this amount, since it applies only to reads or writes (not the accumulated
sum).
+To avoid priority inversion through request starvation, a request
+queue maintains a separate request pool per each cgroup when
+CONFIG_BLK_CGROUP is enabled, and this parameter applies to each such
+per-block-cgroup request pool. IOW, if there are N block cgroups,
+each request queue may have upto N request pools, each independently
+regulated by nr_requests.
+
read_ahead_kb (RW)
------------------
Maximum number of kilobytes to read-ahead for filesystems on this block
static struct blkcg_policy *blkcg_policy[BLKCG_MAX_POLS];
-struct blkcg *cgroup_to_blkcg(struct cgroup *cgroup)
-{
- return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id),
- struct blkcg, css);
-}
-EXPORT_SYMBOL_GPL(cgroup_to_blkcg);
-
-static struct blkcg *task_blkcg(struct task_struct *tsk)
-{
- return container_of(task_subsys_state(tsk, blkio_subsys_id),
- struct blkcg, css);
-}
-
-struct blkcg *bio_blkcg(struct bio *bio)
-{
- if (bio && bio->bi_css)
- return container_of(bio->bi_css, struct blkcg, css);
- return task_blkcg(current);
-}
-EXPORT_SYMBOL_GPL(bio_blkcg);
-
static bool blkcg_policy_enabled(struct request_queue *q,
const struct blkcg_policy *pol)
{
kfree(pd);
}
+ blk_exit_rl(&blkg->rl);
kfree(blkg);
}
* blkg_alloc - allocate a blkg
* @blkcg: block cgroup the new blkg is associated with
* @q: request_queue the new blkg is associated with
+ * @gfp_mask: allocation mask to use
*
* Allocate a new blkg assocating @blkcg and @q.
*/
-static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct request_queue *q)
+static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct request_queue *q,
+ gfp_t gfp_mask)
{
struct blkcg_gq *blkg;
int i;
/* alloc and init base part */
- blkg = kzalloc_node(sizeof(*blkg), GFP_ATOMIC, q->node);
+ blkg = kzalloc_node(sizeof(*blkg), gfp_mask, q->node);
if (!blkg)
return NULL;
blkg->blkcg = blkcg;
blkg->refcnt = 1;
+ /* root blkg uses @q->root_rl, init rl only for !root blkgs */
+ if (blkcg != &blkcg_root) {
+ if (blk_init_rl(&blkg->rl, q, gfp_mask))
+ goto err_free;
+ blkg->rl.blkg = blkg;
+ }
+
for (i = 0; i < BLKCG_MAX_POLS; i++) {
struct blkcg_policy *pol = blkcg_policy[i];
struct blkg_policy_data *pd;
continue;
/* alloc per-policy data and attach it to blkg */
- pd = kzalloc_node(pol->pd_size, GFP_ATOMIC, q->node);
- if (!pd) {
- blkg_free(blkg);
- return NULL;
- }
+ pd = kzalloc_node(pol->pd_size, gfp_mask, q->node);
+ if (!pd)
+ goto err_free;
blkg->pd[i] = pd;
pd->blkg = blkg;
}
return blkg;
+
+err_free:
+ blkg_free(blkg);
+ return NULL;
}
static struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg,
}
EXPORT_SYMBOL_GPL(blkg_lookup);
+/*
+ * If @new_blkg is %NULL, this function tries to allocate a new one as
+ * necessary using %GFP_ATOMIC. @new_blkg is always consumed on return.
+ */
static struct blkcg_gq *__blkg_lookup_create(struct blkcg *blkcg,
- struct request_queue *q)
- __releases(q->queue_lock) __acquires(q->queue_lock)
+ struct request_queue *q,
+ struct blkcg_gq *new_blkg)
{
struct blkcg_gq *blkg;
int ret;
blkg = __blkg_lookup(blkcg, q);
if (blkg) {
rcu_assign_pointer(blkcg->blkg_hint, blkg);
- return blkg;
+ goto out_free;
}
/* blkg holds a reference to blkcg */
- if (!css_tryget(&blkcg->css))
- return ERR_PTR(-EINVAL);
+ if (!css_tryget(&blkcg->css)) {
+ blkg = ERR_PTR(-EINVAL);
+ goto out_free;
+ }
/* allocate */
- ret = -ENOMEM;
- blkg = blkg_alloc(blkcg, q);
- if (unlikely(!blkg))
- goto err_put;
+ if (!new_blkg) {
+ new_blkg = blkg_alloc(blkcg, q, GFP_ATOMIC);
+ if (unlikely(!new_blkg)) {
+ blkg = ERR_PTR(-ENOMEM);
+ goto out_put;
+ }
+ }
+ blkg = new_blkg;
/* insert */
- ret = radix_tree_preload(GFP_ATOMIC);
- if (ret)
- goto err_free;
-
spin_lock(&blkcg->lock);
ret = radix_tree_insert(&blkcg->blkg_tree, q->id, blkg);
if (likely(!ret)) {
}
spin_unlock(&blkcg->lock);
- radix_tree_preload_end();
-
if (!ret)
return blkg;
-err_free:
- blkg_free(blkg);
-err_put:
+
+ blkg = ERR_PTR(ret);
+out_put:
css_put(&blkcg->css);
- return ERR_PTR(ret);
+out_free:
+ blkg_free(new_blkg);
+ return blkg;
}
struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
*/
if (unlikely(blk_queue_bypass(q)))
return ERR_PTR(blk_queue_dead(q) ? -EINVAL : -EBUSY);
- return __blkg_lookup_create(blkcg, q);
+ return __blkg_lookup_create(blkcg, q, NULL);
}
EXPORT_SYMBOL_GPL(blkg_lookup_create);
}
EXPORT_SYMBOL_GPL(__blkg_release);
+/*
+ * The next function used by blk_queue_for_each_rl(). It's a bit tricky
+ * because the root blkg uses @q->root_rl instead of its own rl.
+ */
+struct request_list *__blk_queue_next_rl(struct request_list *rl,
+ struct request_queue *q)
+{
+ struct list_head *ent;
+ struct blkcg_gq *blkg;
+
+ /*
+ * Determine the current blkg list_head. The first entry is
+ * root_rl which is off @q->blkg_list and mapped to the head.
+ */
+ if (rl == &q->root_rl) {
+ ent = &q->blkg_list;
+ } else {
+ blkg = container_of(rl, struct blkcg_gq, rl);
+ ent = &blkg->q_node;
+ }
+
+ /* walk to the next list_head, skip root blkcg */
+ ent = ent->next;
+ if (ent == &q->root_blkg->q_node)
+ ent = ent->next;
+ if (ent == &q->blkg_list)
+ return NULL;
+
+ blkg = container_of(ent, struct blkcg_gq, q_node);
+ return &blkg->rl;
+}
+
static int blkcg_reset_stats(struct cgroup *cgroup, struct cftype *cftype,
u64 val)
{
struct blkcg_gq *blkg;
struct blkg_policy_data *pd, *n;
int cnt = 0, ret;
+ bool preloaded;
if (blkcg_policy_enabled(q, pol))
return 0;
+ /* preallocations for root blkg */
+ blkg = blkg_alloc(&blkcg_root, q, GFP_KERNEL);
+ if (!blkg)
+ return -ENOMEM;
+
+ preloaded = !radix_tree_preload(GFP_KERNEL);
+
blk_queue_bypass_start(q);
/* make sure the root blkg exists and count the existing blkgs */
spin_lock_irq(q->queue_lock);
rcu_read_lock();
- blkg = __blkg_lookup_create(&blkcg_root, q);
+ blkg = __blkg_lookup_create(&blkcg_root, q, blkg);
rcu_read_unlock();
+ if (preloaded)
+ radix_tree_preload_end();
+
if (IS_ERR(blkg)) {
ret = PTR_ERR(blkg);
goto out_unlock;
}
q->root_blkg = blkg;
+ q->root_rl.blkg = blkg;
list_for_each_entry(blkg, &q->blkg_list, q_node)
cnt++;
#include <linux/u64_stats_sync.h>
#include <linux/seq_file.h>
#include <linux/radix-tree.h>
+#include <linux/blkdev.h>
/* Max limits for throttle policy */
#define THROTL_IOPS_MAX UINT_MAX
struct list_head q_node;
struct hlist_node blkcg_node;
struct blkcg *blkcg;
+ /* request allocation list for this blkcg-q pair */
+ struct request_list rl;
/* reference count */
int refcnt;
extern struct blkcg blkcg_root;
-struct blkcg *cgroup_to_blkcg(struct cgroup *cgroup);
-struct blkcg *bio_blkcg(struct bio *bio);
struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q);
struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
struct request_queue *q);
void blkg_conf_finish(struct blkg_conf_ctx *ctx);
+static inline struct blkcg *cgroup_to_blkcg(struct cgroup *cgroup)
+{
+ return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id),
+ struct blkcg, css);
+}
+
+static inline struct blkcg *task_blkcg(struct task_struct *tsk)
+{
+ return container_of(task_subsys_state(tsk, blkio_subsys_id),
+ struct blkcg, css);
+}
+
+static inline struct blkcg *bio_blkcg(struct bio *bio)
+{
+ if (bio && bio->bi_css)
+ return container_of(bio->bi_css, struct blkcg, css);
+ return task_blkcg(current);
+}
+
/**
* blkg_to_pdata - get policy private data
* @blkg: blkg of interest
__blkg_release(blkg);
}
+/**
+ * blk_get_rl - get request_list to use
+ * @q: request_queue of interest
+ * @bio: bio which will be attached to the allocated request (may be %NULL)
+ *
+ * The caller wants to allocate a request from @q to use for @bio. Find
+ * the request_list to use and obtain a reference on it. Should be called
+ * under queue_lock. This function is guaranteed to return non-%NULL
+ * request_list.
+ */
+static inline struct request_list *blk_get_rl(struct request_queue *q,
+ struct bio *bio)
+{
+ struct blkcg *blkcg;
+ struct blkcg_gq *blkg;
+
+ rcu_read_lock();
+
+ blkcg = bio_blkcg(bio);
+
+ /* bypass blkg lookup and use @q->root_rl directly for root */
+ if (blkcg == &blkcg_root)
+ goto root_rl;
+
+ /*
+ * Try to use blkg->rl. blkg lookup may fail under memory pressure
+ * or if either the blkcg or queue is going away. Fall back to
+ * root_rl in such cases.
+ */
+ blkg = blkg_lookup_create(blkcg, q);
+ if (unlikely(IS_ERR(blkg)))
+ goto root_rl;
+
+ blkg_get(blkg);
+ rcu_read_unlock();
+ return &blkg->rl;
+root_rl:
+ rcu_read_unlock();
+ return &q->root_rl;
+}
+
+/**
+ * blk_put_rl - put request_list
+ * @rl: request_list to put
+ *
+ * Put the reference acquired by blk_get_rl(). Should be called under
+ * queue_lock.
+ */
+static inline void blk_put_rl(struct request_list *rl)
+{
+ /* root_rl may not have blkg set */
+ if (rl->blkg && rl->blkg->blkcg != &blkcg_root)
+ blkg_put(rl->blkg);
+}
+
+/**
+ * blk_rq_set_rl - associate a request with a request_list
+ * @rq: request of interest
+ * @rl: target request_list
+ *
+ * Associate @rq with @rl so that accounting and freeing can know the
+ * request_list @rq came from.
+ */
+static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl)
+{
+ rq->rl = rl;
+}
+
+/**
+ * blk_rq_rl - return the request_list a request came from
+ * @rq: request of interest
+ *
+ * Return the request_list @rq is allocated from.
+ */
+static inline struct request_list *blk_rq_rl(struct request *rq)
+{
+ return rq->rl;
+}
+
+struct request_list *__blk_queue_next_rl(struct request_list *rl,
+ struct request_queue *q);
+/**
+ * blk_queue_for_each_rl - iterate through all request_lists of a request_queue
+ *
+ * Should be used under queue_lock.
+ */
+#define blk_queue_for_each_rl(rl, q) \
+ for ((rl) = &(q)->root_rl; (rl); (rl) = __blk_queue_next_rl((rl), (q)))
+
/**
* blkg_stat_add - add a value to a blkg_stat
* @stat: target blkg_stat
#else /* CONFIG_BLK_CGROUP */
struct cgroup;
+struct blkcg;
struct blkg_policy_data {
};
struct blkcg_policy {
};
-static inline struct blkcg *cgroup_to_blkcg(struct cgroup *cgroup) { return NULL; }
-static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; }
static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }
static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
static inline void blkcg_drain_queue(struct request_queue *q) { }
static inline void blkcg_deactivate_policy(struct request_queue *q,
const struct blkcg_policy *pol) { }
+static inline struct blkcg *cgroup_to_blkcg(struct cgroup *cgroup) { return NULL; }
+static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; }
+
static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
struct blkcg_policy *pol) { return NULL; }
static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) { return NULL; }
static inline void blkg_get(struct blkcg_gq *blkg) { }
static inline void blkg_put(struct blkcg_gq *blkg) { }
+static inline struct request_list *blk_get_rl(struct request_queue *q,
+ struct bio *bio) { return &q->root_rl; }
+static inline void blk_put_rl(struct request_list *rl) { }
+static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl) { }
+static inline struct request_list *blk_rq_rl(struct request *rq) { return &rq->q->root_rl; }
+
+#define blk_queue_for_each_rl(rl, q) \
+ for ((rl) = &(q)->root_rl; (rl); (rl) = NULL)
+
#endif /* CONFIG_BLK_CGROUP */
#endif /* _BLK_CGROUP_H */
if (!list_empty(&q->queue_head) && q->request_fn)
__blk_run_queue(q);
- drain |= q->rq.elvpriv;
+ drain |= q->nr_rqs_elvpriv;
/*
* Unfortunately, requests are queued at and tracked from
if (drain_all) {
drain |= !list_empty(&q->queue_head);
for (i = 0; i < 2; i++) {
- drain |= q->rq.count[i];
+ drain |= q->nr_rqs[i];
drain |= q->in_flight[i];
drain |= !list_empty(&q->flush_queue[i]);
}
* left with hung waiters. We need to wake up those waiters.
*/
if (q->request_fn) {
+ struct request_list *rl;
+
spin_lock_irq(q->queue_lock);
- for (i = 0; i < ARRAY_SIZE(q->rq.wait); i++)
- wake_up_all(&q->rq.wait[i]);
+
+ blk_queue_for_each_rl(rl, q)
+ for (i = 0; i < ARRAY_SIZE(rl->wait); i++)
+ wake_up_all(&rl->wait[i]);
+
spin_unlock_irq(q->queue_lock);
}
}
}
EXPORT_SYMBOL(blk_cleanup_queue);
-static int blk_init_free_list(struct request_queue *q)
+int blk_init_rl(struct request_list *rl, struct request_queue *q,
+ gfp_t gfp_mask)
{
- struct request_list *rl = &q->rq;
-
if (unlikely(rl->rq_pool))
return 0;
+ rl->q = q;
rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0;
rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0;
- rl->elvpriv = 0;
init_waitqueue_head(&rl->wait[BLK_RW_SYNC]);
init_waitqueue_head(&rl->wait[BLK_RW_ASYNC]);
rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab,
- mempool_free_slab, request_cachep, q->node);
-
+ mempool_free_slab, request_cachep,
+ gfp_mask, q->node);
if (!rl->rq_pool)
return -ENOMEM;
return 0;
}
+void blk_exit_rl(struct request_list *rl)
+{
+ if (rl->rq_pool)
+ mempool_destroy(rl->rq_pool);
+}
+
struct request_queue *blk_alloc_queue(gfp_t gfp_mask)
{
return blk_alloc_queue_node(gfp_mask, -1);
if (!q)
return NULL;
- if (blk_init_free_list(q))
+ if (blk_init_rl(&q->root_rl, q, GFP_KERNEL))
return NULL;
q->request_fn = rfn;
}
EXPORT_SYMBOL(blk_get_queue);
-static inline void blk_free_request(struct request_queue *q, struct request *rq)
+static inline void blk_free_request(struct request_list *rl, struct request *rq)
{
if (rq->cmd_flags & REQ_ELVPRIV) {
- elv_put_request(q, rq);
+ elv_put_request(rl->q, rq);
if (rq->elv.icq)
put_io_context(rq->elv.icq->ioc);
}
- mempool_free(rq, q->rq.rq_pool);
+ mempool_free(rq, rl->rq_pool);
}
/*
ioc->last_waited = jiffies;
}
-static void __freed_request(struct request_queue *q, int sync)
+static void __freed_request(struct request_list *rl, int sync)
{
- struct request_list *rl = &q->rq;
+ struct request_queue *q = rl->q;
- if (rl->count[sync] < queue_congestion_off_threshold(q))
+ /*
+ * bdi isn't aware of blkcg yet. As all async IOs end up root
+ * blkcg anyway, just use root blkcg state.
+ */
+ if (rl == &q->root_rl &&
+ rl->count[sync] < queue_congestion_off_threshold(q))
blk_clear_queue_congested(q, sync);
if (rl->count[sync] + 1 <= q->nr_requests) {
if (waitqueue_active(&rl->wait[sync]))
wake_up(&rl->wait[sync]);
- blk_clear_queue_full(q, sync);
+ blk_clear_rl_full(rl, sync);
}
}
* A request has just been released. Account for it, update the full and
* congestion status, wake up any waiters. Called under q->queue_lock.
*/
-static void freed_request(struct request_queue *q, unsigned int flags)
+static void freed_request(struct request_list *rl, unsigned int flags)
{
- struct request_list *rl = &q->rq;
+ struct request_queue *q = rl->q;
int sync = rw_is_sync(flags);
+ q->nr_rqs[sync]--;
rl->count[sync]--;
if (flags & REQ_ELVPRIV)
- rl->elvpriv--;
+ q->nr_rqs_elvpriv--;
- __freed_request(q, sync);
+ __freed_request(rl, sync);
if (unlikely(rl->starved[sync ^ 1]))
- __freed_request(q, sync ^ 1);
+ __freed_request(rl, sync ^ 1);
}
/*
}
/**
- * get_request - get a free request
- * @q: request_queue to allocate request from
+ * __get_request - get a free request
+ * @rl: request list to allocate from
* @rw_flags: RW and SYNC flags
* @bio: bio to allocate request for (can be %NULL)
* @gfp_mask: allocation mask
* Returns %NULL on failure, with @q->queue_lock held.
* Returns !%NULL on success, with @q->queue_lock *not held*.
*/
-static struct request *get_request(struct request_queue *q, int rw_flags,
- struct bio *bio, gfp_t gfp_mask)
+static struct request *__get_request(struct request_list *rl, int rw_flags,
+ struct bio *bio, gfp_t gfp_mask)
{
+ struct request_queue *q = rl->q;
struct request *rq;
- struct request_list *rl = &q->rq;
- struct elevator_type *et;
- struct io_context *ioc;
+ struct elevator_type *et = q->elevator->type;
+ struct io_context *ioc = rq_ioc(bio);
struct io_cq *icq = NULL;
const bool is_sync = rw_is_sync(rw_flags) != 0;
- bool retried = false;
int may_queue;
-retry:
- et = q->elevator->type;
- ioc = rq_ioc(bio);
if (unlikely(blk_queue_dead(q)))
return NULL;
if (rl->count[is_sync]+1 >= queue_congestion_on_threshold(q)) {
if (rl->count[is_sync]+1 >= q->nr_requests) {
- /*
- * We want ioc to record batching state. If it's
- * not already there, creating a new one requires
- * dropping queue_lock, which in turn requires
- * retesting conditions to avoid queue hang.
- */
- if (!ioc && !retried) {
- spin_unlock_irq(q->queue_lock);
- create_io_context(gfp_mask, q->node);
- spin_lock_irq(q->queue_lock);
- retried = true;
- goto retry;
- }
-
/*
* The queue will fill after this allocation, so set
* it as full, and mark this process as "batching".
* This process will be allowed to complete a batch of
* requests, others will be blocked.
*/
- if (!blk_queue_full(q, is_sync)) {
+ if (!blk_rl_full(rl, is_sync)) {
ioc_set_batching(q, ioc);
- blk_set_queue_full(q, is_sync);
+ blk_set_rl_full(rl, is_sync);
} else {
if (may_queue != ELV_MQUEUE_MUST
&& !ioc_batching(q, ioc)) {
}
}
}
- blk_set_queue_congested(q, is_sync);
+ /*
+ * bdi isn't aware of blkcg yet. As all async IOs end up
+ * root blkcg anyway, just use root blkcg state.
+ */
+ if (rl == &q->root_rl)
+ blk_set_queue_congested(q, is_sync);
}
/*
if (rl->count[is_sync] >= (3 * q->nr_requests / 2))
return NULL;
+ q->nr_rqs[is_sync]++;
rl->count[is_sync]++;
rl->starved[is_sync] = 0;
*/
if (blk_rq_should_init_elevator(bio) && !blk_queue_bypass(q)) {
rw_flags |= REQ_ELVPRIV;
- rl->elvpriv++;
+ q->nr_rqs_elvpriv++;
if (et->icq_cache && ioc)
icq = ioc_lookup_icq(ioc, q);
}
spin_unlock_irq(q->queue_lock);
/* allocate and init request */
- rq = mempool_alloc(q->rq.rq_pool, gfp_mask);
+ rq = mempool_alloc(rl->rq_pool, gfp_mask);
if (!rq)
goto fail_alloc;
blk_rq_init(q, rq);
+ blk_rq_set_rl(rq, rl);
rq->cmd_flags = rw_flags | REQ_ALLOCED;
/* init elvpriv */
if (rw_flags & REQ_ELVPRIV) {
if (unlikely(et->icq_cache && !icq)) {
- create_io_context(gfp_mask, q->node);
- ioc = rq_ioc(bio);
- if (!ioc)
- goto fail_elvpriv;
-
- icq = ioc_create_icq(ioc, q, gfp_mask);
+ if (ioc)
+ icq = ioc_create_icq(ioc, q, gfp_mask);
if (!icq)
goto fail_elvpriv;
}
rq->elv.icq = NULL;
spin_lock_irq(q->queue_lock);
- rl->elvpriv--;
+ q->nr_rqs_elvpriv--;
spin_unlock_irq(q->queue_lock);
goto out;
* queue, but this is pretty rare.
*/
spin_lock_irq(q->queue_lock);
- freed_request(q, rw_flags);
+ freed_request(rl, rw_flags);
/*
* in the very unlikely event that allocation failed and no
}
/**
- * get_request_wait - get a free request with retry
+ * get_request - get a free request
* @q: request_queue to allocate request from
* @rw_flags: RW and SYNC flags
* @bio: bio to allocate request for (can be %NULL)
+ * @gfp_mask: allocation mask
*
- * Get a free request from @q. This function keeps retrying under memory
- * pressure and fails iff @q is dead.
+ * Get a free request from @q. If %__GFP_WAIT is set in @gfp_mask, this
+ * function keeps retrying under memory pressure and fails iff @q is dead.
*
* Must be callled with @q->queue_lock held and,
* Returns %NULL on failure, with @q->queue_lock held.
* Returns !%NULL on success, with @q->queue_lock *not held*.
*/
-static struct request *get_request_wait(struct request_queue *q, int rw_flags,
- struct bio *bio)
+static struct request *get_request(struct request_queue *q, int rw_flags,
+ struct bio *bio, gfp_t gfp_mask)
{
const bool is_sync = rw_is_sync(rw_flags) != 0;
+ DEFINE_WAIT(wait);
+ struct request_list *rl;
struct request *rq;
- rq = get_request(q, rw_flags, bio, GFP_NOIO);
- while (!rq) {
- DEFINE_WAIT(wait);
- struct request_list *rl = &q->rq;
-
- if (unlikely(blk_queue_dead(q)))
- return NULL;
+ rl = blk_get_rl(q, bio); /* transferred to @rq on success */
+retry:
+ rq = __get_request(rl, rw_flags, bio, gfp_mask);
+ if (rq)
+ return rq;
- prepare_to_wait_exclusive(&rl->wait[is_sync], &wait,
- TASK_UNINTERRUPTIBLE);
+ if (!(gfp_mask & __GFP_WAIT) || unlikely(blk_queue_dead(q))) {
+ blk_put_rl(rl);
+ return NULL;
+ }
- trace_block_sleeprq(q, bio, rw_flags & 1);
+ /* wait on @rl and retry */
+ prepare_to_wait_exclusive(&rl->wait[is_sync], &wait,
+ TASK_UNINTERRUPTIBLE);
- spin_unlock_irq(q->queue_lock);
- io_schedule();
+ trace_block_sleeprq(q, bio, rw_flags & 1);
- /*
- * After sleeping, we become a "batching" process and
- * will be able to allocate at least one request, and
- * up to a big batch of them for a small period time.
- * See ioc_batching, ioc_set_batching
- */
- create_io_context(GFP_NOIO, q->node);
- ioc_set_batching(q, current->io_context);
+ spin_unlock_irq(q->queue_lock);
+ io_schedule();
- spin_lock_irq(q->queue_lock);
- finish_wait(&rl->wait[is_sync], &wait);
+ /*
+ * After sleeping, we become a "batching" process and will be able
+ * to allocate at least one request, and up to a big batch of them
+ * for a small period time. See ioc_batching, ioc_set_batching
+ */
+ ioc_set_batching(q, current->io_context);
- rq = get_request(q, rw_flags, bio, GFP_NOIO);
- };
+ spin_lock_irq(q->queue_lock);
+ finish_wait(&rl->wait[is_sync], &wait);
- return rq;
+ goto retry;
}
struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask)
BUG_ON(rw != READ && rw != WRITE);
+ /* create ioc upfront */
+ create_io_context(gfp_mask, q->node);
+
spin_lock_irq(q->queue_lock);
- if (gfp_mask & __GFP_WAIT)
- rq = get_request_wait(q, rw, NULL);
- else
- rq = get_request(q, rw, NULL, gfp_mask);
+ rq = get_request(q, rw, NULL, gfp_mask);
if (!rq)
spin_unlock_irq(q->queue_lock);
/* q->queue_lock is unlocked at this point */
*/
if (req->cmd_flags & REQ_ALLOCED) {
unsigned int flags = req->cmd_flags;
+ struct request_list *rl = blk_rq_rl(req);
BUG_ON(!list_empty(&req->queuelist));
BUG_ON(!hlist_unhashed(&req->hash));
- blk_free_request(q, req);
- freed_request(q, flags);
+ blk_free_request(rl, req);
+ freed_request(rl, flags);
+ blk_put_rl(rl);
}
}
EXPORT_SYMBOL_GPL(__blk_put_request);
* Grab a free request. This is might sleep but can not fail.
* Returns with the queue unlocked.
*/
- req = get_request_wait(q, rw_flags, bio);
+ req = get_request(q, rw_flags, bio, GFP_NOIO);
if (unlikely(!req)) {
bio_endio(bio, -ENODEV); /* @q is dead */
goto out_unlock;
goto end_io;
}
+ /*
+ * Various block parts want %current->io_context and lazy ioc
+ * allocation ends up trading a lot of pain for a small amount of
+ * memory. Just allocate it upfront. This may fail and block
+ * layer knows how to live with it.
+ */
+ create_io_context(GFP_ATOMIC, q->node);
+
if (blk_throtl_bio(q, bio))
return false; /* throttled, will be resubmitted later */
/* initialize */
atomic_long_set(&ioc->refcount, 1);
+ atomic_set(&ioc->nr_tasks, 1);
atomic_set(&ioc->active_ref, 1);
spin_lock_init(&ioc->lock);
INIT_RADIX_TREE(&ioc->icq_tree, GFP_ATOMIC | __GFP_HIGH);
lim->discard_zeroes_data = 1;
lim->max_segments = USHRT_MAX;
lim->max_hw_sectors = UINT_MAX;
-
- lim->max_sectors = BLK_DEF_MAX_SECTORS;
+ lim->max_sectors = UINT_MAX;
}
EXPORT_SYMBOL(blk_set_stacking_limits);
static ssize_t
queue_requests_store(struct request_queue *q, const char *page, size_t count)
{
- struct request_list *rl = &q->rq;
+ struct request_list *rl;
unsigned long nr;
int ret;
q->nr_requests = nr;
blk_queue_congestion_threshold(q);
+ /* congestion isn't cgroup aware and follows root blkcg for now */
+ rl = &q->root_rl;
+
if (rl->count[BLK_RW_SYNC] >= queue_congestion_on_threshold(q))
blk_set_queue_congested(q, BLK_RW_SYNC);
else if (rl->count[BLK_RW_SYNC] < queue_congestion_off_threshold(q))
else if (rl->count[BLK_RW_ASYNC] < queue_congestion_off_threshold(q))
blk_clear_queue_congested(q, BLK_RW_ASYNC);
- if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
- blk_set_queue_full(q, BLK_RW_SYNC);
- } else {
- blk_clear_queue_full(q, BLK_RW_SYNC);
- wake_up(&rl->wait[BLK_RW_SYNC]);
+ blk_queue_for_each_rl(rl, q) {
+ if (rl->count[BLK_RW_SYNC] >= q->nr_requests) {
+ blk_set_rl_full(rl, BLK_RW_SYNC);
+ } else {
+ blk_clear_rl_full(rl, BLK_RW_SYNC);
+ wake_up(&rl->wait[BLK_RW_SYNC]);
+ }
+
+ if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
+ blk_set_rl_full(rl, BLK_RW_ASYNC);
+ } else {
+ blk_clear_rl_full(rl, BLK_RW_ASYNC);
+ wake_up(&rl->wait[BLK_RW_ASYNC]);
+ }
}
- if (rl->count[BLK_RW_ASYNC] >= q->nr_requests) {
- blk_set_queue_full(q, BLK_RW_ASYNC);
- } else {
- blk_clear_queue_full(q, BLK_RW_ASYNC);
- wake_up(&rl->wait[BLK_RW_ASYNC]);
- }
spin_unlock_irq(q->queue_lock);
return ret;
}
{
struct request_queue *q =
container_of(kobj, struct request_queue, kobj);
- struct request_list *rl = &q->rq;
blk_sync_queue(q);
elevator_exit(q->elevator);
}
- if (rl->rq_pool)
- mempool_destroy(rl->rq_pool);
+ blk_exit_rl(&q->root_rl);
if (q->queue_tags)
__blk_queue_free_tags(q);
goto out;
}
- /* bio_associate_current() needs ioc, try creating */
- create_io_context(GFP_ATOMIC, q->node);
-
/*
* A throtl_grp pointer retrieved under rcu can be used to access
* basic fields like stats and io rates. If a group has no rules,
kobject_get(&q->kobj);
}
+int blk_init_rl(struct request_list *rl, struct request_queue *q,
+ gfp_t gfp_mask);
+void blk_exit_rl(struct request_list *rl);
void init_request_from_bio(struct request *req, struct bio *bio);
void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
struct bio *bio);
void blk_rq_timed_out_timer(unsigned long data);
void blk_delete_timer(struct request *);
void blk_add_timer(struct request *);
-void __generic_unplug_device(struct request_queue *);
/*
* Internal atomic flags for request handling
return 0;
}
EXPORT_SYMBOL_GPL(bsg_setup_queue);
-
-/**
- * bsg_remove_queue - Deletes the bsg dev from the q
- * @q: the request_queue that is to be torn down.
- *
- * Notes:
- * Before unregistering the queue empty any requests that are blocked
- */
-void bsg_remove_queue(struct request_queue *q)
-{
- struct request *req; /* block request */
- int counts; /* totals for request_list count and starved */
-
- if (!q)
- return;
-
- /* Stop taking in new requests */
- spin_lock_irq(q->queue_lock);
- blk_stop_queue(q);
-
- /* drain all requests in the queue */
- while (1) {
- /* need the lock to fetch a request
- * this may fetch the same reqeust as the previous pass
- */
- req = blk_fetch_request(q);
- /* save requests in use and starved */
- counts = q->rq.count[0] + q->rq.count[1] +
- q->rq.starved[0] + q->rq.starved[1];
- spin_unlock_irq(q->queue_lock);
- /* any requests still outstanding? */
- if (counts == 0)
- break;
-
- /* This may be the same req as the previous iteration,
- * always send the blk_end_request_all after a prefetch.
- * It is not okay to not end the request because the
- * prefetch started the request.
- */
- if (req) {
- /* return -ENXIO to indicate that this queue is
- * going away
- */
- req->errors = -ENXIO;
- blk_end_request_all(req, -ENXIO);
- }
-
- msleep(200); /* allow bsg to possibly finish */
- spin_lock_irq(q->queue_lock);
- }
- bsg_unregister_queue(q);
-}
-EXPORT_SYMBOL_GPL(bsg_remove_queue);
part = rcu_dereference(ptbl->part[piter->idx]);
if (!part)
continue;
- if (!part->nr_sects &&
+ if (!part_nr_sects_read(part) &&
!(piter->flags & DISK_PITER_INCL_EMPTY) &&
!(piter->flags & DISK_PITER_INCL_EMPTY_PART0 &&
piter->idx == 0))
static inline int sector_in_part(struct hd_struct *part, sector_t sector)
{
return part->start_sect <= sector &&
- sector < part->start_sect + part->nr_sects;
+ sector < part->start_sect + part_nr_sects_read(part);
}
/**
printk("%s%s %10llu %s %s", is_part0 ? "" : " ",
bdevt_str(part_devt(part), devt_buf),
- (unsigned long long)part->nr_sects >> 1,
- disk_name(disk, part->partno, name_buf),
+ (unsigned long long)part_nr_sects_read(part) >> 1
+ , disk_name(disk, part->partno, name_buf),
uuid_buf);
if (is_part0) {
if (disk->driverfs_dev != NULL &&
while ((part = disk_part_iter_next(&piter)))
seq_printf(seqf, "%4d %7d %10llu %s\n",
MAJOR(part_devt(part)), MINOR(part_devt(part)),
- (unsigned long long)part->nr_sects >> 1,
+ (unsigned long long)part_nr_sects_read(part) >> 1,
disk_name(sgp, part->partno, buf));
disk_part_iter_exit(&piter);
}
disk->part_tbl->part[0] = &disk->part0;
+ /*
+ * set_capacity() and get_capacity() currently don't use
+ * seqcounter to read/update the part0->nr_sects. Still init
+ * the counter as we can read the sectors in IO submission
+ * patch using seqence counters.
+ *
+ * TODO: Ideally set_capacity() and get_capacity() should be
+ * converted to make use of bd_mutex and sequence counters.
+ */
+ seqcount_init(&disk->part0.nr_sects_seq);
hd_ref_init(&disk->part0);
disk->minors = minors;
{
struct block_device *bdevp;
struct gendisk *disk;
- struct hd_struct *part;
+ struct hd_struct *part, *lpart;
struct blkpg_ioctl_arg a;
struct blkpg_partition p;
struct disk_part_iter piter;
case BLKPG_ADD_PARTITION:
start = p.start >> 9;
length = p.length >> 9;
- /* check for fit in a hd_struct */
- if (sizeof(sector_t) == sizeof(long) &&
+ /* check for fit in a hd_struct */
+ if (sizeof(sector_t) == sizeof(long) &&
sizeof(long long) > sizeof(long)) {
long pstart = start, plength = length;
if (pstart != start || plength != length
mutex_unlock(&bdevp->bd_mutex);
bdput(bdevp);
+ return 0;
+ case BLKPG_RESIZE_PARTITION:
+ start = p.start >> 9;
+ /* new length of partition in bytes */
+ length = p.length >> 9;
+ /* check for fit in a hd_struct */
+ if (sizeof(sector_t) == sizeof(long) &&
+ sizeof(long long) > sizeof(long)) {
+ long pstart = start, plength = length;
+ if (pstart != start || plength != length
+ || pstart < 0 || plength < 0)
+ return -EINVAL;
+ }
+ part = disk_get_part(disk, partno);
+ if (!part)
+ return -ENXIO;
+ bdevp = bdget(part_devt(part));
+ if (!bdevp) {
+ disk_put_part(part);
+ return -ENOMEM;
+ }
+ mutex_lock(&bdevp->bd_mutex);
+ mutex_lock_nested(&bdev->bd_mutex, 1);
+ if (start != part->start_sect) {
+ mutex_unlock(&bdevp->bd_mutex);
+ mutex_unlock(&bdev->bd_mutex);
+ bdput(bdevp);
+ disk_put_part(part);
+ return -EINVAL;
+ }
+ /* overlap? */
+ disk_part_iter_init(&piter, disk,
+ DISK_PITER_INCL_EMPTY);
+ while ((lpart = disk_part_iter_next(&piter))) {
+ if (lpart->partno != partno &&
+ !(start + length <= lpart->start_sect ||
+ start >= lpart->start_sect + lpart->nr_sects)
+ ) {
+ disk_part_iter_exit(&piter);
+ mutex_unlock(&bdevp->bd_mutex);
+ mutex_unlock(&bdev->bd_mutex);
+ bdput(bdevp);
+ disk_put_part(part);
+ return -EBUSY;
+ }
+ }
+ disk_part_iter_exit(&piter);
+ part_nr_sects_write(part, (sector_t)length);
+ i_size_write(bdevp->bd_inode, p.length);
+ mutex_unlock(&bdevp->bd_mutex);
+ mutex_unlock(&bdev->bd_mutex);
+ bdput(bdevp);
+ disk_put_part(part);
return 0;
default:
return -EINVAL;
struct device_attribute *attr, char *buf)
{
struct hd_struct *p = dev_to_part(dev);
- return sprintf(buf, "%llu\n",(unsigned long long)p->nr_sects);
+ return sprintf(buf, "%llu\n",(unsigned long long)part_nr_sects_read(p));
}
static ssize_t part_ro_show(struct device *dev,
err = -ENOMEM;
goto out_free;
}
+
+ seqcount_init(&p->nr_sects_seq);
pdev = part_to_dev(p);
p->start_sect = start;
static void
fc_bsg_remove(struct request_queue *q)
{
- struct request *req; /* block request */
- int counts; /* totals for request_list count and starved */
-
if (q) {
- /* Stop taking in new requests */
- spin_lock_irq(q->queue_lock);
- blk_stop_queue(q);
-
- /* drain all requests in the queue */
- while (1) {
- /* need the lock to fetch a request
- * this may fetch the same reqeust as the previous pass
- */
- req = blk_fetch_request(q);
- /* save requests in use and starved */
- counts = q->rq.count[0] + q->rq.count[1] +
- q->rq.starved[0] + q->rq.starved[1];
- spin_unlock_irq(q->queue_lock);
- /* any requests still outstanding? */
- if (counts == 0)
- break;
-
- /* This may be the same req as the previous iteration,
- * always send the blk_end_request_all after a prefetch.
- * It is not okay to not end the request because the
- * prefetch started the request.
- */
- if (req) {
- /* return -ENXIO to indicate that this queue is
- * going away
- */
- req->errors = -ENXIO;
- blk_end_request_all(req, -ENXIO);
- }
-
- msleep(200); /* allow bsg to possibly finish */
- spin_lock_irq(q->queue_lock);
- }
-
bsg_unregister_queue(q);
blk_cleanup_queue(q);
}
struct iscsi_cls_host *ihost = shost->shost_data;
if (ihost->bsg_q) {
- bsg_remove_queue(ihost->bsg_q);
+ bsg_unregister_queue(ihost->bsg_q);
blk_cleanup_queue(ihost->bsg_q);
}
return 0;
struct request;
typedef void (rq_end_io_fn)(struct request *, int);
+#define BLK_RL_SYNCFULL (1U << 0)
+#define BLK_RL_ASYNCFULL (1U << 1)
+
struct request_list {
+ struct request_queue *q; /* the queue this rl belongs to */
+#ifdef CONFIG_BLK_CGROUP
+ struct blkcg_gq *blkg; /* blkg this request pool belongs to */
+#endif
/*
* count[], starved[], and wait[] are indexed by
* BLK_RW_SYNC/BLK_RW_ASYNC
*/
- int count[2];
- int starved[2];
- int elvpriv;
- mempool_t *rq_pool;
- wait_queue_head_t wait[2];
+ int count[2];
+ int starved[2];
+ mempool_t *rq_pool;
+ wait_queue_head_t wait[2];
+ unsigned int flags;
};
/*
struct hd_struct *part;
unsigned long start_time;
#ifdef CONFIG_BLK_CGROUP
+ struct request_list *rl; /* rl this rq is alloced from */
unsigned long long start_time_ns;
unsigned long long io_start_time_ns; /* when passed to hardware */
#endif
struct list_head queue_head;
struct request *last_merge;
struct elevator_queue *elevator;
+ int nr_rqs[2]; /* # allocated [a]sync rqs */
+ int nr_rqs_elvpriv; /* # allocated rqs w/ elvpriv */
/*
- * the queue request freelist, one for reads and one for writes
+ * If blkcg is not used, @q->root_rl serves all requests. If blkcg
+ * is used, root blkg allocates from @q->root_rl and all other
+ * blkgs from their own blkg->rl. Which one to use should be
+ * determined using bio_request_list().
*/
- struct request_list rq;
+ struct request_list root_rl;
request_fn_proc *request_fn;
make_request_fn *make_request_fn;
return rw_is_sync(rq->cmd_flags);
}
-static inline int blk_queue_full(struct request_queue *q, int sync)
+static inline bool blk_rl_full(struct request_list *rl, bool sync)
{
- if (sync)
- return test_bit(QUEUE_FLAG_SYNCFULL, &q->queue_flags);
- return test_bit(QUEUE_FLAG_ASYNCFULL, &q->queue_flags);
+ unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
+
+ return rl->flags & flag;
}
-static inline void blk_set_queue_full(struct request_queue *q, int sync)
+static inline void blk_set_rl_full(struct request_list *rl, bool sync)
{
- if (sync)
- queue_flag_set(QUEUE_FLAG_SYNCFULL, q);
- else
- queue_flag_set(QUEUE_FLAG_ASYNCFULL, q);
+ unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
+
+ rl->flags |= flag;
}
-static inline void blk_clear_queue_full(struct request_queue *q, int sync)
+static inline void blk_clear_rl_full(struct request_list *rl, bool sync)
{
- if (sync)
- queue_flag_clear(QUEUE_FLAG_SYNCFULL, q);
- else
- queue_flag_clear(QUEUE_FLAG_ASYNCFULL, q);
+ unsigned int flag = sync ? BLK_RL_SYNCFULL : BLK_RL_ASYNCFULL;
+
+ rl->flags &= ~flag;
}
/* The subfunctions (for the op field) */
#define BLKPG_ADD_PARTITION 1
#define BLKPG_DEL_PARTITION 2
+#define BLKPG_RESIZE_PARTITION 3
/* Sizes of name fields. Unused at present. */
#define BLKPG_DEVNAMELTH 64
int bsg_setup_queue(struct device *dev, struct request_queue *q, char *name,
bsg_job_fn *job_fn, int dd_job_size);
void bsg_request_fn(struct request_queue *q);
-void bsg_remove_queue(struct request_queue *q);
void bsg_goose_queue(struct request_queue *q);
#endif
struct hd_struct {
sector_t start_sect;
+ /*
+ * nr_sects is protected by sequence counter. One might extend a
+ * partition while IO is happening to it and update of nr_sects
+ * can be non-atomic on 32bit machines with 64bit sector_t.
+ */
sector_t nr_sects;
+ seqcount_t nr_sects_seq;
sector_t alignment_offset;
unsigned int discard_alignment;
struct device __dev;
__delete_partition(part);
}
+/*
+ * Any access of part->nr_sects which is not protected by partition
+ * bd_mutex or gendisk bdev bd_mutex, should be done using this
+ * accessor function.
+ *
+ * Code written along the lines of i_size_read() and i_size_write().
+ * CONFIG_PREEMPT case optimizes the case of UP kernel with preemption
+ * on.
+ */
+static inline sector_t part_nr_sects_read(struct hd_struct *part)
+{
+#if BITS_PER_LONG==32 && defined(CONFIG_LBDAF) && defined(CONFIG_SMP)
+ sector_t nr_sects;
+ unsigned seq;
+ do {
+ seq = read_seqcount_begin(&part->nr_sects_seq);
+ nr_sects = part->nr_sects;
+ } while (read_seqcount_retry(&part->nr_sects_seq, seq));
+ return nr_sects;
+#elif BITS_PER_LONG==32 && defined(CONFIG_LBDAF) && defined(CONFIG_PREEMPT)
+ sector_t nr_sects;
+
+ preempt_disable();
+ nr_sects = part->nr_sects;
+ preempt_enable();
+ return nr_sects;
+#else
+ return part->nr_sects;
+#endif
+}
+
+/*
+ * Should be called with mutex lock held (typically bd_mutex) of partition
+ * to provide mutual exlusion among writers otherwise seqcount might be
+ * left in wrong state leaving the readers spinning infinitely.
+ */
+static inline void part_nr_sects_write(struct hd_struct *part, sector_t size)
+{
+#if BITS_PER_LONG==32 && defined(CONFIG_LBDAF) && defined(CONFIG_SMP)
+ write_seqcount_begin(&part->nr_sects_seq);
+ part->nr_sects = size;
+ write_seqcount_end(&part->nr_sects_seq);
+#elif BITS_PER_LONG==32 && defined(CONFIG_LBDAF) && defined(CONFIG_PREEMPT)
+ preempt_disable();
+ part->nr_sects = size;
+ preempt_enable();
+#else
+ part->nr_sects = size;
+#endif
+}
+
#else /* CONFIG_BLOCK */
static inline void printk_all_partitions(void) { }
extern mempool_t *mempool_create(int min_nr, mempool_alloc_t *alloc_fn,
mempool_free_t *free_fn, void *pool_data);
extern mempool_t *mempool_create_node(int min_nr, mempool_alloc_t *alloc_fn,
- mempool_free_t *free_fn, void *pool_data, int nid);
+ mempool_free_t *free_fn, void *pool_data,
+ gfp_t gfp_mask, int nid);
extern int mempool_resize(mempool_t *pool, int new_min_nr, gfp_t gfp_mask);
extern void mempool_destroy(mempool_t *pool);
mempool_t *mempool_create(int min_nr, mempool_alloc_t *alloc_fn,
mempool_free_t *free_fn, void *pool_data)
{
- return mempool_create_node(min_nr,alloc_fn,free_fn, pool_data,-1);
+ return mempool_create_node(min_nr,alloc_fn,free_fn, pool_data,
+ GFP_KERNEL, NUMA_NO_NODE);
}
EXPORT_SYMBOL(mempool_create);
mempool_t *mempool_create_node(int min_nr, mempool_alloc_t *alloc_fn,
- mempool_free_t *free_fn, void *pool_data, int node_id)
+ mempool_free_t *free_fn, void *pool_data,
+ gfp_t gfp_mask, int node_id)
{
mempool_t *pool;
- pool = kmalloc_node(sizeof(*pool), GFP_KERNEL | __GFP_ZERO, node_id);
+ pool = kmalloc_node(sizeof(*pool), gfp_mask | __GFP_ZERO, node_id);
if (!pool)
return NULL;
pool->elements = kmalloc_node(min_nr * sizeof(void *),
- GFP_KERNEL, node_id);
+ gfp_mask, node_id);
if (!pool->elements) {
kfree(pool);
return NULL;
while (pool->curr_nr < pool->min_nr) {
void *element;
- element = pool->alloc(GFP_KERNEL, pool->pool_data);
+ element = pool->alloc(gfp_mask, pool->pool_data);
if (unlikely(!element)) {
mempool_destroy(pool);
return NULL;
projects / firefly-linux-kernel-4.4.55.git / commitdiff