg = dd_blkcg_from_css(css);
+ const u8 prio = cft->private;
+
+ return atomic_read(&blkcg->inserted[prio]) -
+ atomic_read(&blkcg->completed[prio]);
+}
+
+static u64 dd_show_merged(struct cgroup_subsys_state *css, struct cftype *cft)
+{
+ struct dd_blkcg *blkcg = dd_blkcg_from_css(css);
+ const u8 prio = cft->private;
+
+ return atomic_read(&blkcg->merged[prio]);
+}
+
+/* Number of dispatched but not completed requests for priority cft->private. */
+static u64 dd_show_dispatched(struct cgroup_subsys_state *css,
+ struct cftype *cft)
+{
+ struct dd_blkcg *blkcg = dd_blkcg_from_css(css);
+ const u8 prio = cft->private;
+
+ return atomic_read(&blkcg->dispatched[prio]) +
+ atomic_read(&blkcg->merged[prio]) -
+ atomic_read(&blkcg->completed[prio]);
+}
+
+#define IOPRI_ATTRS(pfx, cft_flags, callback) \
+ { \
+ .name = pfx "0", \
+ .private = IOPRIO_CLASS_NONE, \
+ .flags = cft_flags, \
+ .read_u64 = callback, \
+ }, \
+ { \
+ .name = pfx "1", \
+ .private = IOPRIO_CLASS_RT, \
+ .flags = cft_flags, \
+ .read_u64 = callback, \
+ }, \
+ { \
+ .name = pfx "2", \
+ .private = IOPRIO_CLASS_BE, \
+ .flags = cft_flags, \
+ .read_u64 = callback, \
+ }, \
+ { \
+ .name = pfx "3", \
+ .private = IOPRIO_CLASS_IDLE, \
+ .flags = cft_flags, \
+ .read_u64 = callback, \
+ }
+
+#define DD_ATTRS \
+ { \
+ .name = "dd.prio", \
+ .read_u64 = dd_show_prio, \
+ .write_u64 = dd_set_prio, \
+ }, \
+ IOPRI_ATTRS("dd.nocg_pri", CFTYPE_ONLY_ON_ROOT, dd_show_nocg), \
+ IOPRI_ATTRS("dd.inserted_pri", 0, dd_show_inserted), \
+ IOPRI_ATTRS("dd.merged_pri", 0, dd_show_merged), \
+ IOPRI_ATTRS("dd.dispatched_pri", 0, dd_show_dispatched), \
+ { } /* sentinel */
+
+/* cgroup v2 attributes */
+static struct cftype dd_blkcg_files[] = {
+ DD_ATTRS
+};
+
+/* cgroup v1 attributes */
+static struct cftype dd_blkcg_legacy_files[] = {
+ DD_ATTRS
+};
+
+static struct blkcg_policy_data *dd_cpd_alloc(gfp_t gfp)
+{
+ struct dd_blkcg *pd;
+
+ pd = kzalloc(sizeof(*pd), gfp);
+ if (!pd)
+ return NULL;
+ pd->prio = IOPRIO_CLASS_NONE;
+ return &pd->cpd;
+}
+
+static void dd_cpd_free(struct blkcg_policy_data *cpd)
+{
+ struct dd_blkcg *dd_blkcg = container_of(cpd, typeof(*dd_blkcg), cpd);
+
+ kfree(dd_blkcg);
+}
+
+/*
+ * Convert an association between a block cgroup and a request queue into a
+ * pointer to the mq-deadline information associated with a (blkcg, queue) pair.
+ */
+struct dd_blkcg *dd_blkcg_from_bio(struct bio *bio)
+{
+ struct blkg_policy_data *pd;
+
+ pd = blkg_to_pd(bio->bi_blkg, &dd_blkcg_policy);
+ if (!pd)
+ return NULL;
+
+ return container_of(blkcg_to_cpd(pd->blkg->blkcg, &dd_blkcg_policy),
+ struct dd_blkcg, cpd);
+}
+
+static struct blkg_policy_data *dd_pd_alloc(gfp_t gfp, struct request_queue *q,
+ struct blkcg *blkcg)
+{
+ struct dd_blkg *pd;
+
+ pd = kzalloc(sizeof(*pd), gfp);
+ if (!pd)
+ return NULL;
+ return &pd->pd;
+}
+
+static void dd_pd_free(struct blkg_policy_data *pd)
+{
+ struct dd_blkg *dd_blkg = container_of(pd, typeof(*dd_blkg), pd);
+
+ kfree(dd_blkg);
+}
+
+static struct blkcg_policy dd_blkcg_policy = {
+ .dfl_cftypes = dd_blkcg_files,
+ .legacy_cftypes = dd_blkcg_legacy_files,
+
+ .cpd_alloc_fn = dd_cpd_alloc,
+ .cpd_free_fn = dd_cpd_free,
+
+ .pd_alloc_fn = dd_pd_alloc,
+ .pd_free_fn = dd_pd_free,
+};
+
+int dd_activate_policy(struct request_queue *q)
+{
+ return blkcg_activate_policy(q, &dd_blkcg_policy);
+}
+
+void dd_deactivate_policy(struct request_queue *q)
+{
+ blkcg_deactivate_policy(q, &dd_blkcg_policy);
+}
+
+int __init dd_blkcg_init(void)
+{
+ return blkcg_policy_register(&dd_blkcg_policy);
+}
+
+void __exit dd_blkcg_exit(void)
+{
+ blkcg_policy_unregister(&dd_blkcg_policy);
+}
diff --git a/block/mq-deadline-cgroup.h b/block/mq-deadline-cgroup.h
new file mode 100644
index 000000000000..0996a1a28412
--- /dev/null
+++ b/block/mq-deadline-cgroup.h
@@ -0,0 +1,73 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#if !defined(_MQ_DEADLINE_CGROUP_H_)
+#define _MQ_DEADLINE_CGROUP_H_
+
+#include <linux/blk-cgroup.h>
+
+struct request_queue;
+
+extern atomic_t nocg_inserted[4];
+
+/**
+ * struct dd_blkcg - Per cgroup data.
+ * @cpd: blkcg_policy_data structure.
+ * @prio: One of the IOPRIO_CLASS_* values. See also <linux/ioprio.h>.
+ * @inserted: Number of inserted requests for the given IOPRIO_CLASS_*.
+ * @merged: Number of merged requests for the given I/O priority level.
+ * @dispatched: Number of dispatched requests for the given IOPRIO_CLASS_*.
+ * @completed: Number of completions per I/O priority level.
+ */
+struct dd_blkcg {
+ struct blkcg_policy_data cpd; /* must be the first member */
+ u8 prio;
+ atomic_t inserted[4];
+ atomic_t merged[4];
+ atomic_t dispatched[4];
+ atomic_t completed[4];
+};
+
+#ifdef CONFIG_BLK_CGROUP
+
+/**
+ * struct dd_blkg - Per (cgroup, request queue) data.
+ * @pd: blkg_policy_data structure.
+ */
+struct dd_blkg {
+ struct blkg_policy_data pd; /* must be the first member */
+};
+
+struct dd_blkcg *dd_blkcg_from_bio(struct bio *bio);
+int dd_activate_policy(struct request_queue *q);
+void dd_deactivate_policy(struct request_queue *q);
+int __init dd_blkcg_init(void);
+void __exit dd_blkcg_exit(void);
+
+#else /* CONFIG_BLK_CGROUP */
+
+static inline struct dd_blkcg *dd_blkcg_from_bio(struct bio *bio)
+{
+ return NULL;
+}
+
+static inline int dd_activate_policy(struct request_queue *q)
+{
+ return 0;
+}
+
+static inline void dd_deactivate_policy(struct request_queue *q)
+{
+}
+
+static inline int dd_blkcg_init(void)
+{
+ return 0;
+}
+
+static inline void dd_blkcg_exit(void)
+{
+}
+
+#endif /* CONFIG_BLK_CGROUP */
+
+#endif /* _MQ_DEADLINE_CGROUP_H_ */
diff --git a/block/mq-deadline.c b/block/mq-deadline.c
index 5a703e1228fa..0aa14cc302fd 100644
--- a/block/mq-deadline.c
+++ b/block/mq-deadline.c
@@ -25,6 +25,7 @@
#include "blk-mq-debugfs.h"
#include "blk-mq-tag.h"
#include "blk-mq-sched.h"
+#include "mq-deadline-cgroup.h"
/*
* See Documentation/block/deadline-iosched.rst
@@ -58,6 +59,9 @@ struct deadline_data {
* run time data
*/
+ /* Request queue that owns this data structure. */
+ struct request_queue *queue;
+
/*
* Requests are present on both sort_list[] and fifo_list[][]. The
* first index of fifo_list[][] is the I/O priority class (DD_*_PRIO).
@@ -101,6 +105,9 @@ static const enum dd_prio ioprio_class_to_prio[] = {
[IOPRIO_CLASS_IDLE] = DD_IDLE_PRIO,
};
+/* To track requests not associated with any cgroup. */
+atomic_t nocg_inserted[4];
+
static inline struct rb_root *
deadline_rb_root(struct deadline_data *dd, struct request *rq)
{
@@ -189,9 +196,11 @@ static void dd_merged_requests(struct request_queue *q, struct request *req,
struct deadline_data *dd = q->elevator->elevator_data;
const u8 ioprio_class = dd_rq_ioclass(next);
const enum dd_prio prio = ioprio_class_to_prio[ioprio_class];
+ struct dd_blkcg *blkcg = next->elv.priv[0];
- if (next->elv.priv[0]) {
+ if (blkcg) {
atomic_inc(&dd->merged[prio]);
+ atomic_inc(&blkcg->merged[ioprio_class]);
} else {
WARN_ON_ONCE(true);
}
@@ -334,6 +343,7 @@ static struct request *__dd_dispatch_request(struct deadline_data *dd,
{
struct request *rq, *next_rq;
enum dd_data_dir data_dir;
+ struct dd_blkcg *blkcg;
u8 ioprio_class;
lockdep_assert_held(&dd->lock);
@@ -426,10 +436,12 @@ static struct request *__dd_dispatch_request(struct deadline_data *dd,
dd->batching++;
deadline_move_request(dd, rq);
done:
+ blkcg = rq->elv.priv[0];
ioprio_class = dd_rq_ioclass(rq);
prio = ioprio_class_to_prio[ioprio_class];
- if (rq->elv.priv[0]) {
+ if (blkcg) {
atomic_inc(&dd->dispatched[prio]);
+ atomic_inc(&blkcg->dispatched[ioprio_class]);
} else {
WARN_ON_ONCE(true);
}
@@ -503,6 +515,8 @@ static void dd_exit_sched(struct elevator_queue *e)
struct deadline_data *dd = e->elevator_data;
enum dd_prio prio;
+ dd_deactivate_policy(dd->queue);
+
for (prio = 0; prio <= DD_PRIO_MAX; prio++) {
WARN_ON_ONCE(!list_empty(&dd->fifo_list[prio][DD_READ]));
WARN_ON_ONCE(!list_empty(&dd->fifo_list[prio][DD_WRITE]));
@@ -512,25 +526,33 @@ static void dd_exit_sched(struct elevator_queue *e)
}
/*
- * initialize elevator private data (deadline_data).
+ * Initialize elevator private data (deadline_data) and associate with blkcg.
*/
static int dd_init_sched(struct request_queue *q, struct elevator_type *e)
{
struct deadline_data *dd;
struct elevator_queue *eq;
enum dd_prio prio;
+ int ret = -ENOMEM;
+
+ /*
+ * Initialization would be very tricky if the queue is not frozen,
+ * hence the warning statement below.
+ */
+ WARN_ON_ONCE(!percpu_ref_is_zero(&q->q_usage_counter));
eq = elevator_alloc(q, e);
if (!eq)
- return -ENOMEM;
+ goto out;
dd = kzalloc_node(sizeof(*dd), GFP_KERNEL, q->node);
- if (!dd) {
- kobject_put(&eq->kobj);
- return -ENOMEM;
- }
+ if (!dd)
+ goto put_eq;
+
eq->elevator_data = dd;
+ dd->queue = q;
+
for (prio = 0; prio <= DD_PRIO_MAX; prio++) {
INIT_LIST_HEAD(&dd->fifo_list[prio][DD_READ]);
INIT_LIST_HEAD(&dd->fifo_list[prio][DD_WRITE]);
@@ -547,8 +569,23 @@ static int dd_init_sched(struct request_queue *q, struct elevator_type *e)
spin_lock_init(&dd->lock);
spin_lock_init(&dd->zone_lock);
+ ret = dd_activate_policy(q);
+ if (ret)
+ goto free_dd;
+
+ ret = 0;
q->elevator = eq;
- return 0;
+
+out:
+ return ret;
+
+free_dd:
+ eq->elevator_data = NULL;
+ kfree(dd);
+
+put_eq:
+ kobject_put(&eq->kobj);
+ goto out;
}
/*
@@ -611,6 +648,7 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
u16 ioprio = req_get_ioprio(rq);
u8 ioprio_class = IOPRIO_PRIO_CLASS(ioprio);
enum dd_prio prio;
+ struct dd_blkcg *blkcg;
lockdep_assert_held(&dd->lock);
@@ -620,10 +658,27 @@ static void dd_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
*/
blk_req_zone_write_unlock(rq);
+ /*
+ * If a block cgroup has been associated with the submitter and if an
+ * I/O priority has been set in the associated block cgroup, use the
+ * lowest of the cgroup priority and the request priority for the
+ * request. If no priority has been set in the request, use the cgroup
+ * priority.
+ */
+ blkcg = dd_blkcg_from_bio(rq->bio);
+ if (blkcg) {
+ ioprio_class = max(ioprio_class, blkcg->prio);
+ rq->ioprio = IOPRIO_PRIO_VALUE(ioprio_class,
+ IOPRIO_PRIO_DATA(ioprio));
+ atomic_inc(&blkcg->inserted[ioprio_class]);
+ } else {
+ WARN_ON_ONCE(true);
+ atomic_inc(&nocg_inserted[ioprio_class]);
+ }
prio = ioprio_class_to_prio[ioprio_class];
atomic_inc(&dd->inserted[prio]);
WARN_ON_ONCE(rq->elv.priv[0]);
- rq->elv.priv[0] = (void *)1ULL;
+ rq->elv.priv[0] = blkcg;
rq->elv.priv[1] = (void *)(uintptr_t)ioprio_class;
if (blk_mq_sched_try_insert_merge(q, rq))
@@ -696,11 +751,14 @@ static void dd_finish_request(struct request *rq)
{
struct request_queue *q = rq->q;
struct deadline_data *dd = q->elevator->elevator_data;
+ struct dd_blkcg *blkcg = rq->elv.priv[0];
const u8 ioprio_class = dd_rq_ioclass(rq);
const enum dd_prio prio = ioprio_class_to_prio[ioprio_class];
- if (rq->elv.priv[0])
+ if (blkcg) {
atomic_inc(&dd->completed[prio]);
+ atomic_inc(&blkcg->completed[ioprio_class]);
+ }
if (blk_queue_is_zoned(q)) {
unsigned long flags;
@@ -1021,11 +1079,25 @@ MODULE_ALIAS("mq-deadline-iosched");
static int __init deadline_init(void)
{
- return elv_register(&mq_deadline);
+ int ret;
+ ret = elv_register(&mq_deadline);
+ if (ret)
+ goto out;
+ ret = dd_blkcg_init();
+ if (ret)
+ goto unreg;
+
+out:
+ return ret;
+
+unreg:
+ elv_unregister(&mq_deadline);
+ goto out;
}
static void __exit deadline_exit(void)
{
+ dd_blkcg_exit();
elv_unregister(&mq_deadline);
}
