If a cgroup is inactive for some time, it should be excluded from bandwidth calculation.
Signed-off-by: Shaohua Li <[email protected]> --- block/blk-throttle.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 67 insertions(+), 4 deletions(-) diff --git a/block/blk-throttle.c b/block/blk-throttle.c index b3f847d..5c11270 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -15,6 +15,9 @@ #define MAX_WEIGHT (1000) #define WEIGHT_RATIO_SHIFT (12) #define WEIGHT_RATIO (1 << WEIGHT_RATIO_SHIFT) +/* must less than the interval we update bandwidth */ +#define CGCHECK_TIME (msecs_to_jiffies(20)) + /* Max dispatch from a group in 1 round */ static int throtl_grp_quantum = 8; @@ -81,6 +84,9 @@ struct throtl_service_queue { unsigned int weight; unsigned int children_weight; unsigned int ratio; + + unsigned long active_timestamp; + bool active; }; enum tg_state_flags { @@ -162,6 +168,7 @@ struct throtl_data bool bw_based; bool weight_based; + unsigned long last_check_timestamp; }; static void throtl_pending_timer_fn(unsigned long arg); @@ -390,7 +397,6 @@ static void throtl_pd_init(struct blkg_policy_data *pd) sq->parent_sq = &td->service_queue; if (cgroup_subsys_on_dfl(io_cgrp_subsys) && blkg->parent) sq->parent_sq = &blkg_to_tg(blkg->parent)->service_queue; - sq->parent_sq->children_weight += sq->weight; tg->td = td; } @@ -424,7 +430,7 @@ static void throtl_pd_free(struct blkg_policy_data *pd) struct throtl_grp *tg = pd_to_tg(pd); struct throtl_service_queue *sq = &tg->service_queue; - if (sq->parent_sq) + if (sq->active && sq->parent_sq) sq->parent_sq->children_weight -= sq->weight; del_timer_sync(&tg->service_queue.pending_timer); @@ -930,7 +936,7 @@ static void tg_update_bps(struct throtl_grp *tg) sq = &tg->service_queue; parent_sq = sq->parent_sq; - if (!tg->td->weight_based || !parent_sq) + if (!tg->td->weight_based || !parent_sq || !sq->active) return; sq->ratio = max_t(unsigned int, parent_sq->ratio * sq->weight / parent_sq->children_weight, @@ -965,6 +971,26 @@ static void tg_update_ratio(struct throtl_grp *tg) } } +static void tg_update_active_time(struct throtl_grp *tg) +{ + struct throtl_service_queue *sq = &tg->service_queue; + bool update_ratio = false; + unsigned long now = jiffies; + + while (sq->parent_sq) { + sq->active_timestamp = now; + if (!sq->active) { + sq->parent_sq->children_weight += sq->weight; + sq->active = true; + update_ratio = true; + } + sq = sq->parent_sq; + }; + + if (update_ratio) + tg_update_ratio(tg); +} + static void tg_dispatch_one_bio(struct throtl_grp *tg, bool rw) { struct throtl_service_queue *sq = &tg->service_queue; @@ -984,6 +1010,8 @@ static void tg_dispatch_one_bio(struct throtl_grp *tg, bool rw) throtl_charge_bio(tg, bio); + tg_update_active_time(tg); + /* * If our parent is another tg, we just need to transfer @bio to * the parent using throtl_add_bio_tg(). If our parent is @@ -1319,7 +1347,7 @@ static ssize_t tg_set_weight(struct kernfs_open_file *of, old_weight = tg->service_queue.weight; tg->service_queue.weight = v; - if (tg->service_queue.parent_sq) { + if (tg->service_queue.active && tg->service_queue.parent_sq) { struct throtl_service_queue *psq = tg->service_queue.parent_sq; if (v > old_weight) psq->children_weight += v - old_weight; @@ -1524,6 +1552,39 @@ static struct blkcg_policy blkcg_policy_throtl = { .pd_free_fn = throtl_pd_free, }; +static void detect_inactive_cg(struct throtl_grp *tg) +{ + struct throtl_data *td = tg->td; + struct throtl_service_queue *sq = &tg->service_queue; + unsigned long now = jiffies; + struct cgroup_subsys_state *pos_css; + struct blkcg_gq *blkg; + bool update_ratio = false; + + tg_update_active_time(tg); + + if (time_before(now, td->last_check_timestamp)) + return; + td->last_check_timestamp = now + CGCHECK_TIME; + + blkg_for_each_descendant_post(blkg, pos_css, td->queue->root_blkg) { + tg = blkg_to_tg(blkg); + sq = &tg->service_queue; + if (sq->parent_sq && + time_before(sq->active_timestamp + CGCHECK_TIME, now) && + !(sq->nr_queued[READ] || sq->nr_queued[WRITE])) { + if (sq->active && sq->parent_sq) { + sq->active = false; + sq->parent_sq->children_weight -= sq->weight; + update_ratio = true; + } + } + } + + if (update_ratio) + tg_update_ratio(tg); +} + bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg, struct bio *bio) { @@ -1546,6 +1607,7 @@ bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg, sq = &tg->service_queue; + detect_inactive_cg(tg); tg_update_bps(tg); while (true) { /* throtl is FIFO - if bios are already queued, should queue */ @@ -1696,6 +1758,7 @@ int blk_throtl_init(struct request_queue *q) INIT_WORK(&td->dispatch_work, blk_throtl_dispatch_work_fn); throtl_service_queue_init(&td->service_queue); td->service_queue.ratio = WEIGHT_RATIO; + td->service_queue.active = true; q->td = td; td->queue = q; -- 2.4.6
