#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/elevator.h>
+#include <linux/jiffies.h>
#include <linux/rbtree.h>
#include <linux/ioprio.h>
#include <linux/blktrace_api.h>
+#include "blk-cgroup.h"
/*
* tunables
#define CFQ_SLICE_SCALE (5)
#define CFQ_HW_QUEUE_MIN (5)
+#define CFQ_SERVICE_SHIFT 12
#define RQ_CIC(rq) \
((struct cfq_io_context *) (rq)->elevator_private)
#define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT)
#define sample_valid(samples) ((samples) > 80)
+#define rb_entry_cfqg(node) rb_entry((node), struct cfq_group, rb_node)
/*
* Most of our rbtree usage is for sorting with min extraction, so
struct rb_root rb;
struct rb_node *left;
unsigned count;
+ u64 min_vdisktime;
+ struct rb_node *active;
+ unsigned total_weight;
};
-#define CFQ_RB_ROOT (struct cfq_rb_root) { RB_ROOT, NULL, 0, }
+#define CFQ_RB_ROOT (struct cfq_rb_root) { RB_ROOT, NULL, 0, 0, }
/*
* Per process-grouping structure
/* fifo list of requests in sort_list */
struct list_head fifo;
+ /* time when queue got scheduled in to dispatch first request. */
+ unsigned long dispatch_start;
+ unsigned int allocated_slice;
+ /* time when first request from queue completed and slice started. */
+ unsigned long slice_start;
unsigned long slice_end;
long slice_resid;
unsigned int slice_dispatch;
struct cfq_rb_root *service_tree;
struct cfq_queue *new_cfqq;
+ struct cfq_group *cfqg;
+ struct cfq_group *orig_cfqg;
+ /* Sectors dispatched in current dispatch round */
+ unsigned long nr_sectors;
};
/*
* IDLE is handled separately, so it has negative index
*/
enum wl_prio_t {
- IDLE_WORKLOAD = -1,
BE_WORKLOAD = 0,
- RT_WORKLOAD = 1
+ RT_WORKLOAD = 1,
+ IDLE_WORKLOAD = 2,
};
/*
SYNC_WORKLOAD = 2
};
+/* This is per cgroup per device grouping structure */
+struct cfq_group {
+ /* group service_tree member */
+ struct rb_node rb_node;
-/*
- * Per block device queue structure
- */
-struct cfq_data {
- struct request_queue *queue;
+ /* group service_tree key */
+ u64 vdisktime;
+ unsigned int weight;
+ bool on_st;
+ /* number of cfqq currently on this group */
+ int nr_cfqq;
+
+ /* Per group busy queus average. Useful for workload slice calc. */
+ unsigned int busy_queues_avg[2];
/*
* rr lists of queues with requests, onle rr for each priority class.
* Counts are embedded in the cfq_rb_root
*/
struct cfq_rb_root service_trees[2][3];
struct cfq_rb_root service_tree_idle;
+
+ unsigned long saved_workload_slice;
+ enum wl_type_t saved_workload;
+ enum wl_prio_t saved_serving_prio;
+ struct blkio_group blkg;
+#ifdef CONFIG_CFQ_GROUP_IOSCHED
+ struct hlist_node cfqd_node;
+ atomic_t ref;
+#endif
+};
+
+/*
+ * Per block device queue structure
+ */
+struct cfq_data {
+ struct request_queue *queue;
+ /* Root service tree for cfq_groups */
+ struct cfq_rb_root grp_service_tree;
+ struct cfq_group root_group;
+
/*
* The priority currently being served
*/
enum wl_prio_t serving_prio;
enum wl_type_t serving_type;
unsigned long workload_expires;
+ struct cfq_group *serving_group;
+ bool noidle_tree_requires_idle;
/*
* Each priority tree is sorted by next_request position. These
struct rb_root prio_trees[CFQ_PRIO_LISTS];
unsigned int busy_queues;
- unsigned int busy_queues_avg[2];
int rq_in_driver[2];
int sync_flight;
*/
int rq_queued;
int hw_tag;
- int hw_tag_samples;
- int rq_in_driver_peak;
+ /*
+ * hw_tag can be
+ * -1 => indeterminate, (cfq will behave as if NCQ is present, to allow better detection)
+ * 1 => NCQ is present (hw_tag_est_depth is the estimated max depth)
+ * 0 => no NCQ
+ */
+ int hw_tag_est_depth;
+ unsigned int hw_tag_samples;
/*
* idle window management
unsigned int cfq_slice_async_rq;
unsigned int cfq_slice_idle;
unsigned int cfq_latency;
+ unsigned int cfq_group_isolation;
struct list_head cic_list;
*/
struct cfq_queue oom_cfqq;
- unsigned long last_end_sync_rq;
+ unsigned long last_delayed_sync;
+
+ /* List of cfq groups being managed on this device*/
+ struct hlist_head cfqg_list;
+ struct rcu_head rcu;
};
-static struct cfq_rb_root *service_tree_for(enum wl_prio_t prio,
- enum wl_type_t type,
- struct cfq_data *cfqd)
+static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd);
+
+static struct cfq_rb_root *service_tree_for(struct cfq_group *cfqg,
+ enum wl_prio_t prio,
+ enum wl_type_t type)
{
+ if (!cfqg)
+ return NULL;
+
if (prio == IDLE_WORKLOAD)
- return &cfqd->service_tree_idle;
+ return &cfqg->service_tree_idle;
- return &cfqd->service_trees[prio][type];
+ return &cfqg->service_trees[prio][type];
}
enum cfqq_state_flags {
CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */
CFQ_CFQQ_FLAG_sync, /* synchronous queue */
CFQ_CFQQ_FLAG_coop, /* cfqq is shared */
- CFQ_CFQQ_FLAG_coop_preempt, /* coop preempt */
+ CFQ_CFQQ_FLAG_deep, /* sync cfqq experienced large depth */
+ CFQ_CFQQ_FLAG_wait_busy, /* Waiting for next request */
};
#define CFQ_CFQQ_FNS(name) \
CFQ_CFQQ_FNS(slice_new);
CFQ_CFQQ_FNS(sync);
CFQ_CFQQ_FNS(coop);
-CFQ_CFQQ_FNS(coop_preempt);
+CFQ_CFQQ_FNS(deep);
+CFQ_CFQQ_FNS(wait_busy);
#undef CFQ_CFQQ_FNS
+#ifdef CONFIG_DEBUG_CFQ_IOSCHED
+#define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \
+ blk_add_trace_msg((cfqd)->queue, "cfq%d%c %s " fmt, (cfqq)->pid, \
+ cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \
+ blkg_path(&(cfqq)->cfqg->blkg), ##args);
+
+#define cfq_log_cfqg(cfqd, cfqg, fmt, args...) \
+ blk_add_trace_msg((cfqd)->queue, "%s " fmt, \
+ blkg_path(&(cfqg)->blkg), ##args); \
+
+#else
#define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \
blk_add_trace_msg((cfqd)->queue, "cfq%d " fmt, (cfqq)->pid, ##args)
+#define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do {} while (0);
+#endif
#define cfq_log(cfqd, fmt, args...) \
blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args)
+/* Traverses through cfq group service trees */
+#define for_each_cfqg_st(cfqg, i, j, st) \
+ for (i = 0; i <= IDLE_WORKLOAD; i++) \
+ for (j = 0, st = i < IDLE_WORKLOAD ? &cfqg->service_trees[i][j]\
+ : &cfqg->service_tree_idle; \
+ (i < IDLE_WORKLOAD && j <= SYNC_WORKLOAD) || \
+ (i == IDLE_WORKLOAD && j == 0); \
+ j++, st = i < IDLE_WORKLOAD ? \
+ &cfqg->service_trees[i][j]: NULL) \
+
+
static inline enum wl_prio_t cfqq_prio(struct cfq_queue *cfqq)
{
if (cfq_class_idle(cfqq))
return SYNC_WORKLOAD;
}
-static inline int cfq_busy_queues_wl(enum wl_prio_t wl, struct cfq_data *cfqd)
+static inline int cfq_group_busy_queues_wl(enum wl_prio_t wl,
+ struct cfq_data *cfqd,
+ struct cfq_group *cfqg)
{
if (wl == IDLE_WORKLOAD)
- return cfqd->service_tree_idle.count;
+ return cfqg->service_tree_idle.count;
- return cfqd->service_trees[wl][ASYNC_WORKLOAD].count
- + cfqd->service_trees[wl][SYNC_NOIDLE_WORKLOAD].count
- + cfqd->service_trees[wl][SYNC_WORKLOAD].count;
+ return cfqg->service_trees[wl][ASYNC_WORKLOAD].count
+ + cfqg->service_trees[wl][SYNC_NOIDLE_WORKLOAD].count
+ + cfqg->service_trees[wl][SYNC_WORKLOAD].count;
+}
+
+static inline int cfqg_busy_async_queues(struct cfq_data *cfqd,
+ struct cfq_group *cfqg)
+{
+ return cfqg->service_trees[RT_WORKLOAD][ASYNC_WORKLOAD].count
+ + cfqg->service_trees[BE_WORKLOAD][ASYNC_WORKLOAD].count;
}
static void cfq_dispatch_insert(struct request_queue *, struct request *);
{
struct cfq_data *cfqd = q->elevator->elevator_data;
- return !cfqd->busy_queues;
+ return !cfqd->rq_queued;
}
/*
return cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio);
}
+static inline u64 cfq_scale_slice(unsigned long delta, struct cfq_group *cfqg)
+{
+ u64 d = delta << CFQ_SERVICE_SHIFT;
+
+ d = d * BLKIO_WEIGHT_DEFAULT;
+ do_div(d, cfqg->weight);
+ return d;
+}
+
+static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime)
+{
+ s64 delta = (s64)(vdisktime - min_vdisktime);
+ if (delta > 0)
+ min_vdisktime = vdisktime;
+
+ return min_vdisktime;
+}
+
+static inline u64 min_vdisktime(u64 min_vdisktime, u64 vdisktime)
+{
+ s64 delta = (s64)(vdisktime - min_vdisktime);
+ if (delta < 0)
+ min_vdisktime = vdisktime;
+
+ return min_vdisktime;
+}
+
+static void update_min_vdisktime(struct cfq_rb_root *st)
+{
+ u64 vdisktime = st->min_vdisktime;
+ struct cfq_group *cfqg;
+
+ if (st->active) {
+ cfqg = rb_entry_cfqg(st->active);
+ vdisktime = cfqg->vdisktime;
+ }
+
+ if (st->left) {
+ cfqg = rb_entry_cfqg(st->left);
+ vdisktime = min_vdisktime(vdisktime, cfqg->vdisktime);
+ }
+
+ st->min_vdisktime = max_vdisktime(st->min_vdisktime, vdisktime);
+}
+
/*
* get averaged number of queues of RT/BE priority.
* average is updated, with a formula that gives more weight to higher numbers,
* to quickly follows sudden increases and decrease slowly
*/
-static inline unsigned cfq_get_avg_queues(struct cfq_data *cfqd, bool rt)
+static inline unsigned cfq_group_get_avg_queues(struct cfq_data *cfqd,
+ struct cfq_group *cfqg, bool rt)
{
unsigned min_q, max_q;
unsigned mult = cfq_hist_divisor - 1;
unsigned round = cfq_hist_divisor / 2;
- unsigned busy = cfq_busy_queues_wl(rt, cfqd);
+ unsigned busy = cfq_group_busy_queues_wl(rt, cfqd, cfqg);
- min_q = min(cfqd->busy_queues_avg[rt], busy);
- max_q = max(cfqd->busy_queues_avg[rt], busy);
- cfqd->busy_queues_avg[rt] = (mult * max_q + min_q + round) /
+ min_q = min(cfqg->busy_queues_avg[rt], busy);
+ max_q = max(cfqg->busy_queues_avg[rt], busy);
+ cfqg->busy_queues_avg[rt] = (mult * max_q + min_q + round) /
cfq_hist_divisor;
- return cfqd->busy_queues_avg[rt];
+ return cfqg->busy_queues_avg[rt];
+}
+
+static inline unsigned
+cfq_group_slice(struct cfq_data *cfqd, struct cfq_group *cfqg)
+{
+ struct cfq_rb_root *st = &cfqd->grp_service_tree;
+
+ return cfq_target_latency * cfqg->weight / st->total_weight;
}
static inline void
{
unsigned slice = cfq_prio_to_slice(cfqd, cfqq);
if (cfqd->cfq_latency) {
- /* interested queues (we consider only the ones with the same
- * priority class) */
- unsigned iq = cfq_get_avg_queues(cfqd, cfq_class_rt(cfqq));
+ /*
+ * interested queues (we consider only the ones with the same
+ * priority class in the cfq group)
+ */
+ unsigned iq = cfq_group_get_avg_queues(cfqd, cfqq->cfqg,
+ cfq_class_rt(cfqq));
unsigned sync_slice = cfqd->cfq_slice[1];
unsigned expect_latency = sync_slice * iq;
- if (expect_latency > cfq_target_latency) {
+ unsigned group_slice = cfq_group_slice(cfqd, cfqq->cfqg);
+
+ if (expect_latency > group_slice) {
unsigned base_low_slice = 2 * cfqd->cfq_slice_idle;
/* scale low_slice according to IO priority
* and sync vs async */
min(slice, base_low_slice * slice / sync_slice);
/* the adapted slice value is scaled to fit all iqs
* into the target latency */
- slice = max(slice * cfq_target_latency / expect_latency,
+ slice = max(slice * group_slice / expect_latency,
low_slice);
}
}
+ cfqq->slice_start = jiffies;
cfqq->slice_end = jiffies + slice;
+ cfqq->allocated_slice = slice;
cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies);
}
* behind the head is penalized and only allowed to a certain extent.
*/
static struct request *
-cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2)
+cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2, sector_t last)
{
- sector_t last, s1, s2, d1 = 0, d2 = 0;
+ sector_t s1, s2, d1 = 0, d2 = 0;
unsigned long back_max;
#define CFQ_RQ1_WRAP 0x01 /* request 1 wraps */
#define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */
s1 = blk_rq_pos(rq1);
s2 = blk_rq_pos(rq2);
- last = cfqd->last_position;
-
/*
* by definition, 1KiB is 2 sectors
*/
*/
static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root)
{
+ /* Service tree is empty */
+ if (!root->count)
+ return NULL;
+
if (!root->left)
root->left = rb_first(&root->rb);
return NULL;
}
+static struct cfq_group *cfq_rb_first_group(struct cfq_rb_root *root)
+{
+ if (!root->left)
+ root->left = rb_first(&root->rb);
+
+ if (root->left)
+ return rb_entry_cfqg(root->left);
+
+ return NULL;
+}
+
static void rb_erase_init(struct rb_node *n, struct rb_root *root)
{
rb_erase(n, root);
next = rb_entry_rq(rbnext);
}
- return cfq_choose_req(cfqd, next, prev);
+ return cfq_choose_req(cfqd, next, prev, blk_rq_pos(last));
}
static unsigned long cfq_slice_offset(struct cfq_data *cfqd,
/*
* just an approximation, should be ok.
*/
- return (cfqd->busy_queues - 1) * (cfq_prio_slice(cfqd, 1, 0) -
+ return (cfqq->cfqg->nr_cfqq - 1) * (cfq_prio_slice(cfqd, 1, 0) -
cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio));
}
+static inline s64
+cfqg_key(struct cfq_rb_root *st, struct cfq_group *cfqg)
+{
+ return cfqg->vdisktime - st->min_vdisktime;
+}
+
+static void
+__cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg)
+{
+ struct rb_node **node = &st->rb.rb_node;
+ struct rb_node *parent = NULL;
+ struct cfq_group *__cfqg;
+ s64 key = cfqg_key(st, cfqg);
+ int left = 1;
+
+ while (*node != NULL) {
+ parent = *node;
+ __cfqg = rb_entry_cfqg(parent);
+
+ if (key < cfqg_key(st, __cfqg))
+ node = &parent->rb_left;
+ else {
+ node = &parent->rb_right;
+ left = 0;
+ }
+ }
+
+ if (left)
+ st->left = &cfqg->rb_node;
+
+ rb_link_node(&cfqg->rb_node, parent, node);
+ rb_insert_color(&cfqg->rb_node, &st->rb);
+}
+
+static void
+cfq_group_service_tree_add(struct cfq_data *cfqd, struct cfq_group *cfqg)
+{
+ struct cfq_rb_root *st = &cfqd->grp_service_tree;
+ struct cfq_group *__cfqg;
+ struct rb_node *n;
+
+ cfqg->nr_cfqq++;
+ if (cfqg->on_st)
+ return;
+
+ /*
+ * Currently put the group at the end. Later implement something
+ * so that groups get lesser vtime based on their weights, so that
+ * if group does not loose all if it was not continously backlogged.
+ */
+ n = rb_last(&st->rb);
+ if (n) {
+ __cfqg = rb_entry_cfqg(n);
+ cfqg->vdisktime = __cfqg->vdisktime + CFQ_IDLE_DELAY;
+ } else
+ cfqg->vdisktime = st->min_vdisktime;
+
+ __cfq_group_service_tree_add(st, cfqg);
+ cfqg->on_st = true;
+ st->total_weight += cfqg->weight;
+}
+
+static void
+cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
+{
+ struct cfq_rb_root *st = &cfqd->grp_service_tree;
+
+ if (st->active == &cfqg->rb_node)
+ st->active = NULL;
+
+ BUG_ON(cfqg->nr_cfqq < 1);
+ cfqg->nr_cfqq--;
+
+ /* If there are other cfq queues under this group, don't delete it */
+ if (cfqg->nr_cfqq)
+ return;
+
+ cfq_log_cfqg(cfqd, cfqg, "del_from_rr group");
+ cfqg->on_st = false;
+ st->total_weight -= cfqg->weight;
+ if (!RB_EMPTY_NODE(&cfqg->rb_node))
+ cfq_rb_erase(&cfqg->rb_node, st);
+ cfqg->saved_workload_slice = 0;
+ blkiocg_update_blkio_group_dequeue_stats(&cfqg->blkg, 1);
+}
+
+static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq)
+{
+ unsigned int slice_used;
+
+ /*
+ * Queue got expired before even a single request completed or
+ * got expired immediately after first request completion.
+ */
+ if (!cfqq->slice_start || cfqq->slice_start == jiffies) {
+ /*
+ * Also charge the seek time incurred to the group, otherwise
+ * if there are mutiple queues in the group, each can dispatch
+ * a single request on seeky media and cause lots of seek time
+ * and group will never know it.
+ */
+ slice_used = max_t(unsigned, (jiffies - cfqq->dispatch_start),
+ 1);
+ } else {
+ slice_used = jiffies - cfqq->slice_start;
+ if (slice_used > cfqq->allocated_slice)
+ slice_used = cfqq->allocated_slice;
+ }
+
+ cfq_log_cfqq(cfqq->cfqd, cfqq, "sl_used=%u sect=%lu", slice_used,
+ cfqq->nr_sectors);
+ return slice_used;
+}
+
+static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg,
+ struct cfq_queue *cfqq)
+{
+ struct cfq_rb_root *st = &cfqd->grp_service_tree;
+ unsigned int used_sl, charge_sl;
+ int nr_sync = cfqg->nr_cfqq - cfqg_busy_async_queues(cfqd, cfqg)
+ - cfqg->service_tree_idle.count;
+
+ BUG_ON(nr_sync < 0);
+ used_sl = charge_sl = cfq_cfqq_slice_usage(cfqq);
+
+ if (!cfq_cfqq_sync(cfqq) && !nr_sync)
+ charge_sl = cfqq->allocated_slice;
+
+ /* Can't update vdisktime while group is on service tree */
+ cfq_rb_erase(&cfqg->rb_node, st);
+ cfqg->vdisktime += cfq_scale_slice(charge_sl, cfqg);
+ __cfq_group_service_tree_add(st, cfqg);
+
+ /* This group is being expired. Save the context */
+ if (time_after(cfqd->workload_expires, jiffies)) {
+ cfqg->saved_workload_slice = cfqd->workload_expires
+ - jiffies;
+ cfqg->saved_workload = cfqd->serving_type;
+ cfqg->saved_serving_prio = cfqd->serving_prio;
+ } else
+ cfqg->saved_workload_slice = 0;
+
+ cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime,
+ st->min_vdisktime);
+ blkiocg_update_blkio_group_stats(&cfqg->blkg, used_sl,
+ cfqq->nr_sectors);
+}
+
+#ifdef CONFIG_CFQ_GROUP_IOSCHED
+static inline struct cfq_group *cfqg_of_blkg(struct blkio_group *blkg)
+{
+ if (blkg)
+ return container_of(blkg, struct cfq_group, blkg);
+ return NULL;
+}
+
+void
+cfq_update_blkio_group_weight(struct blkio_group *blkg, unsigned int weight)
+{
+ cfqg_of_blkg(blkg)->weight = weight;
+}
+
+static struct cfq_group *
+cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create)
+{
+ struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);
+ struct cfq_group *cfqg = NULL;
+ void *key = cfqd;
+ int i, j;
+ struct cfq_rb_root *st;
+ struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info;
+ unsigned int major, minor;
+
+ /* Do we need to take this reference */
+ if (!blkiocg_css_tryget(blkcg))
+ return NULL;;
+
+ cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key));
+ if (cfqg || !create)
+ goto done;
+
+ cfqg = kzalloc_node(sizeof(*cfqg), GFP_ATOMIC, cfqd->queue->node);
+ if (!cfqg)
+ goto done;
+
+ cfqg->weight = blkcg->weight;
+ for_each_cfqg_st(cfqg, i, j, st)
+ *st = CFQ_RB_ROOT;
+ RB_CLEAR_NODE(&cfqg->rb_node);
+
+ /*
+ * Take the initial reference that will be released on destroy
+ * This can be thought of a joint reference by cgroup and
+ * elevator which will be dropped by either elevator exit
+ * or cgroup deletion path depending on who is exiting first.
+ */
+ atomic_set(&cfqg->ref, 1);
+
+ /* Add group onto cgroup list */
+ sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
+ blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd,
+ MKDEV(major, minor));
+
+ /* Add group on cfqd list */
+ hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list);
+
+done:
+ blkiocg_css_put(blkcg);
+ return cfqg;
+}
+
+/*
+ * Search for the cfq group current task belongs to. If create = 1, then also
+ * create the cfq group if it does not exist. request_queue lock must be held.
+ */
+static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create)
+{
+ struct cgroup *cgroup;
+ struct cfq_group *cfqg = NULL;
+
+ rcu_read_lock();
+ cgroup = task_cgroup(current, blkio_subsys_id);
+ cfqg = cfq_find_alloc_cfqg(cfqd, cgroup, create);
+ if (!cfqg && create)
+ cfqg = &cfqd->root_group;
+ rcu_read_unlock();
+ return cfqg;
+}
+
+static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg)
+{
+ /* Currently, all async queues are mapped to root group */
+ if (!cfq_cfqq_sync(cfqq))
+ cfqg = &cfqq->cfqd->root_group;
+
+ cfqq->cfqg = cfqg;
+ /* cfqq reference on cfqg */
+ atomic_inc(&cfqq->cfqg->ref);
+}
+
+static void cfq_put_cfqg(struct cfq_group *cfqg)
+{
+ struct cfq_rb_root *st;
+ int i, j;
+
+ BUG_ON(atomic_read(&cfqg->ref) <= 0);
+ if (!atomic_dec_and_test(&cfqg->ref))
+ return;
+ for_each_cfqg_st(cfqg, i, j, st)
+ BUG_ON(!RB_EMPTY_ROOT(&st->rb) || st->active != NULL);
+ kfree(cfqg);
+}
+
+static void cfq_destroy_cfqg(struct cfq_data *cfqd, struct cfq_group *cfqg)
+{
+ /* Something wrong if we are trying to remove same group twice */
+ BUG_ON(hlist_unhashed(&cfqg->cfqd_node));
+
+ hlist_del_init(&cfqg->cfqd_node);
+
+ /*
+ * Put the reference taken at the time of creation so that when all
+ * queues are gone, group can be destroyed.
+ */
+ cfq_put_cfqg(cfqg);
+}
+
+static void cfq_release_cfq_groups(struct cfq_data *cfqd)
+{
+ struct hlist_node *pos, *n;
+ struct cfq_group *cfqg;
+
+ hlist_for_each_entry_safe(cfqg, pos, n, &cfqd->cfqg_list, cfqd_node) {
+ /*
+ * If cgroup removal path got to blk_group first and removed
+ * it from cgroup list, then it will take care of destroying
+ * cfqg also.
+ */
+ if (!blkiocg_del_blkio_group(&cfqg->blkg))
+ cfq_destroy_cfqg(cfqd, cfqg);
+ }
+}
+
+/*
+ * Blk cgroup controller notification saying that blkio_group object is being
+ * delinked as associated cgroup object is going away. That also means that
+ * no new IO will come in this group. So get rid of this group as soon as
+ * any pending IO in the group is finished.
+ *
+ * This function is called under rcu_read_lock(). key is the rcu protected
+ * pointer. That means "key" is a valid cfq_data pointer as long as we are rcu
+ * read lock.
+ *
+ * "key" was fetched from blkio_group under blkio_cgroup->lock. That means
+ * it should not be NULL as even if elevator was exiting, cgroup deltion
+ * path got to it first.
+ */
+void cfq_unlink_blkio_group(void *key, struct blkio_group *blkg)
+{
+ unsigned long flags;
+ struct cfq_data *cfqd = key;
+
+ spin_lock_irqsave(cfqd->queue->queue_lock, flags);
+ cfq_destroy_cfqg(cfqd, cfqg_of_blkg(blkg));
+ spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
+}
+
+#else /* GROUP_IOSCHED */
+static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create)
+{
+ return &cfqd->root_group;
+}
+static inline void
+cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) {
+ cfqq->cfqg = cfqg;
+}
+
+static void cfq_release_cfq_groups(struct cfq_data *cfqd) {}
+static inline void cfq_put_cfqg(struct cfq_group *cfqg) {}
+
+#endif /* GROUP_IOSCHED */
+
/*
* The cfqd->service_trees holds all pending cfq_queue's that have
* requests waiting to be processed. It is sorted in the order that
unsigned long rb_key;
struct cfq_rb_root *service_tree;
int left;
-
- service_tree = service_tree_for(cfqq_prio(cfqq), cfqq_type(cfqq), cfqd);
+ int new_cfqq = 1;
+ int group_changed = 0;
+
+#ifdef CONFIG_CFQ_GROUP_IOSCHED
+ if (!cfqd->cfq_group_isolation
+ && cfqq_type(cfqq) == SYNC_NOIDLE_WORKLOAD
+ && cfqq->cfqg && cfqq->cfqg != &cfqd->root_group) {
+ /* Move this cfq to root group */
+ cfq_log_cfqq(cfqd, cfqq, "moving to root group");
+ if (!RB_EMPTY_NODE(&cfqq->rb_node))
+ cfq_group_service_tree_del(cfqd, cfqq->cfqg);
+ cfqq->orig_cfqg = cfqq->cfqg;
+ cfqq->cfqg = &cfqd->root_group;
+ atomic_inc(&cfqd->root_group.ref);
+ group_changed = 1;
+ } else if (!cfqd->cfq_group_isolation
+ && cfqq_type(cfqq) == SYNC_WORKLOAD && cfqq->orig_cfqg) {
+ /* cfqq is sequential now needs to go to its original group */
+ BUG_ON(cfqq->cfqg != &cfqd->root_group);
+ if (!RB_EMPTY_NODE(&cfqq->rb_node))
+ cfq_group_service_tree_del(cfqd, cfqq->cfqg);
+ cfq_put_cfqg(cfqq->cfqg);
+ cfqq->cfqg = cfqq->orig_cfqg;
+ cfqq->orig_cfqg = NULL;
+ group_changed = 1;
+ cfq_log_cfqq(cfqd, cfqq, "moved to origin group");
+ }
+#endif
+
+ service_tree = service_tree_for(cfqq->cfqg, cfqq_prio(cfqq),
+ cfqq_type(cfqq));
if (cfq_class_idle(cfqq)) {
rb_key = CFQ_IDLE_DELAY;
parent = rb_last(&service_tree->rb);
}
if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
+ new_cfqq = 0;
/*
* same position, nothing more to do
*/
rb_link_node(&cfqq->rb_node, parent, p);
rb_insert_color(&cfqq->rb_node, &service_tree->rb);
service_tree->count++;
+ if ((add_front || !new_cfqq) && !group_changed)
+ return;
+ cfq_group_service_tree_add(cfqd, cfqq->cfqg);
}
static struct cfq_queue *
cfqq->p_root = NULL;
}
+ cfq_group_service_tree_del(cfqd, cfqq->cfqg);
BUG_ON(!cfqd->busy_queues);
cfqd->busy_queues--;
}
static void cfq_del_rq_rb(struct request *rq)
{
struct cfq_queue *cfqq = RQ_CFQQ(rq);
- struct cfq_data *cfqd = cfqq->cfqd;
const int sync = rq_is_sync(rq);
BUG_ON(!cfqq->queued[sync]);
elv_rb_del(&cfqq->sort_list, rq);
- if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list))
- cfq_del_cfqq_rr(cfqd, cfqq);
+ if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list)) {
+ /*
+ * Queue will be deleted from service tree when we actually
+ * expire it later. Right now just remove it from prio tree
+ * as it is empty.
+ */
+ if (cfqq->p_root) {
+ rb_erase(&cfqq->p_node, cfqq->p_root);
+ cfqq->p_root = NULL;
+ }
+ }
}
static void cfq_add_rq_rb(struct request *rq)
* check if this request is a better next-serve candidate
*/
prev = cfqq->next_rq;
- cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq);
+ cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq, cfqd->last_position);
/*
* adjust priority tree position, if ->next_rq changes
cfq_merged_requests(struct request_queue *q, struct request *rq,
struct request *next)
{
+ struct cfq_queue *cfqq = RQ_CFQQ(rq);
/*
* reposition in fifo if next is older than rq
*/
rq_set_fifo_time(rq, rq_fifo_time(next));
}
+ if (cfqq->next_rq == next)
+ cfqq->next_rq = rq;
cfq_remove_request(next);
}
{
if (cfqq) {
cfq_log_cfqq(cfqd, cfqq, "set_active");
+ cfqq->slice_start = 0;
+ cfqq->dispatch_start = jiffies;
+ cfqq->allocated_slice = 0;
cfqq->slice_end = 0;
cfqq->slice_dispatch = 0;
+ cfqq->nr_sectors = 0;
cfq_clear_cfqq_wait_request(cfqq);
cfq_clear_cfqq_must_dispatch(cfqq);
del_timer(&cfqd->idle_slice_timer);
cfq_clear_cfqq_wait_request(cfqq);
+ cfq_clear_cfqq_wait_busy(cfqq);
/*
* store what was left of this slice, if the queue idled/timed out
cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid);
}
+ cfq_group_served(cfqd, cfqq->cfqg, cfqq);
+
+ if (cfq_cfqq_on_rr(cfqq) && RB_EMPTY_ROOT(&cfqq->sort_list))
+ cfq_del_cfqq_rr(cfqd, cfqq);
+
cfq_resort_rr_list(cfqd, cfqq);
if (cfqq == cfqd->active_queue)
cfqd->active_queue = NULL;
+ if (&cfqq->cfqg->rb_node == cfqd->grp_service_tree.active)
+ cfqd->grp_service_tree.active = NULL;
+
if (cfqd->active_cic) {
put_io_context(cfqd->active_cic->ioc);
cfqd->active_cic = NULL;
static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
{
struct cfq_rb_root *service_tree =
- service_tree_for(cfqd->serving_prio, cfqd->serving_type, cfqd);
+ service_tree_for(cfqd->serving_group, cfqd->serving_prio,
+ cfqd->serving_type);
+
+ if (!cfqd->rq_queued)
+ return NULL;
+ /* There is nothing to dispatch */
+ if (!service_tree)
+ return NULL;
if (RB_EMPTY_ROOT(&service_tree->rb))
return NULL;
return cfq_rb_first(service_tree);
}
+static struct cfq_queue *cfq_get_next_queue_forced(struct cfq_data *cfqd)
+{
+ struct cfq_group *cfqg;
+ struct cfq_queue *cfqq;
+ int i, j;
+ struct cfq_rb_root *st;
+
+ if (!cfqd->rq_queued)
+ return NULL;
+
+ cfqg = cfq_get_next_cfqg(cfqd);
+ if (!cfqg)
+ return NULL;
+
+ for_each_cfqg_st(cfqg, i, j, st)
+ if ((cfqq = cfq_rb_first(st)) != NULL)
+ return cfqq;
+ return NULL;
+}
+
/*
* Get and set a new active queue for service.
*/
static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd,
struct cfq_queue *cfqq)
{
- if (!cfqq) {
+ if (!cfqq)
cfqq = cfq_get_next_queue(cfqd);
- if (cfqq && !cfq_cfqq_coop_preempt(cfqq))
- cfq_clear_cfqq_coop(cfqq);
- }
-
- if (cfqq)
- cfq_clear_cfqq_coop_preempt(cfqq);
-
__cfq_set_active_queue(cfqd, cfqq);
return cfqq;
}
#define CFQQ_SEEKY(cfqq) ((cfqq)->seek_mean > CFQQ_SEEK_THR)
static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- struct request *rq)
+ struct request *rq, bool for_preempt)
{
sector_t sdist = cfqq->seek_mean;
if (!sample_valid(cfqq->seek_samples))
sdist = CFQQ_SEEK_THR;
+ /* if seek_mean is big, using it as close criteria is meaningless */
+ if (sdist > CFQQ_SEEK_THR && !for_preempt)
+ sdist = CFQQ_SEEK_THR;
+
return cfq_dist_from_last(cfqd, rq) <= sdist;
}
* will contain the closest sector.
*/
__cfqq = rb_entry(parent, struct cfq_queue, p_node);
- if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq))
+ if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq, false))
return __cfqq;
if (blk_rq_pos(__cfqq->next_rq) < sector)
return NULL;
__cfqq = rb_entry(node, struct cfq_queue, p_node);
- if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq))
+ if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq, false))
return __cfqq;
return NULL;
return NULL;
/*
+ * Don't search priority tree if it's the only queue in the group.
+ */
+ if (cur_cfqq->cfqg->nr_cfqq == 1)
+ return NULL;
+
+ /*
* We should notice if some of the queues are cooperating, eg
* working closely on the same area of the disk. In that case,
* we can group them together and don't waste time idling.
if (!cfqq)
return NULL;
+ /* If new queue belongs to different cfq_group, don't choose it */
+ if (cur_cfqq->cfqg != cfqq->cfqg)
+ return NULL;
+
/*
* It only makes sense to merge sync queues.
*/
enum wl_prio_t prio = cfqq_prio(cfqq);
struct cfq_rb_root *service_tree = cfqq->service_tree;
+ BUG_ON(!service_tree);
+ BUG_ON(!service_tree->count);
+
/* We never do for idle class queues. */
if (prio == IDLE_WORKLOAD)
return false;
/* We do for queues that were marked with idle window flag. */
- if (cfq_cfqq_idle_window(cfqq))
+ if (cfq_cfqq_idle_window(cfqq) &&
+ !(blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag))
return true;
/*
* Otherwise, we do only if they are the last ones
* in their service tree.
*/
- if (!service_tree)
- service_tree = service_tree_for(prio, cfqq_type(cfqq), cfqd);
-
- if (service_tree->count == 0)
- return true;
-
- return (service_tree->count == 1 && cfq_rb_first(service_tree) == cfqq);
+ return service_tree->count == 1;
}
static void cfq_arm_slice_timer(struct cfq_data *cfqd)
return;
/*
- * still requests with the driver, don't idle
+ * still active requests from this queue, don't idle
*/
- if (rq_in_driver(cfqd))
+ if (cfqq->dispatched)
return;
/*
cfq_mark_cfqq_wait_request(cfqq);
sl = cfqd->cfq_slice_idle;
- /* are we servicing noidle tree, and there are more queues?
- * non-rotational or NCQ: no idle
- * non-NCQ rotational : very small idle, to allow
- * fair distribution of slice time for a process doing back-to-back
- * seeks.
- */
- if (cfqd->serving_type == SYNC_NOIDLE_WORKLOAD &&
- service_tree_for(cfqd->serving_prio, SYNC_NOIDLE_WORKLOAD, cfqd)
- ->count > 0) {
- if (blk_queue_nonrot(cfqd->queue) || cfqd->hw_tag)
- return;
- sl = min(sl, msecs_to_jiffies(CFQ_MIN_TT));
- }
mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu", sl);
if (cfq_cfqq_sync(cfqq))
cfqd->sync_flight++;
+ cfqq->nr_sectors += blk_rq_sectors(rq);
}
/*
}
}
-static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd, enum wl_prio_t prio,
- bool prio_changed)
+static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd,
+ struct cfq_group *cfqg, enum wl_prio_t prio)
{
struct cfq_queue *queue;
int i;
unsigned long lowest_key = 0;
enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD;
- if (prio_changed) {
- /*
- * When priorities switched, we prefer starting
- * from SYNC_NOIDLE (first choice), or just SYNC
- * over ASYNC
- */
- if (service_tree_for(prio, cur_best, cfqd)->count)
- return cur_best;
- cur_best = SYNC_WORKLOAD;
- if (service_tree_for(prio, cur_best, cfqd)->count)
- return cur_best;
-
- return ASYNC_WORKLOAD;
- }
-
- for (i = 0; i < 3; ++i) {
- /* otherwise, select the one with lowest rb_key */
- queue = cfq_rb_first(service_tree_for(prio, i, cfqd));
+ for (i = 0; i <= SYNC_WORKLOAD; ++i) {
+ /* select the one with lowest rb_key */
+ queue = cfq_rb_first(service_tree_for(cfqg, prio, i));
if (queue &&
(!key_valid || time_before(queue->rb_key, lowest_key))) {
lowest_key = queue->rb_key;
return cur_best;
}
-static void choose_service_tree(struct cfq_data *cfqd)
+static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
{
- enum wl_prio_t previous_prio = cfqd->serving_prio;
- bool prio_changed;
unsigned slice;
unsigned count;
+ struct cfq_rb_root *st;
+ unsigned group_slice;
+
+ if (!cfqg) {
+ cfqd->serving_prio = IDLE_WORKLOAD;
+ cfqd->workload_expires = jiffies + 1;
+ return;
+ }
/* Choose next priority. RT > BE > IDLE */
- if (cfq_busy_queues_wl(RT_WORKLOAD, cfqd))
+ if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg))
cfqd->serving_prio = RT_WORKLOAD;
- else if (cfq_busy_queues_wl(BE_WORKLOAD, cfqd))
+ else if (cfq_group_busy_queues_wl(BE_WORKLOAD, cfqd, cfqg))
cfqd->serving_prio = BE_WORKLOAD;
else {
cfqd->serving_prio = IDLE_WORKLOAD;
* (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload
* expiration time
*/
- prio_changed = (cfqd->serving_prio != previous_prio);
- count = service_tree_for(cfqd->serving_prio, cfqd->serving_type, cfqd)
- ->count;
+ st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type);
+ count = st->count;
/*
- * If priority didn't change, check workload expiration,
- * and that we still have other queues ready
+ * check workload expiration, and that we still have other queues ready
*/
- if (!prio_changed && count &&
- !time_after(jiffies, cfqd->workload_expires))
+ if (count && !time_after(jiffies, cfqd->workload_expires))
return;
/* otherwise select new workload type */
cfqd->serving_type =
- cfq_choose_wl(cfqd, cfqd->serving_prio, prio_changed);
- count = service_tree_for(cfqd->serving_prio, cfqd->serving_type, cfqd)
- ->count;
+ cfq_choose_wl(cfqd, cfqg, cfqd->serving_prio);
+ st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type);
+ count = st->count;
/*
* the workload slice is computed as a fraction of target latency
* proportional to the number of queues in that workload, over
* all the queues in the same priority class
*/
- slice = cfq_target_latency * count /
- max_t(unsigned, cfqd->busy_queues_avg[cfqd->serving_prio],
- cfq_busy_queues_wl(cfqd->serving_prio, cfqd));
+ group_slice = cfq_group_slice(cfqd, cfqg);
+
+ slice = group_slice * count /
+ max_t(unsigned, cfqg->busy_queues_avg[cfqd->serving_prio],
+ cfq_group_busy_queues_wl(cfqd->serving_prio, cfqd, cfqg));
+
+ if (cfqd->serving_type == ASYNC_WORKLOAD) {
+ unsigned int tmp;
+
+ /*
+ * Async queues are currently system wide. Just taking
+ * proportion of queues with-in same group will lead to higher
+ * async ratio system wide as generally root group is going
+ * to have higher weight. A more accurate thing would be to
+ * calculate system wide asnc/sync ratio.
+ */
+ tmp = cfq_target_latency * cfqg_busy_async_queues(cfqd, cfqg);
+ tmp = tmp/cfqd->busy_queues;
+ slice = min_t(unsigned, slice, tmp);
- if (cfqd->serving_type == ASYNC_WORKLOAD)
/* async workload slice is scaled down according to
* the sync/async slice ratio. */
slice = slice * cfqd->cfq_slice[0] / cfqd->cfq_slice[1];
- else
+ } else
/* sync workload slice is at least 2 * cfq_slice_idle */
slice = max(slice, 2 * cfqd->cfq_slice_idle);
slice = max_t(unsigned, slice, CFQ_MIN_TT);
cfqd->workload_expires = jiffies + slice;
+ cfqd->noidle_tree_requires_idle = false;
+}
+
+static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd)
+{
+ struct cfq_rb_root *st = &cfqd->grp_service_tree;
+ struct cfq_group *cfqg;
+
+ if (RB_EMPTY_ROOT(&st->rb))
+ return NULL;
+ cfqg = cfq_rb_first_group(st);
+ st->active = &cfqg->rb_node;
+ update_min_vdisktime(st);
+ return cfqg;
+}
+
+static void cfq_choose_cfqg(struct cfq_data *cfqd)
+{
+ struct cfq_group *cfqg = cfq_get_next_cfqg(cfqd);
+
+ cfqd->serving_group = cfqg;
+
+ /* Restore the workload type data */
+ if (cfqg->saved_workload_slice) {
+ cfqd->workload_expires = jiffies + cfqg->saved_workload_slice;
+ cfqd->serving_type = cfqg->saved_workload;
+ cfqd->serving_prio = cfqg->saved_serving_prio;
+ } else
+ cfqd->workload_expires = jiffies - 1;
+
+ choose_service_tree(cfqd, cfqg);
}
/*
if (!cfqq)
goto new_queue;
+ if (!cfqd->rq_queued)
+ return NULL;
+
/*
- * The active queue has run out of time, expire it and select new.
+ * We were waiting for group to get backlogged. Expire the queue
*/
- if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq))
+ if (cfq_cfqq_wait_busy(cfqq) && !RB_EMPTY_ROOT(&cfqq->sort_list))
goto expire;
/*
+ * The active queue has run out of time, expire it and select new.
+ */
+ if (cfq_slice_used(cfqq) && !cfq_cfqq_must_dispatch(cfqq)) {
+ /*
+ * If slice had not expired at the completion of last request
+ * we might not have turned on wait_busy flag. Don't expire
+ * the queue yet. Allow the group to get backlogged.
+ *
+ * The very fact that we have used the slice, that means we
+ * have been idling all along on this queue and it should be
+ * ok to wait for this request to complete.
+ */
+ if (cfqq->cfqg->nr_cfqq == 1 && RB_EMPTY_ROOT(&cfqq->sort_list)
+ && cfqq->dispatched && cfq_should_idle(cfqd, cfqq)) {
+ cfqq = NULL;
+ goto keep_queue;
+ } else
+ goto expire;
+ }
+
+ /*
* The active queue has requests and isn't expired, allow it to
* dispatch.
*/
* service tree
*/
if (!new_cfqq)
- choose_service_tree(cfqd);
+ cfq_choose_cfqg(cfqd);
cfqq = cfq_set_active_queue(cfqd, new_cfqq);
keep_queue:
}
BUG_ON(!list_empty(&cfqq->fifo));
+
+ /* By default cfqq is not expired if it is empty. Do it explicitly */
+ __cfq_slice_expired(cfqq->cfqd, cfqq, 0);
return dispatched;
}
{
struct cfq_queue *cfqq;
int dispatched = 0;
- int i, j;
- for (i = 0; i < 2; ++i)
- for (j = 0; j < 3; ++j)
- while ((cfqq = cfq_rb_first(&cfqd->service_trees[i][j]))
- != NULL)
- dispatched += __cfq_forced_dispatch_cfqq(cfqq);
- while ((cfqq = cfq_rb_first(&cfqd->service_tree_idle)) != NULL)
+ while ((cfqq = cfq_get_next_queue_forced(cfqd)) != NULL)
dispatched += __cfq_forced_dispatch_cfqq(cfqq);
cfq_slice_expired(cfqd, 0);
-
BUG_ON(cfqd->busy_queues);
cfq_log(cfqd, "forced_dispatch=%d", dispatched);
return false;
/*
- * Sole queue user, allow bigger slice
+ * Sole queue user, no limit
*/
- max_dispatch *= 4;
+ max_dispatch = -1;
}
/*
* based on the last sync IO we serviced
*/
if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) {
- unsigned long last_sync = jiffies - cfqd->last_end_sync_rq;
+ unsigned long last_sync = jiffies - cfqd->last_delayed_sync;
unsigned int depth;
depth = last_sync / cfqd->cfq_slice[1];
* task holds one reference to the queue, dropped when task exits. each rq
* in-flight on this queue also holds a reference, dropped when rq is freed.
*
+ * Each cfq queue took a reference on the parent group. Drop it now.
* queue lock must be held here.
*/
static void cfq_put_queue(struct cfq_queue *cfqq)
{
struct cfq_data *cfqd = cfqq->cfqd;
+ struct cfq_group *cfqg, *orig_cfqg;
BUG_ON(atomic_read(&cfqq->ref) <= 0);
cfq_log_cfqq(cfqd, cfqq, "put_queue");
BUG_ON(rb_first(&cfqq->sort_list));
BUG_ON(cfqq->allocated[READ] + cfqq->allocated[WRITE]);
- BUG_ON(cfq_cfqq_on_rr(cfqq));
+ cfqg = cfqq->cfqg;
+ orig_cfqg = cfqq->orig_cfqg;
if (unlikely(cfqd->active_queue == cfqq)) {
__cfq_slice_expired(cfqd, cfqq, 0);
cfq_schedule_dispatch(cfqd);
}
+ BUG_ON(cfq_cfqq_on_rr(cfqq));
kmem_cache_free(cfq_pool, cfqq);
+ cfq_put_cfqg(cfqg);
+ if (orig_cfqg)
+ cfq_put_cfqg(orig_cfqg);
}
/*
cfqq->pid = pid;
}
+#ifdef CONFIG_CFQ_GROUP_IOSCHED
+static void changed_cgroup(struct io_context *ioc, struct cfq_io_context *cic)
+{
+ struct cfq_queue *sync_cfqq = cic_to_cfqq(cic, 1);
+ struct cfq_data *cfqd = cic->key;
+ unsigned long flags;
+ struct request_queue *q;
+
+ if (unlikely(!cfqd))
+ return;
+
+ q = cfqd->queue;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+
+ if (sync_cfqq) {
+ /*
+ * Drop reference to sync queue. A new sync queue will be
+ * assigned in new group upon arrival of a fresh request.
+ */
+ cfq_log_cfqq(cfqd, sync_cfqq, "changed cgroup");
+ cic_set_cfqq(cic, NULL, 1);
+ cfq_put_queue(sync_cfqq);
+ }
+
+ spin_unlock_irqrestore(q->queue_lock, flags);
+}
+
+static void cfq_ioc_set_cgroup(struct io_context *ioc)
+{
+ call_for_each_cic(ioc, changed_cgroup);
+ ioc->cgroup_changed = 0;
+}
+#endif /* CONFIG_CFQ_GROUP_IOSCHED */
+
static struct cfq_queue *
cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync,
struct io_context *ioc, gfp_t gfp_mask)
{
struct cfq_queue *cfqq, *new_cfqq = NULL;
struct cfq_io_context *cic;
+ struct cfq_group *cfqg;
retry:
+ cfqg = cfq_get_cfqg(cfqd, 1);
cic = cfq_cic_lookup(cfqd, ioc);
/* cic always exists here */
cfqq = cic_to_cfqq(cic, is_sync);
if (cfqq) {
cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync);
cfq_init_prio_data(cfqq, ioc);
+ cfq_link_cfqq_cfqg(cfqq, cfqg);
cfq_log_cfqq(cfqd, cfqq, "alloced");
} else
cfqq = &cfqd->oom_cfqq;
if (unlikely(ioc->ioprio_changed))
cfq_ioc_set_ioprio(ioc);
+#ifdef CONFIG_CFQ_GROUP_IOSCHED
+ if (unlikely(ioc->cgroup_changed))
+ cfq_ioc_set_cgroup(ioc);
+#endif
return cic;
err_free:
cfq_cic_free(cic);
enable_idle = old_idle = cfq_cfqq_idle_window(cfqq);
+ if (cfqq->queued[0] + cfqq->queued[1] >= 4)
+ cfq_mark_cfqq_deep(cfqq);
+
if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle ||
- (sample_valid(cfqq->seek_samples) && CFQQ_SEEKY(cfqq)))
+ (!cfq_cfqq_deep(cfqq) && sample_valid(cfqq->seek_samples)
+ && CFQQ_SEEKY(cfqq)))
enable_idle = 0;
else if (sample_valid(cic->ttime_samples)) {
if (cic->ttime_mean > cfqd->cfq_slice_idle)
if (!cfqq)
return false;
- if (cfq_slice_used(cfqq))
- return true;
-
if (cfq_class_idle(new_cfqq))
return false;
if (cfq_class_idle(cfqq))
return true;
- if (cfqd->serving_type == SYNC_NOIDLE_WORKLOAD
- && new_cfqq->service_tree == cfqq->service_tree)
- return true;
+ /*
+ * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice.
+ */
+ if (cfq_class_rt(cfqq) && !cfq_class_rt(new_cfqq))
+ return false;
/*
* if the new request is sync, but the currently running queue is
if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq))
return true;
+ if (new_cfqq->cfqg != cfqq->cfqg)
+ return false;
+
+ if (cfq_slice_used(cfqq))
+ return true;
+
+ /* Allow preemption only if we are idling on sync-noidle tree */
+ if (cfqd->serving_type == SYNC_NOIDLE_WORKLOAD &&
+ cfqq_type(new_cfqq) == SYNC_NOIDLE_WORKLOAD &&
+ new_cfqq->service_tree->count == 2 &&
+ RB_EMPTY_ROOT(&cfqq->sort_list))
+ return true;
+
/*
* So both queues are sync. Let the new request get disk time if
* it's a metadata request and the current queue is doing regular IO.
* if this request is as-good as one we would expect from the
* current cfqq, let it preempt
*/
- if (cfq_rq_close(cfqd, cfqq, rq) && (!cfq_cfqq_coop(new_cfqq) ||
- cfqd->busy_queues == 1)) {
- /*
- * Mark new queue coop_preempt, so its coop flag will not be
- * cleared when new queue gets scheduled at the very first time
- */
- cfq_mark_cfqq_coop_preempt(new_cfqq);
- cfq_mark_cfqq_coop(new_cfqq);
+ if (cfq_rq_close(cfqd, cfqq, rq, true))
return true;
- }
return false;
}
if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE ||
cfqd->busy_queues > 1) {
del_timer(&cfqd->idle_slice_timer);
- __blk_run_queue(cfqd->queue);
- }
- cfq_mark_cfqq_must_dispatch(cfqq);
+ cfq_clear_cfqq_wait_request(cfqq);
+ __blk_run_queue(cfqd->queue);
+ } else
+ cfq_mark_cfqq_must_dispatch(cfqq);
}
} else if (cfq_should_preempt(cfqd, cfqq, rq)) {
/*
{
struct cfq_queue *cfqq = cfqd->active_queue;
- if (rq_in_driver(cfqd) > cfqd->rq_in_driver_peak)
- cfqd->rq_in_driver_peak = rq_in_driver(cfqd);
+ if (rq_in_driver(cfqd) > cfqd->hw_tag_est_depth)
+ cfqd->hw_tag_est_depth = rq_in_driver(cfqd);
+
+ if (cfqd->hw_tag == 1)
+ return;
if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN &&
rq_in_driver(cfqd) <= CFQ_HW_QUEUE_MIN)
if (cfqd->hw_tag_samples++ < 50)
return;
- if (cfqd->rq_in_driver_peak >= CFQ_HW_QUEUE_MIN)
+ if (cfqd->hw_tag_est_depth >= CFQ_HW_QUEUE_MIN)
cfqd->hw_tag = 1;
else
cfqd->hw_tag = 0;
+}
+
+static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+{
+ struct cfq_io_context *cic = cfqd->active_cic;
+
+ /* If there are other queues in the group, don't wait */
+ if (cfqq->cfqg->nr_cfqq > 1)
+ return false;
+
+ if (cfq_slice_used(cfqq))
+ return true;
+
+ /* if slice left is less than think time, wait busy */
+ if (cic && sample_valid(cic->ttime_samples)
+ && (cfqq->slice_end - jiffies < cic->ttime_mean))
+ return true;
+
+ /*
+ * If think times is less than a jiffy than ttime_mean=0 and above
+ * will not be true. It might happen that slice has not expired yet
+ * but will expire soon (4-5 ns) during select_queue(). To cover the
+ * case where think time is less than a jiffy, mark the queue wait
+ * busy if only 1 jiffy is left in the slice.
+ */
+ if (cfqq->slice_end - jiffies == 1)
+ return true;
- cfqd->hw_tag_samples = 0;
- cfqd->rq_in_driver_peak = 0;
+ return false;
}
static void cfq_completed_request(struct request_queue *q, struct request *rq)
unsigned long now;
now = jiffies;
- cfq_log_cfqq(cfqd, cfqq, "complete");
+ cfq_log_cfqq(cfqd, cfqq, "complete rqnoidle %d", !!rq_noidle(rq));
cfq_update_hw_tag(cfqd);
if (sync) {
RQ_CIC(rq)->last_end_request = now;
- cfqd->last_end_sync_rq = now;
+ if (!time_after(rq->start_time + cfqd->cfq_fifo_expire[1], now))
+ cfqd->last_delayed_sync = now;
}
/*
cfq_set_prio_slice(cfqd, cfqq);
cfq_clear_cfqq_slice_new(cfqq);
}
+
+ /*
+ * Should we wait for next request to come in before we expire
+ * the queue.
+ */
+ if (cfq_should_wait_busy(cfqd, cfqq)) {
+ cfqq->slice_end = jiffies + cfqd->cfq_slice_idle;
+ cfq_mark_cfqq_wait_busy(cfqq);
+ }
+
/*
- * If there are no requests waiting in this queue, and
- * there are other queues ready to issue requests, AND
- * those other queues are issuing requests within our
- * mean seek distance, give them a chance to run instead
- * of idling.
+ * Idling is not enabled on:
+ * - expired queues
+ * - idle-priority queues
+ * - async queues
+ * - queues with still some requests queued
+ * - when there is a close cooperator
*/
if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq))
cfq_slice_expired(cfqd, 1);
- else if (cfqq_empty && !cfq_close_cooperator(cfqd, cfqq) &&
- sync && !rq_noidle(rq))
- cfq_arm_slice_timer(cfqd);
+ else if (sync && cfqq_empty &&
+ !cfq_close_cooperator(cfqd, cfqq)) {
+ cfqd->noidle_tree_requires_idle |= !rq_noidle(rq);
+ /*
+ * Idling is enabled for SYNC_WORKLOAD.
+ * SYNC_NOIDLE_WORKLOAD idles at the end of the tree
+ * only if we processed at least one !rq_noidle request
+ */
+ if (cfqd->serving_type == SYNC_WORKLOAD
+ || cfqd->noidle_tree_requires_idle
+ || cfqq->cfqg->nr_cfqq == 1)
+ cfq_arm_slice_timer(cfqd);
+ }
}
if (!rq_in_driver(cfqd))
*/
if (!RB_EMPTY_ROOT(&cfqq->sort_list))
goto out_kick;
+
+ /*
+ * Queue depth flag is reset only when the idle didn't succeed
+ */
+ cfq_clear_cfqq_deep(cfqq);
}
expire:
cfq_slice_expired(cfqd, timed_out);
cfq_put_queue(cfqd->async_idle_cfqq);
}
+static void cfq_cfqd_free(struct rcu_head *head)
+{
+ kfree(container_of(head, struct cfq_data, rcu));
+}
+
static void cfq_exit_queue(struct elevator_queue *e)
{
struct cfq_data *cfqd = e->elevator_data;
}
cfq_put_async_queues(cfqd);
+ cfq_release_cfq_groups(cfqd);
+ blkiocg_del_blkio_group(&cfqd->root_group.blkg);
spin_unlock_irq(q->queue_lock);
cfq_shutdown_timer_wq(cfqd);
- kfree(cfqd);
+ /* Wait for cfqg->blkg->key accessors to exit their grace periods. */
+ call_rcu(&cfqd->rcu, cfq_cfqd_free);
}
static void *cfq_init_queue(struct request_queue *q)
{
struct cfq_data *cfqd;
int i, j;
+ struct cfq_group *cfqg;
+ struct cfq_rb_root *st;
cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node);
if (!cfqd)
return NULL;
- for (i = 0; i < 2; ++i)
- for (j = 0; j < 3; ++j)
- cfqd->service_trees[i][j] = CFQ_RB_ROOT;
- cfqd->service_tree_idle = CFQ_RB_ROOT;
+ /* Init root service tree */
+ cfqd->grp_service_tree = CFQ_RB_ROOT;
+
+ /* Init root group */
+ cfqg = &cfqd->root_group;
+ for_each_cfqg_st(cfqg, i, j, st)
+ *st = CFQ_RB_ROOT;
+ RB_CLEAR_NODE(&cfqg->rb_node);
+
+ /* Give preference to root group over other groups */
+ cfqg->weight = 2*BLKIO_WEIGHT_DEFAULT;
+#ifdef CONFIG_CFQ_GROUP_IOSCHED
+ /*
+ * Take a reference to root group which we never drop. This is just
+ * to make sure that cfq_put_cfqg() does not try to kfree root group
+ */
+ atomic_set(&cfqg->ref, 1);
+ blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg, (void *)cfqd,
+ 0);
+#endif
/*
* Not strictly needed (since RB_ROOT just clears the node and we
* zeroed cfqd on alloc), but better be safe in case someone decides
*/
cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0);
atomic_inc(&cfqd->oom_cfqq.ref);
+ cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group);
INIT_LIST_HEAD(&cfqd->cic_list);
cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
cfqd->cfq_slice_idle = cfq_slice_idle;
cfqd->cfq_latency = 1;
- cfqd->hw_tag = 1;
- cfqd->last_end_sync_rq = jiffies;
+ cfqd->cfq_group_isolation = 0;
+ cfqd->hw_tag = -1;
+ /*
+ * we optimistically start assuming sync ops weren't delayed in last
+ * second, in order to have larger depth for async operations.
+ */
+ cfqd->last_delayed_sync = jiffies - HZ;
+ INIT_RCU_HEAD(&cfqd->rcu);
return cfqd;
}
SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1);
SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0);
SHOW_FUNCTION(cfq_low_latency_show, cfqd->cfq_latency, 0);
+SHOW_FUNCTION(cfq_group_isolation_show, cfqd->cfq_group_isolation, 0);
#undef SHOW_FUNCTION
#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1,
UINT_MAX, 0);
STORE_FUNCTION(cfq_low_latency_store, &cfqd->cfq_latency, 0, 1, 0);
+STORE_FUNCTION(cfq_group_isolation_store, &cfqd->cfq_group_isolation, 0, 1, 0);
#undef STORE_FUNCTION
#define CFQ_ATTR(name) \
CFQ_ATTR(slice_async_rq),
CFQ_ATTR(slice_idle),
CFQ_ATTR(low_latency),
+ CFQ_ATTR(group_isolation),
__ATTR_NULL
};
.elevator_owner = THIS_MODULE,
};
+#ifdef CONFIG_CFQ_GROUP_IOSCHED
+static struct blkio_policy_type blkio_policy_cfq = {
+ .ops = {
+ .blkio_unlink_group_fn = cfq_unlink_blkio_group,
+ .blkio_update_group_weight_fn = cfq_update_blkio_group_weight,
+ },
+};
+#else
+static struct blkio_policy_type blkio_policy_cfq;
+#endif
+
static int __init cfq_init(void)
{
/*
return -ENOMEM;
elv_register(&iosched_cfq);
+ blkio_policy_register(&blkio_policy_cfq);
return 0;
}
static void __exit cfq_exit(void)
{
DECLARE_COMPLETION_ONSTACK(all_gone);
+ blkio_policy_unregister(&blkio_policy_cfq);
elv_unregister(&iosched_cfq);
ioc_gone = &all_gone;
/* ioc_gone's update must be visible before reading ioc_count */
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff