From edd75ffd92a5b7f6244431e8ff6c32b846f9ba86 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Thu, 19 Apr 2007 12:03:34 +0200 Subject: [PATCH] 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 --- block/cfq-iosched.c | 87 +++++++++++++++++---------------------------- 1 file changed, 32 insertions(+), 55 deletions(-) diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 4a0397022f5..a8437042e28 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -45,9 +45,6 @@ static int cfq_slice_idle = HZ / 125; */ #define CFQ_QHASH_SHIFT 6 #define CFQ_QHASH_ENTRIES (1 << CFQ_QHASH_SHIFT) -#define list_entry_qhash(entry) hlist_entry((entry), struct cfq_queue, cfq_hash) - -#define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list) #define RQ_CIC(rq) ((struct cfq_io_context*)(rq)->elevator_private) #define RQ_CFQQ(rq) ((rq)->elevator_private2) @@ -91,7 +88,6 @@ struct cfq_data { * rr list of queues with requests and the count of them */ struct cfq_rb_root service_tree; - struct list_head cur_rr; unsigned int busy_queues; /* @@ -146,8 +142,6 @@ struct cfq_queue { struct hlist_node cfq_hash; /* hash key */ unsigned int key; - /* member of the rr/busy/cur/idle cfqd list */ - struct list_head cfq_list; /* service_tree member */ struct rb_node rb_node; /* service_tree key */ @@ -452,16 +446,19 @@ static unsigned long cfq_slice_offset(struct cfq_data *cfqd, * we will service the queues. */ static void cfq_service_tree_add(struct cfq_data *cfqd, - struct cfq_queue *cfqq) + struct cfq_queue *cfqq, int add_front) { struct rb_node **p = &cfqd->service_tree.rb.rb_node; struct rb_node *parent = NULL; unsigned long rb_key; int left; - rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies; - rb_key += cfqq->slice_resid; - cfqq->slice_resid = 0; + if (!add_front) { + rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies; + rb_key += cfqq->slice_resid; + cfqq->slice_resid = 0; + } else + rb_key = 0; if (!RB_EMPTY_NODE(&cfqq->rb_node)) { /* @@ -516,13 +513,13 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, /* * Update cfqq's position in the service tree. */ -static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted) +static void cfq_resort_rr_list(struct cfq_data *cfqd, struct cfq_queue *cfqq) { /* * Resorting requires the cfqq to be on the RR list already. */ if (cfq_cfqq_on_rr(cfqq)) - cfq_service_tree_add(cfqq->cfqd, cfqq); + cfq_service_tree_add(cfqd, cfqq, 0); } /* @@ -536,7 +533,7 @@ cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) cfq_mark_cfqq_on_rr(cfqq); cfqd->busy_queues++; - cfq_resort_rr_list(cfqq, 0); + cfq_resort_rr_list(cfqd, cfqq); } /* @@ -548,7 +545,6 @@ cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq) { BUG_ON(!cfq_cfqq_on_rr(cfqq)); cfq_clear_cfqq_on_rr(cfqq); - list_del_init(&cfqq->cfq_list); if (!RB_EMPTY_NODE(&cfqq->rb_node)) cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree); @@ -771,7 +767,7 @@ __cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq, if (timed_out && !cfq_cfqq_slice_new(cfqq)) cfqq->slice_resid = cfqq->slice_end - jiffies; - cfq_resort_rr_list(cfqq, preempted); + cfq_resort_rr_list(cfqd, cfqq); if (cfqq == cfqd->active_queue) cfqd->active_queue = NULL; @@ -799,31 +795,28 @@ static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted, */ static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) { - struct cfq_queue *cfqq = NULL; + struct cfq_queue *cfqq; + struct rb_node *n; - if (!list_empty(&cfqd->cur_rr)) { - /* - * if current list is non-empty, grab first entry. - */ - cfqq = list_entry_cfqq(cfqd->cur_rr.next); - } else if (!RB_EMPTY_ROOT(&cfqd->service_tree.rb)) { - struct rb_node *n = cfq_rb_first(&cfqd->service_tree); + if (RB_EMPTY_ROOT(&cfqd->service_tree.rb)) + return NULL; - cfqq = rb_entry(n, struct cfq_queue, rb_node); - if (cfq_class_idle(cfqq)) { - unsigned long end; + n = cfq_rb_first(&cfqd->service_tree); + cfqq = rb_entry(n, struct cfq_queue, rb_node); - /* - * if we have idle queues and no rt or be queues had - * pending requests, either allow immediate service if - * the grace period has passed or arm the idle grace - * timer - */ - end = cfqd->last_end_request + CFQ_IDLE_GRACE; - if (time_before(jiffies, end)) { - mod_timer(&cfqd->idle_class_timer, end); - cfqq = NULL; - } + if (cfq_class_idle(cfqq)) { + unsigned long end; + + /* + * if we have idle queues and no rt or be queues had + * pending requests, either allow immediate service if + * the grace period has passed or arm the idle grace + * timer + */ + end = cfqd->last_end_request + CFQ_IDLE_GRACE; + if (time_before(jiffies, end)) { + mod_timer(&cfqd->idle_class_timer, end); + cfqq = NULL; } } @@ -1075,18 +1068,6 @@ static inline int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq) return dispatched; } -static int cfq_forced_dispatch_cfqqs(struct list_head *list) -{ - struct cfq_queue *cfqq, *next; - int dispatched; - - dispatched = 0; - list_for_each_entry_safe(cfqq, next, list, cfq_list) - dispatched += __cfq_forced_dispatch_cfqq(cfqq); - - return dispatched; -} - /* * Drain our current requests. Used for barriers and when switching * io schedulers on-the-fly. @@ -1102,8 +1083,6 @@ static int cfq_forced_dispatch(struct cfq_data *cfqd) dispatched += __cfq_forced_dispatch_cfqq(cfqq); } - dispatched += cfq_forced_dispatch_cfqqs(&cfqd->cur_rr); - cfq_slice_expired(cfqd, 0, 0); BUG_ON(cfqd->busy_queues); @@ -1433,7 +1412,6 @@ retry: memset(cfqq, 0, sizeof(*cfqq)); INIT_HLIST_NODE(&cfqq->cfq_hash); - INIT_LIST_HEAD(&cfqq->cfq_list); RB_CLEAR_NODE(&cfqq->rb_node); INIT_LIST_HEAD(&cfqq->fifo); @@ -1712,8 +1690,8 @@ static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq) * so we know that it will be selected next. */ BUG_ON(!cfq_cfqq_on_rr(cfqq)); - list_del_init(&cfqq->cfq_list); - list_add(&cfqq->cfq_list, &cfqd->cur_rr); + + cfq_service_tree_add(cfqd, cfqq, 1); cfqq->slice_end = 0; cfq_mark_cfqq_slice_new(cfqq); @@ -2077,7 +2055,6 @@ static void *cfq_init_queue(request_queue_t *q) memset(cfqd, 0, sizeof(*cfqd)); cfqd->service_tree = CFQ_RB_ROOT; - INIT_LIST_HEAD(&cfqd->cur_rr); INIT_LIST_HEAD(&cfqd->cic_list); cfqd->cfq_hash = kmalloc_node(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL, q->node); -- 2.41.1