diff options
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-throttle.c | 49 |
1 files changed, 42 insertions, 7 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 7477f332c8dc..27f006bb363b 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -124,6 +124,9 @@ struct throtl_grp { unsigned int flags; + /* are there any throtl rules between this group and td? */ + bool has_rules[2]; + /* bytes per second rate limits */ uint64_t bps[2]; @@ -422,6 +425,30 @@ static void throtl_pd_init(struct blkcg_gq *blkg) spin_unlock_irqrestore(&tg_stats_alloc_lock, flags); } +/* + * Set has_rules[] if @tg or any of its parents have limits configured. + * This doesn't require walking up to the top of the hierarchy as the + * parent's has_rules[] is guaranteed to be correct. + */ +static void tg_update_has_rules(struct throtl_grp *tg) +{ + struct throtl_grp *parent_tg = sq_to_tg(tg->service_queue.parent_sq); + int rw; + + for (rw = READ; rw <= WRITE; rw++) + tg->has_rules[rw] = (parent_tg && parent_tg->has_rules[rw]) || + (tg->bps[rw] != -1 || tg->iops[rw] != -1); +} + +static void throtl_pd_online(struct blkcg_gq *blkg) +{ + /* + * We don't want new groups to escape the limits of its ancestors. + * Update has_rules[] after a new group is brought online. + */ + tg_update_has_rules(blkg_to_tg(blkg)); +} + static void throtl_pd_exit(struct blkcg_gq *blkg) { struct throtl_grp *tg = blkg_to_tg(blkg); @@ -843,12 +870,6 @@ static bool tg_with_in_bps_limit(struct throtl_grp *tg, struct bio *bio, return 0; } -static bool tg_no_rule_group(struct throtl_grp *tg, bool rw) { - if (tg->bps[rw] == -1 && tg->iops[rw] == -1) - return 1; - return 0; -} - /* * Returns whether one can dispatch a bio or not. Also returns approx number * of jiffies to wait before this bio is with-in IO rate and can be dispatched @@ -1307,6 +1328,8 @@ static int tg_set_conf(struct cgroup *cgrp, struct cftype *cft, const char *buf, struct blkg_conf_ctx ctx; struct throtl_grp *tg; struct throtl_service_queue *sq; + struct blkcg_gq *blkg; + struct cgroup *pos_cgrp; int ret; ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx); @@ -1330,6 +1353,17 @@ static int tg_set_conf(struct cgroup *cgrp, struct cftype *cft, const char *buf, tg->iops[READ], tg->iops[WRITE]); /* + * Update has_rules[] flags for the updated tg's subtree. A tg is + * considered to have rules if either the tg itself or any of its + * ancestors has rules. This identifies groups without any + * restrictions in the whole hierarchy and allows them to bypass + * blk-throttle. + */ + tg_update_has_rules(tg); + blkg_for_each_descendant_pre(blkg, pos_cgrp, ctx.blkg) + tg_update_has_rules(blkg_to_tg(blkg)); + + /* * We're already holding queue_lock and know @tg is valid. Let's * apply the new config directly. * @@ -1415,6 +1449,7 @@ static struct blkcg_policy blkcg_policy_throtl = { .cftypes = throtl_files, .pd_init_fn = throtl_pd_init, + .pd_online_fn = throtl_pd_online, .pd_exit_fn = throtl_pd_exit, .pd_reset_stats_fn = throtl_pd_reset_stats, }; @@ -1442,7 +1477,7 @@ bool blk_throtl_bio(struct request_queue *q, struct bio *bio) blkcg = bio_blkcg(bio); tg = throtl_lookup_tg(td, blkcg); if (tg) { - if (tg_no_rule_group(tg, rw)) { + if (!tg->has_rules[rw]) { throtl_update_dispatch_stats(tg_to_blkg(tg), bio->bi_size, bio->bi_rw); goto out_unlock_rcu; |