* Based on ideas from a previously unfinished io
* scheduler (round robin per-process disk scheduling) and Andrea Arcangeli.
*
- * Copyright (C) 2003 Jens Axboe <axboe@suse.de>
+ * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
*/
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/elevator.h>
-#include <linux/hash.h>
#include <linux/rbtree.h>
#include <linux/ioprio.h>
+#include <linux/blktrace_api.h>
/*
* tunables
*/
-static const int cfq_quantum = 4; /* max queue in one round of service */
-static const int cfq_queued = 8; /* minimum rq allocate limit per-queue*/
+/* 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;
-#define CFQ_IDLE_GRACE (HZ / 10)
-#define CFQ_SLICE_SCALE (5)
-
-#define CFQ_KEY_ASYNC (0)
-
-static DEFINE_SPINLOCK(cfq_exit_lock);
-
/*
- * for the hash of cfqq inside the cfqd
+ * offset from end of service tree
*/
-#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 CFQ_IDLE_DELAY (HZ / 5)
/*
- * for the hash of crq inside the cfqq
+ * below this threshold, we consider thinktime immediate
*/
-#define CFQ_MHASH_SHIFT 6
-#define CFQ_MHASH_BLOCK(sec) ((sec) >> 3)
-#define CFQ_MHASH_ENTRIES (1 << CFQ_MHASH_SHIFT)
-#define CFQ_MHASH_FN(sec) hash_long(CFQ_MHASH_BLOCK(sec), CFQ_MHASH_SHIFT)
-#define rq_hash_key(rq) ((rq)->sector + (rq)->nr_sectors)
-#define list_entry_hash(ptr) hlist_entry((ptr), struct cfq_rq, hash)
-
-#define list_entry_cfqq(ptr) list_entry((ptr), struct cfq_queue, cfq_list)
-#define list_entry_fifo(ptr) list_entry((ptr), struct request, queuelist)
+#define CFQ_MIN_TT (2)
-#define RQ_DATA(rq) (rq)->elevator_private
+#define CFQ_SLICE_SCALE (5)
+#define CFQ_HW_QUEUE_MIN (5)
-/*
- * rb-tree defines
- */
-#define rb_entry_crq(node) rb_entry((node), struct cfq_rq, rb_node)
-#define rq_rb_key(rq) (rq)->sector
+#define RQ_CIC(rq) \
+ ((struct cfq_io_context *) (rq)->elevator_private)
+#define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private2)
-static kmem_cache_t *crq_pool;
-static kmem_cache_t *cfq_pool;
-static kmem_cache_t *cfq_ioc_pool;
+static struct kmem_cache *cfq_pool;
+static struct kmem_cache *cfq_ioc_pool;
-static atomic_t ioc_count = ATOMIC_INIT(0);
+static DEFINE_PER_CPU(unsigned long, 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_be(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_BE)
#define cfq_class_rt(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_RT)
#define ASYNC (0)
#define SYNC (1)
-#define cfq_cfqq_dispatched(cfqq) \
- ((cfqq)->on_dispatch[ASYNC] + (cfqq)->on_dispatch[SYNC])
-
-#define cfq_cfqq_class_sync(cfqq) ((cfqq)->key != CFQ_KEY_ASYNC)
-
-#define cfq_cfqq_sync(cfqq) \
- (cfq_cfqq_class_sync(cfqq) || (cfqq)->on_dispatch[SYNC])
-
#define sample_valid(samples) ((samples) > 80)
/*
+ * 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;
+};
+#define CFQ_RB_ROOT (struct cfq_rb_root) { RB_ROOT, NULL, }
+
+/*
* Per block device queue structure
*/
struct cfq_data {
- request_queue_t *queue;
+ struct request_queue *queue;
/*
* rr list of queues with requests and the count of them
*/
- struct list_head rr_list[CFQ_PRIO_LISTS];
- struct list_head busy_rr;
- struct list_head cur_rr;
- struct list_head idle_rr;
+ struct cfq_rb_root service_tree;
unsigned int busy_queues;
-
/*
- * non-ordered list of empty cfqq's
+ * Used to track any pending rt requests so we can pre-empt current
+ * non-RT cfqq in service when this value is non-zero.
*/
- struct list_head empty_list;
+ unsigned int busy_rt_queues;
- /*
- * cfqq lookup hash
- */
- struct hlist_head *cfq_hash;
+ int rq_in_driver;
+ int sync_flight;
/*
- * global crq hash for all queues
+ * queue-depth detection
*/
- struct hlist_head *crq_hash;
-
- mempool_t *crq_pool;
-
- int rq_in_driver;
+ int rq_queued;
int hw_tag;
+ int hw_tag_samples;
+ int rq_in_driver_peak;
/*
- * schedule slice state info
- */
- /*
* idle window management
*/
struct timer_list idle_slice_timer;
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;
+ sector_t last_position;
unsigned long last_end_request;
- unsigned int rq_starved;
-
/*
* tunables, see top of file
*/
unsigned int cfq_quantum;
- unsigned int cfq_queued;
unsigned int cfq_fifo_expire[2];
unsigned int cfq_back_penalty;
unsigned int cfq_back_max;
struct cfq_queue {
/* reference count */
atomic_t ref;
+ /* various state flags, see below */
+ unsigned int flags;
/* parent cfq_data */
struct cfq_data *cfqd;
- /* cfqq lookup hash */
- struct hlist_node cfq_hash;
- /* hash key */
- unsigned int key;
- /* on either rr or empty list of cfqd */
- struct list_head cfq_list;
+ /* service_tree member */
+ struct rb_node rb_node;
+ /* service_tree key */
+ unsigned long rb_key;
/* sorted list of pending requests */
struct rb_root sort_list;
/* if fifo isn't expired, next request to serve */
- struct cfq_rq *next_crq;
+ struct request *next_rq;
/* requests queued in sort_list */
int queued[2];
/* currently allocated requests */
/* fifo list of requests in sort_list */
struct list_head fifo;
- unsigned long slice_start;
unsigned long slice_end;
- unsigned long slice_left;
- unsigned long service_last;
+ long slice_resid;
- /* number of requests that are on the dispatch list */
- int on_dispatch[2];
+ /* 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;
- /* various state flags, see below */
- unsigned int flags;
-};
-
-struct cfq_rq {
- struct rb_node rb_node;
- sector_t rb_key;
- struct request *request;
- struct hlist_node hash;
-
- struct cfq_queue *cfq_queue;
- struct cfq_io_context *io_context;
-
- unsigned int crq_flags;
+ pid_t pid;
};
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_on_rr = 0, /* on round-robin busy list */
+ CFQ_CFQQ_FLAG_wait_request, /* waiting for a request */
+ CFQ_CFQQ_FLAG_must_alloc, /* must be allowed rq alloc */
+ CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */
+ CFQ_CFQQ_FLAG_must_dispatch, /* must dispatch, even if expired */
+ 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_queue_new, /* queue never been serviced */
+ CFQ_CFQQ_FLAG_slice_new, /* no requests dispatched in slice */
+ CFQ_CFQQ_FLAG_sync, /* synchronous queue */
};
#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(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);
#undef CFQ_CFQQ_FNS
-enum cfq_rq_state_flags {
- CFQ_CRQ_FLAG_is_sync = 0,
-};
-
-#define CFQ_CRQ_FNS(name) \
-static inline void cfq_mark_crq_##name(struct cfq_rq *crq) \
-{ \
- crq->crq_flags |= (1 << CFQ_CRQ_FLAG_##name); \
-} \
-static inline void cfq_clear_crq_##name(struct cfq_rq *crq) \
-{ \
- crq->crq_flags &= ~(1 << CFQ_CRQ_FLAG_##name); \
-} \
-static inline int cfq_crq_##name(const struct cfq_rq *crq) \
-{ \
- return (crq->crq_flags & (1 << CFQ_CRQ_FLAG_##name)) != 0; \
-}
-
-CFQ_CRQ_FNS(is_sync);
-#undef CFQ_CRQ_FNS
+#define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \
+ blk_add_trace_msg((cfqd)->queue, "cfq%d " fmt, (cfqq)->pid, ##args)
+#define cfq_log(cfqd, fmt, args...) \
+ blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args)
-static struct cfq_queue *cfq_find_cfq_hash(struct cfq_data *, unsigned int, unsigned short);
-static void cfq_dispatch_insert(request_queue_t *, struct cfq_rq *);
-static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, unsigned int key, struct task_struct *tsk, gfp_t gfp_mask);
+static void cfq_dispatch_insert(struct request_queue *, struct request *);
+static struct cfq_queue *cfq_get_queue(struct cfq_data *, int,
+ struct io_context *, gfp_t);
+static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *,
+ struct io_context *);
-/*
- * lots of deadline iosched dupes, can be abstracted later...
- */
-static inline void cfq_del_crq_hash(struct cfq_rq *crq)
+static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic,
+ int is_sync)
{
- hlist_del_init(&crq->hash);
+ return cic->cfqq[!!is_sync];
}
-static inline void cfq_add_crq_hash(struct cfq_data *cfqd, struct cfq_rq *crq)
+static inline void cic_set_cfqq(struct cfq_io_context *cic,
+ struct cfq_queue *cfqq, int is_sync)
{
- const int hash_idx = CFQ_MHASH_FN(rq_hash_key(crq->request));
-
- hlist_add_head(&crq->hash, &cfqd->crq_hash[hash_idx]);
+ cic->cfqq[!!is_sync] = cfqq;
}
-static struct request *cfq_find_rq_hash(struct cfq_data *cfqd, sector_t offset)
+/*
+ * 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 int cfq_bio_sync(struct bio *bio)
{
- struct hlist_head *hash_list = &cfqd->crq_hash[CFQ_MHASH_FN(offset)];
- struct hlist_node *entry, *next;
-
- hlist_for_each_safe(entry, next, hash_list) {
- struct cfq_rq *crq = list_entry_hash(entry);
- struct request *__rq = crq->request;
-
- if (!rq_mergeable(__rq)) {
- cfq_del_crq_hash(crq);
- continue;
- }
-
- if (rq_hash_key(__rq) == offset)
- return __rq;
- }
+ if (bio_data_dir(bio) == READ || bio_sync(bio))
+ return 1;
- return NULL;
+ return 0;
}
/*
*/
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;
}
-static inline pid_t cfq_queue_pid(struct task_struct *task, int rw)
+/*
+ * 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, int sync,
+ unsigned short prio)
{
- if (rw == READ || rw == WRITE_SYNC)
- return task->pid;
+ const int base_slice = cfqd->cfq_slice[sync];
+
+ WARN_ON(prio >= IOPRIO_BE_NR);
- return CFQ_KEY_ASYNC;
+ 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 void
+cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+{
+ cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies;
+ cfq_log_cfqq(cfqd, cfqq, "set_slice=%lu", cfqq->slice_end - jiffies);
}
/*
- * Lifted from AS - choose which of crq1 and crq2 that is best served now.
+ * 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 int 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;
+}
+
+/*
+ * Lifted from AS - choose which of rq1 and rq2 that is best served now.
* We choose the request that is closest to the head right now. Distance
* behind the head is penalized and only allowed to a certain extent.
*/
-static struct cfq_rq *
-cfq_choose_req(struct cfq_data *cfqd, struct cfq_rq *crq1, struct cfq_rq *crq2)
+static struct request *
+cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2)
{
sector_t last, s1, s2, d1 = 0, d2 = 0;
unsigned long back_max;
#define CFQ_RQ2_WRAP 0x02 /* request 2 wraps */
unsigned wrap = 0; /* bit mask: requests behind the disk head? */
- if (crq1 == NULL || crq1 == crq2)
- return crq2;
- if (crq2 == NULL)
- return crq1;
+ if (rq1 == NULL || rq1 == rq2)
+ return rq2;
+ if (rq2 == NULL)
+ return rq1;
- if (cfq_crq_is_sync(crq1) && !cfq_crq_is_sync(crq2))
- return crq1;
- else if (cfq_crq_is_sync(crq2) && !cfq_crq_is_sync(crq1))
- return crq2;
+ if (rq_is_sync(rq1) && !rq_is_sync(rq2))
+ return rq1;
+ else if (rq_is_sync(rq2) && !rq_is_sync(rq1))
+ return rq2;
+ if (rq_is_meta(rq1) && !rq_is_meta(rq2))
+ return rq1;
+ else if (rq_is_meta(rq2) && !rq_is_meta(rq1))
+ return rq2;
- s1 = crq1->request->sector;
- s2 = crq2->request->sector;
+ s1 = rq1->sector;
+ s2 = rq2->sector;
- last = cfqd->last_sector;
+ last = cfqd->last_position;
/*
* by definition, 1KiB is 2 sectors
* check two variables for all permutations: --> faster!
*/
switch (wrap) {
- case 0: /* common case for CFQ: crq1 and crq2 not wrapped */
+ case 0: /* common case for CFQ: rq1 and rq2 not wrapped */
if (d1 < d2)
- return crq1;
+ return rq1;
else if (d2 < d1)
- return crq2;
+ return rq2;
else {
if (s1 >= s2)
- return crq1;
+ return rq1;
else
- return crq2;
+ return rq2;
}
case CFQ_RQ2_WRAP:
- return crq1;
+ return rq1;
case CFQ_RQ1_WRAP:
- return crq2;
- case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both crqs wrapped */
+ return rq2;
+ case (CFQ_RQ1_WRAP|CFQ_RQ2_WRAP): /* both rqs wrapped */
default:
/*
* Since both rqs are wrapped,
* since back seek takes more time than forward.
*/
if (s1 <= s2)
- return crq1;
+ return rq1;
else
- return crq2;
+ return rq2;
}
}
/*
- * would be nice to take fifo expire time into account as well
+ * The below is leftmost cache rbtree addon
*/
-static struct cfq_rq *
-cfq_find_next_crq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- struct cfq_rq *last)
+static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root)
{
- struct cfq_rq *crq_next = NULL, *crq_prev = NULL;
- struct rb_node *rbnext, *rbprev;
+ if (!root->left)
+ root->left = rb_first(&root->rb);
- if (!(rbnext = rb_next(&last->rb_node))) {
- rbnext = rb_first(&cfqq->sort_list);
- if (rbnext == &last->rb_node)
- rbnext = NULL;
- }
+ if (root->left)
+ return rb_entry(root->left, struct cfq_queue, rb_node);
+
+ return NULL;
+}
- rbprev = rb_prev(&last->rb_node);
+static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root)
+{
+ if (root->left == n)
+ root->left = NULL;
+
+ rb_erase(n, &root->rb);
+ RB_CLEAR_NODE(n);
+}
+
+/*
+ * would be nice to take fifo expire time into account as well
+ */
+static struct request *
+cfq_find_next_rq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
+ struct request *last)
+{
+ struct rb_node *rbnext = rb_next(&last->rb_node);
+ struct rb_node *rbprev = rb_prev(&last->rb_node);
+ struct request *next = NULL, *prev = NULL;
+
+ BUG_ON(RB_EMPTY_NODE(&last->rb_node));
if (rbprev)
- crq_prev = rb_entry_crq(rbprev);
+ prev = rb_entry_rq(rbprev);
+
if (rbnext)
- crq_next = rb_entry_crq(rbnext);
+ next = rb_entry_rq(rbnext);
+ else {
+ rbnext = rb_first(&cfqq->sort_list);
+ if (rbnext && rbnext != &last->rb_node)
+ next = rb_entry_rq(rbnext);
+ }
- return cfq_choose_req(cfqd, crq_next, crq_prev);
+ return cfq_choose_req(cfqd, next, prev);
}
-static void cfq_update_next_crq(struct cfq_rq *crq)
+static unsigned long cfq_slice_offset(struct cfq_data *cfqd,
+ struct cfq_queue *cfqq)
{
- struct cfq_queue *cfqq = crq->cfq_queue;
-
- if (cfqq->next_crq == crq)
- cfqq->next_crq = cfq_find_next_crq(cfqq->cfqd, cfqq, crq);
+ /*
+ * just an approximation, should be ok.
+ */
+ return (cfqd->busy_queues - 1) * (cfq_prio_slice(cfqd, 1, 0) -
+ cfq_prio_slice(cfqd, cfq_cfqq_sync(cfqq), cfqq->ioprio));
}
-static void cfq_resort_rr_list(struct cfq_queue *cfqq, int preempted)
+/*
+ * The cfqd->service_tree 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, int add_front)
{
- struct cfq_data *cfqd = cfqq->cfqd;
- struct list_head *list, *entry;
+ struct rb_node **p, *parent;
+ struct cfq_queue *__cfqq;
+ unsigned long rb_key;
+ int left;
+
+ if (cfq_class_idle(cfqq)) {
+ rb_key = CFQ_IDLE_DELAY;
+ parent = rb_last(&cfqd->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) {
+ rb_key = cfq_slice_offset(cfqd, cfqq) + jiffies;
+ rb_key += cfqq->slice_resid;
+ cfqq->slice_resid = 0;
+ } else
+ rb_key = 0;
- BUG_ON(!cfq_cfqq_on_rr(cfqq));
+ if (!RB_EMPTY_NODE(&cfqq->rb_node)) {
+ /*
+ * same position, nothing more to do
+ */
+ if (rb_key == cfqq->rb_key)
+ return;
- list_del(&cfqq->cfq_list);
+ cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree);
+ }
+
+ left = 1;
+ parent = NULL;
+ p = &cfqd->service_tree.rb.rb_node;
+ while (*p) {
+ struct rb_node **n;
+
+ parent = *p;
+ __cfqq = rb_entry(parent, struct cfq_queue, rb_node);
- 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
+ * sort RT queues first, we always want to give
+ * preference to them. IDLE queues goes to the back.
+ * after that, sort on the next service time.
*/
- if (cfq_cfqq_dispatched(cfqq))
- list = &cfqd->busy_rr;
+ if (cfq_class_rt(cfqq) > cfq_class_rt(__cfqq))
+ n = &(*p)->rb_left;
+ else if (cfq_class_rt(cfqq) < cfq_class_rt(__cfqq))
+ n = &(*p)->rb_right;
+ else if (cfq_class_idle(cfqq) < cfq_class_idle(__cfqq))
+ n = &(*p)->rb_left;
+ else if (cfq_class_idle(cfqq) > cfq_class_idle(__cfqq))
+ n = &(*p)->rb_right;
+ else if (rb_key < __cfqq->rb_key)
+ n = &(*p)->rb_left;
else
- list = &cfqd->rr_list[cfqq->ioprio];
- }
+ n = &(*p)->rb_right;
- /*
- * if queue was preempted, just add to front to be fair. busy_rr
- * isn't sorted, but insert at the back for fairness.
- */
- if (preempted || list == &cfqd->busy_rr) {
- if (preempted)
- list = list->prev;
+ if (n == &(*p)->rb_right)
+ left = 0;
- list_add_tail(&cfqq->cfq_list, list);
- return;
+ p = n;
}
- /*
- * sort by when queue was last serviced
- */
- entry = list;
- while ((entry = entry->prev) != list) {
- struct cfq_queue *__cfqq = list_entry_cfqq(entry);
+ if (left)
+ cfqd->service_tree.left = &cfqq->rb_node;
- if (!__cfqq->service_last)
- break;
- if (time_before(__cfqq->service_last, cfqq->service_last))
- break;
- }
+ cfqq->rb_key = rb_key;
+ rb_link_node(&cfqq->rb_node, parent, p);
+ rb_insert_color(&cfqq->rb_node, &cfqd->service_tree.rb);
+}
- list_add(&cfqq->cfq_list, entry);
+/*
+ * 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);
}
/*
* 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++;
+ if (cfq_class_rt(cfqq))
+ cfqd->busy_rt_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_move(&cfqq->cfq_list, &cfqd->empty_list);
+
+ if (!RB_EMPTY_NODE(&cfqq->rb_node))
+ cfq_rb_erase(&cfqq->rb_node, &cfqd->service_tree);
BUG_ON(!cfqd->busy_queues);
cfqd->busy_queues--;
+ if (cfq_class_rt(cfqq))
+ cfqd->busy_rt_queues--;
}
/*
* rb tree support functions
*/
-static inline void cfq_del_crq_rb(struct cfq_rq *crq)
+static void cfq_del_rq_rb(struct request *rq)
{
- struct cfq_queue *cfqq = crq->cfq_queue;
+ struct cfq_queue *cfqq = RQ_CFQQ(rq);
struct cfq_data *cfqd = cfqq->cfqd;
- const int sync = cfq_crq_is_sync(crq);
+ const int sync = rq_is_sync(rq);
BUG_ON(!cfqq->queued[sync]);
cfqq->queued[sync]--;
- cfq_update_next_crq(crq);
-
- rb_erase(&crq->rb_node, &cfqq->sort_list);
+ 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);
}
-static struct cfq_rq *
-__cfq_add_crq_rb(struct cfq_rq *crq)
+static void cfq_add_rq_rb(struct request *rq)
{
- struct rb_node **p = &crq->cfq_queue->sort_list.rb_node;
- struct rb_node *parent = NULL;
- struct cfq_rq *__crq;
-
- while (*p) {
- parent = *p;
- __crq = rb_entry_crq(parent);
-
- if (crq->rb_key < __crq->rb_key)
- p = &(*p)->rb_left;
- else if (crq->rb_key > __crq->rb_key)
- p = &(*p)->rb_right;
- else
- return __crq;
- }
-
- rb_link_node(&crq->rb_node, parent, p);
- return NULL;
-}
-
-static void cfq_add_crq_rb(struct cfq_rq *crq)
-{
- struct cfq_queue *cfqq = crq->cfq_queue;
+ struct cfq_queue *cfqq = RQ_CFQQ(rq);
struct cfq_data *cfqd = cfqq->cfqd;
- struct request *rq = crq->request;
- struct cfq_rq *__alias;
+ struct request *__alias;
- crq->rb_key = rq_rb_key(rq);
- cfqq->queued[cfq_crq_is_sync(crq)]++;
+ cfqq->queued[rq_is_sync(rq)]++;
/*
* looks a little odd, but the first insert might return an alias.
* if that happens, put the alias on the dispatch list
*/
- while ((__alias = __cfq_add_crq_rb(crq)) != NULL)
+ while ((__alias = elv_rb_add(&cfqq->sort_list, rq)) != NULL)
cfq_dispatch_insert(cfqd->queue, __alias);
- rb_insert_color(&crq->rb_node, &cfqq->sort_list);
-
if (!cfq_cfqq_on_rr(cfqq))
cfq_add_cfqq_rr(cfqd, cfqq);
/*
* check if this request is a better next-serve candidate
*/
- cfqq->next_crq = cfq_choose_req(cfqd, cfqq->next_crq, crq);
+ cfqq->next_rq = cfq_choose_req(cfqd, cfqq->next_rq, rq);
+ BUG_ON(!cfqq->next_rq);
}
-static inline void
-cfq_reposition_crq_rb(struct cfq_queue *cfqq, struct cfq_rq *crq)
+static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq)
{
- rb_erase(&crq->rb_node, &cfqq->sort_list);
- cfqq->queued[cfq_crq_is_sync(crq)]--;
-
- cfq_add_crq_rb(crq);
+ elv_rb_del(&cfqq->sort_list, rq);
+ cfqq->queued[rq_is_sync(rq)]--;
+ cfq_add_rq_rb(rq);
}
static struct request *
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));
+ struct cfq_io_context *cic;
struct cfq_queue *cfqq;
- struct rb_node *n;
- sector_t sector;
- cfqq = cfq_find_cfq_hash(cfqd, key, tsk->ioprio);
- if (!cfqq)
- goto out;
+ cic = cfq_cic_lookup(cfqd, tsk->io_context);
+ if (!cic)
+ return NULL;
- sector = bio->bi_sector + bio_sectors(bio);
- n = cfqq->sort_list.rb_node;
- while (n) {
- struct cfq_rq *crq = rb_entry_crq(n);
+ cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio));
+ if (cfqq) {
+ sector_t sector = bio->bi_sector + bio_sectors(bio);
- if (sector < crq->rb_key)
- n = n->rb_left;
- else if (sector > crq->rb_key)
- n = n->rb_right;
- else
- return crq->request;
+ return elv_rb_find(&cfqq->sort_list, sector);
}
-out:
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++;
+ cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d",
+ cfqd->rq_in_driver);
- /*
- * 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 = rq->hard_sector + rq->hard_nr_sectors;
}
-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;
WARN_ON(!cfqd->rq_in_driver);
cfqd->rq_in_driver--;
+ cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d",
+ cfqd->rq_in_driver);
}
static void cfq_remove_request(struct request *rq)
{
- struct cfq_rq *crq = RQ_DATA(rq);
+ struct cfq_queue *cfqq = RQ_CFQQ(rq);
+
+ if (cfqq->next_rq == rq)
+ cfqq->next_rq = cfq_find_next_rq(cfqq->cfqd, cfqq, rq);
list_del_init(&rq->queuelist);
- cfq_del_crq_rb(crq);
- cfq_del_crq_hash(crq);
+ 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;
- int ret;
-
- __rq = cfq_find_rq_hash(cfqd, bio->bi_sector);
- if (__rq && elv_rq_merge_ok(__rq, bio)) {
- ret = ELEVATOR_BACK_MERGE;
- goto out;
- }
__rq = cfq_find_rq_fmerge(cfqd, bio);
if (__rq && elv_rq_merge_ok(__rq, bio)) {
- ret = ELEVATOR_FRONT_MERGE;
- goto out;
+ *req = __rq;
+ return ELEVATOR_FRONT_MERGE;
}
return ELEVATOR_NO_MERGE;
-out:
- *req = __rq;
- return ret;
}
-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)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
- struct cfq_rq *crq = RQ_DATA(req);
+ if (type == ELEVATOR_FRONT_MERGE) {
+ struct cfq_queue *cfqq = RQ_CFQQ(req);
- cfq_del_crq_hash(crq);
- cfq_add_crq_hash(cfqd, crq);
-
- if (rq_rb_key(req) != crq->rb_key) {
- struct cfq_queue *cfqq = crq->cfq_queue;
-
- cfq_update_next_crq(crq);
- cfq_reposition_crq_rb(cfqq, crq);
+ cfq_reposition_rq_rb(cfqq, req);
}
}
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)
{
- cfq_merged_request(q, rq);
-
/*
* reposition in fifo if next is older than 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 0;
+
+ /*
+ * 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 0;
+
+ cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio));
+ if (cfqq == RQ_CFQQ(rq))
+ return 1;
+
+ return 0;
+}
- 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_end = 0;
- cfqq->slice_left = 0;
cfq_clear_cfqq_must_alloc_slice(cfqq);
cfq_clear_cfqq_fifo_expire(cfqq);
+ cfq_mark_cfqq_slice_new(cfqq);
+ cfq_clear_cfqq_queue_new(cfqq);
}
cfqd->active_queue = cfqq;
*/
static void
__cfq_slice_expired(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- int preempted)
+ int 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)) {
- cfqq->service_last = now;
- cfq_schedule_dispatch(cfqd);
- }
-
cfq_clear_cfqq_must_dispatch(cfqq);
cfq_clear_cfqq_wait_request(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_resort_rr_list(cfqd, cfqq);
if (cfqq == cfqd->active_queue)
cfqd->active_queue = NULL;
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, int 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;
-
- prio = -1;
- wrap = 0;
- do {
- int p;
-
- for (p = cfqd->cur_prio; p <= cfqd->cur_end_prio; p++) {
- if (!list_empty(&cfqd->rr_list[p])) {
- prio = p;
- break;
- }
- }
-
- 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);
-
- if (unlikely(prio == -1))
- return -1;
+ if (RB_EMPTY_ROOT(&cfqd->service_tree.rb))
+ return NULL;
- BUG_ON(prio >= CFQ_PRIO_LISTS);
+ return cfq_rb_first(&cfqd->service_tree);
+}
- list_splice_init(&cfqd->rr_list[prio], &cfqd->cur_rr);
+/*
+ * 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;
- 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;
- }
+ cfqq = cfq_get_next_queue(cfqd);
+ __cfq_set_active_queue(cfqd, cfqq);
+ return cfqq;
+}
- return prio;
+static inline sector_t cfq_dist_from_last(struct cfq_data *cfqd,
+ struct request *rq)
+{
+ if (rq->sector >= cfqd->last_position)
+ return rq->sector - cfqd->last_position;
+ else
+ return cfqd->last_position - rq->sector;
}
-static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd)
+static inline int cfq_rq_close(struct cfq_data *cfqd, struct request *rq)
{
- struct cfq_queue *cfqq = NULL;
+ struct cfq_io_context *cic = cfqd->active_cic;
- /*
- * 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
- */
- if (!list_empty(&cfqd->cur_rr) || cfq_get_next_prio_level(cfqd) != -1)
- cfqq = list_entry_cfqq(cfqd->cur_rr.next);
+ if (!sample_valid(cic->seek_samples))
+ return 0;
- /*
- * If no new queues are available, check if the busy list has some
- * before falling back to idle io.
- */
- if (!cfqq && !list_empty(&cfqd->busy_rr))
- cfqq = list_entry_cfqq(cfqd->busy_rr.next);
+ return cfq_dist_from_last(cfqd, rq) <= cic->seek_mean;
+}
+static int cfq_close_cooperator(struct cfq_data *cfq_data,
+ struct cfq_queue *cfqq)
+{
/*
- * 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
+ * We should notice if some of the queues are cooperating, eg
+ * working closely on the same area of the disk. In that case,
+ * we can group them together and don't waste time idling.
*/
- if (!cfqq && !list_empty(&cfqd->idle_rr)) {
- unsigned long end = cfqd->last_end_request + CFQ_IDLE_GRACE;
-
- if (time_after_eq(jiffies, end))
- cfqq = list_entry_cfqq(cfqd->idle_rr.next);
- else
- mod_timer(&cfqd->idle_class_timer, end);
- }
-
- __cfq_set_active_queue(cfqd, cfqq);
- return cfqq;
+ return 0;
}
-#define CIC_SEEKY(cic) ((cic)->seek_mean > (128 * 1024))
-
-static int cfq_arm_slice_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+#define CIC_SEEKY(cic) ((cic)->seek_mean > (8 * 1024))
+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_cfqq_idle_window(cfqq))
+ return;
+
+ /*
+ * still requests with the driver, don't idle
+ */
+ if (cfqd->rq_in_driver)
+ return;
+
/*
* task has exited, don't wait
*/
cic = cfqd->active_cic;
- if (!cic || !cic->ioc->task)
- return 0;
+ if (!cic || !atomic_read(&cic->ioc->nr_tasks))
+ return;
+
+ /*
+ * See if this prio level has a good candidate
+ */
+ if (cfq_close_cooperator(cfqd, cfqq) &&
+ (sample_valid(cic->ttime_samples) && cic->ttime_mean > 2))
+ return;
cfq_mark_cfqq_must_dispatch(cfqq);
cfq_mark_cfqq_wait_request(cfqq);
- sl = min(cfqq->slice_end - 1, (unsigned long) cfqd->cfq_slice_idle);
-
/*
* 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
*/
+ sl = cfqd->cfq_slice_idle;
if (sample_valid(cic->seek_samples) && CIC_SEEKY(cic))
- sl = 2;
+ sl = min(sl, msecs_to_jiffies(CFQ_MIN_TT));
mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
- return 1;
+ cfq_log(cfqd, "arm_idle: %lu", sl);
}
-static void cfq_dispatch_insert(request_queue_t *q, struct cfq_rq *crq)
+/*
+ * 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 = crq->cfq_queue;
- struct request *rq;
+ struct cfq_queue *cfqq = RQ_CFQQ(rq);
+
+ cfq_log_cfqq(cfqd, cfqq, "dispatch_insert");
- cfqq->next_crq = cfq_find_next_crq(cfqd, cfqq, crq);
- cfq_remove_request(crq->request);
- cfqq->on_dispatch[cfq_crq_is_sync(crq)]++;
- elv_dispatch_sort(q, crq->request);
+ cfq_remove_request(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++;
}
/*
* return expired entry, or NULL to just start from scratch in rbtree
*/
-static inline struct cfq_rq *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;
- struct cfq_rq *crq;
+ int fifo;
if (cfq_cfqq_fifo_expire(cfqq))
return NULL;
- if (!list_empty(&cfqq->fifo)) {
- int fifo = cfq_cfqq_class_sync(cfqq);
+ cfq_mark_cfqq_fifo_expire(cfqq);
- crq = RQ_DATA(list_entry_fifo(cfqq->fifo.next));
- rq = crq->request;
- if (time_after(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo])) {
- cfq_mark_cfqq_fifo_expire(cfqq);
- return crq;
- }
- }
+ if (list_empty(&cfqq->fifo))
+ return NULL;
- return NULL;
-}
+ fifo = cfq_cfqq_sync(cfqq);
+ rq = rq_entry_fifo(cfqq->fifo.next);
-/*
- * 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_to_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- const int base_slice = cfqd->cfq_slice[cfq_cfqq_sync(cfqq)];
-
- WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
+ if (time_before(jiffies, rq->start_time + cfqd->cfq_fifo_expire[fifo]))
+ rq = NULL;
- return base_slice + (base_slice/CFQ_SLICE_SCALE * (4 - cfqq->ioprio));
-}
-
-static inline void
-cfq_set_prio_slice(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- cfqq->slice_end = cfq_prio_to_slice(cfqd, cfqq) + jiffies;
+ cfq_log_cfqq(cfqd, cfqq, "fifo=%p", rq);
+ return rq;
}
static inline int
}
/*
- * 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;
cfqq = cfqd->active_queue;
goto new_queue;
/*
- * slice has expired
+ * The active queue has run out of time, expire it and select new.
*/
- if (!cfq_cfqq_must_dispatch(cfqq) && time_after(now, cfqq->slice_end))
+ if (cfq_slice_used(cfqq))
goto expire;
/*
- * if queue has requests, dispatch one. if not, check if
- * enough slice is left to wait for one
+ * If we have a RT cfqq waiting, then we pre-empt the current non-rt
+ * cfqq.
+ */
+ if (!cfq_class_rt(cfqq) && cfqd->busy_rt_queues) {
+ /*
+ * We simulate this as cfqq timed out so that it gets to bank
+ * the remaining of its time slice.
+ */
+ cfq_log_cfqq(cfqd, cfqq, "preempt");
+ cfq_slice_expired(cfqd, 1);
+ goto new_queue;
+ }
+
+ /*
+ * 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)) {
+
+ /*
+ * 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_cfqq_idle_window(cfqq))) {
cfqq = NULL;
goto keep_queue;
- } else if (cfq_cfqq_class_sync(cfqq)) {
- if (cfq_arm_slice_timer(cfqd, cfqq))
- return NULL;
}
expire:
return cfqq;
}
+/*
+ * Dispatch some requests from cfqq, moving them to the request queue
+ * dispatch list.
+ */
static int
__cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
int max_dispatch)
BUG_ON(RB_EMPTY_ROOT(&cfqq->sort_list));
do {
- struct cfq_rq *crq;
+ struct request *rq;
/*
* follow expired path, else get first next available
*/
- if ((crq = cfq_check_fifo(cfqq)) == NULL)
- crq = cfqq->next_crq;
+ rq = cfq_check_fifo(cfqq);
+ if (rq == NULL)
+ rq = cfqq->next_rq;
/*
* finally, insert request into driver dispatch list
*/
- cfq_dispatch_insert(cfqd->queue, crq);
+ cfq_dispatch_insert(cfqd->queue, rq);
- cfqd->dispatch_slice++;
dispatched++;
if (!cfqd->active_cic) {
- atomic_inc(&crq->io_context->ioc->refcount);
- cfqd->active_cic = crq->io_context;
+ atomic_inc(&RQ_CIC(rq)->ioc->refcount);
+ cfqd->active_cic = RQ_CIC(rq);
}
if (RB_EMPTY_ROOT(&cfqq->sort_list))
break;
- } while (dispatched < max_dispatch);
+ /*
+ * If there is a non-empty RT cfqq waiting for current
+ * cfqq's timeslice to complete, pre-empt this cfqq
+ */
+ if (!cfq_class_rt(cfqq) && cfqd->busy_rt_queues)
+ break;
- /*
- * if slice end isn't set yet, set it.
- */
- if (!cfqq->slice_end)
- cfq_set_prio_slice(cfqd, cfqq);
+ } while (dispatched < max_dispatch);
/*
* expire an async queue immediately if it has used up its slice. idle
* queue always expire after 1 dispatch round.
*/
- if ((!cfq_cfqq_sync(cfqq) &&
- cfqd->dispatch_slice >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
- cfq_class_idle(cfqq) ||
- !cfq_cfqq_idle_window(cfqq))
+ if (cfqd->busy_queues > 1 && ((!cfq_cfqq_sync(cfqq) &&
+ dispatched >= cfq_prio_to_maxrq(cfqd, cfqq)) ||
+ cfq_class_idle(cfqq))) {
+ cfqq->slice_end = jiffies + 1;
cfq_slice_expired(cfqd, 0);
+ }
return dispatched;
}
-static int
-cfq_forced_dispatch_cfqqs(struct list_head *list)
+static int __cfq_forced_dispatch_cfqq(struct cfq_queue *cfqq)
{
- struct cfq_queue *cfqq, *next;
- struct cfq_rq *crq;
- int dispatched;
+ int dispatched = 0;
- dispatched = 0;
- list_for_each_entry_safe(cfqq, next, list, cfq_list) {
- while ((crq = cfqq->next_crq)) {
- cfq_dispatch_insert(cfqq->cfqd->queue, crq);
- dispatched++;
- }
- BUG_ON(!list_empty(&cfqq->fifo));
+ while (cfqq->next_rq) {
+ cfq_dispatch_insert(cfqq->cfqd->queue, cfqq->next_rq);
+ dispatched++;
}
+ BUG_ON(!list_empty(&cfqq->fifo));
return dispatched;
}
-static int
-cfq_forced_dispatch(struct cfq_data *cfqd)
+/*
+ * Drain our current requests. Used for barriers and when switching
+ * io schedulers on-the-fly.
+ */
+static int cfq_forced_dispatch(struct cfq_data *cfqd)
{
- int i, dispatched = 0;
-
- for (i = 0; i < CFQ_PRIO_LISTS; i++)
- dispatched += cfq_forced_dispatch_cfqqs(&cfqd->rr_list[i]);
+ struct cfq_queue *cfqq;
+ int dispatched = 0;
- dispatched += cfq_forced_dispatch_cfqqs(&cfqd->busy_rr);
- dispatched += cfq_forced_dispatch_cfqqs(&cfqd->cur_rr);
- dispatched += cfq_forced_dispatch_cfqqs(&cfqd->idle_rr);
+ while ((cfqq = cfq_rb_first(&cfqd->service_tree)) != NULL)
+ dispatched += __cfq_forced_dispatch_cfqq(cfqq);
cfq_slice_expired(cfqd, 0);
BUG_ON(cfqd->busy_queues);
+ cfq_log(cfqd, "forced_dispatch=%d\n", dispatched);
return dispatched;
}
-static int
-cfq_dispatch_requests(request_queue_t *q, int force)
+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;
+ struct cfq_queue *cfqq;
int dispatched;
if (!cfqd->busy_queues)
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;
- dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
+ if (cfqq->dispatched >= max_dispatch && cfqd->busy_queues > 1)
+ break;
- /*
- * If the dispatch cfqq has idling enabled and is still
- * the active queue, break out.
- */
- if (cfq_cfqq_idle_window(cfqq) && cfqd->active_queue)
+ if (cfqd->sync_flight && !cfq_cfqq_sync(cfqq))
break;
- prev_cfqq = cfqq;
+ cfq_clear_cfqq_must_dispatch(cfqq);
+ cfq_clear_cfqq_wait_request(cfqq);
+ del_timer(&cfqd->idle_slice_timer);
+
+ dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
}
+ cfq_log(cfqd, "dispatched=%d", dispatched);
return dispatched;
}
/*
- * task holds one reference to the queue, dropped when task exits. each crq
- * in-flight on this queue also holds a reference, dropped when crq is freed.
+ * 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.
*
* queue lock must be held here.
*/
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));
- 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);
kmem_cache_free(cfq_pool, cfqq);
}
-static inline 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;
-
- hlist_for_each_entry(__cfqq, entry, hash_list, cfq_hash) {
- const unsigned short __p = IOPRIO_PRIO_VALUE(__cfqq->org_ioprio_class, __cfqq->org_ioprio);
-
- if (__cfqq->key == key && (__p == prio || !prio))
- return __cfqq;
- }
+ struct cfq_io_context *cic;
+ struct hlist_node *n;
- return NULL;
+ hlist_for_each_entry_rcu(cic, n, &ioc->cic_list, cic_list)
+ func(ioc, cic);
}
-static struct cfq_queue *
-cfq_find_cfq_hash(struct cfq_data *cfqd, unsigned int key, unsigned short prio)
+/*
+ * 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 *))
{
- return __cfq_find_cfq_hash(cfqd, key, prio, hash_long(key, CFQ_QHASH_SHIFT));
+ rcu_read_lock();
+ __call_for_each_cic(ioc, func);
+ rcu_read_unlock();
}
-static void cfq_free_io_context(struct io_context *ioc)
+static void cfq_cic_free_rcu(struct rcu_head *head)
{
- struct cfq_io_context *__cic;
- struct rb_node *n;
- int freed = 0;
+ 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(ioc_count);
- 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++;
+ 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(ioc_count)) {
+ complete(ioc_gone);
+ ioc_gone = NULL;
+ }
+ spin_unlock(&ioc_gone_lock);
}
+}
- if (atomic_sub_and_test(freed, &ioc_count) && ioc_gone)
- complete(ioc_gone);
+static void cfq_cic_free(struct cfq_io_context *cic)
+{
+ call_rcu(&cic->rcu_head, cfq_cic_free_rcu);
}
-static void cfq_trim(struct io_context *ioc)
+static void cic_free_func(struct io_context *ioc, struct cfq_io_context *cic)
{
- ioc->set_ioprio = NULL;
- cfq_free_io_context(ioc);
+ unsigned long flags;
+
+ BUG_ON(!cic->dead_key);
+
+ 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);
}
/*
- * Called with interrupts disabled
+ * 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_exit_single_io_context(struct cfq_io_context *cic)
+static void cfq_free_io_context(struct io_context *ioc)
{
- struct cfq_data *cfqd = cic->key;
- request_queue_t *q;
+ /*
+ * 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);
+}
- if (!cfqd)
- return;
+static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
+{
+ if (unlikely(cfqq == cfqd->active_queue)) {
+ __cfq_slice_expired(cfqd, cfqq, 0);
+ cfq_schedule_dispatch(cfqd);
+ }
+
+ cfq_put_queue(cfqq);
+}
- q = cfqd->queue;
+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);
- WARN_ON(!irqs_disabled());
+ /*
+ * Make sure key == NULL is seen for dead queues
+ */
+ smp_wmb();
+ cic->dead_key = (unsigned long) cic->key;
+ cic->key = NULL;
- spin_lock(q->queue_lock);
+ if (ioc->ioc_data == cic)
+ rcu_assign_pointer(ioc->ioc_data, NULL);
if (cic->cfqq[ASYNC]) {
- if (unlikely(cic->cfqq[ASYNC] == cfqd->active_queue))
- __cfq_slice_expired(cfqd, cic->cfqq[ASYNC], 0);
- cfq_put_queue(cic->cfqq[ASYNC]);
+ cfq_exit_cfqq(cfqd, cic->cfqq[ASYNC]);
cic->cfqq[ASYNC] = NULL;
}
if (cic->cfqq[SYNC]) {
- if (unlikely(cic->cfqq[SYNC] == cfqd->active_queue))
- __cfq_slice_expired(cfqd, cic->cfqq[SYNC], 0);
- cfq_put_queue(cic->cfqq[SYNC]);
+ cfq_exit_cfqq(cfqd, cic->cfqq[SYNC]);
cic->cfqq[SYNC] = NULL;
}
-
- cic->key = NULL;
- list_del_init(&cic->queue_list);
- spin_unlock(q->queue_lock);
}
-static void cfq_exit_io_context(struct io_context *ioc)
+static void cfq_exit_single_io_context(struct io_context *ioc,
+ struct cfq_io_context *cic)
{
- struct cfq_io_context *__cic;
- unsigned long flags;
- struct rb_node *n;
+ struct cfq_data *cfqd = cic->key;
- /*
- * put the reference this task is holding to the various queues
- */
- spin_lock_irqsave(&cfq_exit_lock, flags);
+ if (cfqd) {
+ struct request_queue *q = cfqd->queue;
+ unsigned long flags;
- n = rb_first(&ioc->cic_root);
- while (n != NULL) {
- __cic = rb_entry(n, struct cfq_io_context, rb_node);
+ 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);
- cfq_exit_single_io_context(__cic);
- n = rb_next(n);
+ spin_unlock_irqrestore(q->queue_lock, flags);
}
+}
- spin_unlock_irqrestore(&cfq_exit_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)
+{
+ call_for_each_cic(ioc, cfq_exit_single_io_context);
}
static struct cfq_io_context *
cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
{
- struct cfq_io_context *cic = kmem_cache_alloc(cfq_ioc_pool, gfp_mask);
+ struct cfq_io_context *cic;
+ 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;
- atomic_inc(&ioc_count);
+ elv_ioc_count_inc(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;
+ unsigned long flags;
if (unlikely(!cfqd))
return;
- spin_lock(cfqd->queue->queue_lock);
+ spin_lock_irqsave(cfqd->queue->queue_lock, flags);
cfqq = cic->cfqq[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, ASYNC, cic->ioc, GFP_ATOMIC);
if (new_cfqq) {
cic->cfqq[ASYNC] = new_cfqq;
cfq_put_queue(cfqq);
if (cfqq)
cfq_mark_cfqq_prio_changed(cfqq);
- spin_unlock(cfqd->queue->queue_lock);
+ spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
}
-/*
- * callback from sys_ioprio_set, irqs are disabled
- */
-static int cfq_ioc_set_ioprio(struct io_context *ioc, unsigned int ioprio)
+static void cfq_ioc_set_ioprio(struct io_context *ioc)
{
- struct cfq_io_context *cic;
- struct rb_node *n;
-
- spin_lock(&cfq_exit_lock);
-
- n = rb_first(&ioc->cic_root);
- while (n != NULL) {
- cic = rb_entry(n, struct cfq_io_context, rb_node);
-
- changed_ioprio(cic);
- n = rb_next(n);
- }
-
- spin_unlock(&cfq_exit_lock);
-
- return 0;
+ call_for_each_cic(ioc, changed_ioprio);
+ ioc->ioprio_changed = 0;
}
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, int 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;
retry:
- ioprio = tsk->ioprio;
- cfqq = __cfq_find_cfq_hash(cfqd, key, ioprio, hashval);
+ cic = cfq_cic_lookup(cfqd, ioc);
+ /* cic always exists here */
+ cfqq = cic_to_cfqq(cic, is_sync);
if (!cfqq) {
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(cfq_pool, gfp_mask);
+ new_cfqq = kmem_cache_alloc_node(cfq_pool,
+ gfp_mask | __GFP_NOFAIL | __GFP_ZERO,
+ cfqd->queue->node);
spin_lock_irq(cfqd->queue->queue_lock);
goto retry;
} else {
- cfqq = kmem_cache_alloc(cfq_pool, gfp_mask);
+ cfqq = kmem_cache_alloc_node(cfq_pool,
+ gfp_mask | __GFP_ZERO,
+ cfqd->queue->node);
if (!cfqq)
goto out;
}
- memset(cfqq, 0, sizeof(*cfqq));
+ RB_CLEAR_NODE(&cfqq->rb_node);
+ INIT_LIST_HEAD(&cfqq->fifo);
+
+ atomic_set(&cfqq->ref, 0);
+ cfqq->cfqd = cfqd;
+
+ cfq_mark_cfqq_prio_changed(cfqq);
+ cfq_mark_cfqq_queue_new(cfqq);
+
+ cfq_init_prio_data(cfqq, ioc);
+
+ if (is_sync) {
+ if (!cfq_class_idle(cfqq))
+ cfq_mark_cfqq_idle_window(cfqq);
+ cfq_mark_cfqq_sync(cfqq);
+ }
+ cfqq->pid = current->pid;
+ cfq_log_cfqq(cfqd, cfqq, "alloced");
+ }
+
+ if (new_cfqq)
+ kmem_cache_free(cfq_pool, new_cfqq);
+
+out:
+ WARN_ON((gfp_mask & __GFP_WAIT) && !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, int 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;
- INIT_HLIST_NODE(&cfqq->cfq_hash);
- INIT_LIST_HEAD(&cfqq->cfq_list);
- INIT_LIST_HEAD(&cfqq->fifo);
+ if (!is_sync) {
+ async_cfqq = cfq_async_queue_prio(cfqd, ioprio_class, ioprio);
+ cfqq = *async_cfqq;
+ }
- cfqq->key = key;
- hlist_add_head(&cfqq->cfq_hash, &cfqd->cfq_hash[hashval]);
- atomic_set(&cfqq->ref, 0);
- cfqq->cfqd = cfqd;
- cfqq->service_last = 0;
- /*
- * 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_init_prio_data(cfqq);
+ if (!cfqq) {
+ cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask);
+ if (!cfqq)
+ return NULL;
}
- if (new_cfqq)
- kmem_cache_free(cfq_pool, new_cfqq);
+ /*
+ * 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)
{
- spin_lock(&cfq_exit_lock);
- rb_erase(&cic->rb_node, &ioc->cic_root);
- list_del_init(&cic->queue_list);
- spin_unlock(&cfq_exit_lock);
- kmem_cache_free(cfq_ioc_pool, cic);
- atomic_dec(&ioc_count);
+ unsigned long flags;
+
+ WARN_ON(!list_empty(&cic->queue_list));
+
+ 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)
+cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc)
{
- struct rb_node *n;
struct cfq_io_context *cic;
- void *k, *key = cfqd;
+ unsigned long flags;
+ void *k;
+
+ if (unlikely(!ioc))
+ return NULL;
+
+ rcu_read_lock();
-restart:
- n = ioc->cic_root.rb_node;
- while (n) {
- cic = rb_entry(n, struct cfq_io_context, rb_node);
+ /*
+ * 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;
+ }
+
+ 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;
- void *k;
+ unsigned long flags;
+ int ret;
- cic->ioc = ioc;
- cic->key = cfqd;
+ ret = radix_tree_preload(gfp_mask);
+ if (!ret) {
+ cic->ioc = ioc;
+ cic->key = cfqd;
- ioc->set_ioprio = cfq_ioc_set_ioprio;
-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);
+ }
}
- spin_lock(&cfq_exit_lock);
- rb_link_node(&cic->rb_node, parent, p);
- rb_insert_color(&cic->rb_node, &ioc->cic_root);
- list_add(&cic->queue_list, &cfqd->cic_list);
- spin_unlock(&cfq_exit_lock);
+ if (ret)
+ printk(KERN_ERR "cfq: cic link failed!\n");
+
+ return ret;
}
/*
might_sleep_if(gfp_mask & __GFP_WAIT);
- ioc = get_io_context(gfp_mask);
+ ioc = get_io_context(gfp_mask, cfqd->queue->node);
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);
+
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_data *cfqd, struct cfq_io_context *cic,
- struct cfq_rq *crq)
+ struct request *rq)
{
sector_t sdist;
u64 total;
- if (cic->last_request_pos < crq->request->sector)
- sdist = crq->request->sector - cic->last_request_pos;
+ if (cic->last_request_pos < rq->sector)
+ sdist = rq->sector - cic->last_request_pos;
else
- sdist = cic->last_request_pos - crq->request->sector;
+ sdist = cic->last_request_pos - rq->sector;
/*
* Don't allow the seek distance to get too large from the
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 (!cic->ioc->task || !cfqd->cfq_slice_idle ||
+ if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle ||
(cfqd->hw_tag && CIC_SEEKY(cic)))
enable_idle = 0;
else if (sample_valid(cic->ttime_samples)) {
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
cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
- struct cfq_rq *crq)
+ struct request *rq)
{
- struct cfq_queue *cfqq = cfqd->active_queue;
+ struct cfq_queue *cfqq;
- if (cfq_class_idle(new_cfqq))
+ cfqq = cfqd->active_queue;
+ if (!cfqq)
return 0;
- if (!cfqq)
+ if (cfq_slice_used(cfqq))
+ return 1;
+
+ if (cfq_class_idle(new_cfqq))
return 0;
if (cfq_class_idle(cfqq))
return 1;
- if (!cfq_cfqq_wait_request(new_cfqq))
- return 0;
+
+ /*
+ * 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;
+
+ /*
+ * 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;
+
/*
- * if it doesn't have slice left, forget it
+ * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice.
*/
- if (new_cfqq->slice_left < cfqd->cfq_slice_idle)
+ if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq))
+ return 1;
+
+ if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq))
return 0;
- if (cfq_crq_is_sync(crq) && !cfq_cfqq_sync(cfqq))
+
+ /*
+ * if this request is as-good as one we would expect from the
+ * current cfqq, let it preempt
+ */
+ if (cfq_rq_close(cfqd, rq))
return 1;
return 0;
*/
static void cfq_preempt_queue(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
- struct cfq_queue *__cfqq, *next;
-
- list_for_each_entry_safe(__cfqq, next, &cfqd->cur_rr, cfq_list)
- cfq_resort_rr_list(__cfqq, 1);
-
- if (!cfqq->slice_left)
- cfqq->slice_left = cfq_prio_to_slice(cfqd, cfqq) / 2;
-
- cfqq->slice_end = cfqq->slice_left + jiffies;
+ cfq_log_cfqq(cfqd, cfqq, "preempt");
cfq_slice_expired(cfqd, 1);
- __cfq_set_active_queue(cfqd, cfqq);
-}
-/*
- * should really be a ll_rw_blk.c helper
- */
-static void cfq_start_queueing(struct cfq_data *cfqd, struct cfq_queue *cfqq)
-{
- request_queue_t *q = cfqd->queue;
+ /*
+ * 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));
- if (!blk_queue_plugged(q))
- q->request_fn(q);
- else
- __generic_unplug_device(q);
+ cfq_service_tree_add(cfqd, cfqq, 1);
+
+ cfqq->slice_end = 0;
+ cfq_mark_cfqq_slice_new(cfqq);
}
/*
- * Called when a new fs request (crq) is added (to cfqq). Check if there's
+ * Called when a new fs request (rq) is added (to cfqq). Check if there's
* something we should do about it
*/
static void
-cfq_crq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- struct cfq_rq *crq)
+cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
+ struct request *rq)
{
- struct cfq_io_context *cic = crq->io_context;
+ struct cfq_io_context *cic = RQ_CIC(rq);
- /*
- * we never wait for an async request and we don't allow preemption
- * of an async request. so just return early
- */
- if (!cfq_crq_is_sync(crq)) {
- /*
- * 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);
- cfq_start_queueing(cfqd, cfqq);
- }
- return;
- }
+ cfqd->rq_queued++;
+ if (rq_is_meta(rq))
+ cfqq->meta_pending++;
cfq_update_io_thinktime(cfqd, cic);
- cfq_update_io_seektime(cfqd, cic, crq);
+ cfq_update_io_seektime(cfqd, cic, rq);
cfq_update_idle_window(cfqd, cfqq, cic);
- cic->last_queue = jiffies;
- cic->last_request_pos = crq->request->sector + crq->request->nr_sectors;
+ cic->last_request_pos = rq->sector + rq->nr_sectors;
if (cfqq == cfqd->active_queue) {
/*
if (cfq_cfqq_wait_request(cfqq)) {
cfq_mark_cfqq_must_dispatch(cfqq);
del_timer(&cfqd->idle_slice_timer);
- cfq_start_queueing(cfqd, cfqq);
+ blk_start_queueing(cfqd->queue);
}
- } else if (cfq_should_preempt(cfqd, cfqq, crq)) {
+ } 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);
- cfq_start_queueing(cfqd, cfqq);
+ blk_start_queueing(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_rq *crq = RQ_DATA(rq);
- struct cfq_queue *cfqq = crq->cfq_queue;
+ struct cfq_queue *cfqq = RQ_CFQQ(rq);
- cfq_init_prio_data(cfqq);
+ cfq_log_cfqq(cfqd, cfqq, "insert_request");
+ cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc);
- cfq_add_crq_rb(crq);
+ cfq_add_rq_rb(rq);
list_add_tail(&rq->queuelist, &cfqq->fifo);
- if (rq_mergeable(rq))
- cfq_add_crq_hash(cfqd, crq);
+ cfq_rq_enqueued(cfqd, cfqq, 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)
+{
+ if (cfqd->rq_in_driver > cfqd->rq_in_driver_peak)
+ cfqd->rq_in_driver_peak = cfqd->rq_in_driver;
+
+ if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN &&
+ cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN)
+ return;
+
+ if (cfqd->hw_tag_samples++ < 50)
+ return;
+
+ if (cfqd->rq_in_driver_peak >= CFQ_HW_QUEUE_MIN)
+ cfqd->hw_tag = 1;
+ else
+ cfqd->hw_tag = 0;
- cfq_crq_enqueued(cfqd, cfqq, crq);
+ cfqd->hw_tag_samples = 0;
+ cfqd->rq_in_driver_peak = 0;
}
-static void cfq_completed_request(request_queue_t *q, struct request *rq)
+static void cfq_completed_request(struct request_queue *q, struct request *rq)
{
- struct cfq_rq *crq = RQ_DATA(rq);
- struct cfq_queue *cfqq = crq->cfq_queue;
+ struct cfq_queue *cfqq = RQ_CFQQ(rq);
struct cfq_data *cfqd = cfqq->cfqd;
- const int sync = cfq_crq_is_sync(crq);
+ const int sync = rq_is_sync(rq);
unsigned long now;
now = jiffies;
+ cfq_log_cfqq(cfqd, cfqq, "complete");
+
+ cfq_update_hw_tag(cfqd);
WARN_ON(!cfqd->rq_in_driver);
- WARN_ON(!cfqq->on_dispatch[sync]);
+ WARN_ON(!cfqq->dispatched);
cfqd->rq_in_driver--;
- cfqq->on_dispatch[sync]--;
+ cfqq->dispatched--;
+
+ if (cfq_cfqq_sync(cfqq))
+ cfqd->sync_flight--;
if (!cfq_class_idle(cfqq))
cfqd->last_end_request = now;
- if (!cfq_cfqq_dispatched(cfqq)) {
- if (cfq_cfqq_on_rr(cfqq)) {
- cfqq->service_last = now;
- cfq_resort_rr_list(cfqq, 0);
- }
- }
-
if (sync)
- crq->io_context->last_end_request = now;
+ RQ_CIC(rq)->last_end_request = 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);
+ if (cfq_cfqq_slice_new(cfqq)) {
+ cfq_set_prio_slice(cfqd, cfqq);
+ cfq_clear_cfqq_slice_new(cfqq);
}
+ if (cfq_slice_used(cfqq) || cfq_class_idle(cfqq))
+ cfq_slice_expired(cfqd, 1);
+ else if (sync && RB_EMPTY_ROOT(&cfqq->sort_list))
+ cfq_arm_slice_timer(cfqd);
}
-}
-
-static struct request *
-cfq_former_request(request_queue_t *q, struct request *rq)
-{
- struct cfq_rq *crq = RQ_DATA(rq);
- struct rb_node *rbprev = rb_prev(&crq->rb_node);
-
- if (rbprev)
- return rb_entry_crq(rbprev)->request;
-
- return NULL;
-}
-
-static struct request *
-cfq_latter_request(request_queue_t *q, struct request *rq)
-{
- struct cfq_rq *crq = RQ_DATA(rq);
- struct rb_node *rbnext = rb_next(&crq->rb_node);
-
- if (rbnext)
- return rb_entry_crq(rbnext)->request;
- return NULL;
+ if (!cfqd->rq_in_driver)
+ 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
if (cfqq->ioprio != cfqq->org_ioprio)
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_data *cfqd, struct cfq_queue *cfqq,
- struct task_struct *task, int rw)
+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)) {
return ELV_MQUEUE_MAY;
}
-static int cfq_may_queue(request_queue_t *q, int rw, struct bio *bio)
+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;
/*
* so just lookup a possibly existing queue, or return 'may queue'
* if that fails
*/
- cfqq = cfq_find_cfq_hash(cfqd, cfq_queue_pid(tsk, rw), tsk->ioprio);
+ cic = cfq_cic_lookup(cfqd, tsk->io_context);
+ if (!cic)
+ return ELV_MQUEUE_MAY;
+
+ cfqq = cic_to_cfqq(cic, rw & REQ_RW_SYNC);
if (cfqq) {
- cfq_init_prio_data(cfqq);
+ cfq_init_prio_data(cfqq, cic->ioc);
cfq_prio_boost(cfqq);
- return __cfq_may_queue(cfqd, cfqq, tsk, rw);
+ return __cfq_may_queue(cfqq);
}
return ELV_MQUEUE_MAY;
}
-static void cfq_check_waiters(request_queue_t *q, struct cfq_queue *cfqq)
-{
- struct cfq_data *cfqd = q->elevator->elevator_data;
-
- if (unlikely(cfqd->rq_starved)) {
- struct request_list *rl = &q->rq;
-
- smp_mb();
- if (waitqueue_active(&rl->wait[READ]))
- wake_up(&rl->wait[READ]);
- if (waitqueue_active(&rl->wait[WRITE]))
- wake_up(&rl->wait[WRITE]);
- }
-}
-
/*
* queue lock held here
*/
-static void cfq_put_request(request_queue_t *q, struct request *rq)
+static void cfq_put_request(struct request *rq)
{
- struct cfq_data *cfqd = q->elevator->elevator_data;
- struct cfq_rq *crq = RQ_DATA(rq);
+ struct cfq_queue *cfqq = RQ_CFQQ(rq);
- if (crq) {
- struct cfq_queue *cfqq = crq->cfq_queue;
+ if (cfqq) {
const int rw = rq_data_dir(rq);
BUG_ON(!cfqq->allocated[rw]);
cfqq->allocated[rw]--;
- put_io_context(crq->io_context->ioc);
+ put_io_context(RQ_CIC(rq)->ioc);
- mempool_free(crq, cfqd->crq_pool);
rq->elevator_private = NULL;
+ rq->elevator_private2 = NULL;
- cfq_check_waiters(q, cfqq);
cfq_put_queue(cfqq);
}
}
* Allocate cfq data structures associated with this request.
*/
static int
-cfq_set_request(request_queue_t *q, struct request *rq, struct bio *bio,
- 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);
- pid_t key = cfq_queue_pid(tsk, rw);
+ const int is_sync = rq_is_sync(rq);
struct cfq_queue *cfqq;
- struct cfq_rq *crq;
unsigned long flags;
- int is_sync = key != CFQ_KEY_ASYNC;
might_sleep_if(gfp_mask & __GFP_WAIT);
if (!cic)
goto queue_fail;
- if (!cic->cfqq[is_sync]) {
- cfqq = cfq_get_queue(cfqd, key, tsk, gfp_mask);
+ cfqq = cic_to_cfqq(cic, is_sync);
+ if (!cfqq) {
+ cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask);
+
if (!cfqq)
goto queue_fail;
- cic->cfqq[is_sync] = cfqq;
- } else
- cfqq = cic->cfqq[is_sync];
+ cic_set_cfqq(cic, cfqq, is_sync);
+ }
cfqq->allocated[rw]++;
cfq_clear_cfqq_must_alloc(cfqq);
- cfqd->rq_starved = 0;
atomic_inc(&cfqq->ref);
- spin_unlock_irqrestore(q->queue_lock, flags);
- crq = mempool_alloc(cfqd->crq_pool, gfp_mask);
- if (crq) {
- RB_CLEAR_NODE(&crq->rb_node);
- crq->rb_key = 0;
- crq->request = rq;
- INIT_HLIST_NODE(&crq->hash);
- crq->cfq_queue = cfqq;
- crq->io_context = cic;
-
- if (is_sync)
- cfq_mark_crq_is_sync(crq);
- else
- cfq_clear_crq_is_sync(crq);
+ spin_unlock_irqrestore(q->queue_lock, flags);
- rq->elevator_private = crq;
- return 0;
- }
+ rq->elevator_private = cic;
+ rq->elevator_private2 = cfqq;
+ return 0;
- spin_lock_irqsave(q->queue_lock, flags);
- cfqq->allocated[rw]--;
- if (!(cfqq->allocated[0] + cfqq->allocated[1]))
- cfq_mark_cfqq_must_alloc(cfqq);
- cfq_put_queue(cfqq);
queue_fail:
if (cic)
put_io_context(cic->ioc);
- /*
- * mark us rq allocation starved. we need to kickstart the process
- * ourselves if there are no pending requests that can do it for us.
- * that would be an extremely rare OOM situation
- */
- cfqd->rq_starved = 1;
+
cfq_schedule_dispatch(cfqd);
spin_unlock_irqrestore(q->queue_lock, flags);
+ cfq_log(cfqd, "set_request fail");
return 1;
}
-static void cfq_kick_queue(void *data)
+static void cfq_kick_queue(struct work_struct *work)
{
- request_queue_t *q = data;
- struct cfq_data *cfqd = q->elevator->elevator_data;
+ struct cfq_data *cfqd =
+ container_of(work, struct cfq_data, unplug_work);
+ struct request_queue *q = cfqd->queue;
unsigned long flags;
spin_lock_irqsave(q->queue_lock, flags);
-
- if (cfqd->rq_starved) {
- struct request_list *rl = &q->rq;
-
- /*
- * we aren't guaranteed to get a request after this, but we
- * have to be opportunistic
- */
- smp_mb();
- if (waitqueue_active(&rl->wait[READ]))
- wake_up(&rl->wait[READ]);
- if (waitqueue_active(&rl->wait[WRITE]))
- wake_up(&rl->wait[WRITE]);
- }
-
- blk_remove_plug(q);
- q->request_fn(q);
+ blk_start_queueing(q);
spin_unlock_irqrestore(q->queue_lock, flags);
}
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;
/*
* expired
*/
- if (time_after(now, cfqq->slice_end))
+ if (cfq_slice_used(cfqq))
goto expire;
/*
}
}
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;
-
- spin_lock_irqsave(cfqd->queue->queue_lock, flags);
-
- /*
- * 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);
-
- spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
+ del_timer_sync(&cfqd->idle_slice_timer);
+ cancel_work_sync(&cfqd->unplug_work);
}
-static void cfq_shutdown_timer_wq(struct cfq_data *cfqd)
+static void cfq_put_async_queues(struct cfq_data *cfqd)
{
- del_timer_sync(&cfqd->idle_slice_timer);
- del_timer_sync(&cfqd->idle_class_timer);
- blk_sync_queue(cfqd->queue);
+ int i;
+
+ 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]);
+ }
+
+ if (cfqd->async_idle_cfqq)
+ cfq_put_queue(cfqd->async_idle_cfqq);
}
-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);
- spin_lock(&cfq_exit_lock);
spin_lock_irq(q->queue_lock);
if (cfqd->active_queue)
struct cfq_io_context *cic = list_entry(cfqd->cic_list.next,
struct cfq_io_context,
queue_list);
- if (cic->cfqq[ASYNC]) {
- cfq_put_queue(cic->cfqq[ASYNC]);
- cic->cfqq[ASYNC] = NULL;
- }
- if (cic->cfqq[SYNC]) {
- cfq_put_queue(cic->cfqq[SYNC]);
- cic->cfqq[SYNC] = NULL;
- }
- cic->key = NULL;
- list_del_init(&cic->queue_list);
+
+ __cfq_exit_single_io_context(cfqd, cic);
}
+ cfq_put_async_queues(cfqd);
+
spin_unlock_irq(q->queue_lock);
- spin_unlock(&cfq_exit_lock);
cfq_shutdown_timer_wq(cfqd);
- mempool_destroy(cfqd->crq_pool);
- kfree(cfqd->crq_hash);
- kfree(cfqd->cfq_hash);
kfree(cfqd);
}
-static void *cfq_init_queue(request_queue_t *q, elevator_t *e)
+static void *cfq_init_queue(struct request_queue *q)
{
struct cfq_data *cfqd;
- int i;
- cfqd = kmalloc(sizeof(*cfqd), GFP_KERNEL);
+ cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node);
if (!cfqd)
return NULL;
- memset(cfqd, 0, sizeof(*cfqd));
-
- for (i = 0; i < CFQ_PRIO_LISTS; i++)
- INIT_LIST_HEAD(&cfqd->rr_list[i]);
-
- INIT_LIST_HEAD(&cfqd->busy_rr);
- INIT_LIST_HEAD(&cfqd->cur_rr);
- INIT_LIST_HEAD(&cfqd->idle_rr);
- INIT_LIST_HEAD(&cfqd->empty_list);
+ cfqd->service_tree = CFQ_RB_ROOT;
INIT_LIST_HEAD(&cfqd->cic_list);
- cfqd->crq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_MHASH_ENTRIES, GFP_KERNEL);
- if (!cfqd->crq_hash)
- goto out_crqhash;
-
- cfqd->cfq_hash = kmalloc(sizeof(struct hlist_head) * CFQ_QHASH_ENTRIES, GFP_KERNEL);
- if (!cfqd->cfq_hash)
- goto out_cfqhash;
-
- cfqd->crq_pool = mempool_create_slab_pool(BLKDEV_MIN_RQ, crq_pool);
- if (!cfqd->crq_pool)
- goto out_crqpool;
-
- for (i = 0; i < CFQ_MHASH_ENTRIES; i++)
- INIT_HLIST_HEAD(&cfqd->crq_hash[i]);
- for (i = 0; i < CFQ_QHASH_ENTRIES; i++)
- INIT_HLIST_HEAD(&cfqd->cfq_hash[i]);
-
cfqd->queue = q;
init_timer(&cfqd->idle_slice_timer);
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);
- INIT_WORK(&cfqd->unplug_work, cfq_kick_queue, q);
-
- cfqd->cfq_queued = cfq_queued;
+ cfqd->last_end_request = jiffies;
cfqd->cfq_quantum = cfq_quantum;
cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0];
cfqd->cfq_fifo_expire[1] = cfq_fifo_expire[1];
cfqd->cfq_slice[1] = cfq_slice_sync;
cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
cfqd->cfq_slice_idle = cfq_slice_idle;
+ cfqd->hw_tag = 1;
return cfqd;
-out_crqpool:
- kfree(cfqd->cfq_hash);
-out_cfqhash:
- kfree(cfqd->crq_hash);
-out_crqhash:
- kfree(cfqd);
- return NULL;
}
static void cfq_slab_kill(void)
{
- if (crq_pool)
- kmem_cache_destroy(crq_pool);
+ /*
+ * 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)
{
- crq_pool = kmem_cache_create("crq_pool", sizeof(struct cfq_rq), 0, 0,
- NULL, NULL);
- if (!crq_pool)
- goto fail;
-
- 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; \
return cfq_var_show(__data, (page)); \
}
SHOW_FUNCTION(cfq_quantum_show, cfqd->cfq_quantum, 0);
-SHOW_FUNCTION(cfq_queued_show, cfqd->cfq_queued, 0);
SHOW_FUNCTION(cfq_fifo_expire_sync_show, cfqd->cfq_fifo_expire[1], 1);
SHOW_FUNCTION(cfq_fifo_expire_async_show, cfqd->cfq_fifo_expire[0], 1);
SHOW_FUNCTION(cfq_back_seek_max_show, cfqd->cfq_back_max, 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_queued_store, &cfqd->cfq_queued, 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);
#undef STORE_FUNCTION
#define CFQ_ATTR(name) \
static struct elv_fs_entry cfq_attrs[] = {
CFQ_ATTR(quantum),
- CFQ_ATTR(queued),
CFQ_ATTR(fifo_expire_sync),
CFQ_ATTR(fifo_expire_async),
CFQ_ATTR(back_seek_max),
.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_deactivate_req_fn = cfq_deactivate_request,
.elevator_queue_empty_fn = cfq_queue_empty,
.elevator_completed_req_fn = cfq_completed_request,
- .elevator_former_req_fn = cfq_former_request,
- .elevator_latter_req_fn = cfq_latter_request,
+ .elevator_former_req_fn = elv_rb_former_request,
+ .elevator_latter_req_fn = elv_rb_latter_request,
.elevator_set_req_fn = cfq_set_request,
.elevator_put_req_fn = cfq_put_request,
.elevator_may_queue_fn = cfq_may_queue,
.elevator_init_fn = cfq_init_queue,
.elevator_exit_fn = cfq_exit_queue,
- .trim = cfq_trim,
+ .trim = cfq_free_io_context,
},
.elevator_attrs = cfq_attrs,
.elevator_name = "cfq",
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);
- return ret;
+ return 0;
}
static void __exit cfq_exit(void)
{
- DECLARE_COMPLETION(all_gone);
+ DECLARE_COMPLETION_ONSTACK(all_gone);
elv_unregister(&iosched_cfq);
ioc_gone = &all_gone;
/* ioc_gone's update must be visible before reading ioc_count */
smp_wmb();
- if (atomic_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(ioc_count))
+ wait_for_completion(&all_gone);
cfq_slab_kill();
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff