From 8692d2db8e01f1a5718f9b67c219b823a64b2088 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Tue, 1 Sep 2020 14:52:45 -0400 Subject: blk-iocost: replace iocg->has_surplus with ->surplus_list Instead of marking iocgs with surplus with a flag and filtering for them while walking all active iocgs, build a surpluses list. This doesn't make much difference now but will help implementing improved donation logic which will iterate iocgs with surplus multiple times. Signed-off-by: Tejun Heo Signed-off-by: Jens Axboe --- block/blk-iocost.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) (limited to 'block/blk-iocost.c') diff --git a/block/blk-iocost.c b/block/blk-iocost.c index 2496674bbbf4..c1cd66cfa2a8 100644 --- a/block/blk-iocost.c +++ b/block/blk-iocost.c @@ -494,9 +494,9 @@ struct ioc_gq { int hweight_gen; u32 hweight_active; u32 hweight_inuse; - bool has_surplus; struct list_head walk_list; + struct list_head surplus_list; struct wait_queue_head waitq; struct hrtimer waitq_timer; @@ -1507,6 +1507,7 @@ static void ioc_timer_fn(struct timer_list *timer) struct ioc *ioc = container_of(timer, struct ioc, timer); struct ioc_gq *iocg, *tiocg; struct ioc_now now; + LIST_HEAD(surpluses); int nr_surpluses = 0, nr_shortages = 0, nr_lagging = 0; u32 ppm_rthr = MILLION - ioc->params.qos[QOS_RPPM]; u32 ppm_wthr = MILLION - ioc->params.qos[QOS_WPPM]; @@ -1630,8 +1631,7 @@ static void ioc_timer_fn(struct timer_list *timer) /* see whether there's surplus vtime */ vmin = now.vnow - ioc->margins.max; - iocg->has_surplus = false; - + WARN_ON_ONCE(!list_empty(&iocg->surplus_list)); if (!waitqueue_active(&iocg->waitq) && time_before64(vtime, vmin)) { u64 delta = vmin - vtime; @@ -1641,7 +1641,7 @@ static void ioc_timer_fn(struct timer_list *timer) atomic64_add(delta, &iocg->done_vtime); /* if usage is sufficiently low, maybe it can donate */ if (surplus_adjusted_hweight_inuse(usage, hw_inuse)) { - iocg->has_surplus = true; + list_add(&iocg->surplus_list, &surpluses); nr_surpluses++; } } else if (hw_inuse < hw_active) { @@ -1677,13 +1677,10 @@ static void ioc_timer_fn(struct timer_list *timer) goto skip_surplus_transfers; /* there are both shortages and surpluses, transfer surpluses */ - list_for_each_entry(iocg, &ioc->active_iocgs, active_list) { + list_for_each_entry(iocg, &surpluses, surplus_list) { u32 usage, hw_active, hw_inuse, new_hwi, new_inuse; int nr_valid = 0; - if (!iocg->has_surplus) - continue; - /* base the decision on max historical usage */ for (i = 0, usage = 0; i < NR_USAGE_SLOTS; i++) { if (iocg->usages[i]) { @@ -1711,6 +1708,10 @@ static void ioc_timer_fn(struct timer_list *timer) skip_surplus_transfers: commit_weights(ioc); + /* surplus list should be dissolved after use */ + list_for_each_entry_safe(iocg, tiocg, &surpluses, surplus_list) + list_del_init(&iocg->surplus_list); + /* * If q is getting clogged or we're missing too much, we're issuing * too much IO and should lower vtime rate. If we're not missing @@ -2284,6 +2285,7 @@ static void ioc_pd_init(struct blkg_policy_data *pd) atomic64_set(&iocg->active_period, atomic64_read(&ioc->cur_period)); INIT_LIST_HEAD(&iocg->active_list); INIT_LIST_HEAD(&iocg->walk_list); + INIT_LIST_HEAD(&iocg->surplus_list); iocg->hweight_active = WEIGHT_ONE; iocg->hweight_inuse = WEIGHT_ONE; @@ -2320,6 +2322,7 @@ static void ioc_pd_free(struct blkg_policy_data *pd) } WARN_ON_ONCE(!list_empty(&iocg->walk_list)); + WARN_ON_ONCE(!list_empty(&iocg->surplus_list)); spin_unlock_irqrestore(&ioc->lock, flags); -- cgit v1.2.3