diff options
| -rw-r--r-- | block/blk-throttle.c | 112 |
1 files changed, 25 insertions, 87 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c index f1dd691c5359..3c869768cfdd 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -144,9 +144,6 @@ struct throtl_grp { /* Per cpu stats pointer */ struct tg_stats_cpu __percpu *stats_cpu; - - /* List of tgs waiting for per cpu stats memory to be allocated */ - struct list_head stats_alloc_node; }; struct throtl_data @@ -168,13 +165,6 @@ struct throtl_data struct work_struct dispatch_work; }; -/* list and work item to allocate percpu group stats */ -static DEFINE_SPINLOCK(tg_stats_alloc_lock); -static LIST_HEAD(tg_stats_alloc_list); - -static void tg_stats_alloc_fn(struct work_struct *); -static DECLARE_DELAYED_WORK(tg_stats_alloc_work, tg_stats_alloc_fn); - static void throtl_pending_timer_fn(unsigned long arg); static inline struct throtl_grp *pd_to_tg(struct blkg_policy_data *pd) @@ -256,53 +246,6 @@ static struct throtl_data *sq_to_td(struct throtl_service_queue *sq) } \ } while (0) -static void tg_stats_init(struct tg_stats_cpu *tg_stats) -{ - blkg_rwstat_init(&tg_stats->service_bytes); - blkg_rwstat_init(&tg_stats->serviced); -} - -/* - * Worker for allocating per cpu stat for tgs. This is scheduled on the - * system_wq once there are some groups on the alloc_list waiting for - * allocation. - */ -static void tg_stats_alloc_fn(struct work_struct *work) -{ - static struct tg_stats_cpu *stats_cpu; /* this fn is non-reentrant */ - struct delayed_work *dwork = to_delayed_work(work); - bool empty = false; - -alloc_stats: - if (!stats_cpu) { - int cpu; - - stats_cpu = alloc_percpu(struct tg_stats_cpu); - if (!stats_cpu) { - /* allocation failed, try again after some time */ - schedule_delayed_work(dwork, msecs_to_jiffies(10)); - return; - } - for_each_possible_cpu(cpu) - tg_stats_init(per_cpu_ptr(stats_cpu, cpu)); - } - - spin_lock_irq(&tg_stats_alloc_lock); - - if (!list_empty(&tg_stats_alloc_list)) { - struct throtl_grp *tg = list_first_entry(&tg_stats_alloc_list, - struct throtl_grp, - stats_alloc_node); - swap(tg->stats_cpu, stats_cpu); - list_del_init(&tg->stats_alloc_node); - } - - empty = list_empty(&tg_stats_alloc_list); - spin_unlock_irq(&tg_stats_alloc_lock); - if (!empty) - goto alloc_stats; -} - static void throtl_qnode_init(struct throtl_qnode *qn, struct throtl_grp *tg) { INIT_LIST_HEAD(&qn->node); @@ -405,7 +348,27 @@ static void throtl_service_queue_exit(struct throtl_service_queue *sq) static struct blkg_policy_data *throtl_pd_alloc(gfp_t gfp, int node) { - return kzalloc_node(sizeof(struct throtl_grp), gfp, node); + struct throtl_grp *tg; + int cpu; + + tg = kzalloc_node(sizeof(*tg), gfp, node); + if (!tg) + return NULL; + + tg->stats_cpu = alloc_percpu_gfp(struct tg_stats_cpu, gfp); + if (!tg->stats_cpu) { + kfree(tg); + return NULL; + } + + for_each_possible_cpu(cpu) { + struct tg_stats_cpu *stats_cpu = per_cpu_ptr(tg->stats_cpu, cpu); + + blkg_rwstat_init(&stats_cpu->service_bytes); + blkg_rwstat_init(&stats_cpu->serviced); + } + + return &tg->pd; } static void throtl_pd_init(struct blkcg_gq *blkg) @@ -413,7 +376,6 @@ static void throtl_pd_init(struct blkcg_gq *blkg) struct throtl_grp *tg = blkg_to_tg(blkg); struct throtl_data *td = blkg->q->td; struct throtl_service_queue *parent_sq; - unsigned long flags; int rw; /* @@ -448,16 +410,6 @@ static void throtl_pd_init(struct blkcg_gq *blkg) tg->bps[WRITE] = -1; tg->iops[READ] = -1; tg->iops[WRITE] = -1; - - /* - * Ugh... We need to perform per-cpu allocation for tg->stats_cpu - * but percpu allocator can't be called from IO path. Queue tg on - * tg_stats_alloc_list and allocate from work item. - */ - spin_lock_irqsave(&tg_stats_alloc_lock, flags); - list_add(&tg->stats_alloc_node, &tg_stats_alloc_list); - schedule_delayed_work(&tg_stats_alloc_work, 0); - spin_unlock_irqrestore(&tg_stats_alloc_lock, flags); } /* @@ -487,20 +439,16 @@ static void throtl_pd_online(struct blkcg_gq *blkg) static void throtl_pd_exit(struct blkcg_gq *blkg) { struct throtl_grp *tg = blkg_to_tg(blkg); - unsigned long flags; - - spin_lock_irqsave(&tg_stats_alloc_lock, flags); - list_del_init(&tg->stats_alloc_node); - spin_unlock_irqrestore(&tg_stats_alloc_lock, flags); - - free_percpu(tg->stats_cpu); throtl_service_queue_exit(&tg->service_queue); } static void throtl_pd_free(struct blkg_policy_data *pd) { - kfree(pd); + struct throtl_grp *tg = pd_to_tg(pd); + + free_percpu(tg->stats_cpu); + kfree(tg); } static void throtl_pd_reset_stats(struct blkcg_gq *blkg) @@ -508,9 +456,6 @@ static void throtl_pd_reset_stats(struct blkcg_gq *blkg) struct throtl_grp *tg = blkg_to_tg(blkg); int cpu; - if (tg->stats_cpu == NULL) - return; - for_each_possible_cpu(cpu) { struct tg_stats_cpu *sc = per_cpu_ptr(tg->stats_cpu, cpu); @@ -973,10 +918,6 @@ static void throtl_update_dispatch_stats(struct blkcg_gq *blkg, u64 bytes, struct tg_stats_cpu *stats_cpu; unsigned long flags; - /* If per cpu stats are not allocated yet, don't do any accounting. */ - if (tg->stats_cpu == NULL) - return; - /* * Disabling interrupts to provide mutual exclusion between two * writes on same cpu. It probably is not needed for 64bit. Not @@ -1302,9 +1243,6 @@ static u64 tg_prfill_cpu_rwstat(struct seq_file *sf, struct blkg_rwstat rwstat = { }, tmp; int i, cpu; - if (tg->stats_cpu == NULL) - return 0; - for_each_possible_cpu(cpu) { struct tg_stats_cpu *sc = per_cpu_ptr(tg->stats_cpu, cpu); |