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author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-10-09 17:32:20 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-10-09 17:32:20 -0700 |
commit | 24532f768121b07b16178ffb40442ece43365cbd (patch) | |
tree | ca2eaf2c3ed031dd3aa977af95df77bfa2e18cc6 /block/blk-mq.c | |
parent | 12e3d3cdd975fe986cc5c35f60b1467a8ec20b80 (diff) | |
parent | 97a32864e6de5944c6356049f60569de01e9ba1f (diff) | |
download | linux-24532f768121b07b16178ffb40442ece43365cbd.tar.gz linux-24532f768121b07b16178ffb40442ece43365cbd.tar.bz2 linux-24532f768121b07b16178ffb40442ece43365cbd.zip |
Merge branch 'for-4.9/block-smp' of git://git.kernel.dk/linux-block
Pull blk-mq CPU hotplug update from Jens Axboe:
"This is the conversion of blk-mq to the new hotplug state machine"
* 'for-4.9/block-smp' of git://git.kernel.dk/linux-block:
blk-mq: fixup "Convert to new hotplug state machine"
blk-mq: Convert to new hotplug state machine
blk-mq/cpu-notif: Convert to new hotplug state machine
Diffstat (limited to 'block/blk-mq.c')
-rw-r--r-- | block/blk-mq.c | 123 |
1 files changed, 56 insertions, 67 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index b65f572a4faf..ddc2eed64771 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1563,11 +1563,13 @@ fail: * software queue to the hw queue dispatch list, and ensure that it * gets run. */ -static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx *hctx, int cpu) +static int blk_mq_hctx_notify_dead(unsigned int cpu, struct hlist_node *node) { + struct blk_mq_hw_ctx *hctx; struct blk_mq_ctx *ctx; LIST_HEAD(tmp); + hctx = hlist_entry_safe(node, struct blk_mq_hw_ctx, cpuhp_dead); ctx = __blk_mq_get_ctx(hctx->queue, cpu); spin_lock(&ctx->lock); @@ -1578,30 +1580,20 @@ static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx *hctx, int cpu) spin_unlock(&ctx->lock); if (list_empty(&tmp)) - return NOTIFY_OK; + return 0; spin_lock(&hctx->lock); list_splice_tail_init(&tmp, &hctx->dispatch); spin_unlock(&hctx->lock); blk_mq_run_hw_queue(hctx, true); - return NOTIFY_OK; + return 0; } -static int blk_mq_hctx_notify(void *data, unsigned long action, - unsigned int cpu) +static void blk_mq_remove_cpuhp(struct blk_mq_hw_ctx *hctx) { - struct blk_mq_hw_ctx *hctx = data; - - if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) - return blk_mq_hctx_cpu_offline(hctx, cpu); - - /* - * In case of CPU online, tags may be reallocated - * in blk_mq_map_swqueue() after mapping is updated. - */ - - return NOTIFY_OK; + cpuhp_state_remove_instance_nocalls(CPUHP_BLK_MQ_DEAD, + &hctx->cpuhp_dead); } /* hctx->ctxs will be freed in queue's release handler */ @@ -1621,7 +1613,7 @@ static void blk_mq_exit_hctx(struct request_queue *q, if (set->ops->exit_hctx) set->ops->exit_hctx(hctx, hctx_idx); - blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier); + blk_mq_remove_cpuhp(hctx); blk_free_flush_queue(hctx->fq); sbitmap_free(&hctx->ctx_map); } @@ -1668,9 +1660,7 @@ static int blk_mq_init_hctx(struct request_queue *q, hctx->queue_num = hctx_idx; hctx->flags = set->flags & ~BLK_MQ_F_TAG_SHARED; - blk_mq_init_cpu_notifier(&hctx->cpu_notifier, - blk_mq_hctx_notify, hctx); - blk_mq_register_cpu_notifier(&hctx->cpu_notifier); + cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD, &hctx->cpuhp_dead); hctx->tags = set->tags[hctx_idx]; @@ -1715,8 +1705,7 @@ static int blk_mq_init_hctx(struct request_queue *q, free_ctxs: kfree(hctx->ctxs); unregister_cpu_notifier: - blk_mq_unregister_cpu_notifier(&hctx->cpu_notifier); - + blk_mq_remove_cpuhp(hctx); return -1; } @@ -2089,50 +2078,18 @@ static void blk_mq_queue_reinit(struct request_queue *q, blk_mq_sysfs_register(q); } -static int blk_mq_queue_reinit_notify(struct notifier_block *nb, - unsigned long action, void *hcpu) +/* + * New online cpumask which is going to be set in this hotplug event. + * Declare this cpumasks as global as cpu-hotplug operation is invoked + * one-by-one and dynamically allocating this could result in a failure. + */ +static struct cpumask cpuhp_online_new; + +static void blk_mq_queue_reinit_work(void) { struct request_queue *q; - int cpu = (unsigned long)hcpu; - /* - * New online cpumask which is going to be set in this hotplug event. - * Declare this cpumasks as global as cpu-hotplug operation is invoked - * one-by-one and dynamically allocating this could result in a failure. - */ - static struct cpumask online_new; - - /* - * Before hotadded cpu starts handling requests, new mappings must - * be established. Otherwise, these requests in hw queue might - * never be dispatched. - * - * For example, there is a single hw queue (hctx) and two CPU queues - * (ctx0 for CPU0, and ctx1 for CPU1). - * - * Now CPU1 is just onlined and a request is inserted into - * ctx1->rq_list and set bit0 in pending bitmap as ctx1->index_hw is - * still zero. - * - * And then while running hw queue, flush_busy_ctxs() finds bit0 is - * set in pending bitmap and tries to retrieve requests in - * hctx->ctxs[0]->rq_list. But htx->ctxs[0] is a pointer to ctx0, - * so the request in ctx1->rq_list is ignored. - */ - switch (action & ~CPU_TASKS_FROZEN) { - case CPU_DEAD: - case CPU_UP_CANCELED: - cpumask_copy(&online_new, cpu_online_mask); - break; - case CPU_UP_PREPARE: - cpumask_copy(&online_new, cpu_online_mask); - cpumask_set_cpu(cpu, &online_new); - break; - default: - return NOTIFY_OK; - } mutex_lock(&all_q_mutex); - /* * We need to freeze and reinit all existing queues. Freezing * involves synchronous wait for an RCU grace period and doing it @@ -2153,13 +2110,43 @@ static int blk_mq_queue_reinit_notify(struct notifier_block *nb, } list_for_each_entry(q, &all_q_list, all_q_node) - blk_mq_queue_reinit(q, &online_new); + blk_mq_queue_reinit(q, &cpuhp_online_new); list_for_each_entry(q, &all_q_list, all_q_node) blk_mq_unfreeze_queue(q); mutex_unlock(&all_q_mutex); - return NOTIFY_OK; +} + +static int blk_mq_queue_reinit_dead(unsigned int cpu) +{ + cpumask_copy(&cpuhp_online_new, cpu_online_mask); + blk_mq_queue_reinit_work(); + return 0; +} + +/* + * Before hotadded cpu starts handling requests, new mappings must be + * established. Otherwise, these requests in hw queue might never be + * dispatched. + * + * For example, there is a single hw queue (hctx) and two CPU queues (ctx0 + * for CPU0, and ctx1 for CPU1). + * + * Now CPU1 is just onlined and a request is inserted into ctx1->rq_list + * and set bit0 in pending bitmap as ctx1->index_hw is still zero. + * + * And then while running hw queue, flush_busy_ctxs() finds bit0 is set in + * pending bitmap and tries to retrieve requests in hctx->ctxs[0]->rq_list. + * But htx->ctxs[0] is a pointer to ctx0, so the request in ctx1->rq_list + * is ignored. + */ +static int blk_mq_queue_reinit_prepare(unsigned int cpu) +{ + cpumask_copy(&cpuhp_online_new, cpu_online_mask); + cpumask_set_cpu(cpu, &cpuhp_online_new); + blk_mq_queue_reinit_work(); + return 0; } static int __blk_mq_alloc_rq_maps(struct blk_mq_tag_set *set) @@ -2378,10 +2365,12 @@ void blk_mq_enable_hotplug(void) static int __init blk_mq_init(void) { - blk_mq_cpu_init(); - - hotcpu_notifier(blk_mq_queue_reinit_notify, 0); + cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL, + blk_mq_hctx_notify_dead); + cpuhp_setup_state_nocalls(CPUHP_BLK_MQ_PREPARE, "block/mq:prepare", + blk_mq_queue_reinit_prepare, + blk_mq_queue_reinit_dead); return 0; } subsys_initcall(blk_mq_init); |