mirror of https://gitee.com/openkylin/linux.git
cfq-iosched: get rid of ->cur_rr and ->cfq_list
It's only used for preemption now that the IDLE and RT queues also use the rbtree. If we pass an 'add_front' variable to cfq_service_tree_add(), we can set ->rb_key to 0 to force insertion at the front of the tree. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Jens Axboe
Jens Axboe
parent
67e6b49e39
commit
edd75ffd92
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@ -45,9 +45,6 @@ static int cfq_slice_idle = HZ / 125;
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*/
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#define CFQ_QHASH_SHIFT 6
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#define CFQ_QHASH_ENTRIES (1 << CFQ_QHASH_SHIFT)
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#define list_entry_qhash(entry) hlist_entry((entry), struct cfq_queue, cfq_hash)
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#define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list)
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#define RQ_CIC(rq) ((struct cfq_io_context*)(rq)->elevator_private)
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#define RQ_CFQQ(rq) ((rq)->elevator_private2)
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@ -91,7 +88,6 @@ struct cfq_data {
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* rr list of queues with requests and the count of them
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*/
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struct cfq_rb_root service_tree;
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struct list_head cur_rr;
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unsigned int busy_queues;
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/*
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@ -146,8 +142,6 @@ struct cfq_queue {
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struct hlist_node cfq_hash;
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/* hash key */
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unsigned int key;
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/* member of the rr/busy/cur/idle cfqd list */
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struct list_head cfq_list;
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/* service_tree member */
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struct rb_node rb_node;
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/* service_tree key */
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@ -452,16 +446,19 @@ static unsigned long cfq_slice_offset(struct cfq_data *cfqd,
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* we will service the queues.
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*/
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static void cfq_service_tree_add(struct cfq_data *cfqd,
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struct cfq_queue *cfqq)
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struct cfq_queue *cfqq, int add_front)
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{
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struct rb_node **p = &cfqd->service_tree.rb.rb_node;
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struct rb_node *parent = NULL;
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unsigned long rb_key;
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int left;
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rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies;
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rb_key += cfqq->slice_resid;
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cfqq->slice_resid = 0;
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if (!add_front) {
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rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies;
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rb_key += cfqq->slice_resid;
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cfqq->slice_resid = 0;
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} else
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rb_key = 0;
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if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
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/*
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@ -516,13 +513,13 @@ static void cfq_service_tree_add(struct cfq_data *cfqd,
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/*
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* Update cfqq's position in the service tree.
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*/
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static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
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static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq)
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{
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/*
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* Resorting requires the cfqq to be on the RR list already.
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*/
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if (cfq_cfqq_on_rr(cfqq))
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cfq_service_tree_add(cfqq->cfqd, cfqq);
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cfq_service_tree_add(cfqd, cfqq, 0);
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}
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/*
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@ -536,7 +533,7 @@ cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
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cfq_mark_cfqq_on_rr(cfqq);
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cfqd->busy_queues++;
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cfq_resort_rr_list(cfqq, 0);
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cfq_resort_rr_list(cfqd, cfqq);
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}
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/*
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@ -548,7 +545,6 @@ cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
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{
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BUG_ON(!cfq_cfqq_on_rr(cfqq));
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cfq_clear_cfqq_on_rr(cfqq);
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list_del_init(&cfqq->cfq_list);
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if (!RB_EMPTY_NODE(&cfqq->rb_node))
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cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree);
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@ -771,7 +767,7 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
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if (timed_out && !cfq_cfqq_slice_new(cfqq))
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cfqq->slice_resid = cfqq->slice_end - jiffies;
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cfq_resort_rr_list(cfqq, preempted);
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cfq_resort_rr_list(cfqd, cfqq);
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if (cfqq == cfqd->active_queue)
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cfqd->active_queue = NULL;
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@ -799,31 +795,28 @@ static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted,
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*/
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static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
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{
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struct cfq_queue *cfqq = NULL;
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struct cfq_queue *cfqq;
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struct rb_node *n;
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if (RB_EMPTY_ROOT(&cfqd->service_tree.rb))
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return NULL;
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n = cfq_rb_first(&cfqd->service_tree);
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cfqq = rb_entry(n, struct cfq_queue, rb_node);
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if (cfq_class_idle(cfqq)) {
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unsigned long end;
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if (!list_empty(&cfqd->cur_rr)) {
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/*
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* if current list is non-empty, grab first entry.
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* if we have idle queues and no rt or be queues had
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* pending requests, either allow immediate service if
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* the grace period has passed or arm the idle grace
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* timer
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*/
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cfqq = list_entry_cfqq(cfqd->cur_rr.next);
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} else if (!RB_EMPTY_ROOT(&cfqd->service_tree.rb)) {
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struct rb_node *n = cfq_rb_first(&cfqd->service_tree);
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cfqq = rb_entry(n, struct cfq_queue, rb_node);
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if (cfq_class_idle(cfqq)) {
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unsigned long end;
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/*
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* if we have idle queues and no rt or be queues had
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* pending requests, either allow immediate service if
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* the grace period has passed or arm the idle grace
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* timer
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*/
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end = cfqd->last_end_request + CFQ_IDLE_GRACE;
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if (time_before(jiffies, end)) {
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mod_timer(&cfqd->idle_class_timer, end);
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cfqq = NULL;
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}
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end = cfqd->last_end_request + CFQ_IDLE_GRACE;
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if (time_before(jiffies, end)) {
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mod_timer(&cfqd->idle_class_timer, end);
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cfqq = NULL;
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}
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}
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@ -1075,18 +1068,6 @@ static inline int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq)
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return dispatched;
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}
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static int cfq_forced_dispatch_cfqqs(struct list_head *list)
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{
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struct cfq_queue *cfqq, *next;
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int dispatched;
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dispatched = 0;
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list_for_each_entry_safe(cfqq, next, list, cfq_list)
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dispatched += __cfq_forced_dispatch_cfqq(cfqq);
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return dispatched;
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}
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/*
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* Drain our current requests. Used for barriers and when switching
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* io schedulers on-the-fly.
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@ -1102,8 +1083,6 @@ static int cfq_forced_dispatch(struct cfq_data *cfqd)
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dispatched += __cfq_forced_dispatch_cfqq(cfqq);
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}
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dispatched += cfq_forced_dispatch_cfqqs(&cfqd->cur_rr);
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cfq_slice_expired(cfqd, 0, 0);
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BUG_ON(cfqd->busy_queues);
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@ -1433,7 +1412,6 @@ cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk,
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memset(cfqq, 0, sizeof(*cfqq));
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INIT_HLIST_NODE(&cfqq->cfq_hash);
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INIT_LIST_HEAD(&cfqq->cfq_list);
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RB_CLEAR_NODE(&cfqq->rb_node);
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INIT_LIST_HEAD(&cfqq->fifo);
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@ -1712,8 +1690,8 @@ static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
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* so we know that it will be selected next.
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*/
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BUG_ON(!cfq_cfqq_on_rr(cfqq));
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list_del_init(&cfqq->cfq_list);
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list_add(&cfqq->cfq_list, &cfqd->cur_rr);
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cfq_service_tree_add(cfqd, cfqq, 1);
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cfqq->slice_end = 0;
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cfq_mark_cfqq_slice_new(cfqq);
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@ -2077,7 +2055,6 @@ static void *cfq_init_queue(request_queue_t *q)
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memset(cfqd, 0, sizeof(*cfqd));
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cfqd->service_tree = CFQ_RB_ROOT;
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INIT_LIST_HEAD(&cfqd->cur_rr);
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INIT_LIST_HEAD(&cfqd->cic_list);
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cfqd->cfq_hash = kmalloc_node(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL, q->node);
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