@@ -32,6 +32,7 @@
#include <linux/psi.h>
#include "blk.h"
#include "blk-ioprio.h"
+#include "blk-throttle.h"
/*
* blkcg_pol_mutex protects blkcg_policy[] and policy [de]activation.
@@ -51,6 +51,7 @@
#include "blk-mq-sched.h"
#include "blk-pm.h"
#include "blk-rq-qos.h"
+#include "blk-throttle.h"
struct dentry *blk_debugfs_root;
@@ -13,6 +13,7 @@
#include "blk.h"
#include "blk-rq-qos.h"
+#include "blk-throttle.h"
static inline bool bio_will_gap(struct request_queue *q,
struct request *prev_rq, struct bio *prev, struct bio *next)
@@ -17,6 +17,7 @@
#include "blk-mq.h"
#include "blk-mq-debugfs.h"
#include "blk-wbt.h"
+#include "blk-throttle.h"
struct queue_sysfs_entry {
struct attribute attr;
@@ -13,6 +13,7 @@
#include <linux/blk-cgroup.h>
#include "blk.h"
#include "blk-cgroup-rwstat.h"
+#include "blk-throttle.h"
/* Max dispatch from a group in 1 round */
#define THROTL_GRP_QUANTUM 8
@@ -37,60 +38,9 @@
*/
#define LATENCY_FILTERED_HD (1000L) /* 1ms */
-static struct blkcg_policy blkcg_policy_throtl;
-
/* A workqueue to queue throttle related work */
static struct workqueue_struct *kthrotld_workqueue;
-/*
- * To implement hierarchical throttling, throtl_grps form a tree and bios
- * are dispatched upwards level by level until they reach the top and get
- * issued. When dispatching bios from the children and local group at each
- * level, if the bios are dispatched into a single bio_list, there's a risk
- * of a local or child group which can queue many bios at once filling up
- * the list starving others.
- *
- * To avoid such starvation, dispatched bios are queued separately
- * according to where they came from. When they are again dispatched to
- * the parent, they're popped in round-robin order so that no single source
- * hogs the dispatch window.
- *
- * throtl_qnode is used to keep the queued bios separated by their sources.
- * Bios are queued to throtl_qnode which in turn is queued to
- * throtl_service_queue and then dispatched in round-robin order.
- *
- * It's also used to track the reference counts on blkg's. A qnode always
- * belongs to a throtl_grp and gets queued on itself or the parent, so
- * incrementing the reference of the associated throtl_grp when a qnode is
- * queued and decrementing when dequeued is enough to keep the whole blkg
- * tree pinned while bios are in flight.
- */
-struct throtl_qnode {
- struct list_head node; /* service_queue->queued[] */
- struct bio_list bios; /* queued bios */
- struct throtl_grp *tg; /* tg this qnode belongs to */
-};
-
-struct throtl_service_queue {
- struct throtl_service_queue *parent_sq; /* the parent service_queue */
-
- /*
- * Bios queued directly to this service_queue or dispatched from
- * children throtl_grp's.
- */
- struct list_head queued[2]; /* throtl_qnode [READ/WRITE] */
- unsigned int nr_queued[2]; /* number of queued bios */
-
- /*
- * RB tree of active children throtl_grp's, which are sorted by
- * their ->disptime.
- */
- struct rb_root_cached pending_tree; /* RB tree of active tgs */
- unsigned int nr_pending; /* # queued in the tree */
- unsigned long first_pending_disptime; /* disptime of the first tg */
- struct timer_list pending_timer; /* fires on first_pending_disptime */
-};
-
enum tg_state_flags {
THROTL_TG_PENDING = 1 << 0, /* on parent's pending tree */
THROTL_TG_WAS_EMPTY = 1 << 1, /* bio_lists[] became non-empty */
@@ -98,93 +48,6 @@ enum tg_state_flags {
#define rb_entry_tg(node) rb_entry((node), struct throtl_grp, rb_node)
-enum {
- LIMIT_LOW,
- LIMIT_MAX,
- LIMIT_CNT,
-};
-
-struct throtl_grp {
- /* must be the first member */
- struct blkg_policy_data pd;
-
- /* active throtl group service_queue member */
- struct rb_node rb_node;
-
- /* throtl_data this group belongs to */
- struct throtl_data *td;
-
- /* this group's service queue */
- struct throtl_service_queue service_queue;
-
- /*
- * qnode_on_self is used when bios are directly queued to this
- * throtl_grp so that local bios compete fairly with bios
- * dispatched from children. qnode_on_parent is used when bios are
- * dispatched from this throtl_grp into its parent and will compete
- * with the sibling qnode_on_parents and the parent's
- * qnode_on_self.
- */
- struct throtl_qnode qnode_on_self[2];
- struct throtl_qnode qnode_on_parent[2];
-
- /*
- * Dispatch time in jiffies. This is the estimated time when group
- * will unthrottle and is ready to dispatch more bio. It is used as
- * key to sort active groups in service tree.
- */
- unsigned long disptime;
-
- unsigned int flags;
-
- /* are there any throtl rules between this group and td? */
- bool has_rules[2];
-
- /* internally used bytes per second rate limits */
- uint64_t bps[2][LIMIT_CNT];
- /* user configured bps limits */
- uint64_t bps_conf[2][LIMIT_CNT];
-
- /* internally used IOPS limits */
- unsigned int iops[2][LIMIT_CNT];
- /* user configured IOPS limits */
- unsigned int iops_conf[2][LIMIT_CNT];
-
- /* Number of bytes dispatched in current slice */
- uint64_t bytes_disp[2];
- /* Number of bio's dispatched in current slice */
- unsigned int io_disp[2];
-
- unsigned long last_low_overflow_time[2];
-
- uint64_t last_bytes_disp[2];
- unsigned int last_io_disp[2];
-
- unsigned long last_check_time;
-
- unsigned long latency_target; /* us */
- unsigned long latency_target_conf; /* us */
- /* When did we start a new slice */
- unsigned long slice_start[2];
- unsigned long slice_end[2];
-
- unsigned long last_finish_time; /* ns / 1024 */
- unsigned long checked_last_finish_time; /* ns / 1024 */
- unsigned long avg_idletime; /* ns / 1024 */
- unsigned long idletime_threshold; /* us */
- unsigned long idletime_threshold_conf; /* us */
-
- unsigned int bio_cnt; /* total bios */
- unsigned int bad_bio_cnt; /* bios exceeding latency threshold */
- unsigned long bio_cnt_reset_time;
-
- atomic_t io_split_cnt[2];
- atomic_t last_io_split_cnt[2];
-
- struct blkg_rwstat stat_bytes;
- struct blkg_rwstat stat_ios;
-};
-
/* We measure latency for request size from <= 4k to >= 1M */
#define LATENCY_BUCKET_SIZE 9
@@ -231,16 +94,6 @@ struct throtl_data
static void throtl_pending_timer_fn(struct timer_list *t);
-static inline struct throtl_grp *pd_to_tg(struct blkg_policy_data *pd)
-{
- return pd ? container_of(pd, struct throtl_grp, pd) : NULL;
-}
-
-static inline struct throtl_grp *blkg_to_tg(struct blkcg_gq *blkg)
-{
- return pd_to_tg(blkg_to_pd(blkg, &blkcg_policy_throtl));
-}
-
static inline struct blkcg_gq *tg_to_blkg(struct throtl_grp *tg)
{
return pd_to_blkg(&tg->pd);
@@ -1794,7 +1647,7 @@ static void throtl_shutdown_wq(struct request_queue *q)
cancel_work_sync(&td->dispatch_work);
}
-static struct blkcg_policy blkcg_policy_throtl = {
+struct blkcg_policy blkcg_policy_throtl = {
.dfl_cftypes = throtl_files,
.legacy_cftypes = throtl_legacy_files,
@@ -2208,7 +2061,7 @@ void blk_throtl_charge_bio_split(struct bio *bio)
} while (parent);
}
-bool blk_throtl_bio(struct bio *bio)
+bool __blk_throtl_bio(struct bio *bio)
{
struct request_queue *q = bio->bi_bdev->bd_disk->queue;
struct blkcg_gq *blkg = bio->bi_blkg;
@@ -2221,19 +2074,12 @@ bool blk_throtl_bio(struct bio *bio)
rcu_read_lock();
- /* see throtl_charge_bio() */
- if (bio_flagged(bio, BIO_THROTTLED))
- goto out;
-
if (!cgroup_subsys_on_dfl(io_cgrp_subsys)) {
blkg_rwstat_add(&tg->stat_bytes, bio->bi_opf,
bio->bi_iter.bi_size);
blkg_rwstat_add(&tg->stat_ios, bio->bi_opf, 1);
}
- if (!tg->has_rules[rw])
- goto out;
-
spin_lock_irq(&q->queue_lock);
throtl_update_latency_buckets(td);
@@ -2317,7 +2163,6 @@ bool blk_throtl_bio(struct bio *bio)
out_unlock:
spin_unlock_irq(&q->queue_lock);
-out:
bio_set_flag(bio, BIO_THROTTLED);
#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
new file mode 100644
@@ -0,0 +1,182 @@
+#ifndef BLK_THROTTLE_H
+#define BLK_THROTTLE_H
+
+#include "blk-cgroup-rwstat.h"
+
+/*
+ * To implement hierarchical throttling, throtl_grps form a tree and bios
+ * are dispatched upwards level by level until they reach the top and get
+ * issued. When dispatching bios from the children and local group at each
+ * level, if the bios are dispatched into a single bio_list, there's a risk
+ * of a local or child group which can queue many bios at once filling up
+ * the list starving others.
+ *
+ * To avoid such starvation, dispatched bios are queued separately
+ * according to where they came from. When they are again dispatched to
+ * the parent, they're popped in round-robin order so that no single source
+ * hogs the dispatch window.
+ *
+ * throtl_qnode is used to keep the queued bios separated by their sources.
+ * Bios are queued to throtl_qnode which in turn is queued to
+ * throtl_service_queue and then dispatched in round-robin order.
+ *
+ * It's also used to track the reference counts on blkg's. A qnode always
+ * belongs to a throtl_grp and gets queued on itself or the parent, so
+ * incrementing the reference of the associated throtl_grp when a qnode is
+ * queued and decrementing when dequeued is enough to keep the whole blkg
+ * tree pinned while bios are in flight.
+ */
+struct throtl_qnode {
+ struct list_head node; /* service_queue->queued[] */
+ struct bio_list bios; /* queued bios */
+ struct throtl_grp *tg; /* tg this qnode belongs to */
+};
+
+struct throtl_service_queue {
+ struct throtl_service_queue *parent_sq; /* the parent service_queue */
+
+ /*
+ * Bios queued directly to this service_queue or dispatched from
+ * children throtl_grp's.
+ */
+ struct list_head queued[2]; /* throtl_qnode [READ/WRITE] */
+ unsigned int nr_queued[2]; /* number of queued bios */
+
+ /*
+ * RB tree of active children throtl_grp's, which are sorted by
+ * their ->disptime.
+ */
+ struct rb_root_cached pending_tree; /* RB tree of active tgs */
+ unsigned int nr_pending; /* # queued in the tree */
+ unsigned long first_pending_disptime; /* disptime of the first tg */
+ struct timer_list pending_timer; /* fires on first_pending_disptime */
+};
+
+enum {
+ LIMIT_LOW,
+ LIMIT_MAX,
+ LIMIT_CNT,
+};
+
+struct throtl_grp {
+ /* must be the first member */
+ struct blkg_policy_data pd;
+
+ /* active throtl group service_queue member */
+ struct rb_node rb_node;
+
+ /* throtl_data this group belongs to */
+ struct throtl_data *td;
+
+ /* this group's service queue */
+ struct throtl_service_queue service_queue;
+
+ /*
+ * qnode_on_self is used when bios are directly queued to this
+ * throtl_grp so that local bios compete fairly with bios
+ * dispatched from children. qnode_on_parent is used when bios are
+ * dispatched from this throtl_grp into its parent and will compete
+ * with the sibling qnode_on_parents and the parent's
+ * qnode_on_self.
+ */
+ struct throtl_qnode qnode_on_self[2];
+ struct throtl_qnode qnode_on_parent[2];
+
+ /*
+ * Dispatch time in jiffies. This is the estimated time when group
+ * will unthrottle and is ready to dispatch more bio. It is used as
+ * key to sort active groups in service tree.
+ */
+ unsigned long disptime;
+
+ unsigned int flags;
+
+ /* are there any throtl rules between this group and td? */
+ bool has_rules[2];
+
+ /* internally used bytes per second rate limits */
+ uint64_t bps[2][LIMIT_CNT];
+ /* user configured bps limits */
+ uint64_t bps_conf[2][LIMIT_CNT];
+
+ /* internally used IOPS limits */
+ unsigned int iops[2][LIMIT_CNT];
+ /* user configured IOPS limits */
+ unsigned int iops_conf[2][LIMIT_CNT];
+
+ /* Number of bytes dispatched in current slice */
+ uint64_t bytes_disp[2];
+ /* Number of bio's dispatched in current slice */
+ unsigned int io_disp[2];
+
+ unsigned long last_low_overflow_time[2];
+
+ uint64_t last_bytes_disp[2];
+ unsigned int last_io_disp[2];
+
+ unsigned long last_check_time;
+
+ unsigned long latency_target; /* us */
+ unsigned long latency_target_conf; /* us */
+ /* When did we start a new slice */
+ unsigned long slice_start[2];
+ unsigned long slice_end[2];
+
+ unsigned long last_finish_time; /* ns / 1024 */
+ unsigned long checked_last_finish_time; /* ns / 1024 */
+ unsigned long avg_idletime; /* ns / 1024 */
+ unsigned long idletime_threshold; /* us */
+ unsigned long idletime_threshold_conf; /* us */
+
+ unsigned int bio_cnt; /* total bios */
+ unsigned int bad_bio_cnt; /* bios exceeding latency threshold */
+ unsigned long bio_cnt_reset_time;
+
+ atomic_t io_split_cnt[2];
+ atomic_t last_io_split_cnt[2];
+
+ struct blkg_rwstat stat_bytes;
+ struct blkg_rwstat stat_ios;
+};
+
+extern struct blkcg_policy blkcg_policy_throtl;
+
+static inline struct throtl_grp *pd_to_tg(struct blkg_policy_data *pd)
+{
+ return pd ? container_of(pd, struct throtl_grp, pd) : NULL;
+}
+
+static inline struct throtl_grp *blkg_to_tg(struct blkcg_gq *blkg)
+{
+ return pd_to_tg(blkg_to_pd(blkg, &blkcg_policy_throtl));
+}
+
+/*
+ * Internal throttling interface
+ */
+#ifndef CONFIG_BLK_DEV_THROTTLING
+static inline int blk_throtl_init(struct request_queue *q) { return 0; }
+static inline void blk_throtl_exit(struct request_queue *q) { }
+static inline void blk_throtl_register_queue(struct request_queue *q) { }
+static inline void blk_throtl_charge_bio_split(struct bio *bio) { }
+static inline bool blk_throtl_bio(struct bio *bio) { return false; }
+#else /* CONFIG_BLK_DEV_THROTTLING */
+int blk_throtl_init(struct request_queue *q);
+void blk_throtl_exit(struct request_queue *q);
+void blk_throtl_register_queue(struct request_queue *q);
+void blk_throtl_charge_bio_split(struct bio *bio);
+bool __blk_throtl_bio(struct bio *bio);
+static inline bool blk_throtl_bio(struct bio *bio)
+{
+ struct throtl_grp *tg = blkg_to_tg(bio->bi_blkg);
+
+ if (bio_flagged(bio, BIO_THROTTLED))
+ return false;
+ if (!tg->has_rules[bio_data_dir(bio)])
+ return false;
+
+ return __blk_throtl_bio(bio);
+}
+#endif /* CONFIG_BLK_DEV_THROTTLING */
+
+#endif
@@ -323,22 +323,6 @@ void ioc_clear_queue(struct request_queue *q);
int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
-/*
- * Internal throttling interface
- */
-#ifdef CONFIG_BLK_DEV_THROTTLING
-extern int blk_throtl_init(struct request_queue *q);
-extern void blk_throtl_exit(struct request_queue *q);
-extern void blk_throtl_register_queue(struct request_queue *q);
-extern void blk_throtl_charge_bio_split(struct bio *bio);
-bool blk_throtl_bio(struct bio *bio);
-#else /* CONFIG_BLK_DEV_THROTTLING */
-static inline int blk_throtl_init(struct request_queue *q) { return 0; }
-static inline void blk_throtl_exit(struct request_queue *q) { }
-static inline void blk_throtl_register_queue(struct request_queue *q) { }
-static inline void blk_throtl_charge_bio_split(struct bio *bio) { }
-static inline bool blk_throtl_bio(struct bio *bio) { return false; }
-#endif /* CONFIG_BLK_DEV_THROTTLING */
#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
extern ssize_t blk_throtl_sample_time_show(struct request_queue *q, char *page);
extern ssize_t blk_throtl_sample_time_store(struct request_queue *q,
Even if no policies are defined, we spend ~2% of the total IO time checking. Move the fast path inline. Signed-off-by: Jens Axboe <axboe@kernel.dk> --- block/blk-cgroup.c | 1 + block/blk-core.c | 1 + block/blk-merge.c | 1 + block/blk-sysfs.c | 1 + block/blk-throttle.c | 161 +------------------------------------- block/blk-throttle.h | 182 +++++++++++++++++++++++++++++++++++++++++++ block/blk.h | 16 ---- 7 files changed, 189 insertions(+), 174 deletions(-) create mode 100644 block/blk-throttle.h