#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/elevator.h>
-#include <linux/hash.h>
+#include <linux/jiffies.h>
#include <linux/rbtree.h>
#include <linux/ioprio.h>
+#include <linux/blktrace_api.h>
+#include "blk-cgroup.h"
/*
* tunables
*/
-static const int cfq_quantum = 4; /* max queue in one round of service */
+/* max queue in one round of service */
+static const int cfq_quantum = 4;
static const int cfq_fifo_expire[2] = { HZ / 4, HZ / 8 };
-static const int cfq_back_max = 16 * 1024; /* maximum backwards seek, in KiB */
-static const int cfq_back_penalty = 2; /* penalty of a backwards seek */
-
+/* maximum backwards seek, in KiB */
+static const int cfq_back_max = 16 * 1024;
+/* penalty of a backwards seek */
+static const int cfq_back_penalty = 2;
static const int cfq_slice_sync = HZ / 10;
static int cfq_slice_async = HZ / 25;
static const int cfq_slice_async_rq = 2;
static int cfq_slice_idle = HZ / 125;
+static const int cfq_target_latency = HZ * 3/10; /* 300 ms */
+static const int cfq_hist_divisor = 4;
-#define CFQ_IDLE_GRACE (HZ / 10)
-#define CFQ_SLICE_SCALE (5)
+/*
+ * offset from end of service tree
+ */
+#define CFQ_IDLE_DELAY (HZ / 5)
-#define CFQ_KEY_ASYNC (0)
+/*
+ * below this threshold, we consider thinktime immediate
+ */
+#define CFQ_MIN_TT (2)
/*
- * for the hash of cfqq inside the cfqd
+ * Allow merged cfqqs to perform this amount of seeky I/O before
+ * deciding to break the queues up again.
*/
-#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 CFQQ_COOP_TOUT (HZ)
-#define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list)
+#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 RQ_CFQQ(rq) ((rq)->elevator_private2)
+#define RQ_CIC(rq) \
+ ((struct cfq_io_context *) (rq)->elevator_private)
+#define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private2)
static struct kmem_cache *cfq_pool;
static struct kmem_cache *cfq_ioc_pool;
-static DEFINE_PER_CPU(unsigned long, ioc_count);
+static DEFINE_PER_CPU(unsigned long, cfq_ioc_count);
static struct completion *ioc_gone;
+static DEFINE_SPINLOCK(ioc_gone_lock);
#define CFQ_PRIO_LISTS IOPRIO_BE_NR
#define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
#define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT)
-#define ASYNC (0)
-#define SYNC (1)
+#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
+ * if we cache the leftmost node we don't have to walk down the tree
+ * to find it. Idea borrowed from Ingo Molnars CFS scheduler. We should
+ * move this into the elevator for the rq sorting as well.
+ */
+struct cfq_rb_root {
+ 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, 0, }
+
+/*
+ * Per process-grouping structure
+ */
+struct cfq_queue {
+ /* reference count */
+ atomic_t ref;
+ /* various state flags, see below */
+ unsigned int flags;
+ /* parent cfq_data */
+ struct cfq_data *cfqd;
+ /* service_tree member */
+ struct rb_node rb_node;
+ /* service_tree key */
+ unsigned long rb_key;
+ /* prio tree member */
+ struct rb_node p_node;
+ /* prio tree root we belong to, if any */
+ struct rb_root *p_root;
+ /* sorted list of pending requests */
+ struct rb_root sort_list;
+ /* if fifo isn't expired, next request to serve */
+ struct request *next_rq;
+ /* requests queued in sort_list */
+ int queued[2];
+ /* currently allocated requests */
+ int allocated[2];
+ /* 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;
+
+ /* pending metadata requests */
+ int meta_pending;
+ /* number of requests that are on the dispatch list or inside driver */
+ int dispatched;
+
+ /* io prio of this group */
+ unsigned short ioprio, org_ioprio;
+ unsigned short ioprio_class, org_ioprio_class;
-#define cfq_cfqq_dispatched(cfqq) \
- ((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC])
+ unsigned int seek_samples;
+ u64 seek_total;
+ sector_t seek_mean;
+ sector_t last_request_pos;
+ unsigned long seeky_start;
-#define cfq_cfqq_class_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC)
+ pid_t pid;
-#define cfq_cfqq_sync(cfqq) \
- (cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC])
+ 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;
+};
-#define sample_valid(samples) ((samples) > 80)
+/*
+ * First index in the service_trees.
+ * IDLE is handled separately, so it has negative index
+ */
+enum wl_prio_t {
+ BE_WORKLOAD = 0,
+ RT_WORKLOAD = 1,
+ IDLE_WORKLOAD = 2,
+};
+
+/*
+ * Second index in the service_trees.
+ */
+enum wl_type_t {
+ ASYNC_WORKLOAD = 0,
+ SYNC_NOIDLE_WORKLOAD = 1,
+ SYNC_WORKLOAD = 2
+};
+
+/* This is per cgroup per device grouping structure */
+struct cfq_group {
+ /* group service_tree member */
+ struct rb_node rb_node;
+
+ /* 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 {
- request_queue_t *queue;
+ struct request_queue *queue;
+ /* Root service tree for cfq_groups */
+ struct cfq_rb_root grp_service_tree;
+ struct cfq_group root_group;
/*
- * rr list of queues with requests and the count of them
+ * The priority currently being served
*/
- struct list_head rr_list[CFQ_PRIO_LISTS];
- struct list_head busy_rr;
- struct list_head cur_rr;
- struct list_head idle_rr;
- unsigned int busy_queues;
+ 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;
/*
- * cfqq lookup hash
+ * Each priority tree is sorted by next_request position. These
+ * trees are used when determining if two or more queues are
+ * interleaving requests (see cfq_close_cooperator).
*/
- struct hlist_head *cfq_hash;
+ struct rb_root prio_trees[CFQ_PRIO_LISTS];
+
+ unsigned int busy_queues;
+
+ int rq_in_driver[2];
+ int sync_flight;
- int rq_in_driver;
+ /*
+ * queue-depth detection
+ */
+ int rq_queued;
int hw_tag;
+ /*
+ * 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
struct cfq_queue *active_queue;
struct cfq_io_context *active_cic;
- int cur_prio, cur_end_prio;
- unsigned int dispatch_slice;
- struct timer_list idle_class_timer;
+ /*
+ * async queue for each priority case
+ */
+ struct cfq_queue *async_cfqq[2][IOPRIO_BE_NR];
+ struct cfq_queue *async_idle_cfqq;
- sector_t last_sector;
- unsigned long last_end_request;
+ sector_t last_position;
/*
* tunables, see top of file
unsigned int cfq_slice[2];
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;
-};
-/*
- * Per process-grouping structure
- */
-struct cfq_queue {
- /* reference count */
- atomic_t ref;
- /* parent cfq_data */
- struct cfq_data *cfqd;
- /* cfqq lookup hash */
- struct hlist_node cfq_hash;
- /* hash key */
- unsigned int key;
- /* member of the rr/busy/cur/idle cfqd list */
- struct list_head cfq_list;
- /* sorted list of pending requests */
- struct rb_root sort_list;
- /* if fifo isn't expired, next request to serve */
- struct request *next_rq;
- /* requests queued in sort_list */
- int queued[2];
- /* currently allocated requests */
- int allocated[2];
- /* pending metadata requests */
- int meta_pending;
- /* fifo list of requests in sort_list */
- struct list_head fifo;
+ /*
+ * Fallback dummy cfqq for extreme OOM conditions
+ */
+ struct cfq_queue oom_cfqq;
- unsigned long slice_start;
- unsigned long slice_end;
- unsigned long slice_left;
+ unsigned long last_delayed_sync;
- /* number of requests that are on the dispatch list */
- int on_dispatch[2];
+ /* List of cfq groups being managed on this device*/
+ struct hlist_head cfqg_list;
+ struct rcu_head rcu;
+};
- /* io prio of this group */
- unsigned short ioprio, org_ioprio;
- unsigned short ioprio_class, org_ioprio_class;
+static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd);
- /* various state flags, see below */
- unsigned int flags;
-};
+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 &cfqg->service_tree_idle;
+
+ return &cfqg->service_trees[prio][type];
+}
enum cfqq_state_flags {
- CFQ_CFQQ_FLAG_on_rr = 0,
- CFQ_CFQQ_FLAG_wait_request,
- CFQ_CFQQ_FLAG_must_alloc,
- CFQ_CFQQ_FLAG_must_alloc_slice,
- CFQ_CFQQ_FLAG_must_dispatch,
- CFQ_CFQQ_FLAG_fifo_expire,
- CFQ_CFQQ_FLAG_idle_window,
- CFQ_CFQQ_FLAG_prio_changed,
- CFQ_CFQQ_FLAG_queue_new,
+ CFQ_CFQQ_FLAG_on_rr = 0, /* on round-robin busy list */
+ CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */
+ CFQ_CFQQ_FLAG_must_dispatch, /* must be allowed a dispatch */
+ CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */
+ CFQ_CFQQ_FLAG_fifo_expire, /* FIFO checked in this slice */
+ CFQ_CFQQ_FLAG_idle_window, /* slice idling enabled */
+ CFQ_CFQQ_FLAG_prio_changed, /* task priority has changed */
+ 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_deep, /* sync cfqq experienced large depth */
+ CFQ_CFQQ_FLAG_wait_busy, /* Waiting for next request */
};
#define CFQ_CFQQ_FNS(name) \
static inline void cfq_mark_cfqq_##name(struct cfq_queue *cfqq) \
{ \
- cfqq->flags |= (1 << CFQ_CFQQ_FLAG_##name); \
+ (cfqq)->flags |= (1 << CFQ_CFQQ_FLAG_##name); \
} \
static inline void cfq_clear_cfqq_##name(struct cfq_queue *cfqq) \
{ \
- cfqq->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \
+ (cfqq)->flags &= ~(1 << CFQ_CFQQ_FLAG_##name); \
} \
static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq) \
{ \
- return (cfqq->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \
+ return ((cfqq)->flags & (1 << CFQ_CFQQ_FLAG_##name)) != 0; \
}
CFQ_CFQQ_FNS(on_rr);
CFQ_CFQQ_FNS(wait_request);
-CFQ_CFQQ_FNS(must_alloc);
-CFQ_CFQQ_FNS(must_alloc_slice);
CFQ_CFQQ_FNS(must_dispatch);
+CFQ_CFQQ_FNS(must_alloc_slice);
CFQ_CFQQ_FNS(fifo_expire);
CFQ_CFQQ_FNS(idle_window);
CFQ_CFQQ_FNS(prio_changed);
-CFQ_CFQQ_FNS(queue_new);
+CFQ_CFQQ_FNS(slice_new);
+CFQ_CFQQ_FNS(sync);
+CFQ_CFQQ_FNS(coop);
+CFQ_CFQQ_FNS(deep);
+CFQ_CFQQ_FNS(wait_busy);
#undef CFQ_CFQQ_FNS
-static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short);
-static void cfq_dispatch_insert(request_queue_t *, struct request *);
-static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, gfp_t gfp_mask);
+#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 IDLE_WORKLOAD;
+ if (cfq_class_rt(cfqq))
+ return RT_WORKLOAD;
+ return BE_WORKLOAD;
+}
+
+
+static enum wl_type_t cfqq_type(struct cfq_queue *cfqq)
+{
+ if (!cfq_cfqq_sync(cfqq))
+ return ASYNC_WORKLOAD;
+ if (!cfq_cfqq_idle_window(cfqq))
+ return SYNC_NOIDLE_WORKLOAD;
+ return SYNC_WORKLOAD;
+}
+
+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 cfqg->service_tree_idle.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 *);
+static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool,
+ struct io_context *, gfp_t);
+static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *,
+ struct io_context *);
+
+static inline int rq_in_driver(struct cfq_data *cfqd)
+{
+ return cfqd->rq_in_driver[0] + cfqd->rq_in_driver[1];
+}
+
+static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic,
+ bool is_sync)
+{
+ return cic->cfqq[is_sync];
+}
+
+static inline void cic_set_cfqq(struct cfq_io_context *cic,
+ struct cfq_queue *cfqq, bool is_sync)
+{
+ cic->cfqq[is_sync] = cfqq;
+}
+
+/*
+ * We regard a request as SYNC, if it's either a read or has the SYNC bit
+ * set (in which case it could also be direct WRITE).
+ */
+static inline bool cfq_bio_sync(struct bio *bio)
+{
+ return bio_data_dir(bio) == READ || bio_rw_flagged(bio, BIO_RW_SYNCIO);
+}
/*
* scheduler run of queue, if there are requests pending and no one in the
*/
static inline void cfq_schedule_dispatch(struct cfq_data *cfqd)
{
- if (cfqd->busy_queues)
- kblockd_schedule_work(&cfqd->unplug_work);
+ if (cfqd->busy_queues) {
+ cfq_log(cfqd, "schedule dispatch");
+ kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work);
+ }
}
-static int cfq_queue_empty(request_queue_t *q)
+static int cfq_queue_empty(struct request_queue *q)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
- return !cfqd->busy_queues;
+ return !cfqd->rq_queued;
}
-static inline pid_t cfq_queue_pid(struct task_struct *task, int rw, int is_sync)
+/*
+ * Scale schedule slice based on io priority. Use the sync time slice only
+ * if a queue is marked sync and has sync io queued. A sync queue with async
+ * io only, should not get full sync slice length.
+ */
+static inline int cfq_prio_slice(struct cfq_data *cfqd, bool sync,
+ unsigned short prio)
{
- /*
- * Use the per-process queue, for read requests and syncronous writes
- */
- if (!(rw & REQ_RW) || is_sync)
- return task->pid;
+ const int base_slice = cfqd->cfq_slice[sync];
+
+ WARN_ON(prio >= IOPRIO_BE_NR);
+
+ return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - prio));
+}
+
+static inline int
+cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+{
+ 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_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_group_busy_queues_wl(rt, cfqd, cfqg);
+
+ 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 cfqg->busy_queues_avg[rt];
+}
- return CFQ_KEY_ASYNC;
+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
+cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+{
+ unsigned slice = cfq_prio_to_slice(cfqd, cfqq);
+ if (cfqd->cfq_latency) {
+ /*
+ * 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;
+ 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 */
+ unsigned low_slice =
+ 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 * 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);
+}
+
+/*
+ * We need to wrap this check in cfq_cfqq_slice_new(), since ->slice_end
+ * isn't valid until the first request from the dispatch is activated
+ * and the slice time set.
+ */
+static inline bool cfq_slice_used(struct cfq_queue *cfqq)
+{
+ if (cfq_cfqq_slice_new(cfqq))
+ return 0;
+ if (time_before(jiffies, cfqq->slice_end))
+ return 0;
+
+ return 1;
}
/*
* 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 */
else if (rq_is_meta(rq2) && !rq_is_meta(rq1))
return rq2;
- s1 = rq1->sector;
- s2 = rq2->sector;
-
- last = cfqd->last_sector;
+ s1 = blk_rq_pos(rq1);
+ s2 = blk_rq_pos(rq2);
/*
* by definition, 1KiB is 2 sectors
}
}
+/*
+ * The below is leftmost cache rbtree addon
+ */
+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);
+
+ if (root->left)
+ return rb_entry(root->left, struct cfq_queue, rb_node);
+
+ 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);
+ RB_CLEAR_NODE(n);
+}
+
+static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root)
+{
+ if (root->left == n)
+ root->left = NULL;
+ rb_erase_init(n, &root->rb);
+ --root->count;
+}
+
/*
* would be nice to take fifo expire time into account as well
*/
next = rb_entry_rq(rbnext);
}
- return cfq_choose_req(cfqd, next, prev);
+ return cfq_choose_req(cfqd, next, prev, blk_rq_pos(last));
}
-static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
+static unsigned long cfq_slice_offset(struct cfq_data *cfqd,
+ struct cfq_queue *cfqq)
{
- struct cfq_data *cfqd = cfqq->cfqd;
- struct list_head *list;
-
- BUG_ON(!cfq_cfqq_on_rr(cfqq));
-
- list_del(&cfqq->cfq_list);
-
- if (cfq_class_rt(cfqq))
- list = &cfqd->cur_rr;
- else if (cfq_class_idle(cfqq))
- list = &cfqd->idle_rr;
- else {
- /*
- * if cfqq has requests in flight, don't allow it to be
- * found in cfq_set_active_queue before it has finished them.
- * this is done to increase fairness between a process that
- * has lots of io pending vs one that only generates one
- * sporadically or synchronously
- */
- if (cfq_cfqq_dispatched(cfqq))
- list = &cfqd->busy_rr;
- else
- list = &cfqd->rr_list[cfqq->ioprio];
- }
-
/*
- * If this queue was preempted or is new (never been serviced), let
- * it be added first for fairness but beind other new queues.
- * Otherwise, just add to the back of the list.
+ * just an approximation, should be ok.
*/
- if (preempted || cfq_cfqq_queue_new(cfqq)) {
- struct list_head *n = list;
- struct cfq_queue *__cfqq;
+ return (cfqq->cfqg->nr_cfqq - 1) * (cfq_prio_slice(cfqd, 1, 0) -
+ cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio));
+}
- while (n->next != list) {
- __cfqq = list_entry_cfqq(n->next);
- if (!cfq_cfqq_queue_new(__cfqq))
- break;
+static inline s64
+cfqg_key(struct cfq_rb_root *st, struct cfq_group *cfqg)
+{
+ return cfqg->vdisktime - st->min_vdisktime;
+}
- n = n->next;
- }
+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);
- list = n;
+ if (key < cfqg_key(st, __cfqg))
+ node = &parent->rb_left;
+ else {
+ node = &parent->rb_right;
+ left = 0;
+ }
}
- list_add_tail(&cfqq->cfq_list, list);
+ 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
+ * we will service the queues.
+ */
+static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
+ bool add_front)
+{
+ struct rb_node **p, *parent;
+ struct cfq_queue *__cfqq;
+ unsigned long rb_key;
+ struct cfq_rb_root *service_tree;
+ int left;
+ 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 (parent && parent != &cfqq->rb_node) {
+ __cfqq = rb_entry(parent, struct cfq_queue, rb_node);
+ rb_key += __cfqq->rb_key;
+ } else
+ rb_key += jiffies;
+ } else if (!add_front) {
+ /*
+ * Get our rb key offset. Subtract any residual slice
+ * value carried from last service. A negative resid
+ * count indicates slice overrun, and this should position
+ * the next service time further away in the tree.
+ */
+ rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies;
+ rb_key -= cfqq->slice_resid;
+ cfqq->slice_resid = 0;
+ } else {
+ rb_key = -HZ;
+ __cfqq = cfq_rb_first(service_tree);
+ rb_key += __cfqq ? __cfqq->rb_key : jiffies;
+ }
+
+ if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
+ new_cfqq = 0;
+ /*
+ * same position, nothing more to do
+ */
+ if (rb_key == cfqq->rb_key &&
+ cfqq->service_tree == service_tree)
+ return;
+
+ cfq_rb_erase(&cfqq->rb_node, cfqq->service_tree);
+ cfqq->service_tree = NULL;
+ }
+
+ left = 1;
+ parent = NULL;
+ cfqq->service_tree = service_tree;
+ p = &service_tree->rb.rb_node;
+ while (*p) {
+ struct rb_node **n;
+
+ parent = *p;
+ __cfqq = rb_entry(parent, struct cfq_queue, rb_node);
+
+ /*
+ * sort by key, that represents service time.
+ */
+ if (time_before(rb_key, __cfqq->rb_key))
+ n = &(*p)->rb_left;
+ else {
+ n = &(*p)->rb_right;
+ left = 0;
+ }
+
+ p = n;
+ }
+
+ if (left)
+ service_tree->left = &cfqq->rb_node;
+
+ cfqq->rb_key = rb_key;
+ 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 *
+cfq_prio_tree_lookup(struct cfq_data *cfqd, struct rb_root *root,
+ sector_t sector, struct rb_node **ret_parent,
+ struct rb_node ***rb_link)
+{
+ struct rb_node **p, *parent;
+ struct cfq_queue *cfqq = NULL;
+
+ parent = NULL;
+ p = &root->rb_node;
+ while (*p) {
+ struct rb_node **n;
+
+ parent = *p;
+ cfqq = rb_entry(parent, struct cfq_queue, p_node);
+
+ /*
+ * Sort strictly based on sector. Smallest to the left,
+ * largest to the right.
+ */
+ if (sector > blk_rq_pos(cfqq->next_rq))
+ n = &(*p)->rb_right;
+ else if (sector < blk_rq_pos(cfqq->next_rq))
+ n = &(*p)->rb_left;
+ else
+ break;
+ p = n;
+ cfqq = NULL;
+ }
+
+ *ret_parent = parent;
+ if (rb_link)
+ *rb_link = p;
+ return cfqq;
+}
+
+static void cfq_prio_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+{
+ struct rb_node **p, *parent;
+ struct cfq_queue *__cfqq;
+
+ if (cfqq->p_root) {
+ rb_erase(&cfqq->p_node, cfqq->p_root);
+ cfqq->p_root = NULL;
+ }
+
+ if (cfq_class_idle(cfqq))
+ return;
+ if (!cfqq->next_rq)
+ return;
+
+ cfqq->p_root = &cfqd->prio_trees[cfqq->org_ioprio];
+ __cfqq = cfq_prio_tree_lookup(cfqd, cfqq->p_root,
+ blk_rq_pos(cfqq->next_rq), &parent, &p);
+ if (!__cfqq) {
+ rb_link_node(&cfqq->p_node, parent, p);
+ rb_insert_color(&cfqq->p_node, cfqq->p_root);
+ } else
+ cfqq->p_root = NULL;
+}
+
+/*
+ * Update cfqq's position in the service tree.
+ */
+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(cfqd, cfqq, 0);
+ cfq_prio_tree_add(cfqd, cfqq);
+ }
}
/*
* add to busy list of queues for service, trying to be fair in ordering
* the pending list according to last request service
*/
-static inline void
-cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
+ cfq_log_cfqq(cfqd, cfqq, "add_to_rr");
BUG_ON(cfq_cfqq_on_rr(cfqq));
cfq_mark_cfqq_on_rr(cfqq);
cfqd->busy_queues++;
- cfq_resort_rr_list(cfqq, 0);
+ cfq_resort_rr_list(cfqd, cfqq);
}
-static inline void
-cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+/*
+ * Called when the cfqq no longer has requests pending, remove it from
+ * the service tree.
+ */
+static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
+ cfq_log_cfqq(cfqd, cfqq, "del_from_rr");
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, cfqq->service_tree);
+ cfqq->service_tree = NULL;
+ }
+ if (cfqq->p_root) {
+ rb_erase(&cfqq->p_node, cfqq->p_root);
+ cfqq->p_root = NULL;
+ }
+
+ cfq_group_service_tree_del(cfqd, cfqq->cfqg);
BUG_ON(!cfqd->busy_queues);
cfqd->busy_queues--;
}
/*
* rb tree support functions
*/
-static inline void cfq_del_rq_rb(struct request *rq)
+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)
{
struct cfq_queue *cfqq = RQ_CFQQ(rq);
struct cfq_data *cfqd = cfqq->cfqd;
- struct request *__alias;
+ struct request *__alias, *prev;
cfqq->queued[rq_is_sync(rq)]++;
if (!cfq_cfqq_on_rr(cfqq))
cfq_add_cfqq_rr(cfqd, cfqq);
+
+ /*
+ * 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, cfqd->last_position);
+
+ /*
+ * adjust priority tree position, if ->next_rq changes
+ */
+ if (prev != cfqq->next_rq)
+ cfq_prio_tree_add(cfqd, cfqq);
+
+ BUG_ON(!cfqq->next_rq);
}
-static inline void
-cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq)
+static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq)
{
elv_rb_del(&cfqq->sort_list, rq);
cfqq->queued[rq_is_sync(rq)]--;
cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio)
{
struct task_struct *tsk = current;
- pid_t key = cfq_queue_pid(tsk, bio_data_dir(bio), bio_sync(bio));
+ struct cfq_io_context *cic;
struct cfq_queue *cfqq;
- cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio);
+ cic = cfq_cic_lookup(cfqd, tsk->io_context);
+ if (!cic)
+ return NULL;
+
+ cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio));
if (cfqq) {
sector_t sector = bio->bi_sector + bio_sectors(bio);
return NULL;
}
-static void cfq_activate_request(request_queue_t *q, struct request *rq)
+static void cfq_activate_request(struct request_queue *q, struct request *rq)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
- cfqd->rq_in_driver++;
+ cfqd->rq_in_driver[rq_is_sync(rq)]++;
+ cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d",
+ rq_in_driver(cfqd));
- /*
- * If the depth is larger 1, it really could be queueing. But lets
- * make the mark a little higher - idling could still be good for
- * low queueing, and a low queueing number could also just indicate
- * a SCSI mid layer like behaviour where limit+1 is often seen.
- */
- if (!cfqd->hw_tag && cfqd->rq_in_driver > 4)
- cfqd->hw_tag = 1;
+ cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq);
}
-static void cfq_deactivate_request(request_queue_t *q, struct request *rq)
+static void cfq_deactivate_request(struct request_queue *q, struct request *rq)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
+ const int sync = rq_is_sync(rq);
- WARN_ON(!cfqd->rq_in_driver);
- cfqd->rq_in_driver--;
+ WARN_ON(!cfqd->rq_in_driver[sync]);
+ cfqd->rq_in_driver[sync]--;
+ cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d",
+ rq_in_driver(cfqd));
}
static void cfq_remove_request(struct request *rq)
list_del_init(&rq->queuelist);
cfq_del_rq_rb(rq);
+ cfqq->cfqd->rq_queued--;
if (rq_is_meta(rq)) {
WARN_ON(!cfqq->meta_pending);
cfqq->meta_pending--;
}
}
-static int
-cfq_merge(request_queue_t *q, struct request **req, struct bio *bio)
+static int cfq_merge(struct request_queue *q, struct request **req,
+ struct bio *bio)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct request *__rq;
return ELEVATOR_NO_MERGE;
}
-static void cfq_merged_request(request_queue_t *q, struct request *req,
+static void cfq_merged_request(struct request_queue *q, struct request *req,
int type)
{
if (type == ELEVATOR_FRONT_MERGE) {
}
static void
-cfq_merged_requests(request_queue_t *q, struct request *rq,
+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
*/
if (!list_empty(&rq->queuelist) && !list_empty(&next->queuelist) &&
- time_before(next->start_time, rq->start_time))
+ time_before(rq_fifo_time(next), rq_fifo_time(rq))) {
list_move(&rq->queuelist, &next->queuelist);
+ rq_set_fifo_time(rq, rq_fifo_time(next));
+ }
+ if (cfqq->next_rq == next)
+ cfqq->next_rq = rq;
cfq_remove_request(next);
}
-static inline void
-__cfq_set_active_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+static int cfq_allow_merge(struct request_queue *q, struct request *rq,
+ struct bio *bio)
{
- if (cfqq) {
- /*
- * stop potential idle class queues waiting service
- */
- del_timer(&cfqd->idle_class_timer);
+ struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_io_context *cic;
+ struct cfq_queue *cfqq;
+
+ /*
+ * Disallow merge of a sync bio into an async request.
+ */
+ if (cfq_bio_sync(bio) && !rq_is_sync(rq))
+ return false;
+
+ /*
+ * Lookup the cfqq that this bio will be queued with. Allow
+ * merge only if rq is queued there.
+ */
+ cic = cfq_cic_lookup(cfqd, current->io_context);
+ if (!cic)
+ return false;
+
+ cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio));
+ return cfqq == RQ_CFQQ(rq);
+}
- cfqq->slice_start = jiffies;
+static void __cfq_set_active_queue(struct cfq_data *cfqd,
+ struct cfq_queue *cfqq)
+{
+ 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_left = 0;
+ cfqq->slice_dispatch = 0;
+ cfqq->nr_sectors = 0;
+
+ cfq_clear_cfqq_wait_request(cfqq);
+ cfq_clear_cfqq_must_dispatch(cfqq);
cfq_clear_cfqq_must_alloc_slice(cfqq);
cfq_clear_cfqq_fifo_expire(cfqq);
+ cfq_mark_cfqq_slice_new(cfqq);
+
+ del_timer(&cfqd->idle_slice_timer);
}
cfqd->active_queue = cfqq;
*/
static void
__cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- int preempted)
+ bool timed_out)
{
- unsigned long now = jiffies;
+ cfq_log_cfqq(cfqd, cfqq, "slice expired t=%d", timed_out);
if (cfq_cfqq_wait_request(cfqq))
del_timer(&cfqd->idle_slice_timer);
- if (!preempted && !cfq_cfqq_dispatched(cfqq))
- cfq_schedule_dispatch(cfqd);
-
- cfq_clear_cfqq_must_dispatch(cfqq);
cfq_clear_cfqq_wait_request(cfqq);
- cfq_clear_cfqq_queue_new(cfqq);
+ cfq_clear_cfqq_wait_busy(cfqq);
/*
- * store what was left of this slice, if the queue idled out
- * or was preempted
+ * store what was left of this slice, if the queue idled/timed out
*/
- if (time_after(cfqq->slice_end, now))
- cfqq->slice_left = cfqq->slice_end - now;
- else
- cfqq->slice_left = 0;
+ if (timed_out && !cfq_cfqq_slice_new(cfqq)) {
+ cfqq->slice_resid = cfqq->slice_end - jiffies;
+ cfq_log_cfqq(cfqd, cfqq, "resid=%ld", cfqq->slice_resid);
+ }
- if (cfq_cfqq_on_rr(cfqq))
- cfq_resort_rr_list(cfqq, preempted);
+ 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;
}
-
- cfqd->dispatch_slice = 0;
}
-static inline void cfq_slice_expired(struct cfq_data *cfqd, int preempted)
+static inline void cfq_slice_expired(struct cfq_data *cfqd, bool timed_out)
{
struct cfq_queue *cfqq = cfqd->active_queue;
if (cfqq)
- __cfq_slice_expired(cfqd, cfqq, preempted);
+ __cfq_slice_expired(cfqd, cfqq, timed_out);
}
/*
- * 0
- * 0,1
- * 0,1,2
- * 0,1,2,3
- * 0,1,2,3,4
- * 0,1,2,3,4,5
- * 0,1,2,3,4,5,6
- * 0,1,2,3,4,5,6,7
+ * Get next queue for service. Unless we have a queue preemption,
+ * we'll simply select the first cfqq in the service tree.
*/
-static int cfq_get_next_prio_level(struct cfq_data *cfqd)
+static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
{
- int prio, wrap;
+ struct cfq_rb_root *service_tree =
+ service_tree_for(cfqd->serving_group, cfqd->serving_prio,
+ cfqd->serving_type);
- prio = -1;
- wrap = 0;
- do {
- int p;
+ if (!cfqd->rq_queued)
+ return NULL;
- for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) {
- if (!list_empty(&cfqd->rr_list[p])) {
- prio = p;
- break;
- }
- }
+ /* 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);
+}
- if (prio != -1)
- break;
- cfqd->cur_prio = 0;
- if (++cfqd->cur_end_prio == CFQ_PRIO_LISTS) {
- cfqd->cur_end_prio = 0;
- if (wrap)
- break;
- wrap = 1;
- }
- } while (1);
+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 (unlikely(prio == -1))
- return -1;
+ if (!cfqd->rq_queued)
+ return NULL;
- BUG_ON(prio >= CFQ_PRIO_LISTS);
+ cfqg = cfq_get_next_cfqg(cfqd);
+ if (!cfqg)
+ return NULL;
- list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr);
+ for_each_cfqg_st(cfqg, i, j, st)
+ if ((cfqq = cfq_rb_first(st)) != NULL)
+ return cfqq;
+ return NULL;
+}
- cfqd->cur_prio = prio + 1;
- if (cfqd->cur_prio > cfqd->cur_end_prio) {
- cfqd->cur_end_prio = cfqd->cur_prio;
- cfqd->cur_prio = 0;
- }
- if (cfqd->cur_end_prio == CFQ_PRIO_LISTS) {
- cfqd->cur_prio = 0;
- cfqd->cur_end_prio = 0;
- }
+/*
+ * 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)
+ cfqq = cfq_get_next_queue(cfqd);
- return prio;
+ __cfq_set_active_queue(cfqd, cfqq);
+ return cfqq;
}
-static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
+static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd,
+ struct request *rq)
{
- struct cfq_queue *cfqq = NULL;
+ if (blk_rq_pos(rq) >= cfqd->last_position)
+ return blk_rq_pos(rq) - cfqd->last_position;
+ else
+ return cfqd->last_position - blk_rq_pos(rq);
+}
- if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1) {
- /*
- * if current list is non-empty, grab first entry. if it is
- * empty, get next prio level and grab first entry then if any
- * are spliced
- */
- cfqq = list_entry_cfqq(cfqd->cur_rr.next);
- } else if (!list_empty(&cfqd->busy_rr)) {
- /*
- * If no new queues are available, check if the busy list has
- * some before falling back to idle io.
- */
- cfqq = list_entry_cfqq(cfqd->busy_rr.next);
- } else if (!list_empty(&cfqd->idle_rr)) {
- /*
- * 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
- */
- unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE;
+#define CFQQ_SEEK_THR 8 * 1024
+#define CFQQ_SEEKY(cfqq) ((cfqq)->seek_mean > CFQQ_SEEK_THR)
- if (time_after_eq(jiffies, end))
- cfqq = list_entry_cfqq(cfqd->idle_rr.next);
- else
- mod_timer(&cfqd->idle_class_timer, end);
- }
+static inline int cfq_rq_close(struct cfq_data *cfqd, struct cfq_queue *cfqq,
+ 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;
+}
+
+static struct cfq_queue *cfqq_close(struct cfq_data *cfqd,
+ struct cfq_queue *cur_cfqq)
+{
+ struct rb_root *root = &cfqd->prio_trees[cur_cfqq->org_ioprio];
+ struct rb_node *parent, *node;
+ struct cfq_queue *__cfqq;
+ sector_t sector = cfqd->last_position;
+
+ if (RB_EMPTY_ROOT(root))
+ return NULL;
+
+ /*
+ * First, if we find a request starting at the end of the last
+ * request, choose it.
+ */
+ __cfqq = cfq_prio_tree_lookup(cfqd, root, sector, &parent, NULL);
+ if (__cfqq)
+ return __cfqq;
+
+ /*
+ * If the exact sector wasn't found, the parent of the NULL leaf
+ * will contain the closest sector.
+ */
+ __cfqq = rb_entry(parent, struct cfq_queue, p_node);
+ if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq, false))
+ return __cfqq;
+
+ if (blk_rq_pos(__cfqq->next_rq) < sector)
+ node = rb_next(&__cfqq->p_node);
+ else
+ node = rb_prev(&__cfqq->p_node);
+ if (!node)
+ return NULL;
+
+ __cfqq = rb_entry(node, struct cfq_queue, p_node);
+ if (cfq_rq_close(cfqd, cur_cfqq, __cfqq->next_rq, false))
+ return __cfqq;
+
+ return NULL;
+}
+
+/*
+ * cfqd - obvious
+ * cur_cfqq - passed in so that we don't decide that the current queue is
+ * closely cooperating with itself.
+ *
+ * So, basically we're assuming that that cur_cfqq has dispatched at least
+ * one request, and that cfqd->last_position reflects a position on the disk
+ * associated with the I/O issued by cur_cfqq. I'm not sure this is a valid
+ * assumption.
+ */
+static struct cfq_queue *cfq_close_cooperator(struct cfq_data *cfqd,
+ struct cfq_queue *cur_cfqq)
+{
+ struct cfq_queue *cfqq;
+
+ if (!cfq_cfqq_sync(cur_cfqq))
+ return NULL;
+ if (CFQQ_SEEKY(cur_cfqq))
+ 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.
+ */
+ cfqq = cfqq_close(cfqd, cur_cfqq);
+ 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.
+ */
+ if (!cfq_cfqq_sync(cfqq))
+ return NULL;
+ if (CFQQ_SEEKY(cfqq))
+ return NULL;
+
+ /*
+ * Do not merge queues of different priority classes
+ */
+ if (cfq_class_rt(cfqq) != cfq_class_rt(cur_cfqq))
+ return NULL;
- __cfq_set_active_queue(cfqd, cfqq);
return cfqq;
}
-#define CIC_SEEKY(cic) ((cic)->seek_mean > (128 * 1024))
+/*
+ * Determine whether we should enforce idle window for this queue.
+ */
-static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+{
+ 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) &&
+ !(blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag))
+ return true;
+
+ /*
+ * Otherwise, we do only if they are the last ones
+ * in their service tree.
+ */
+ return service_tree->count == 1;
+}
+static void cfq_arm_slice_timer(struct cfq_data *cfqd)
{
+ struct cfq_queue *cfqq = cfqd->active_queue;
struct cfq_io_context *cic;
unsigned long sl;
+ /*
+ * SSD device without seek penalty, disable idling. But only do so
+ * for devices that support queuing, otherwise we still have a problem
+ * with sync vs async workloads.
+ */
+ if (blk_queue_nonrot(cfqd->queue) && cfqd->hw_tag)
+ return;
+
WARN_ON(!RB_EMPTY_ROOT(&cfqq->sort_list));
- WARN_ON(cfqq != cfqd->active_queue);
+ WARN_ON(cfq_cfqq_slice_new(cfqq));
/*
* idle is disabled, either manually or by past process history
*/
- if (!cfqd->cfq_slice_idle)
- return 0;
- if (!cfq_cfqq_idle_window(cfqq))
- return 0;
+ if (!cfqd->cfq_slice_idle || !cfq_should_idle(cfqd, cfqq))
+ return;
+
+ /*
+ * still active requests from this queue, don't idle
+ */
+ if (cfqq->dispatched)
+ return;
+
/*
* task has exited, don't wait
*/
cic = cfqd->active_cic;
- if (!cic || !cic->ioc->task)
- return 0;
-
- cfq_mark_cfqq_must_dispatch(cfqq);
- cfq_mark_cfqq_wait_request(cfqq);
-
- sl = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle);
+ if (!cic || !atomic_read(&cic->ioc->nr_tasks))
+ return;
/*
- * we don't want to idle for seeks, but we do want to allow
- * fair distribution of slice time for a process doing back-to-back
- * seeks. so allow a little bit of time for him to submit a new rq
+ * If our average think time is larger than the remaining time
+ * slice, then don't idle. This avoids overrunning the allotted
+ * time slice.
*/
- if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic))
- sl = min(sl, msecs_to_jiffies(2));
+ if (sample_valid(cic->ttime_samples) &&
+ (cfqq->slice_end - jiffies < cic->ttime_mean))
+ return;
+
+ cfq_mark_cfqq_wait_request(cfqq);
+
+ sl = cfqd->cfq_slice_idle;
mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
- return 1;
+ cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu", sl);
}
-static void cfq_dispatch_insert(request_queue_t *q, struct request *rq)
+/*
+ * Move request from internal lists to the request queue dispatch list.
+ */
+static void cfq_dispatch_insert(struct request_queue *q, struct request *rq)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_queue *cfqq = RQ_CFQQ(rq);
+ cfq_log_cfqq(cfqd, cfqq, "dispatch_insert");
+
+ cfqq->next_rq = cfq_find_next_rq(cfqd, cfqq, rq);
cfq_remove_request(rq);
- cfqq->on_dispatch[rq_is_sync(rq)]++;
+ cfqq->dispatched++;
elv_dispatch_sort(q, rq);
- rq = list_entry(q->queue_head.prev, struct request, queuelist);
- cfqd->last_sector = rq->sector + rq->nr_sectors;
+ if (cfq_cfqq_sync(cfqq))
+ cfqd->sync_flight++;
+ cfqq->nr_sectors += blk_rq_sectors(rq);
}
/*
* return expired entry, or NULL to just start from scratch in rbtree
*/
-static inline struct request *cfq_check_fifo(struct cfq_queue *cfqq)
+static struct request *cfq_check_fifo(struct cfq_queue *cfqq)
{
- struct cfq_data *cfqd = cfqq->cfqd;
- struct request *rq;
- int fifo;
+ struct request *rq = NULL;
if (cfq_cfqq_fifo_expire(cfqq))
return NULL;
+
+ cfq_mark_cfqq_fifo_expire(cfqq);
+
if (list_empty(&cfqq->fifo))
return NULL;
- fifo = cfq_cfqq_class_sync(cfqq);
rq = rq_entry_fifo(cfqq->fifo.next);
+ if (time_before(jiffies, rq_fifo_time(rq)))
+ rq = NULL;
- if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) {
- cfq_mark_cfqq_fifo_expire(cfqq);
- return rq;
- }
+ cfq_log_cfqq(cfqq->cfqd, cfqq, "fifo=%p", rq);
+ return rq;
+}
- return NULL;
+static inline int
+cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+{
+ const int base_rq = cfqd->cfq_slice_async_rq;
+
+ WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
+
+ return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio));
}
/*
- * Scale schedule slice based on io priority. Use the sync time slice only
- * if a queue is marked sync and has sync io queued. A sync queue with async
- * io only, should not get full sync slice length.
+ * Must be called with the queue_lock held.
*/
-static inline int
-cfq_prio_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+static int cfqq_process_refs(struct cfq_queue *cfqq)
{
- const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)];
+ int process_refs, io_refs;
- WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
+ io_refs = cfqq->allocated[READ] + cfqq->allocated[WRITE];
+ process_refs = atomic_read(&cfqq->ref) - io_refs;
+ BUG_ON(process_refs < 0);
+ return process_refs;
+}
+
+static void cfq_setup_merge(struct cfq_queue *cfqq, struct cfq_queue *new_cfqq)
+{
+ int process_refs, new_process_refs;
+ struct cfq_queue *__cfqq;
+
+ /* Avoid a circular list and skip interim queue merges */
+ while ((__cfqq = new_cfqq->new_cfqq)) {
+ if (__cfqq == cfqq)
+ return;
+ new_cfqq = __cfqq;
+ }
- return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - cfqq->ioprio));
+ process_refs = cfqq_process_refs(cfqq);
+ /*
+ * If the process for the cfqq has gone away, there is no
+ * sense in merging the queues.
+ */
+ if (process_refs == 0)
+ return;
+
+ /*
+ * Merge in the direction of the lesser amount of work.
+ */
+ new_process_refs = cfqq_process_refs(new_cfqq);
+ if (new_process_refs >= process_refs) {
+ cfqq->new_cfqq = new_cfqq;
+ atomic_add(process_refs, &new_cfqq->ref);
+ } else {
+ new_cfqq->new_cfqq = cfqq;
+ atomic_add(new_process_refs, &cfqq->ref);
+ }
}
-static inline void
-cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd,
+ struct cfq_group *cfqg, enum wl_prio_t prio)
{
- cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies;
+ struct cfq_queue *queue;
+ int i;
+ bool key_valid = false;
+ unsigned long lowest_key = 0;
+ enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD;
+
+ 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;
+ cur_best = i;
+ key_valid = true;
+ }
+ }
+
+ return cur_best;
}
-static inline int
-cfq_prio_to_maxrq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg)
{
- const int base_rq = cfqd->cfq_slice_async_rq;
+ unsigned slice;
+ unsigned count;
+ struct cfq_rb_root *st;
+ unsigned group_slice;
- WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
+ if (!cfqg) {
+ cfqd->serving_prio = IDLE_WORKLOAD;
+ cfqd->workload_expires = jiffies + 1;
+ return;
+ }
- return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio));
+ /* Choose next priority. RT > BE > IDLE */
+ if (cfq_group_busy_queues_wl(RT_WORKLOAD, cfqd, cfqg))
+ cfqd->serving_prio = RT_WORKLOAD;
+ else if (cfq_group_busy_queues_wl(BE_WORKLOAD, cfqd, cfqg))
+ cfqd->serving_prio = BE_WORKLOAD;
+ else {
+ cfqd->serving_prio = IDLE_WORKLOAD;
+ cfqd->workload_expires = jiffies + 1;
+ return;
+ }
+
+ /*
+ * For RT and BE, we have to choose also the type
+ * (SYNC, SYNC_NOIDLE, ASYNC), and to compute a workload
+ * expiration time
+ */
+ st = service_tree_for(cfqg, cfqd->serving_prio, cfqd->serving_type);
+ count = st->count;
+
+ /*
+ * check workload expiration, and that we still have other queues ready
+ */
+ if (count && !time_after(jiffies, cfqd->workload_expires))
+ return;
+
+ /* otherwise select new workload type */
+ cfqd->serving_type =
+ 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
+ */
+ 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);
+
+ /* async workload slice is scaled down according to
+ * the sync/async slice ratio. */
+ slice = slice * cfqd->cfq_slice[0] / cfqd->cfq_slice[1];
+ } 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);
}
/*
- * get next queue for service
+ * Select a queue for service. If we have a current active queue,
+ * check whether to continue servicing it, or retrieve and set a new one.
*/
static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
{
- unsigned long now = jiffies;
- struct cfq_queue *cfqq;
+ struct cfq_queue *cfqq, *new_cfqq = NULL;
cfqq = cfqd->active_queue;
if (!cfqq)
goto new_queue;
+ if (!cfqd->rq_queued)
+ return NULL;
+
/*
- * slice has expired
+ * We were waiting for group to get backlogged. Expire the queue
*/
- if (!cfq_cfqq_must_dispatch(cfqq) && time_after(now, cfqq->slice_end))
+ if (cfq_cfqq_wait_busy(cfqq) && !RB_EMPTY_ROOT(&cfqq->sort_list))
goto expire;
/*
- * if queue has requests, dispatch one. if not, check if
- * enough slice is left to wait for one
+ * 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.
*/
if (!RB_EMPTY_ROOT(&cfqq->sort_list))
goto keep_queue;
- else if (cfq_cfqq_dispatched(cfqq)) {
+
+ /*
+ * If another queue has a request waiting within our mean seek
+ * distance, let it run. The expire code will check for close
+ * cooperators and put the close queue at the front of the service
+ * tree. If possible, merge the expiring queue with the new cfqq.
+ */
+ new_cfqq = cfq_close_cooperator(cfqd, cfqq);
+ if (new_cfqq) {
+ if (!cfqq->new_cfqq)
+ cfq_setup_merge(cfqq, new_cfqq);
+ goto expire;
+ }
+
+ /*
+ * No requests pending. If the active queue still has requests in
+ * flight or is idling for a new request, allow either of these
+ * conditions to happen (or time out) before selecting a new queue.
+ */
+ if (timer_pending(&cfqd->idle_slice_timer) ||
+ (cfqq->dispatched && cfq_should_idle(cfqd, cfqq))) {
cfqq = NULL;
goto keep_queue;
- } else if (cfq_cfqq_class_sync(cfqq)) {
- if (cfq_arm_slice_timer(cfqd, cfqq))
- return NULL;
}
expire:
cfq_slice_expired(cfqd, 0);
-new_queue:
- cfqq = cfq_set_active_queue(cfqd);
-keep_queue:
- return cfqq;
+new_queue:
+ /*
+ * Current queue expired. Check if we have to switch to a new
+ * service tree
+ */
+ if (!new_cfqq)
+ cfq_choose_cfqg(cfqd);
+
+ cfqq = cfq_set_active_queue(cfqd, new_cfqq);
+keep_queue:
+ return cfqq;
+}
+
+static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq)
+{
+ int dispatched = 0;
+
+ while (cfqq->next_rq) {
+ cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq);
+ dispatched++;
+ }
+
+ 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;
+}
+
+/*
+ * Drain our current requests. Used for barriers and when switching
+ * io schedulers on-the-fly.
+ */
+static int cfq_forced_dispatch(struct cfq_data *cfqd)
+{
+ struct cfq_queue *cfqq;
+ int dispatched = 0;
+
+ 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 dispatched;
}
-static int
-__cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- int max_dispatch)
+static bool cfq_may_dispatch(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
- int dispatched = 0;
+ unsigned int max_dispatch;
- BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list));
+ /*
+ * Drain async requests before we start sync IO
+ */
+ if (cfq_should_idle(cfqd, cfqq) && cfqd->rq_in_driver[BLK_RW_ASYNC])
+ return false;
- do {
- struct request *rq;
+ /*
+ * If this is an async queue and we have sync IO in flight, let it wait
+ */
+ if (cfqd->sync_flight && !cfq_cfqq_sync(cfqq))
+ return false;
+
+ max_dispatch = cfqd->cfq_quantum;
+ if (cfq_class_idle(cfqq))
+ max_dispatch = 1;
+ /*
+ * Does this cfqq already have too much IO in flight?
+ */
+ if (cfqq->dispatched >= max_dispatch) {
/*
- * follow expired path, else get first next available
+ * idle queue must always only have a single IO in flight
*/
- if ((rq = cfq_check_fifo(cfqq)) == NULL)
- rq = cfqq->next_rq;
+ if (cfq_class_idle(cfqq))
+ return false;
/*
- * finally, insert request into driver dispatch list
+ * We have other queues, don't allow more IO from this one
*/
- cfq_dispatch_insert(cfqd->queue, rq);
-
- cfqd->dispatch_slice++;
- dispatched++;
-
- if (!cfqd->active_cic) {
- atomic_inc(&RQ_CIC(rq)->ioc->refcount);
- cfqd->active_cic = RQ_CIC(rq);
- }
-
- if (RB_EMPTY_ROOT(&cfqq->sort_list))
- break;
+ if (cfqd->busy_queues > 1)
+ return false;
- } while (dispatched < max_dispatch);
+ /*
+ * Sole queue user, no limit
+ */
+ max_dispatch = -1;
+ }
/*
- * if slice end isn't set yet, set it.
+ * Async queues must wait a bit before being allowed dispatch.
+ * We also ramp up the dispatch depth gradually for async IO,
+ * based on the last sync IO we serviced
*/
- if (!cfqq->slice_end)
- cfq_set_prio_slice(cfqd, cfqq);
+ if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) {
+ unsigned long last_sync = jiffies - cfqd->last_delayed_sync;
+ unsigned int depth;
+
+ depth = last_sync / cfqd->cfq_slice[1];
+ if (!depth && !cfqq->dispatched)
+ depth = 1;
+ if (depth < max_dispatch)
+ max_dispatch = depth;
+ }
/*
- * expire an async queue immediately if it has used up its slice. idle
- * queue always expire after 1 dispatch round.
+ * If we're below the current max, allow a dispatch
*/
- if ((!cfq_cfqq_sync(cfqq) &&
- cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
- cfq_class_idle(cfqq) ||
- !cfq_cfqq_idle_window(cfqq))
- cfq_slice_expired(cfqd, 0);
-
- return dispatched;
+ return cfqq->dispatched < max_dispatch;
}
-static int
-cfq_forced_dispatch_cfqqs(struct list_head *list)
+/*
+ * Dispatch a request from cfqq, moving them to the request queue
+ * dispatch list.
+ */
+static bool cfq_dispatch_request(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
- struct cfq_queue *cfqq, *next;
- int dispatched;
-
- dispatched = 0;
- list_for_each_entry_safe(cfqq, next, list, cfq_list) {
- while (cfqq->next_rq) {
- cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq);
- dispatched++;
- }
- BUG_ON(!list_empty(&cfqq->fifo));
- }
+ struct request *rq;
- return dispatched;
-}
+ BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list));
-static int
-cfq_forced_dispatch(struct cfq_data *cfqd)
-{
- int i, dispatched = 0;
+ if (!cfq_may_dispatch(cfqd, cfqq))
+ return false;
- for (i = 0; i < CFQ_PRIO_LISTS; i++)
- dispatched += cfq_forced_dispatch_cfqqs(&cfqd->rr_list[i]);
+ /*
+ * follow expired path, else get first next available
+ */
+ rq = cfq_check_fifo(cfqq);
+ if (!rq)
+ rq = cfqq->next_rq;
- dispatched += cfq_forced_dispatch_cfqqs(&cfqd->busy_rr);
- dispatched += cfq_forced_dispatch_cfqqs(&cfqd->cur_rr);
- dispatched += cfq_forced_dispatch_cfqqs(&cfqd->idle_rr);
+ /*
+ * insert request into driver dispatch list
+ */
+ cfq_dispatch_insert(cfqd->queue, rq);
- cfq_slice_expired(cfqd, 0);
+ if (!cfqd->active_cic) {
+ struct cfq_io_context *cic = RQ_CIC(rq);
- BUG_ON(cfqd->busy_queues);
+ atomic_long_inc(&cic->ioc->refcount);
+ cfqd->active_cic = cic;
+ }
- return dispatched;
+ return true;
}
-static int
-cfq_dispatch_requests(request_queue_t *q, int force)
+/*
+ * Find the cfqq that we need to service and move a request from that to the
+ * dispatch list
+ */
+static int cfq_dispatch_requests(struct request_queue *q, int force)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
- struct cfq_queue *cfqq, *prev_cfqq;
- int dispatched;
+ struct cfq_queue *cfqq;
if (!cfqd->busy_queues)
return 0;
if (unlikely(force))
return cfq_forced_dispatch(cfqd);
- dispatched = 0;
- prev_cfqq = NULL;
- while ((cfqq = cfq_select_queue(cfqd)) != NULL) {
- int max_dispatch;
-
- /*
- * Don't repeat dispatch from the previous queue.
- */
- if (prev_cfqq == cfqq)
- break;
-
- cfq_clear_cfqq_must_dispatch(cfqq);
- cfq_clear_cfqq_wait_request(cfqq);
- del_timer(&cfqd->idle_slice_timer);
-
- max_dispatch = cfqd->cfq_quantum;
- if (cfq_class_idle(cfqq))
- max_dispatch = 1;
+ cfqq = cfq_select_queue(cfqd);
+ if (!cfqq)
+ return 0;
- dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
+ /*
+ * Dispatch a request from this cfqq, if it is allowed
+ */
+ if (!cfq_dispatch_request(cfqd, cfqq))
+ return 0;
- /*
- * If the dispatch cfqq has idling enabled and is still
- * the active queue, break out.
- */
- if (cfq_cfqq_idle_window(cfqq) && cfqd->active_queue)
- break;
+ cfqq->slice_dispatch++;
+ cfq_clear_cfqq_must_dispatch(cfqq);
- prev_cfqq = cfqq;
+ /*
+ * expire an async queue immediately if it has used up its slice. idle
+ * queue always expire after 1 dispatch round.
+ */
+ if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) &&
+ cfqq->slice_dispatch >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
+ cfq_class_idle(cfqq))) {
+ cfqq->slice_end = jiffies + 1;
+ cfq_slice_expired(cfqd, 0);
}
- return dispatched;
+ cfq_log_cfqq(cfqd, cfqq, "dispatched a request");
+ return 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);
if (!atomic_dec_and_test(&cfqq->ref))
return;
+ 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))
+ if (unlikely(cfqd->active_queue == cfqq)) {
__cfq_slice_expired(cfqd, cfqq, 0);
+ cfq_schedule_dispatch(cfqd);
+ }
- /*
- * it's on the empty list and still hashed
- */
- list_del(&cfqq->cfq_list);
- hlist_del(&cfqq->cfq_hash);
+ 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);
}
-static struct cfq_queue *
-__cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned int prio,
- const int hashval)
+/*
+ * Must always be called with the rcu_read_lock() held
+ */
+static void
+__call_for_each_cic(struct io_context *ioc,
+ void (*func)(struct io_context *, struct cfq_io_context *))
{
- struct hlist_head *hash_list = &cfqd->cfq_hash[hashval];
- struct hlist_node *entry;
- struct cfq_queue *__cfqq;
+ struct cfq_io_context *cic;
+ struct hlist_node *n;
- hlist_for_each_entry(__cfqq, entry, hash_list, cfq_hash) {
- const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->org_ioprio_class, __cfqq->org_ioprio);
+ hlist_for_each_entry_rcu(cic, n, &ioc->cic_list, cic_list)
+ func(ioc, cic);
+}
- if (__cfqq->key == key && (__p == prio || !prio))
- return __cfqq;
- }
+/*
+ * Call func for each cic attached to this ioc.
+ */
+static void
+call_for_each_cic(struct io_context *ioc,
+ void (*func)(struct io_context *, struct cfq_io_context *))
+{
+ rcu_read_lock();
+ __call_for_each_cic(ioc, func);
+ rcu_read_unlock();
+}
- return NULL;
+static void cfq_cic_free_rcu(struct rcu_head *head)
+{
+ struct cfq_io_context *cic;
+
+ cic = container_of(head, struct cfq_io_context, rcu_head);
+
+ kmem_cache_free(cfq_ioc_pool, cic);
+ elv_ioc_count_dec(cfq_ioc_count);
+
+ if (ioc_gone) {
+ /*
+ * CFQ scheduler is exiting, grab exit lock and check
+ * the pending io context count. If it hits zero,
+ * complete ioc_gone and set it back to NULL
+ */
+ spin_lock(&ioc_gone_lock);
+ if (ioc_gone && !elv_ioc_count_read(cfq_ioc_count)) {
+ complete(ioc_gone);
+ ioc_gone = NULL;
+ }
+ spin_unlock(&ioc_gone_lock);
+ }
}
-static struct cfq_queue *
-cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned short prio)
+static void cfq_cic_free(struct cfq_io_context *cic)
{
- return __cfq_find_cfq_hash(cfqd, key, prio, hash_long(key, CFQ_QHASH_SHIFT));
+ call_rcu(&cic->rcu_head, cfq_cic_free_rcu);
}
-static void cfq_free_io_context(struct io_context *ioc)
+static void cic_free_func(struct io_context *ioc, struct cfq_io_context *cic)
{
- struct cfq_io_context *__cic;
- struct rb_node *n;
- int freed = 0;
+ unsigned long flags;
- while ((n = rb_first(&ioc->cic_root)) != NULL) {
- __cic = rb_entry(n, struct cfq_io_context, rb_node);
- rb_erase(&__cic->rb_node, &ioc->cic_root);
- kmem_cache_free(cfq_ioc_pool, __cic);
- freed++;
- }
+ BUG_ON(!cic->dead_key);
- elv_ioc_count_mod(ioc_count, -freed);
+ spin_lock_irqsave(&ioc->lock, flags);
+ radix_tree_delete(&ioc->radix_root, cic->dead_key);
+ hlist_del_rcu(&cic->cic_list);
+ spin_unlock_irqrestore(&ioc->lock, flags);
+
+ cfq_cic_free(cic);
+}
- if (ioc_gone && !elv_ioc_count_read(ioc_count))
- complete(ioc_gone);
+/*
+ * Must be called with rcu_read_lock() held or preemption otherwise disabled.
+ * Only two callers of this - ->dtor() which is called with the rcu_read_lock(),
+ * and ->trim() which is called with the task lock held
+ */
+static void cfq_free_io_context(struct io_context *ioc)
+{
+ /*
+ * ioc->refcount is zero here, or we are called from elv_unregister(),
+ * so no more cic's are allowed to be linked into this ioc. So it
+ * should be ok to iterate over the known list, we will see all cic's
+ * since no new ones are added.
+ */
+ __call_for_each_cic(ioc, cic_free_func);
}
static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
- if (unlikely(cfqq == cfqd->active_queue))
+ struct cfq_queue *__cfqq, *next;
+
+ if (unlikely(cfqq == cfqd->active_queue)) {
__cfq_slice_expired(cfqd, cfqq, 0);
+ cfq_schedule_dispatch(cfqd);
+ }
+
+ /*
+ * If this queue was scheduled to merge with another queue, be
+ * sure to drop the reference taken on that queue (and others in
+ * the merge chain). See cfq_setup_merge and cfq_merge_cfqqs.
+ */
+ __cfqq = cfqq->new_cfqq;
+ while (__cfqq) {
+ if (__cfqq == cfqq) {
+ WARN(1, "cfqq->new_cfqq loop detected\n");
+ break;
+ }
+ next = __cfqq->new_cfqq;
+ cfq_put_queue(__cfqq);
+ __cfqq = next;
+ }
cfq_put_queue(cfqq);
}
static void __cfq_exit_single_io_context(struct cfq_data *cfqd,
struct cfq_io_context *cic)
{
+ struct io_context *ioc = cic->ioc;
+
list_del_init(&cic->queue_list);
+
+ /*
+ * Make sure key == NULL is seen for dead queues
+ */
smp_wmb();
+ cic->dead_key = (unsigned long) cic->key;
cic->key = NULL;
- if (cic->cfqq[ASYNC]) {
- cfq_exit_cfqq(cfqd, cic->cfqq[ASYNC]);
- cic->cfqq[ASYNC] = NULL;
+ if (ioc->ioc_data == cic)
+ rcu_assign_pointer(ioc->ioc_data, NULL);
+
+ if (cic->cfqq[BLK_RW_ASYNC]) {
+ cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]);
+ cic->cfqq[BLK_RW_ASYNC] = NULL;
}
- if (cic->cfqq[SYNC]) {
- cfq_exit_cfqq(cfqd, cic->cfqq[SYNC]);
- cic->cfqq[SYNC] = NULL;
+ if (cic->cfqq[BLK_RW_SYNC]) {
+ cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_SYNC]);
+ cic->cfqq[BLK_RW_SYNC] = NULL;
}
}
-
-/*
- * Called with interrupts disabled
- */
-static void cfq_exit_single_io_context(struct cfq_io_context *cic)
+static void cfq_exit_single_io_context(struct io_context *ioc,
+ struct cfq_io_context *cic)
{
struct cfq_data *cfqd = cic->key;
if (cfqd) {
- request_queue_t *q = cfqd->queue;
+ struct request_queue *q = cfqd->queue;
+ unsigned long flags;
- spin_lock_irq(q->queue_lock);
- __cfq_exit_single_io_context(cfqd, cic);
- spin_unlock_irq(q->queue_lock);
+ spin_lock_irqsave(q->queue_lock, flags);
+
+ /*
+ * Ensure we get a fresh copy of the ->key to prevent
+ * race between exiting task and queue
+ */
+ smp_read_barrier_depends();
+ if (cic->key)
+ __cfq_exit_single_io_context(cfqd, cic);
+
+ spin_unlock_irqrestore(q->queue_lock, flags);
}
}
+/*
+ * The process that ioc belongs to has exited, we need to clean up
+ * and put the internal structures we have that belongs to that process.
+ */
static void cfq_exit_io_context(struct io_context *ioc)
{
- struct cfq_io_context *__cic;
- struct rb_node *n;
-
- /*
- * put the reference this task is holding to the various queues
- */
-
- n = rb_first(&ioc->cic_root);
- while (n != NULL) {
- __cic = rb_entry(n, struct cfq_io_context, rb_node);
-
- cfq_exit_single_io_context(__cic);
- n = rb_next(n);
- }
+ call_for_each_cic(ioc, cfq_exit_single_io_context);
}
static struct cfq_io_context *
{
struct cfq_io_context *cic;
- cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask, cfqd->queue->node);
+ cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask | __GFP_ZERO,
+ cfqd->queue->node);
if (cic) {
- memset(cic, 0, sizeof(*cic));
cic->last_end_request = jiffies;
INIT_LIST_HEAD(&cic->queue_list);
+ INIT_HLIST_NODE(&cic->cic_list);
cic->dtor = cfq_free_io_context;
cic->exit = cfq_exit_io_context;
- elv_ioc_count_inc(ioc_count);
+ elv_ioc_count_inc(cfq_ioc_count);
}
return cic;
}
-static void cfq_init_prio_data(struct cfq_queue *cfqq)
+static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc)
{
struct task_struct *tsk = current;
int ioprio_class;
if (!cfq_cfqq_prio_changed(cfqq))
return;
- ioprio_class = IOPRIO_PRIO_CLASS(tsk->ioprio);
+ ioprio_class = IOPRIO_PRIO_CLASS(ioc->ioprio);
switch (ioprio_class) {
- default:
- printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class);
- case IOPRIO_CLASS_NONE:
- /*
- * no prio set, place us in the middle of the BE classes
- */
- cfqq->ioprio = task_nice_ioprio(tsk);
- cfqq->ioprio_class = IOPRIO_CLASS_BE;
- break;
- case IOPRIO_CLASS_RT:
- cfqq->ioprio = task_ioprio(tsk);
- cfqq->ioprio_class = IOPRIO_CLASS_RT;
- break;
- case IOPRIO_CLASS_BE:
- cfqq->ioprio = task_ioprio(tsk);
- cfqq->ioprio_class = IOPRIO_CLASS_BE;
- break;
- case IOPRIO_CLASS_IDLE:
- cfqq->ioprio_class = IOPRIO_CLASS_IDLE;
- cfqq->ioprio = 7;
- cfq_clear_cfqq_idle_window(cfqq);
- break;
+ default:
+ printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class);
+ case IOPRIO_CLASS_NONE:
+ /*
+ * no prio set, inherit CPU scheduling settings
+ */
+ cfqq->ioprio = task_nice_ioprio(tsk);
+ cfqq->ioprio_class = task_nice_ioclass(tsk);
+ break;
+ case IOPRIO_CLASS_RT:
+ cfqq->ioprio = task_ioprio(ioc);
+ cfqq->ioprio_class = IOPRIO_CLASS_RT;
+ break;
+ case IOPRIO_CLASS_BE:
+ cfqq->ioprio = task_ioprio(ioc);
+ cfqq->ioprio_class = IOPRIO_CLASS_BE;
+ break;
+ case IOPRIO_CLASS_IDLE:
+ cfqq->ioprio_class = IOPRIO_CLASS_IDLE;
+ cfqq->ioprio = 7;
+ cfq_clear_cfqq_idle_window(cfqq);
+ break;
}
/*
*/
cfqq->org_ioprio = cfqq->ioprio;
cfqq->org_ioprio_class = cfqq->ioprio_class;
-
- if (cfq_cfqq_on_rr(cfqq))
- cfq_resort_rr_list(cfqq, 0);
-
cfq_clear_cfqq_prio_changed(cfqq);
}
-static inline void changed_ioprio(struct cfq_io_context *cic)
+static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic)
{
struct cfq_data *cfqd = cic->key;
struct cfq_queue *cfqq;
spin_lock_irqsave(cfqd->queue->queue_lock, flags);
- cfqq = cic->cfqq[ASYNC];
+ cfqq = cic->cfqq[BLK_RW_ASYNC];
if (cfqq) {
struct cfq_queue *new_cfqq;
- new_cfqq = cfq_get_queue(cfqd, CFQ_KEY_ASYNC, cic->ioc->task,
- GFP_ATOMIC);
+ new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->ioc,
+ GFP_ATOMIC);
if (new_cfqq) {
- cic->cfqq[ASYNC] = new_cfqq;
+ cic->cfqq[BLK_RW_ASYNC] = new_cfqq;
cfq_put_queue(cfqq);
}
}
- cfqq = cic->cfqq[SYNC];
+ cfqq = cic->cfqq[BLK_RW_SYNC];
if (cfqq)
cfq_mark_cfqq_prio_changed(cfqq);
static void cfq_ioc_set_ioprio(struct io_context *ioc)
{
- struct cfq_io_context *cic;
- struct rb_node *n;
-
+ call_for_each_cic(ioc, changed_ioprio);
ioc->ioprio_changed = 0;
+}
+
+static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
+ pid_t pid, bool is_sync)
+{
+ RB_CLEAR_NODE(&cfqq->rb_node);
+ RB_CLEAR_NODE(&cfqq->p_node);
+ INIT_LIST_HEAD(&cfqq->fifo);
+
+ atomic_set(&cfqq->ref, 0);
+ cfqq->cfqd = cfqd;
+
+ cfq_mark_cfqq_prio_changed(cfqq);
+
+ if (is_sync) {
+ if (!cfq_class_idle(cfqq))
+ cfq_mark_cfqq_idle_window(cfqq);
+ cfq_mark_cfqq_sync(cfqq);
+ }
+ 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;
- n = rb_first(&ioc->cic_root);
- while (n != NULL) {
- cic = rb_entry(n, struct cfq_io_context, rb_node);
+ q = cfqd->queue;
+
+ spin_lock_irqsave(q->queue_lock, flags);
- changed_ioprio(cic);
- n = rb_next(n);
+ 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_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk,
- gfp_t gfp_mask)
+cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync,
+ struct io_context *ioc, gfp_t gfp_mask)
{
- const int hashval = hash_long(key, CFQ_QHASH_SHIFT);
struct cfq_queue *cfqq, *new_cfqq = NULL;
- unsigned short ioprio;
+ struct cfq_io_context *cic;
+ struct cfq_group *cfqg;
retry:
- ioprio = tsk->ioprio;
- cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval);
+ 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) {
+ /*
+ * Always try a new alloc if we fell back to the OOM cfqq
+ * originally, since it should just be a temporary situation.
+ */
+ if (!cfqq || cfqq == &cfqd->oom_cfqq) {
+ cfqq = NULL;
if (new_cfqq) {
cfqq = new_cfqq;
new_cfqq = NULL;
} else if (gfp_mask & __GFP_WAIT) {
- /*
- * Inform the allocator of the fact that we will
- * just repeat this allocation if it fails, to allow
- * the allocator to do whatever it needs to attempt to
- * free memory.
- */
spin_unlock_irq(cfqd->queue->queue_lock);
- new_cfqq = kmem_cache_alloc_node(cfq_pool, gfp_mask|__GFP_NOFAIL, cfqd->queue->node);
+ new_cfqq = kmem_cache_alloc_node(cfq_pool,
+ gfp_mask | __GFP_ZERO,
+ cfqd->queue->node);
spin_lock_irq(cfqd->queue->queue_lock);
- goto retry;
+ if (new_cfqq)
+ goto retry;
} else {
- cfqq = kmem_cache_alloc_node(cfq_pool, gfp_mask, cfqd->queue->node);
- if (!cfqq)
- goto out;
+ cfqq = kmem_cache_alloc_node(cfq_pool,
+ gfp_mask | __GFP_ZERO,
+ cfqd->queue->node);
}
- memset(cfqq, 0, sizeof(*cfqq));
-
- INIT_HLIST_NODE(&cfqq->cfq_hash);
- INIT_LIST_HEAD(&cfqq->cfq_list);
- INIT_LIST_HEAD(&cfqq->fifo);
-
- cfqq->key = key;
- hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]);
- atomic_set(&cfqq->ref, 0);
- cfqq->cfqd = cfqd;
- /*
- * set ->slice_left to allow preemption for a new process
- */
- cfqq->slice_left = 2 * cfqd->cfq_slice_idle;
- cfq_mark_cfqq_idle_window(cfqq);
- cfq_mark_cfqq_prio_changed(cfqq);
- cfq_mark_cfqq_queue_new(cfqq);
- cfq_init_prio_data(cfqq);
+ 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 (new_cfqq)
kmem_cache_free(cfq_pool, new_cfqq);
+ return cfqq;
+}
+
+static struct cfq_queue **
+cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio)
+{
+ switch (ioprio_class) {
+ case IOPRIO_CLASS_RT:
+ return &cfqd->async_cfqq[0][ioprio];
+ case IOPRIO_CLASS_BE:
+ return &cfqd->async_cfqq[1][ioprio];
+ case IOPRIO_CLASS_IDLE:
+ return &cfqd->async_idle_cfqq;
+ default:
+ BUG();
+ }
+}
+
+static struct cfq_queue *
+cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc,
+ gfp_t gfp_mask)
+{
+ const int ioprio = task_ioprio(ioc);
+ const int ioprio_class = task_ioprio_class(ioc);
+ struct cfq_queue **async_cfqq = NULL;
+ struct cfq_queue *cfqq = NULL;
+
+ if (!is_sync) {
+ async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio);
+ cfqq = *async_cfqq;
+ }
+
+ if (!cfqq)
+ cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask);
+
+ /*
+ * pin the queue now that it's allocated, scheduler exit will prune it
+ */
+ if (!is_sync && !(*async_cfqq)) {
+ atomic_inc(&cfqq->ref);
+ *async_cfqq = cfqq;
+ }
+
atomic_inc(&cfqq->ref);
-out:
- WARN_ON((gfp_mask & __GFP_WAIT) && !cfqq);
return cfqq;
}
+/*
+ * We drop cfq io contexts lazily, so we may find a dead one.
+ */
static void
-cfq_drop_dead_cic(struct io_context *ioc, struct cfq_io_context *cic)
+cfq_drop_dead_cic(struct cfq_data *cfqd, struct io_context *ioc,
+ struct cfq_io_context *cic)
{
+ unsigned long flags;
+
WARN_ON(!list_empty(&cic->queue_list));
- rb_erase(&cic->rb_node, &ioc->cic_root);
- kmem_cache_free(cfq_ioc_pool, cic);
- elv_ioc_count_dec(ioc_count);
+
+ spin_lock_irqsave(&ioc->lock, flags);
+
+ BUG_ON(ioc->ioc_data == cic);
+
+ radix_tree_delete(&ioc->radix_root, (unsigned long) cfqd);
+ hlist_del_rcu(&cic->cic_list);
+ spin_unlock_irqrestore(&ioc->lock, flags);
+
+ cfq_cic_free(cic);
}
-static struct cfq_io_context *
-cfq_cic_rb_lookup(struct cfq_data *cfqd, struct io_context *ioc)
-{
- struct rb_node *n;
- struct cfq_io_context *cic;
- void *k, *key = cfqd;
+static struct cfq_io_context *
+cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc)
+{
+ struct cfq_io_context *cic;
+ unsigned long flags;
+ void *k;
+
+ if (unlikely(!ioc))
+ return NULL;
+
+ rcu_read_lock();
+
+ /*
+ * we maintain a last-hit cache, to avoid browsing over the tree
+ */
+ cic = rcu_dereference(ioc->ioc_data);
+ if (cic && cic->key == cfqd) {
+ rcu_read_unlock();
+ return cic;
+ }
-restart:
- n = ioc->cic_root.rb_node;
- while (n) {
- cic = rb_entry(n, struct cfq_io_context, rb_node);
+ do {
+ cic = radix_tree_lookup(&ioc->radix_root, (unsigned long) cfqd);
+ rcu_read_unlock();
+ if (!cic)
+ break;
/* ->key must be copied to avoid race with cfq_exit_queue() */
k = cic->key;
if (unlikely(!k)) {
- cfq_drop_dead_cic(ioc, cic);
- goto restart;
+ cfq_drop_dead_cic(cfqd, ioc, cic);
+ rcu_read_lock();
+ continue;
}
- if (key < k)
- n = n->rb_left;
- else if (key > k)
- n = n->rb_right;
- else
- return cic;
- }
+ spin_lock_irqsave(&ioc->lock, flags);
+ rcu_assign_pointer(ioc->ioc_data, cic);
+ spin_unlock_irqrestore(&ioc->lock, flags);
+ break;
+ } while (1);
- return NULL;
+ return cic;
}
-static inline void
-cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc,
- struct cfq_io_context *cic)
+/*
+ * Add cic into ioc, using cfqd as the search key. This enables us to lookup
+ * the process specific cfq io context when entered from the block layer.
+ * Also adds the cic to a per-cfqd list, used when this queue is removed.
+ */
+static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc,
+ struct cfq_io_context *cic, gfp_t gfp_mask)
{
- struct rb_node **p;
- struct rb_node *parent;
- struct cfq_io_context *__cic;
unsigned long flags;
- void *k;
+ int ret;
- cic->ioc = ioc;
- cic->key = cfqd;
+ ret = radix_tree_preload(gfp_mask);
+ if (!ret) {
+ cic->ioc = ioc;
+ cic->key = cfqd;
-restart:
- parent = NULL;
- p = &ioc->cic_root.rb_node;
- while (*p) {
- parent = *p;
- __cic = rb_entry(parent, struct cfq_io_context, rb_node);
- /* ->key must be copied to avoid race with cfq_exit_queue() */
- k = __cic->key;
- if (unlikely(!k)) {
- cfq_drop_dead_cic(ioc, __cic);
- goto restart;
- }
+ spin_lock_irqsave(&ioc->lock, flags);
+ ret = radix_tree_insert(&ioc->radix_root,
+ (unsigned long) cfqd, cic);
+ if (!ret)
+ hlist_add_head_rcu(&cic->cic_list, &ioc->cic_list);
+ spin_unlock_irqrestore(&ioc->lock, flags);
- if (cic->key < k)
- p = &(*p)->rb_left;
- else if (cic->key > k)
- p = &(*p)->rb_right;
- else
- BUG();
+ radix_tree_preload_end();
+
+ if (!ret) {
+ spin_lock_irqsave(cfqd->queue->queue_lock, flags);
+ list_add(&cic->queue_list, &cfqd->cic_list);
+ spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
+ }
}
- rb_link_node(&cic->rb_node, parent, p);
- rb_insert_color(&cic->rb_node, &ioc->cic_root);
+ if (ret)
+ printk(KERN_ERR "cfq: cic link failed!\n");
- spin_lock_irqsave(cfqd->queue->queue_lock, flags);
- list_add(&cic->queue_list, &cfqd->cic_list);
- spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
+ return ret;
}
/*
if (!ioc)
return NULL;
- cic = cfq_cic_rb_lookup(cfqd, ioc);
+ cic = cfq_cic_lookup(cfqd, ioc);
if (cic)
goto out;
if (cic == NULL)
goto err;
- cfq_cic_link(cfqd, ioc, cic);
+ if (cfq_cic_link(cfqd, ioc, cic, gfp_mask))
+ goto err_free;
+
out:
smp_read_barrier_depends();
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);
err:
put_io_context(ioc);
return NULL;
static void
cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_io_context *cic)
{
- unsigned long elapsed, ttime;
-
- /*
- * if this context already has stuff queued, thinktime is from
- * last queue not last end
- */
-#if 0
- if (time_after(cic->last_end_request, cic->last_queue))
- elapsed = jiffies - cic->last_end_request;
- else
- elapsed = jiffies - cic->last_queue;
-#else
- elapsed = jiffies - cic->last_end_request;
-#endif
-
- ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle);
+ unsigned long elapsed = jiffies - cic->last_end_request;
+ unsigned long ttime = min(elapsed, 2UL * cfqd->cfq_slice_idle);
cic->ttime_samples = (7*cic->ttime_samples + 256) / 8;
cic->ttime_total = (7*cic->ttime_total + 256*ttime) / 8;
}
static void
-cfq_update_io_seektime(struct cfq_io_context *cic, struct request *rq)
+cfq_update_io_seektime(struct cfq_data *cfqd, struct cfq_queue *cfqq,
+ struct request *rq)
{
sector_t sdist;
u64 total;
- if (cic->last_request_pos < rq->sector)
- sdist = rq->sector - cic->last_request_pos;
+ if (!cfqq->last_request_pos)
+ sdist = 0;
+ else if (cfqq->last_request_pos < blk_rq_pos(rq))
+ sdist = blk_rq_pos(rq) - cfqq->last_request_pos;
else
- sdist = cic->last_request_pos - rq->sector;
+ sdist = cfqq->last_request_pos - blk_rq_pos(rq);
/*
* Don't allow the seek distance to get too large from the
* odd fragment, pagein, etc
*/
- if (cic->seek_samples <= 60) /* second&third seek */
- sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*1024);
+ if (cfqq->seek_samples <= 60) /* second&third seek */
+ sdist = min(sdist, (cfqq->seek_mean * 4) + 2*1024*1024);
else
- sdist = min(sdist, (cic->seek_mean * 4) + 2*1024*64);
+ sdist = min(sdist, (cfqq->seek_mean * 4) + 2*1024*64);
- cic->seek_samples = (7*cic->seek_samples + 256) / 8;
- cic->seek_total = (7*cic->seek_total + (u64)256*sdist) / 8;
- total = cic->seek_total + (cic->seek_samples/2);
- do_div(total, cic->seek_samples);
- cic->seek_mean = (sector_t)total;
+ cfqq->seek_samples = (7*cfqq->seek_samples + 256) / 8;
+ cfqq->seek_total = (7*cfqq->seek_total + (u64)256*sdist) / 8;
+ total = cfqq->seek_total + (cfqq->seek_samples/2);
+ do_div(total, cfqq->seek_samples);
+ cfqq->seek_mean = (sector_t)total;
+
+ /*
+ * If this cfqq is shared between multiple processes, check to
+ * make sure that those processes are still issuing I/Os within
+ * the mean seek distance. If not, it may be time to break the
+ * queues apart again.
+ */
+ if (cfq_cfqq_coop(cfqq)) {
+ if (CFQQ_SEEKY(cfqq) && !cfqq->seeky_start)
+ cfqq->seeky_start = jiffies;
+ else if (!CFQQ_SEEKY(cfqq))
+ cfqq->seeky_start = 0;
+ }
}
/*
cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
struct cfq_io_context *cic)
{
- int enable_idle = cfq_cfqq_idle_window(cfqq);
+ int old_idle, enable_idle;
+
+ /*
+ * Don't idle for async or idle io prio class
+ */
+ if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq))
+ return;
+
+ enable_idle = old_idle = cfq_cfqq_idle_window(cfqq);
+
+ if (cfqq->queued[0] + cfqq->queued[1] >= 4)
+ cfq_mark_cfqq_deep(cfqq);
- if (!cic->ioc->task || !cfqd->cfq_slice_idle ||
- (cfqd->hw_tag && CIC_SEEKY(cic)))
+ if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle ||
+ (!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)
enable_idle = 1;
}
- if (enable_idle)
- cfq_mark_cfqq_idle_window(cfqq);
- else
- cfq_clear_cfqq_idle_window(cfqq);
+ if (old_idle != enable_idle) {
+ cfq_log_cfqq(cfqd, cfqq, "idle=%d", enable_idle);
+ if (enable_idle)
+ cfq_mark_cfqq_idle_window(cfqq);
+ else
+ cfq_clear_cfqq_idle_window(cfqq);
+ }
}
-
/*
* Check if new_cfqq should preempt the currently active queue. Return 0 for
* no or if we aren't sure, a 1 will cause a preempt.
*/
-static int
+static bool
cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
struct request *rq)
{
- struct cfq_queue *cfqq = cfqd->active_queue;
-
- if (cfq_class_idle(new_cfqq))
- return 0;
+ struct cfq_queue *cfqq;
+ cfqq = cfqd->active_queue;
if (!cfqq)
- return 0;
+ return false;
+
+ if (cfq_class_idle(new_cfqq))
+ return false;
if (cfq_class_idle(cfqq))
- return 1;
- if (!cfq_cfqq_wait_request(new_cfqq))
- return 0;
+ return true;
+
/*
- * if it doesn't have slice left, forget it
+ * Don't allow a non-RT request to preempt an ongoing RT cfqq timeslice.
*/
- if (new_cfqq->slice_left < cfqd->cfq_slice_idle)
- return 0;
+ if (cfq_class_rt(cfqq) && !cfq_class_rt(new_cfqq))
+ return false;
+
/*
* if the new request is sync, but the currently running queue is
* not, let the sync request have priority.
*/
if (rq_is_sync(rq) && !cfq_cfqq_sync(cfqq))
- return 1;
+ 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 (rq_is_meta(rq) && !cfqq->meta_pending)
- return 1;
+ return true;
- return 0;
+ /*
+ * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice.
+ */
+ if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq))
+ return true;
+
+ if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq))
+ return false;
+
+ /*
+ * 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, true))
+ return true;
+
+ return false;
}
/*
*/
static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
+ cfq_log_cfqq(cfqd, cfqq, "preempt");
cfq_slice_expired(cfqd, 1);
- if (!cfqq->slice_left)
- cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2;
-
/*
* Put the new queue at the front of the of the current list,
* so we know that it will be selected next.
*/
BUG_ON(!cfq_cfqq_on_rr(cfqq));
- list_move(&cfqq->cfq_list, &cfqd->cur_rr);
- cfqq->slice_end = cfqq->slice_left + jiffies;
+ cfq_service_tree_add(cfqd, cfqq, 1);
+
+ cfqq->slice_end = 0;
+ cfq_mark_cfqq_slice_new(cfqq);
}
/*
{
struct cfq_io_context *cic = RQ_CIC(rq);
+ cfqd->rq_queued++;
if (rq_is_meta(rq))
cfqq->meta_pending++;
- /*
- * check if this request is a better next-serve candidate)) {
- */
- cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq);
- BUG_ON(!cfqq->next_rq);
-
- /*
- * we never wait for an async request and we don't allow preemption
- * of an async request. so just return early
- */
- if (!rq_is_sync(rq)) {
- /*
- * sync process issued an async request, if it's waiting
- * then expire it and kick rq handling.
- */
- if (cic == cfqd->active_cic &&
- del_timer(&cfqd->idle_slice_timer)) {
- cfq_slice_expired(cfqd, 0);
- blk_start_queueing(cfqd->queue);
- }
- return;
- }
-
cfq_update_io_thinktime(cfqd, cic);
- cfq_update_io_seektime(cic, rq);
+ cfq_update_io_seektime(cfqd, cfqq, rq);
cfq_update_idle_window(cfqd, cfqq, cic);
- cic->last_queue = jiffies;
- cic->last_request_pos = rq->sector + rq->nr_sectors;
+ cfqq->last_request_pos = blk_rq_pos(rq) + blk_rq_sectors(rq);
if (cfqq == cfqd->active_queue) {
/*
- * if we are waiting for a request for this queue, let it rip
- * immediately and flag that we must not expire this queue
- * just now
+ * Remember that we saw a request from this process, but
+ * don't start queuing just yet. Otherwise we risk seeing lots
+ * of tiny requests, because we disrupt the normal plugging
+ * and merging. If the request is already larger than a single
+ * page, let it rip immediately. For that case we assume that
+ * merging is already done. Ditto for a busy system that
+ * has other work pending, don't risk delaying until the
+ * idle timer unplug to continue working.
*/
if (cfq_cfqq_wait_request(cfqq)) {
- cfq_mark_cfqq_must_dispatch(cfqq);
- del_timer(&cfqd->idle_slice_timer);
- blk_start_queueing(cfqd->queue);
+ if (blk_rq_bytes(rq) > PAGE_CACHE_SIZE ||
+ cfqd->busy_queues > 1) {
+ del_timer(&cfqd->idle_slice_timer);
+ 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)) {
/*
* not the active queue - expire current slice if it is
* idle and has expired it's mean thinktime or this new queue
- * has some old slice time left and is of higher priority
+ * has some old slice time left and is of higher priority or
+ * this new queue is RT and the current one is BE
*/
cfq_preempt_queue(cfqd, cfqq);
- cfq_mark_cfqq_must_dispatch(cfqq);
- blk_start_queueing(cfqd->queue);
+ __blk_run_queue(cfqd->queue);
}
}
-static void cfq_insert_request(request_queue_t *q, struct request *rq)
+static void cfq_insert_request(struct request_queue *q, struct request *rq)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_queue *cfqq = RQ_CFQQ(rq);
- cfq_init_prio_data(cfqq);
-
- cfq_add_rq_rb(rq);
+ cfq_log_cfqq(cfqd, cfqq, "insert_request");
+ cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc);
+ rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]);
list_add_tail(&rq->queuelist, &cfqq->fifo);
+ cfq_add_rq_rb(rq);
cfq_rq_enqueued(cfqd, cfqq, rq);
}
-static void cfq_completed_request(request_queue_t *q, struct request *rq)
+/*
+ * Update hw_tag based on peak queue depth over 50 samples under
+ * sufficient load.
+ */
+static void cfq_update_hw_tag(struct cfq_data *cfqd)
+{
+ struct cfq_queue *cfqq = cfqd->active_queue;
+
+ 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)
+ return;
+
+ /*
+ * If active queue hasn't enough requests and can idle, cfq might not
+ * dispatch sufficient requests to hardware. Don't zero hw_tag in this
+ * case
+ */
+ if (cfqq && cfq_cfqq_idle_window(cfqq) &&
+ cfqq->dispatched + cfqq->queued[0] + cfqq->queued[1] <
+ CFQ_HW_QUEUE_MIN && rq_in_driver(cfqd) < CFQ_HW_QUEUE_MIN)
+ return;
+
+ if (cfqd->hw_tag_samples++ < 50)
+ return;
+
+ 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;
+
+ return false;
+}
+
+static void cfq_completed_request(struct request_queue *q, struct request *rq)
{
struct cfq_queue *cfqq = RQ_CFQQ(rq);
struct cfq_data *cfqd = cfqq->cfqd;
unsigned long now;
now = jiffies;
+ cfq_log_cfqq(cfqd, cfqq, "complete rqnoidle %d", !!rq_noidle(rq));
- WARN_ON(!cfqd->rq_in_driver);
- WARN_ON(!cfqq->on_dispatch[sync]);
- cfqd->rq_in_driver--;
- cfqq->on_dispatch[sync]--;
+ cfq_update_hw_tag(cfqd);
- if (!cfq_class_idle(cfqq))
- cfqd->last_end_request = now;
+ WARN_ON(!cfqd->rq_in_driver[sync]);
+ WARN_ON(!cfqq->dispatched);
+ cfqd->rq_in_driver[sync]--;
+ cfqq->dispatched--;
- if (!cfq_cfqq_dispatched(cfqq) && cfq_cfqq_on_rr(cfqq))
- cfq_resort_rr_list(cfqq, 0);
+ if (cfq_cfqq_sync(cfqq))
+ cfqd->sync_flight--;
- if (sync)
+ if (sync) {
RQ_CIC(rq)->last_end_request = now;
+ if (!time_after(rq->start_time + cfqd->cfq_fifo_expire[1], now))
+ cfqd->last_delayed_sync = now;
+ }
/*
* If this is the active queue, check if it needs to be expired,
* or if we want to idle in case it has no pending requests.
*/
if (cfqd->active_queue == cfqq) {
- if (time_after(now, cfqq->slice_end))
- cfq_slice_expired(cfqd, 0);
- else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list)) {
- if (!cfq_arm_slice_timer(cfqd, cfqq))
- cfq_schedule_dispatch(cfqd);
+ const bool cfqq_empty = RB_EMPTY_ROOT(&cfqq->sort_list);
+
+ if (cfq_cfqq_slice_new(cfqq)) {
+ 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);
+ }
+
+ /*
+ * 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 (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))
+ cfq_schedule_dispatch(cfqd);
}
/*
*/
static void cfq_prio_boost(struct cfq_queue *cfqq)
{
- const int ioprio_class = cfqq->ioprio_class;
- const int ioprio = cfqq->ioprio;
-
if (has_fs_excl()) {
/*
* boost idle prio on transactions that would lock out other
cfqq->ioprio = IOPRIO_NORM;
} else {
/*
- * check if we need to unboost the queue
+ * unboost the queue (if needed)
*/
- if (cfqq->ioprio_class != cfqq->org_ioprio_class)
- cfqq->ioprio_class = cfqq->org_ioprio_class;
- if (cfqq->ioprio != cfqq->org_ioprio)
- cfqq->ioprio = cfqq->org_ioprio;
+ cfqq->ioprio_class = cfqq->org_ioprio_class;
+ cfqq->ioprio = cfqq->org_ioprio;
}
-
- /*
- * refile between round-robin lists if we moved the priority class
- */
- if ((ioprio_class != cfqq->ioprio_class || ioprio != cfqq->ioprio) &&
- cfq_cfqq_on_rr(cfqq))
- cfq_resort_rr_list(cfqq, 0);
}
static inline int __cfq_may_queue(struct cfq_queue *cfqq)
{
- if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) &&
- !cfq_cfqq_must_alloc_slice(cfqq)) {
+ if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) {
cfq_mark_cfqq_must_alloc_slice(cfqq);
return ELV_MQUEUE_MUST;
}
return ELV_MQUEUE_MAY;
}
-static int cfq_may_queue(request_queue_t *q, int rw)
+static int cfq_may_queue(struct request_queue *q, int rw)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct task_struct *tsk = current;
+ struct cfq_io_context *cic;
struct cfq_queue *cfqq;
- unsigned int key;
-
- key = cfq_queue_pid(tsk, rw, rw & REQ_RW_SYNC);
/*
* don't force setup of a queue from here, as a call to may_queue
* so just lookup a possibly existing queue, or return 'may queue'
* if that fails
*/
- cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio);
+ cic = cfq_cic_lookup(cfqd, tsk->io_context);
+ if (!cic)
+ return ELV_MQUEUE_MAY;
+
+ cfqq = cic_to_cfqq(cic, rw_is_sync(rw));
if (cfqq) {
- cfq_init_prio_data(cfqq);
+ cfq_init_prio_data(cfqq, cic->ioc);
cfq_prio_boost(cfqq);
return __cfq_may_queue(cfqq);
}
}
+static struct cfq_queue *
+cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_context *cic,
+ struct cfq_queue *cfqq)
+{
+ cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq);
+ cic_set_cfqq(cic, cfqq->new_cfqq, 1);
+ cfq_mark_cfqq_coop(cfqq->new_cfqq);
+ cfq_put_queue(cfqq);
+ return cic_to_cfqq(cic, 1);
+}
+
+static int should_split_cfqq(struct cfq_queue *cfqq)
+{
+ if (cfqq->seeky_start &&
+ time_after(jiffies, cfqq->seeky_start + CFQQ_COOP_TOUT))
+ return 1;
+ return 0;
+}
+
+/*
+ * Returns NULL if a new cfqq should be allocated, or the old cfqq if this
+ * was the last process referring to said cfqq.
+ */
+static struct cfq_queue *
+split_cfqq(struct cfq_io_context *cic, struct cfq_queue *cfqq)
+{
+ if (cfqq_process_refs(cfqq) == 1) {
+ cfqq->seeky_start = 0;
+ cfqq->pid = current->pid;
+ cfq_clear_cfqq_coop(cfqq);
+ return cfqq;
+ }
+
+ cic_set_cfqq(cic, NULL, 1);
+ cfq_put_queue(cfqq);
+ return NULL;
+}
/*
* Allocate cfq data structures associated with this request.
*/
static int
-cfq_set_request(request_queue_t *q, struct request *rq, gfp_t gfp_mask)
+cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
- struct task_struct *tsk = current;
struct cfq_io_context *cic;
const int rw = rq_data_dir(rq);
- const int is_sync = rq_is_sync(rq);
- pid_t key = cfq_queue_pid(tsk, rw, is_sync);
+ const bool is_sync = rq_is_sync(rq);
struct cfq_queue *cfqq;
unsigned long flags;
if (!cic)
goto queue_fail;
- if (!cic->cfqq[is_sync]) {
- cfqq = cfq_get_queue(cfqd, key, tsk, gfp_mask);
- if (!cfqq)
- goto queue_fail;
+new_queue:
+ cfqq = cic_to_cfqq(cic, is_sync);
+ if (!cfqq || cfqq == &cfqd->oom_cfqq) {
+ cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask);
+ cic_set_cfqq(cic, cfqq, is_sync);
+ } else {
+ /*
+ * If the queue was seeky for too long, break it apart.
+ */
+ if (cfq_cfqq_coop(cfqq) && should_split_cfqq(cfqq)) {
+ cfq_log_cfqq(cfqd, cfqq, "breaking apart cfqq");
+ cfqq = split_cfqq(cic, cfqq);
+ if (!cfqq)
+ goto new_queue;
+ }
- cic->cfqq[is_sync] = cfqq;
- } else
- cfqq = cic->cfqq[is_sync];
+ /*
+ * Check to see if this queue is scheduled to merge with
+ * another, closely cooperating queue. The merging of
+ * queues happens here as it must be done in process context.
+ * The reference on new_cfqq was taken in merge_cfqqs.
+ */
+ if (cfqq->new_cfqq)
+ cfqq = cfq_merge_cfqqs(cfqd, cic, cfqq);
+ }
cfqq->allocated[rw]++;
- cfq_clear_cfqq_must_alloc(cfqq);
atomic_inc(&cfqq->ref);
spin_unlock_irqrestore(q->queue_lock, flags);
cfq_schedule_dispatch(cfqd);
spin_unlock_irqrestore(q->queue_lock, flags);
+ cfq_log(cfqd, "set_request fail");
return 1;
}
{
struct cfq_data *cfqd =
container_of(work, struct cfq_data, unplug_work);
- request_queue_t *q = cfqd->queue;
- unsigned long flags;
+ struct request_queue *q = cfqd->queue;
- spin_lock_irqsave(q->queue_lock, flags);
- blk_start_queueing(q);
- spin_unlock_irqrestore(q->queue_lock, flags);
+ spin_lock_irq(q->queue_lock);
+ __blk_run_queue(cfqd->queue);
+ spin_unlock_irq(q->queue_lock);
}
/*
struct cfq_data *cfqd = (struct cfq_data *) data;
struct cfq_queue *cfqq;
unsigned long flags;
+ int timed_out = 1;
+
+ cfq_log(cfqd, "idle timer fired");
spin_lock_irqsave(cfqd->queue->queue_lock, flags);
- if ((cfqq = cfqd->active_queue) != NULL) {
- unsigned long now = jiffies;
+ cfqq = cfqd->active_queue;
+ if (cfqq) {
+ timed_out = 0;
+
+ /*
+ * We saw a request before the queue expired, let it through
+ */
+ if (cfq_cfqq_must_dispatch(cfqq))
+ goto out_kick;
/*
* expired
*/
- if (time_after(now, cfqq->slice_end))
+ if (cfq_slice_used(cfqq))
goto expire;
/*
/*
* not expired and it has a request pending, let it dispatch
*/
- if (!RB_EMPTY_ROOT(&cfqq->sort_list)) {
- cfq_mark_cfqq_must_dispatch(cfqq);
+ 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, 0);
+ cfq_slice_expired(cfqd, timed_out);
out_kick:
cfq_schedule_dispatch(cfqd);
out_cont:
spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
}
-/*
- * Timer running if an idle class queue is waiting for service
- */
-static void cfq_idle_class_timer(unsigned long data)
+static void cfq_shutdown_timer_wq(struct cfq_data *cfqd)
{
- struct cfq_data *cfqd = (struct cfq_data *) data;
- unsigned long flags, end;
+ del_timer_sync(&cfqd->idle_slice_timer);
+ cancel_work_sync(&cfqd->unplug_work);
+}
- spin_lock_irqsave(cfqd->queue->queue_lock, flags);
+static void cfq_put_async_queues(struct cfq_data *cfqd)
+{
+ int i;
- /*
- * race with a non-idle queue, reset timer
- */
- end = cfqd->last_end_request + CFQ_IDLE_GRACE;
- if (!time_after_eq(jiffies, end))
- mod_timer(&cfqd->idle_class_timer, end);
- else
- cfq_schedule_dispatch(cfqd);
+ for (i = 0; i < IOPRIO_BE_NR; i++) {
+ if (cfqd->async_cfqq[0][i])
+ cfq_put_queue(cfqd->async_cfqq[0][i]);
+ if (cfqd->async_cfqq[1][i])
+ cfq_put_queue(cfqd->async_cfqq[1][i]);
+ }
- spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
+ if (cfqd->async_idle_cfqq)
+ cfq_put_queue(cfqd->async_idle_cfqq);
}
-static void cfq_shutdown_timer_wq(struct cfq_data *cfqd)
+static void cfq_cfqd_free(struct rcu_head *head)
{
- del_timer_sync(&cfqd->idle_slice_timer);
- del_timer_sync(&cfqd->idle_class_timer);
- blk_sync_queue(cfqd->queue);
+ kfree(container_of(head, struct cfq_data, rcu));
}
-static void cfq_exit_queue(elevator_t *e)
+static void cfq_exit_queue(struct elevator_queue *e)
{
struct cfq_data *cfqd = e->elevator_data;
- request_queue_t *q = cfqd->queue;
+ struct request_queue *q = cfqd->queue;
cfq_shutdown_timer_wq(cfqd);
__cfq_exit_single_io_context(cfqd, cic);
}
+ 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->cfq_hash);
- 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(request_queue_t *q)
+static void *cfq_init_queue(struct request_queue *q)
{
struct cfq_data *cfqd;
- int i;
+ int i, j;
+ struct cfq_group *cfqg;
+ struct cfq_rb_root *st;
- cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL, q->node);
+ cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node);
if (!cfqd)
return NULL;
- memset(cfqd, 0, sizeof(*cfqd));
+ /* Init root service tree */
+ cfqd->grp_service_tree = CFQ_RB_ROOT;
- for (i = 0; i < CFQ_PRIO_LISTS; i++)
- INIT_LIST_HEAD(&cfqd->rr_list[i]);
+ /* 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);
- INIT_LIST_HEAD(&cfqd->busy_rr);
- INIT_LIST_HEAD(&cfqd->cur_rr);
- INIT_LIST_HEAD(&cfqd->idle_rr);
- INIT_LIST_HEAD(&cfqd->cic_list);
+ /* Give preference to root group over other groups */
+ cfqg->weight = 2*BLKIO_WEIGHT_DEFAULT;
- cfqd->cfq_hash = kmalloc_node(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL, q->node);
- if (!cfqd->cfq_hash)
- goto out_free;
+#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
+ * to add magic to the rb code
+ */
+ for (i = 0; i < CFQ_PRIO_LISTS; i++)
+ cfqd->prio_trees[i] = RB_ROOT;
+
+ /*
+ * Our fallback cfqq if cfq_find_alloc_queue() runs into OOM issues.
+ * Grab a permanent reference to it, so that the normal code flow
+ * will not attempt to free it.
+ */
+ 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);
- for (i = 0; i < CFQ_QHASH_ENTRIES; i++)
- INIT_HLIST_HEAD(&cfqd->cfq_hash[i]);
+ INIT_LIST_HEAD(&cfqd->cic_list);
cfqd->queue = q;
cfqd->idle_slice_timer.function = cfq_idle_slice_timer;
cfqd->idle_slice_timer.data = (unsigned long) cfqd;
- init_timer(&cfqd->idle_class_timer);
- cfqd->idle_class_timer.function = cfq_idle_class_timer;
- cfqd->idle_class_timer.data = (unsigned long) cfqd;
-
INIT_WORK(&cfqd->unplug_work, cfq_kick_queue);
cfqd->cfq_quantum = cfq_quantum;
cfqd->cfq_slice[1] = cfq_slice_sync;
cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
cfqd->cfq_slice_idle = cfq_slice_idle;
-
+ cfqd->cfq_latency = 1;
+ 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;
-out_free:
- kfree(cfqd);
- return NULL;
}
static void cfq_slab_kill(void)
{
+ /*
+ * Caller already ensured that pending RCU callbacks are completed,
+ * so we should have no busy allocations at this point.
+ */
if (cfq_pool)
kmem_cache_destroy(cfq_pool);
if (cfq_ioc_pool)
static int __init cfq_slab_setup(void)
{
- cfq_pool = kmem_cache_create("cfq_pool", sizeof(struct cfq_queue), 0, 0,
- NULL, NULL);
+ cfq_pool = KMEM_CACHE(cfq_queue, 0);
if (!cfq_pool)
goto fail;
- cfq_ioc_pool = kmem_cache_create("cfq_ioc_pool",
- sizeof(struct cfq_io_context), 0, 0, NULL, NULL);
+ cfq_ioc_pool = KMEM_CACHE(cfq_io_context, 0);
if (!cfq_ioc_pool)
goto fail;
/*
* sysfs parts below -->
*/
-
static ssize_t
cfq_var_show(unsigned int var, char *page)
{
}
#define SHOW_FUNCTION(__FUNC, __VAR, __CONV) \
-static ssize_t __FUNC(elevator_t *e, char *page) \
+static ssize_t __FUNC(struct elevator_queue *e, char *page) \
{ \
struct cfq_data *cfqd = e->elevator_data; \
unsigned int __data = __VAR; \
SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1);
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) \
-static ssize_t __FUNC(elevator_t *e, const char *page, size_t count) \
+static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count) \
{ \
struct cfq_data *cfqd = e->elevator_data; \
unsigned int __data; \
return ret; \
}
STORE_FUNCTION(cfq_quantum_store, &cfqd->cfq_quantum, 1, UINT_MAX, 0);
-STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1, UINT_MAX, 1);
-STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1, UINT_MAX, 1);
+STORE_FUNCTION(cfq_fifo_expire_sync_store, &cfqd->cfq_fifo_expire[1], 1,
+ UINT_MAX, 1);
+STORE_FUNCTION(cfq_fifo_expire_async_store, &cfqd->cfq_fifo_expire[0], 1,
+ UINT_MAX, 1);
STORE_FUNCTION(cfq_back_seek_max_store, &cfqd->cfq_back_max, 0, UINT_MAX, 0);
-STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1, UINT_MAX, 0);
+STORE_FUNCTION(cfq_back_seek_penalty_store, &cfqd->cfq_back_penalty, 1,
+ UINT_MAX, 0);
STORE_FUNCTION(cfq_slice_idle_store, &cfqd->cfq_slice_idle, 0, UINT_MAX, 1);
STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1);
STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1);
-STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1, UINT_MAX, 0);
+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),
CFQ_ATTR(slice_async_rq),
CFQ_ATTR(slice_idle),
+ CFQ_ATTR(low_latency),
+ CFQ_ATTR(group_isolation),
__ATTR_NULL
};
.elevator_merge_fn = cfq_merge,
.elevator_merged_fn = cfq_merged_request,
.elevator_merge_req_fn = cfq_merged_requests,
+ .elevator_allow_merge_fn = cfq_allow_merge,
.elevator_dispatch_fn = cfq_dispatch_requests,
.elevator_add_req_fn = cfq_insert_request,
.elevator_activate_req_fn = cfq_activate_request,
.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)
{
- int ret;
-
/*
* could be 0 on HZ < 1000 setups
*/
if (cfq_slab_setup())
return -ENOMEM;
- ret = elv_register(&iosched_cfq);
- if (ret)
- cfq_slab_kill();
+ elv_register(&iosched_cfq);
+ blkio_policy_register(&blkio_policy_cfq);
- return ret;
+ 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 */
smp_wmb();
- if (elv_ioc_count_read(ioc_count))
- wait_for_completion(ioc_gone);
- synchronize_rcu();
+
+ /*
+ * this also protects us from entering cfq_slab_kill() with
+ * pending RCU callbacks
+ */
+ if (elv_ioc_count_read(cfq_ioc_count))
+ wait_for_completion(&all_gone);
cfq_slab_kill();
}
Code Review / linux-2.6.git / blobdiff