with the previous I/O request are enabled. When set to 2,
all merge tries are disabled. The default value is 0 -
which enables all types of merge tries.
+
+What: /sys/block/<disk>/discard_alignment
+Date: May 2011
+Contact: Martin K. Petersen <martin.petersen@oracle.com>
+Description:
+ Devices that support discard functionality may
+ internally allocate space in units that are bigger than
+ the exported logical block size. The discard_alignment
+ parameter indicates how many bytes the beginning of the
+ device is offset from the internal allocation unit's
+ natural alignment.
+
+What: /sys/block/<disk>/<partition>/discard_alignment
+Date: May 2011
+Contact: Martin K. Petersen <martin.petersen@oracle.com>
+Description:
+ Devices that support discard functionality may
+ internally allocate space in units that are bigger than
+ the exported logical block size. The discard_alignment
+ parameter indicates how many bytes the beginning of the
+ partition is offset from the internal allocation unit's
+ natural alignment.
+
+What: /sys/block/<disk>/queue/discard_granularity
+Date: May 2011
+Contact: Martin K. Petersen <martin.petersen@oracle.com>
+Description:
+ Devices that support discard functionality may
+ internally allocate space using units that are bigger
+ than the logical block size. The discard_granularity
+ parameter indicates the size of the internal allocation
+ unit in bytes if reported by the device. Otherwise the
+ discard_granularity will be set to match the device's
+ physical block size. A discard_granularity of 0 means
+ that the device does not support discard functionality.
+
+What: /sys/block/<disk>/queue/discard_max_bytes
+Date: May 2011
+Contact: Martin K. Petersen <martin.petersen@oracle.com>
+Description:
+ Devices that support discard functionality may have
+ internal limits on the number of bytes that can be
+ trimmed or unmapped in a single operation. Some storage
+ protocols also have inherent limits on the number of
+ blocks that can be described in a single command. The
+ discard_max_bytes parameter is set by the device driver
+ to the maximum number of bytes that can be discarded in
+ a single operation. Discard requests issued to the
+ device must not exceed this limit. A discard_max_bytes
+ value of 0 means that the device does not support
+ discard functionality.
+
+What: /sys/block/<disk>/queue/discard_zeroes_data
+Date: May 2011
+Contact: Martin K. Petersen <martin.petersen@oracle.com>
+Description:
+ Devices that support discard functionality may return
+ stale or random data when a previously discarded block
+ is read back. This can cause problems if the filesystem
+ expects discarded blocks to be explicitly cleared. If a
+ device reports that it deterministically returns zeroes
+ when a discarded area is read the discard_zeroes_data
+ parameter will be set to one. Otherwise it will be 0 and
+ the result of reading a discarded area is undefined.
spin_lock_irqsave(&blkg->stats_lock, flags);
blkg->stats.time += time;
+#ifdef CONFIG_DEBUG_BLK_CGROUP
blkg->stats.unaccounted_time += unaccounted_time;
+#endif
spin_unlock_irqrestore(&blkg->stats_lock, flags);
}
EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used);
+/*
+ * should be called under rcu read lock or queue lock to make sure blkg pointer
+ * is valid.
+ */
void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
uint64_t bytes, bool direction, bool sync)
{
- struct blkio_group_stats *stats;
+ struct blkio_group_stats_cpu *stats_cpu;
unsigned long flags;
- spin_lock_irqsave(&blkg->stats_lock, flags);
- stats = &blkg->stats;
- stats->sectors += bytes >> 9;
- blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICED], 1, direction,
- sync);
- blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_BYTES], bytes,
- direction, sync);
- spin_unlock_irqrestore(&blkg->stats_lock, flags);
+ /*
+ * Disabling interrupts to provide mutual exclusion between two
+ * writes on same cpu. It probably is not needed for 64bit. Not
+ * optimizing that case yet.
+ */
+ local_irq_save(flags);
+
+ stats_cpu = this_cpu_ptr(blkg->stats_cpu);
+
+ u64_stats_update_begin(&stats_cpu->syncp);
+ stats_cpu->sectors += bytes >> 9;
+ blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_SERVICED],
+ 1, direction, sync);
+ blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_SERVICE_BYTES],
+ bytes, direction, sync);
+ u64_stats_update_end(&stats_cpu->syncp);
+ local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(blkiocg_update_dispatch_stats);
}
EXPORT_SYMBOL_GPL(blkiocg_update_completion_stats);
+/* Merged stats are per cpu. */
void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction,
bool sync)
{
+ struct blkio_group_stats_cpu *stats_cpu;
unsigned long flags;
- spin_lock_irqsave(&blkg->stats_lock, flags);
- blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_MERGED], 1, direction,
- sync);
- spin_unlock_irqrestore(&blkg->stats_lock, flags);
+ /*
+ * Disabling interrupts to provide mutual exclusion between two
+ * writes on same cpu. It probably is not needed for 64bit. Not
+ * optimizing that case yet.
+ */
+ local_irq_save(flags);
+
+ stats_cpu = this_cpu_ptr(blkg->stats_cpu);
+
+ u64_stats_update_begin(&stats_cpu->syncp);
+ blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_MERGED], 1,
+ direction, sync);
+ u64_stats_update_end(&stats_cpu->syncp);
+ local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(blkiocg_update_io_merged_stats);
+/*
+ * This function allocates the per cpu stats for blkio_group. Should be called
+ * from sleepable context as alloc_per_cpu() requires that.
+ */
+int blkio_alloc_blkg_stats(struct blkio_group *blkg)
+{
+ /* Allocate memory for per cpu stats */
+ blkg->stats_cpu = alloc_percpu(struct blkio_group_stats_cpu);
+ if (!blkg->stats_cpu)
+ return -ENOMEM;
+ return 0;
+}
+EXPORT_SYMBOL_GPL(blkio_alloc_blkg_stats);
+
void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
struct blkio_group *blkg, void *key, dev_t dev,
enum blkio_policy_id plid)
}
EXPORT_SYMBOL_GPL(blkiocg_lookup_group);
+static void blkio_reset_stats_cpu(struct blkio_group *blkg)
+{
+ struct blkio_group_stats_cpu *stats_cpu;
+ int i, j, k;
+ /*
+ * Note: On 64 bit arch this should not be an issue. This has the
+ * possibility of returning some inconsistent value on 32bit arch
+ * as 64bit update on 32bit is non atomic. Taking care of this
+ * corner case makes code very complicated, like sending IPIs to
+ * cpus, taking care of stats of offline cpus etc.
+ *
+ * reset stats is anyway more of a debug feature and this sounds a
+ * corner case. So I am not complicating the code yet until and
+ * unless this becomes a real issue.
+ */
+ for_each_possible_cpu(i) {
+ stats_cpu = per_cpu_ptr(blkg->stats_cpu, i);
+ stats_cpu->sectors = 0;
+ for(j = 0; j < BLKIO_STAT_CPU_NR; j++)
+ for (k = 0; k < BLKIO_STAT_TOTAL; k++)
+ stats_cpu->stat_arr_cpu[j][k] = 0;
+ }
+}
+
static int
blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val)
{
}
#endif
spin_unlock(&blkg->stats_lock);
+
+ /* Reset Per cpu stats which don't take blkg->stats_lock */
+ blkio_reset_stats_cpu(blkg);
}
+
spin_unlock_irq(&blkcg->lock);
return 0;
}
return val;
}
+
+static uint64_t blkio_read_stat_cpu(struct blkio_group *blkg,
+ enum stat_type_cpu type, enum stat_sub_type sub_type)
+{
+ int cpu;
+ struct blkio_group_stats_cpu *stats_cpu;
+ u64 val = 0, tval;
+
+ for_each_possible_cpu(cpu) {
+ unsigned int start;
+ stats_cpu = per_cpu_ptr(blkg->stats_cpu, cpu);
+
+ do {
+ start = u64_stats_fetch_begin(&stats_cpu->syncp);
+ if (type == BLKIO_STAT_CPU_SECTORS)
+ tval = stats_cpu->sectors;
+ else
+ tval = stats_cpu->stat_arr_cpu[type][sub_type];
+ } while(u64_stats_fetch_retry(&stats_cpu->syncp, start));
+
+ val += tval;
+ }
+
+ return val;
+}
+
+static uint64_t blkio_get_stat_cpu(struct blkio_group *blkg,
+ struct cgroup_map_cb *cb, dev_t dev, enum stat_type_cpu type)
+{
+ uint64_t disk_total, val;
+ char key_str[MAX_KEY_LEN];
+ enum stat_sub_type sub_type;
+
+ if (type == BLKIO_STAT_CPU_SECTORS) {
+ val = blkio_read_stat_cpu(blkg, type, 0);
+ return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, val, cb, dev);
+ }
+
+ for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL;
+ sub_type++) {
+ blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false);
+ val = blkio_read_stat_cpu(blkg, type, sub_type);
+ cb->fill(cb, key_str, val);
+ }
+
+ disk_total = blkio_read_stat_cpu(blkg, type, BLKIO_STAT_READ) +
+ blkio_read_stat_cpu(blkg, type, BLKIO_STAT_WRITE);
+
+ blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false);
+ cb->fill(cb, key_str, disk_total);
+ return disk_total;
+}
+
/* This should be called with blkg->stats_lock held */
static uint64_t blkio_get_stat(struct blkio_group *blkg,
struct cgroup_map_cb *cb, dev_t dev, enum stat_type type)
if (type == BLKIO_STAT_TIME)
return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
blkg->stats.time, cb, dev);
- if (type == BLKIO_STAT_SECTORS)
- return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
- blkg->stats.sectors, cb, dev);
#ifdef CONFIG_DEBUG_BLK_CGROUP
if (type == BLKIO_STAT_UNACCOUNTED_TIME)
return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
}
static int blkio_read_blkg_stats(struct blkio_cgroup *blkcg,
- struct cftype *cft, struct cgroup_map_cb *cb, enum stat_type type,
- bool show_total)
+ struct cftype *cft, struct cgroup_map_cb *cb,
+ enum stat_type type, bool show_total, bool pcpu)
{
struct blkio_group *blkg;
struct hlist_node *n;
if (blkg->dev) {
if (!cftype_blkg_same_policy(cft, blkg))
continue;
- spin_lock_irq(&blkg->stats_lock);
- cgroup_total += blkio_get_stat(blkg, cb, blkg->dev,
- type);
- spin_unlock_irq(&blkg->stats_lock);
+ if (pcpu)
+ cgroup_total += blkio_get_stat_cpu(blkg, cb,
+ blkg->dev, type);
+ else {
+ spin_lock_irq(&blkg->stats_lock);
+ cgroup_total += blkio_get_stat(blkg, cb,
+ blkg->dev, type);
+ spin_unlock_irq(&blkg->stats_lock);
+ }
}
}
if (show_total)
switch(name) {
case BLKIO_PROP_time:
return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_TIME, 0);
+ BLKIO_STAT_TIME, 0, 0);
case BLKIO_PROP_sectors:
return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_SECTORS, 0);
+ BLKIO_STAT_CPU_SECTORS, 0, 1);
case BLKIO_PROP_io_service_bytes:
return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_SERVICE_BYTES, 1);
+ BLKIO_STAT_CPU_SERVICE_BYTES, 1, 1);
case BLKIO_PROP_io_serviced:
return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_SERVICED, 1);
+ BLKIO_STAT_CPU_SERVICED, 1, 1);
case BLKIO_PROP_io_service_time:
return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_SERVICE_TIME, 1);
+ BLKIO_STAT_SERVICE_TIME, 1, 0);
case BLKIO_PROP_io_wait_time:
return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_WAIT_TIME, 1);
+ BLKIO_STAT_WAIT_TIME, 1, 0);
case BLKIO_PROP_io_merged:
return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_MERGED, 1);
+ BLKIO_STAT_CPU_MERGED, 1, 1);
case BLKIO_PROP_io_queued:
return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_QUEUED, 1);
+ BLKIO_STAT_QUEUED, 1, 0);
#ifdef CONFIG_DEBUG_BLK_CGROUP
case BLKIO_PROP_unaccounted_time:
return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_UNACCOUNTED_TIME, 0);
+ BLKIO_STAT_UNACCOUNTED_TIME, 0, 0);
case BLKIO_PROP_dequeue:
return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_DEQUEUE, 0);
+ BLKIO_STAT_DEQUEUE, 0, 0);
case BLKIO_PROP_avg_queue_size:
return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_AVG_QUEUE_SIZE, 0);
+ BLKIO_STAT_AVG_QUEUE_SIZE, 0, 0);
case BLKIO_PROP_group_wait_time:
return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_GROUP_WAIT_TIME, 0);
+ BLKIO_STAT_GROUP_WAIT_TIME, 0, 0);
case BLKIO_PROP_idle_time:
return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_IDLE_TIME, 0);
+ BLKIO_STAT_IDLE_TIME, 0, 0);
case BLKIO_PROP_empty_time:
return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_EMPTY_TIME, 0);
+ BLKIO_STAT_EMPTY_TIME, 0, 0);
#endif
default:
BUG();
switch(name){
case BLKIO_THROTL_io_service_bytes:
return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_SERVICE_BYTES, 1);
+ BLKIO_STAT_CPU_SERVICE_BYTES, 1, 1);
case BLKIO_THROTL_io_serviced:
return blkio_read_blkg_stats(blkcg, cft, cb,
- BLKIO_STAT_SERVICED, 1);
+ BLKIO_STAT_CPU_SERVICED, 1, 1);
default:
BUG();
}
*/
#include <linux/cgroup.h>
+#include <linux/u64_stats_sync.h>
enum blkio_policy_id {
BLKIO_POLICY_PROP = 0, /* Proportional Bandwidth division */
* request completion for IOs doen by this cgroup. This may not be
* accurate when NCQ is turned on. */
BLKIO_STAT_SERVICE_TIME = 0,
- /* Total bytes transferred */
- BLKIO_STAT_SERVICE_BYTES,
- /* Total IOs serviced, post merge */
- BLKIO_STAT_SERVICED,
/* Total time spent waiting in scheduler queue in ns */
BLKIO_STAT_WAIT_TIME,
- /* Number of IOs merged */
- BLKIO_STAT_MERGED,
/* Number of IOs queued up */
BLKIO_STAT_QUEUED,
/* All the single valued stats go below this */
BLKIO_STAT_TIME,
- BLKIO_STAT_SECTORS,
+#ifdef CONFIG_DEBUG_BLK_CGROUP
/* Time not charged to this cgroup */
BLKIO_STAT_UNACCOUNTED_TIME,
-#ifdef CONFIG_DEBUG_BLK_CGROUP
BLKIO_STAT_AVG_QUEUE_SIZE,
BLKIO_STAT_IDLE_TIME,
BLKIO_STAT_EMPTY_TIME,
#endif
};
+/* Per cpu stats */
+enum stat_type_cpu {
+ BLKIO_STAT_CPU_SECTORS,
+ /* Total bytes transferred */
+ BLKIO_STAT_CPU_SERVICE_BYTES,
+ /* Total IOs serviced, post merge */
+ BLKIO_STAT_CPU_SERVICED,
+ /* Number of IOs merged */
+ BLKIO_STAT_CPU_MERGED,
+ BLKIO_STAT_CPU_NR
+};
+
enum stat_sub_type {
BLKIO_STAT_READ = 0,
BLKIO_STAT_WRITE,
struct blkio_group_stats {
/* total disk time and nr sectors dispatched by this group */
uint64_t time;
- uint64_t sectors;
- /* Time not charged to this cgroup */
- uint64_t unaccounted_time;
uint64_t stat_arr[BLKIO_STAT_QUEUED + 1][BLKIO_STAT_TOTAL];
#ifdef CONFIG_DEBUG_BLK_CGROUP
+ /* Time not charged to this cgroup */
+ uint64_t unaccounted_time;
+
/* Sum of number of IOs queued across all samples */
uint64_t avg_queue_size_sum;
/* Count of samples taken for average */
#endif
};
+/* Per cpu blkio group stats */
+struct blkio_group_stats_cpu {
+ uint64_t sectors;
+ uint64_t stat_arr_cpu[BLKIO_STAT_CPU_NR][BLKIO_STAT_TOTAL];
+ struct u64_stats_sync syncp;
+};
+
struct blkio_group {
/* An rcu protected unique identifier for the group */
void *key;
/* Need to serialize the stats in the case of reset/update */
spinlock_t stats_lock;
struct blkio_group_stats stats;
+ /* Per cpu stats pointer */
+ struct blkio_group_stats_cpu __percpu *stats_cpu;
};
struct blkio_policy_node {
extern void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
struct blkio_group *blkg, void *key, dev_t dev,
enum blkio_policy_id plid);
+extern int blkio_alloc_blkg_stats(struct blkio_group *blkg);
extern int blkiocg_del_blkio_group(struct blkio_group *blkg);
extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,
void *key);
struct blkio_group *blkg, void *key, dev_t dev,
enum blkio_policy_id plid) {}
+static inline int blkio_alloc_blkg_stats(struct blkio_group *blkg) { return 0; }
+
static inline int
blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; }
static inline void blk_free_request(struct request_queue *q, struct request *rq)
{
- BUG_ON(rq->cmd_flags & REQ_ON_PLUG);
-
if (rq->cmd_flags & REQ_ELVPRIV)
elv_put_request(q, rq);
mempool_free(rq, q->rq.rq_pool);
{
const int ff = bio->bi_rw & REQ_FAILFAST_MASK;
- /*
- * Debug stuff, kill later
- */
- if (!rq_mergeable(req)) {
- blk_dump_rq_flags(req, "back");
- return false;
- }
-
if (!ll_back_merge_fn(q, req, bio))
return false;
req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));
drive_stat_acct(req, 0);
+ elv_bio_merged(q, req, bio);
return true;
}
const int ff = bio->bi_rw & REQ_FAILFAST_MASK;
sector_t sector;
- /*
- * Debug stuff, kill later
- */
- if (!rq_mergeable(req)) {
- blk_dump_rq_flags(req, "front");
- return false;
- }
-
if (!ll_front_merge_fn(q, req, bio))
return false;
req->ioprio = ioprio_best(req->ioprio, bio_prio(bio));
drive_stat_acct(req, 0);
+ elv_bio_merged(q, req, bio);
return true;
}
el_ret = elv_merge(q, &req, bio);
if (el_ret == ELEVATOR_BACK_MERGE) {
- BUG_ON(req->cmd_flags & REQ_ON_PLUG);
if (bio_attempt_back_merge(q, req, bio)) {
if (!attempt_back_merge(q, req))
elv_merged_request(q, req, el_ret);
goto out_unlock;
}
} else if (el_ret == ELEVATOR_FRONT_MERGE) {
- BUG_ON(req->cmd_flags & REQ_ON_PLUG);
if (bio_attempt_front_merge(q, req, bio)) {
if (!attempt_front_merge(q, req))
elv_merged_request(q, req, el_ret);
if (__rq->q != q)
plug->should_sort = 1;
}
- /*
- * Debug flag, kill later
- */
- req->cmd_flags |= REQ_ON_PLUG;
list_add_tail(&req->queuelist, &plug->list);
drive_stat_acct(req, 1);
} else {
goto end_io;
}
- blk_throtl_bio(q, &bio);
+ if (blk_throtl_bio(q, &bio))
+ goto end_io;
/*
* If bio = NULL, bio has been throttled and will be submitted
while (!list_empty(&list)) {
rq = list_entry_rq(list.next);
list_del_init(&rq->queuelist);
- BUG_ON(!(rq->cmd_flags & REQ_ON_PLUG));
BUG_ON(!rq->q);
if (rq->q != q) {
/*
depth = 0;
spin_lock(q->queue_lock);
}
- rq->cmd_flags &= ~REQ_ON_PLUG;
-
/*
* rq is already accounted, so use raw insert
*/
spin_lock_irq(q->queue_lock);
__elv_add_request(q, rq, where);
__blk_run_queue(q);
- /* the queue is stopped so it won't be plugged+unplugged */
+ /* the queue is stopped so it won't be run */
if (rq->cmd_type == REQ_TYPE_PM_RESUME)
q->request_fn(q);
spin_unlock_irq(q->queue_lock);
}
/*
- * Moving a request silently to empty queue_head may stall the
- * queue. Kick the queue in those cases. This function is called
- * from request completion path and calling directly into
- * request_fn may confuse the driver. Always use kblockd.
+ * Kick the queue to avoid stall for two cases:
+ * 1. Moving a request silently to empty queue_head may stall the
+ * queue.
+ * 2. When flush request is running in non-queueable queue, the
+ * queue is hold. Restart the queue after flush request is finished
+ * to avoid stall.
+ * This function is called from request completion path and calling
+ * directly into request_fn may confuse the driver. Always use
+ * kblockd.
*/
- if (queued)
+ if (queued || q->flush_queue_delayed)
blk_run_queue_async(q);
+ q->flush_queue_delayed = 0;
}
/**
INIT_RADIX_TREE(&ret->radix_root, GFP_ATOMIC | __GFP_HIGH);
INIT_HLIST_HEAD(&ret->cic_list);
ret->ioc_data = NULL;
+#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
+ ret->cgroup_changed = 0;
+#endif
}
return ret;
#include "blk.h"
-static void blkdev_discard_end_io(struct bio *bio, int err)
-{
- if (err) {
- if (err == -EOPNOTSUPP)
- set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
- clear_bit(BIO_UPTODATE, &bio->bi_flags);
- }
+struct bio_batch {
+ atomic_t done;
+ unsigned long flags;
+ struct completion *wait;
+};
- if (bio->bi_private)
- complete(bio->bi_private);
+static void bio_batch_end_io(struct bio *bio, int err)
+{
+ struct bio_batch *bb = bio->bi_private;
+ if (err && (err != -EOPNOTSUPP))
+ clear_bit(BIO_UPTODATE, &bb->flags);
+ if (atomic_dec_and_test(&bb->done))
+ complete(bb->wait);
bio_put(bio);
}
struct request_queue *q = bdev_get_queue(bdev);
int type = REQ_WRITE | REQ_DISCARD;
unsigned int max_discard_sectors;
+ struct bio_batch bb;
struct bio *bio;
int ret = 0;
type |= REQ_SECURE;
}
- while (nr_sects && !ret) {
+ atomic_set(&bb.done, 1);
+ bb.flags = 1 << BIO_UPTODATE;
+ bb.wait = &wait;
+
+ while (nr_sects) {
bio = bio_alloc(gfp_mask, 1);
if (!bio) {
ret = -ENOMEM;
}
bio->bi_sector = sector;
- bio->bi_end_io = blkdev_discard_end_io;
+ bio->bi_end_io = bio_batch_end_io;
bio->bi_bdev = bdev;
- bio->bi_private = &wait;
+ bio->bi_private = &bb;
if (nr_sects > max_discard_sectors) {
bio->bi_size = max_discard_sectors << 9;
nr_sects = 0;
}
- bio_get(bio);
+ atomic_inc(&bb.done);
submit_bio(type, bio);
+ }
+ /* Wait for bios in-flight */
+ if (!atomic_dec_and_test(&bb.done))
wait_for_completion(&wait);
- if (bio_flagged(bio, BIO_EOPNOTSUPP))
- ret = -EOPNOTSUPP;
- else if (!bio_flagged(bio, BIO_UPTODATE))
- ret = -EIO;
- bio_put(bio);
- }
+ if (!test_bit(BIO_UPTODATE, &bb.flags))
+ ret = -EIO;
return ret;
}
EXPORT_SYMBOL(blkdev_issue_discard);
-struct bio_batch
-{
- atomic_t done;
- unsigned long flags;
- struct completion *wait;
-};
-
-static void bio_batch_end_io(struct bio *bio, int err)
-{
- struct bio_batch *bb = bio->bi_private;
-
- if (err) {
- if (err == -EOPNOTSUPP)
- set_bit(BIO_EOPNOTSUPP, &bb->flags);
- else
- clear_bit(BIO_UPTODATE, &bb->flags);
- }
- if (bb)
- if (atomic_dec_and_test(&bb->done))
- complete(bb->wait);
- bio_put(bio);
-}
-
/**
* blkdev_issue_zeroout - generate number of zero filed write bios
* @bdev: blockdev to issue
bb.flags = 1 << BIO_UPTODATE;
bb.wait = &wait;
-submit:
ret = 0;
while (nr_sects != 0) {
bio = bio_alloc(gfp_mask,
while (nr_sects != 0) {
sz = min((sector_t) PAGE_SIZE >> 9 , nr_sects);
- if (sz == 0)
- /* bio has maximum size possible */
- break;
ret = bio_add_page(bio, ZERO_PAGE(0), sz << 9, 0);
nr_sects -= ret >> 9;
sector += ret >> 9;
/* One of bios in the batch was completed with error.*/
ret = -EIO;
- if (ret)
- goto out;
-
- if (test_bit(BIO_EOPNOTSUPP, &bb.flags)) {
- ret = -EOPNOTSUPP;
- goto out;
- }
- if (nr_sects != 0)
- goto submit;
-out:
return ret;
}
EXPORT_SYMBOL(blkdev_issue_zeroout);
lim->discard_granularity = 0;
lim->discard_alignment = 0;
lim->discard_misaligned = 0;
- lim->discard_zeroes_data = -1;
+ lim->discard_zeroes_data = 1;
lim->logical_block_size = lim->physical_block_size = lim->io_min = 512;
lim->bounce_pfn = (unsigned long)(BLK_BOUNCE_ANY >> PAGE_SHIFT);
lim->alignment_offset = 0;
blk_set_default_limits(&q->limits);
blk_queue_max_hw_sectors(q, BLK_SAFE_MAX_SECTORS);
+ q->limits.discard_zeroes_data = 0;
/*
* by default assume old behaviour and bounce for any highmem page
}
EXPORT_SYMBOL_GPL(blk_queue_flush);
+void blk_queue_flush_queueable(struct request_queue *q, bool queueable)
+{
+ q->flush_not_queueable = !queueable;
+}
+EXPORT_SYMBOL_GPL(blk_queue_flush_queueable);
+
static int __init blk_settings_init(void)
{
blk_max_low_pfn = max_low_pfn - 1;
static ssize_t queue_discard_max_show(struct request_queue *q, char *page)
{
- return queue_var_show(q->limits.max_discard_sectors << 9, page);
+ return sprintf(page, "%llu\n",
+ (unsigned long long)q->limits.max_discard_sectors << 9);
}
static ssize_t queue_discard_zeroes_data_show(struct request_queue *q, char *page)
/* Some throttle limits got updated for the group */
int limits_changed;
+
+ struct rcu_head rcu_head;
};
struct throtl_data
/* service tree for active throtl groups */
struct throtl_rb_root tg_service_tree;
- struct throtl_grp root_tg;
+ struct throtl_grp *root_tg;
struct request_queue *queue;
/* Total Number of queued bios on READ and WRITE lists */
return tg;
}
-static void throtl_put_tg(struct throtl_grp *tg)
+static void throtl_free_tg(struct rcu_head *head)
{
- BUG_ON(atomic_read(&tg->ref) <= 0);
- if (!atomic_dec_and_test(&tg->ref))
- return;
+ struct throtl_grp *tg;
+
+ tg = container_of(head, struct throtl_grp, rcu_head);
+ free_percpu(tg->blkg.stats_cpu);
kfree(tg);
}
-static struct throtl_grp * throtl_find_alloc_tg(struct throtl_data *td,
- struct blkio_cgroup *blkcg)
+static void throtl_put_tg(struct throtl_grp *tg)
{
- struct throtl_grp *tg = NULL;
- void *key = td;
- struct backing_dev_info *bdi = &td->queue->backing_dev_info;
- unsigned int major, minor;
+ BUG_ON(atomic_read(&tg->ref) <= 0);
+ if (!atomic_dec_and_test(&tg->ref))
+ return;
/*
- * TODO: Speed up blkiocg_lookup_group() by maintaining a radix
- * tree of blkg (instead of traversing through hash list all
- * the time.
+ * A group is freed in rcu manner. But having an rcu lock does not
+ * mean that one can access all the fields of blkg and assume these
+ * are valid. For example, don't try to follow throtl_data and
+ * request queue links.
+ *
+ * Having a reference to blkg under an rcu allows acess to only
+ * values local to groups like group stats and group rate limits
*/
+ call_rcu(&tg->rcu_head, throtl_free_tg);
+}
- /*
- * This is the common case when there are no blkio cgroups.
- * Avoid lookup in this case
- */
- if (blkcg == &blkio_root_cgroup)
- tg = &td->root_tg;
- else
- tg = tg_of_blkg(blkiocg_lookup_group(blkcg, key));
-
- /* Fill in device details for root group */
- if (tg && !tg->blkg.dev && bdi->dev && dev_name(bdi->dev)) {
- sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
- tg->blkg.dev = MKDEV(major, minor);
- goto done;
- }
-
- if (tg)
- goto done;
-
- tg = kzalloc_node(sizeof(*tg), GFP_ATOMIC, td->queue->node);
- if (!tg)
- goto done;
-
+static void throtl_init_group(struct throtl_grp *tg)
+{
INIT_HLIST_NODE(&tg->tg_node);
RB_CLEAR_NODE(&tg->rb_node);
bio_list_init(&tg->bio_lists[0]);
bio_list_init(&tg->bio_lists[1]);
- td->limits_changed = false;
+ tg->limits_changed = false;
+
+ /* Practically unlimited BW */
+ tg->bps[0] = tg->bps[1] = -1;
+ tg->iops[0] = tg->iops[1] = -1;
/*
* Take the initial reference that will be released on destroy
* exit or cgroup deletion path depending on who is exiting first.
*/
atomic_set(&tg->ref, 1);
+}
+
+/* Should be called with rcu read lock held (needed for blkcg) */
+static void
+throtl_add_group_to_td_list(struct throtl_data *td, struct throtl_grp *tg)
+{
+ hlist_add_head(&tg->tg_node, &td->tg_list);
+ td->nr_undestroyed_grps++;
+}
+
+static void
+__throtl_tg_fill_dev_details(struct throtl_data *td, struct throtl_grp *tg)
+{
+ struct backing_dev_info *bdi = &td->queue->backing_dev_info;
+ unsigned int major, minor;
+
+ if (!tg || tg->blkg.dev)
+ return;
+
+ /*
+ * Fill in device details for a group which might not have been
+ * filled at group creation time as queue was being instantiated
+ * and driver had not attached a device yet
+ */
+ if (bdi->dev && dev_name(bdi->dev)) {
+ sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
+ tg->blkg.dev = MKDEV(major, minor);
+ }
+}
+
+/*
+ * Should be called with without queue lock held. Here queue lock will be
+ * taken rarely. It will be taken only once during life time of a group
+ * if need be
+ */
+static void
+throtl_tg_fill_dev_details(struct throtl_data *td, struct throtl_grp *tg)
+{
+ if (!tg || tg->blkg.dev)
+ return;
+
+ spin_lock_irq(td->queue->queue_lock);
+ __throtl_tg_fill_dev_details(td, tg);
+ spin_unlock_irq(td->queue->queue_lock);
+}
+
+static void throtl_init_add_tg_lists(struct throtl_data *td,
+ struct throtl_grp *tg, struct blkio_cgroup *blkcg)
+{
+ __throtl_tg_fill_dev_details(td, tg);
/* Add group onto cgroup list */
- sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
blkiocg_add_blkio_group(blkcg, &tg->blkg, (void *)td,
- MKDEV(major, minor), BLKIO_POLICY_THROTL);
+ tg->blkg.dev, BLKIO_POLICY_THROTL);
tg->bps[READ] = blkcg_get_read_bps(blkcg, tg->blkg.dev);
tg->bps[WRITE] = blkcg_get_write_bps(blkcg, tg->blkg.dev);
tg->iops[READ] = blkcg_get_read_iops(blkcg, tg->blkg.dev);
tg->iops[WRITE] = blkcg_get_write_iops(blkcg, tg->blkg.dev);
- hlist_add_head(&tg->tg_node, &td->tg_list);
- td->nr_undestroyed_grps++;
-done:
+ throtl_add_group_to_td_list(td, tg);
+}
+
+/* Should be called without queue lock and outside of rcu period */
+static struct throtl_grp *throtl_alloc_tg(struct throtl_data *td)
+{
+ struct throtl_grp *tg = NULL;
+ int ret;
+
+ tg = kzalloc_node(sizeof(*tg), GFP_ATOMIC, td->queue->node);
+ if (!tg)
+ return NULL;
+
+ ret = blkio_alloc_blkg_stats(&tg->blkg);
+
+ if (ret) {
+ kfree(tg);
+ return NULL;
+ }
+
+ throtl_init_group(tg);
return tg;
}
-static struct throtl_grp * throtl_get_tg(struct throtl_data *td)
+static struct
+throtl_grp *throtl_find_tg(struct throtl_data *td, struct blkio_cgroup *blkcg)
{
struct throtl_grp *tg = NULL;
+ void *key = td;
+
+ /*
+ * This is the common case when there are no blkio cgroups.
+ * Avoid lookup in this case
+ */
+ if (blkcg == &blkio_root_cgroup)
+ tg = td->root_tg;
+ else
+ tg = tg_of_blkg(blkiocg_lookup_group(blkcg, key));
+
+ __throtl_tg_fill_dev_details(td, tg);
+ return tg;
+}
+
+/*
+ * This function returns with queue lock unlocked in case of error, like
+ * request queue is no more
+ */
+static struct throtl_grp * throtl_get_tg(struct throtl_data *td)
+{
+ struct throtl_grp *tg = NULL, *__tg = NULL;
struct blkio_cgroup *blkcg;
+ struct request_queue *q = td->queue;
rcu_read_lock();
blkcg = task_blkio_cgroup(current);
- tg = throtl_find_alloc_tg(td, blkcg);
- if (!tg)
- tg = &td->root_tg;
+ tg = throtl_find_tg(td, blkcg);
+ if (tg) {
+ rcu_read_unlock();
+ return tg;
+ }
+
+ /*
+ * Need to allocate a group. Allocation of group also needs allocation
+ * of per cpu stats which in-turn takes a mutex() and can block. Hence
+ * we need to drop rcu lock and queue_lock before we call alloc
+ *
+ * Take the request queue reference to make sure queue does not
+ * go away once we return from allocation.
+ */
+ blk_get_queue(q);
+ rcu_read_unlock();
+ spin_unlock_irq(q->queue_lock);
+
+ tg = throtl_alloc_tg(td);
+ /*
+ * We might have slept in group allocation. Make sure queue is not
+ * dead
+ */
+ if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) {
+ blk_put_queue(q);
+ if (tg)
+ kfree(tg);
+
+ return ERR_PTR(-ENODEV);
+ }
+ blk_put_queue(q);
+
+ /* Group allocated and queue is still alive. take the lock */
+ spin_lock_irq(q->queue_lock);
+
+ /*
+ * Initialize the new group. After sleeping, read the blkcg again.
+ */
+ rcu_read_lock();
+ blkcg = task_blkio_cgroup(current);
+
+ /*
+ * If some other thread already allocated the group while we were
+ * not holding queue lock, free up the group
+ */
+ __tg = throtl_find_tg(td, blkcg);
+
+ if (__tg) {
+ kfree(tg);
+ rcu_read_unlock();
+ return __tg;
+ }
+
+ /* Group allocation failed. Account the IO to root group */
+ if (!tg) {
+ tg = td->root_tg;
+ return tg;
+ }
+
+ throtl_init_add_tg_lists(td, tg, blkcg);
rcu_read_unlock();
return tg;
}
return 0;
}
+static bool tg_no_rule_group(struct throtl_grp *tg, bool rw) {
+ if (tg->bps[rw] == -1 && tg->iops[rw] == -1)
+ return 1;
+ return 0;
+}
+
/*
* Returns whether one can dispatch a bio or not. Also returns approx number
* of jiffies to wait before this bio is with-in IO rate and can be dispatched
tg->bytes_disp[rw] += bio->bi_size;
tg->io_disp[rw]++;
- /*
- * TODO: This will take blkg->stats_lock. Figure out a way
- * to avoid this cost.
- */
blkiocg_update_dispatch_stats(&tg->blkg, bio->bi_size, rw, sync);
}
struct throtl_grp *tg;
struct bio *bio = *biop;
bool rw = bio_data_dir(bio), update_disptime = true;
+ struct blkio_cgroup *blkcg;
if (bio->bi_rw & REQ_THROTTLED) {
bio->bi_rw &= ~REQ_THROTTLED;
return 0;
}
+ /*
+ * 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,
+ * just update the dispatch stats in lockless manner and return.
+ */
+
+ rcu_read_lock();
+ blkcg = task_blkio_cgroup(current);
+ tg = throtl_find_tg(td, blkcg);
+ if (tg) {
+ throtl_tg_fill_dev_details(td, tg);
+
+ if (tg_no_rule_group(tg, rw)) {
+ blkiocg_update_dispatch_stats(&tg->blkg, bio->bi_size,
+ rw, bio->bi_rw & REQ_SYNC);
+ rcu_read_unlock();
+ return 0;
+ }
+ }
+ rcu_read_unlock();
+
+ /*
+ * Either group has not been allocated yet or it is not an unlimited
+ * IO group
+ */
+
spin_lock_irq(q->queue_lock);
tg = throtl_get_tg(td);
+ if (IS_ERR(tg)) {
+ if (PTR_ERR(tg) == -ENODEV) {
+ /*
+ * Queue is gone. No queue lock held here.
+ */
+ return -ENODEV;
+ }
+ }
+
if (tg->nr_queued[rw]) {
/*
* There is already another bio queued in same dir. No
INIT_HLIST_HEAD(&td->tg_list);
td->tg_service_tree = THROTL_RB_ROOT;
td->limits_changed = false;
+ INIT_DELAYED_WORK(&td->throtl_work, blk_throtl_work);
- /* Init root group */
- tg = &td->root_tg;
- INIT_HLIST_NODE(&tg->tg_node);
- RB_CLEAR_NODE(&tg->rb_node);
- bio_list_init(&tg->bio_lists[0]);
- bio_list_init(&tg->bio_lists[1]);
-
- /* Practically unlimited BW */
- tg->bps[0] = tg->bps[1] = -1;
- tg->iops[0] = tg->iops[1] = -1;
- td->limits_changed = false;
+ /* alloc and Init root group. */
+ td->queue = q;
+ tg = throtl_alloc_tg(td);
- /*
- * Set root group reference to 2. One reference will be dropped when
- * all groups on tg_list are being deleted during queue exit. Other
- * reference will remain there as we don't want to delete this group
- * as it is statically allocated and gets destroyed when throtl_data
- * goes away.
- */
- atomic_set(&tg->ref, 2);
- hlist_add_head(&tg->tg_node, &td->tg_list);
- td->nr_undestroyed_grps++;
+ if (!tg) {
+ kfree(td);
+ return -ENOMEM;
+ }
- INIT_DELAYED_WORK(&td->throtl_work, blk_throtl_work);
+ td->root_tg = tg;
rcu_read_lock();
- blkiocg_add_blkio_group(&blkio_root_cgroup, &tg->blkg, (void *)td,
- 0, BLKIO_POLICY_THROTL);
+ throtl_init_add_tg_lists(td, tg, &blkio_root_cgroup);
rcu_read_unlock();
/* Attach throtl data to request queue */
- td->queue = q;
q->td = td;
return 0;
}
return rq;
}
- if (!q->elevator->ops->elevator_dispatch_fn(q, 0))
+ /*
+ * Flush request is running and flush request isn't queueable
+ * in the drive, we can hold the queue till flush request is
+ * finished. Even we don't do this, driver can't dispatch next
+ * requests and will requeue them. And this can improve
+ * throughput too. For example, we have request flush1, write1,
+ * flush 2. flush1 is dispatched, then queue is hold, write1
+ * isn't inserted to queue. After flush1 is finished, flush2
+ * will be dispatched. Since disk cache is already clean,
+ * flush2 will be finished very soon, so looks like flush2 is
+ * folded to flush1.
+ * Since the queue is hold, a flag is set to indicate the queue
+ * should be restarted later. Please see flush_end_io() for
+ * details.
+ */
+ if (q->flush_pending_idx != q->flush_running_idx &&
+ !queue_flush_queueable(q)) {
+ q->flush_queue_delayed = 1;
+ return NULL;
+ }
+ if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags) ||
+ !q->elevator->ops->elevator_dispatch_fn(q, 0))
return NULL;
}
}
/* List of cfq groups being managed on this device*/
struct hlist_head cfqg_list;
- struct rcu_head rcu;
+
+ /* Number of groups which are on blkcg->blkg_list */
+ unsigned int nr_blkcg_linked_grps;
};
static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd);
if (rq2 == NULL)
return rq1;
- if (rq_is_sync(rq1) && !rq_is_sync(rq2))
- return rq1;
- else if (rq_is_sync(rq2) && !rq_is_sync(rq1))
- return rq2;
- if ((rq1->cmd_flags & REQ_META) && !(rq2->cmd_flags & REQ_META))
- return rq1;
- else if ((rq2->cmd_flags & REQ_META) &&
- !(rq1->cmd_flags & REQ_META))
- return rq2;
+ if (rq_is_sync(rq1) != rq_is_sync(rq2))
+ return rq_is_sync(rq1) ? rq1 : rq2;
+
+ if ((rq1->cmd_flags ^ rq2->cmd_flags) & REQ_META)
+ return rq1->cmd_flags & REQ_META ? rq1 : rq2;
s1 = blk_rq_pos(rq1);
s2 = blk_rq_pos(rq2);
cfqg->needs_update = true;
}
-static struct cfq_group * cfq_find_alloc_cfqg(struct cfq_data *cfqd,
- struct blkio_cgroup *blkcg, int create)
+static void cfq_init_add_cfqg_lists(struct cfq_data *cfqd,
+ struct cfq_group *cfqg, struct blkio_cgroup *blkcg)
{
- struct cfq_group *cfqg = NULL;
- void *key = cfqd;
- int i, j;
- struct cfq_rb_root *st;
struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info;
unsigned int major, minor;
- cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key));
- if (cfqg && !cfqg->blkg.dev && bdi->dev && dev_name(bdi->dev)) {
+ /*
+ * Add group onto cgroup list. It might happen that bdi->dev is
+ * not initialized yet. Initialize this new group without major
+ * and minor info and this info will be filled in once a new thread
+ * comes for IO.
+ */
+ if (bdi->dev) {
sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
- cfqg->blkg.dev = MKDEV(major, minor);
- goto done;
- }
- if (cfqg || !create)
- goto done;
+ cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg,
+ (void *)cfqd, MKDEV(major, minor));
+ } else
+ cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg,
+ (void *)cfqd, 0);
+
+ cfqd->nr_blkcg_linked_grps++;
+ cfqg->weight = blkcg_get_weight(blkcg, cfqg->blkg.dev);
+
+ /* Add group on cfqd list */
+ hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list);
+}
+
+/*
+ * Should be called from sleepable context. No request queue lock as per
+ * cpu stats are allocated dynamically and alloc_percpu needs to be called
+ * from sleepable context.
+ */
+static struct cfq_group * cfq_alloc_cfqg(struct cfq_data *cfqd)
+{
+ struct cfq_group *cfqg = NULL;
+ int i, j, ret;
+ struct cfq_rb_root *st;
cfqg = kzalloc_node(sizeof(*cfqg), GFP_ATOMIC, cfqd->queue->node);
if (!cfqg)
- goto done;
+ return NULL;
for_each_cfqg_st(cfqg, i, j, st)
*st = CFQ_RB_ROOT;
*/
cfqg->ref = 1;
+ ret = blkio_alloc_blkg_stats(&cfqg->blkg);
+ if (ret) {
+ kfree(cfqg);
+ return NULL;
+ }
+
+ return cfqg;
+}
+
+static struct cfq_group *
+cfq_find_cfqg(struct cfq_data *cfqd, struct blkio_cgroup *blkcg)
+{
+ struct cfq_group *cfqg = NULL;
+ void *key = cfqd;
+ struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info;
+ unsigned int major, minor;
+
/*
- * Add group onto cgroup list. It might happen that bdi->dev is
- * not initialized yet. Initialize this new group without major
- * and minor info and this info will be filled in once a new thread
- * comes for IO. See code above.
+ * This is the common case when there are no blkio cgroups.
+ * Avoid lookup in this case
*/
- if (bdi->dev) {
- sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
- cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd,
- MKDEV(major, minor));
- } else
- cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd,
- 0);
-
- cfqg->weight = blkcg_get_weight(blkcg, cfqg->blkg.dev);
+ if (blkcg == &blkio_root_cgroup)
+ cfqg = &cfqd->root_group;
+ else
+ cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key));
- /* Add group on cfqd list */
- hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list);
+ if (cfqg && !cfqg->blkg.dev && bdi->dev && dev_name(bdi->dev)) {
+ sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
+ cfqg->blkg.dev = MKDEV(major, minor);
+ }
-done:
return cfqg;
}
/*
- * Search for the cfq group current task belongs to. If create = 1, then also
- * create the cfq group if it does not exist. request_queue lock must be held.
+ * Search for the cfq group current task belongs to. request_queue lock must
+ * be held.
*/
-static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create)
+static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd)
{
struct blkio_cgroup *blkcg;
- struct cfq_group *cfqg = NULL;
+ struct cfq_group *cfqg = NULL, *__cfqg = NULL;
+ struct request_queue *q = cfqd->queue;
rcu_read_lock();
blkcg = task_blkio_cgroup(current);
- cfqg = cfq_find_alloc_cfqg(cfqd, blkcg, create);
- if (!cfqg && create)
+ cfqg = cfq_find_cfqg(cfqd, blkcg);
+ if (cfqg) {
+ rcu_read_unlock();
+ return cfqg;
+ }
+
+ /*
+ * Need to allocate a group. Allocation of group also needs allocation
+ * of per cpu stats which in-turn takes a mutex() and can block. Hence
+ * we need to drop rcu lock and queue_lock before we call alloc.
+ *
+ * Not taking any queue reference here and assuming that queue is
+ * around by the time we return. CFQ queue allocation code does
+ * the same. It might be racy though.
+ */
+
+ rcu_read_unlock();
+ spin_unlock_irq(q->queue_lock);
+
+ cfqg = cfq_alloc_cfqg(cfqd);
+
+ spin_lock_irq(q->queue_lock);
+
+ rcu_read_lock();
+ blkcg = task_blkio_cgroup(current);
+
+ /*
+ * If some other thread already allocated the group while we were
+ * not holding queue lock, free up the group
+ */
+ __cfqg = cfq_find_cfqg(cfqd, blkcg);
+
+ if (__cfqg) {
+ kfree(cfqg);
+ rcu_read_unlock();
+ return __cfqg;
+ }
+
+ if (!cfqg)
cfqg = &cfqd->root_group;
+
+ cfq_init_add_cfqg_lists(cfqd, cfqg, blkcg);
rcu_read_unlock();
return cfqg;
}
return;
for_each_cfqg_st(cfqg, i, j, st)
BUG_ON(!RB_EMPTY_ROOT(&st->rb));
+ free_percpu(cfqg->blkg.stats_cpu);
kfree(cfqg);
}
}
#else /* GROUP_IOSCHED */
-static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd, int create)
+static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd)
{
return &cfqd->root_group;
}
struct cfq_rb_root *service_tree;
int left;
int new_cfqq = 1;
- int group_changed = 0;
service_tree = service_tree_for(cfqq->cfqg, cfqq_prio(cfqq),
cfqq_type(cfqq));
rb_link_node(&cfqq->rb_node, parent, p);
rb_insert_color(&cfqq->rb_node, &service_tree->rb);
service_tree->count++;
- if ((add_front || !new_cfqq) && !group_changed)
+ if (add_front || !new_cfqq)
return;
cfq_group_notify_queue_add(cfqd, cfqq->cfqg);
}
WARN_ON(cfqq->ioprio >= IOPRIO_BE_NR);
- return 2 * (base_rq + base_rq * (CFQ_PRIO_LISTS - 1 - cfqq->ioprio));
+ return 2 * base_rq * (IOPRIO_BE_NR - cfqq->ioprio);
}
/*
struct cfq_group *cfqg;
retry:
- cfqg = cfq_get_cfqg(cfqd, 1);
+ cfqg = cfq_get_cfqg(cfqd);
cic = cfq_cic_lookup(cfqd, ioc);
/* cic always exists here */
cfqq = cic_to_cfqq(cic, is_sync);
cfq_put_queue(cfqd->async_idle_cfqq);
}
-static void cfq_cfqd_free(struct rcu_head *head)
-{
- kfree(container_of(head, struct cfq_data, rcu));
-}
-
static void cfq_exit_queue(struct elevator_queue *e)
{
struct cfq_data *cfqd = e->elevator_data;
struct request_queue *q = cfqd->queue;
+ bool wait = false;
cfq_shutdown_timer_wq(cfqd);
cfq_put_async_queues(cfqd);
cfq_release_cfq_groups(cfqd);
- cfq_blkiocg_del_blkio_group(&cfqd->root_group.blkg);
+
+ /*
+ * If there are groups which we could not unlink from blkcg list,
+ * wait for a rcu period for them to be freed.
+ */
+ if (cfqd->nr_blkcg_linked_grps)
+ wait = true;
spin_unlock_irq(q->queue_lock);
ida_remove(&cic_index_ida, cfqd->cic_index);
spin_unlock(&cic_index_lock);
- /* Wait for cfqg->blkg->key accessors to exit their grace periods. */
- call_rcu(&cfqd->rcu, cfq_cfqd_free);
+ /*
+ * Wait for cfqg->blkg->key accessors to exit their grace periods.
+ * Do this wait only if there are other unlinked groups out
+ * there. This can happen if cgroup deletion path claimed the
+ * responsibility of cleaning up a group before queue cleanup code
+ * get to the group.
+ *
+ * Do not call synchronize_rcu() unconditionally as there are drivers
+ * which create/delete request queue hundreds of times during scan/boot
+ * and synchronize_rcu() can take significant time and slow down boot.
+ */
+ if (wait)
+ synchronize_rcu();
+
+#ifdef CONFIG_CFQ_GROUP_IOSCHED
+ /* Free up per cpu stats for root group */
+ free_percpu(cfqd->root_group.blkg.stats_cpu);
+#endif
+ kfree(cfqd);
}
static int cfq_alloc_cic_index(void)
return NULL;
cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node);
- if (!cfqd)
+ if (!cfqd) {
+ spin_lock(&cic_index_lock);
+ ida_remove(&cic_index_ida, i);
+ spin_unlock(&cic_index_lock);
return NULL;
+ }
/*
* Don't need take queue_lock in the routine, since we are
#ifdef CONFIG_CFQ_GROUP_IOSCHED
/*
- * Take a reference to root group which we never drop. This is just
- * to make sure that cfq_put_cfqg() does not try to kfree root group
+ * Set root group reference to 2. One reference will be dropped when
+ * all groups on cfqd->cfqg_list are being deleted during queue exit.
+ * Other reference will remain there as we don't want to delete this
+ * group as it is statically allocated and gets destroyed when
+ * throtl_data goes away.
*/
- cfqg->ref = 1;
+ cfqg->ref = 2;
+
+ if (blkio_alloc_blkg_stats(&cfqg->blkg)) {
+ kfree(cfqg);
+ kfree(cfqd);
+ return NULL;
+ }
+
rcu_read_lock();
+
cfq_blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg,
(void *)cfqd, 0);
rcu_read_unlock();
+ cfqd->nr_blkcg_linked_grps++;
+
+ /* Add group on cfqd->cfqg_list */
+ hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list);
#endif
/*
* Not strictly needed (since RB_ROOT just clears the node and we
e = elevator_find(name);
if (!e) {
- char elv[ELV_NAME_MAX + strlen("-iosched")];
-
spin_unlock(&elv_list_lock);
-
- snprintf(elv, sizeof(elv), "%s-iosched", name);
-
- request_module("%s", elv);
+ request_module("%s-iosched", name);
spin_lock(&elv_list_lock);
e = elevator_find(name);
}
struct list_head *entry;
int stop_flags;
- BUG_ON(rq->cmd_flags & REQ_ON_PLUG);
-
if (q->last_merge == rq)
q->last_merge = NULL;
rq->q = q;
- BUG_ON(rq->cmd_flags & REQ_ON_PLUG);
-
if (rq->cmd_flags & REQ_SOFTBARRIER) {
/* barriers are scheduling boundary, update end_sector */
if (rq->cmd_type == REQ_TYPE_FS ||
static int ata_scsi_dev_config(struct scsi_device *sdev,
struct ata_device *dev)
{
+ struct request_queue *q = sdev->request_queue;
+
if (!ata_id_has_unload(dev->id))
dev->flags |= ATA_DFLAG_NO_UNLOAD;
/* configure max sectors */
- blk_queue_max_hw_sectors(sdev->request_queue, dev->max_sectors);
+ blk_queue_max_hw_sectors(q, dev->max_sectors);
if (dev->class == ATA_DEV_ATAPI) {
- struct request_queue *q = sdev->request_queue;
void *buf;
sdev->sector_size = ATA_SECT_SIZE;
/* set DMA padding */
- blk_queue_update_dma_pad(sdev->request_queue,
- ATA_DMA_PAD_SZ - 1);
+ blk_queue_update_dma_pad(q, ATA_DMA_PAD_SZ - 1);
/* configure draining */
buf = kmalloc(ATAPI_MAX_DRAIN, q->bounce_gfp | GFP_KERNEL);
"sector_size=%u > PAGE_SIZE, PIO may malfunction\n",
sdev->sector_size);
- blk_queue_update_dma_alignment(sdev->request_queue,
- sdev->sector_size - 1);
+ blk_queue_update_dma_alignment(q, sdev->sector_size - 1);
if (dev->flags & ATA_DFLAG_AN)
set_bit(SDEV_EVT_MEDIA_CHANGE, sdev->supported_events);
scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
}
+ blk_queue_flush_queueable(q, false);
+
dev->sdev = sdev;
return 0;
}
disk->first_minor = unit;
strcpy(disk->disk_name, cd->name); /* umm... */
disk->fops = &pcd_bdops;
+ disk->flags = GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE;
+ disk->events = DISK_EVENT_MEDIA_CHANGE;
}
}
blk_queue_max_hw_sectors(q, 4096 / 512);
gendisk->queue = q;
gendisk->fops = &viocd_fops;
- gendisk->flags = GENHD_FL_CD|GENHD_FL_REMOVABLE;
+ gendisk->flags = GENHD_FL_CD | GENHD_FL_REMOVABLE |
+ GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE;
+ gendisk->events = DISK_EVENT_MEDIA_CHANGE;
set_capacity(gendisk, 0);
gendisk->private_data = d;
d->viocd_disk = gendisk;
ide_cd_read_toc(drive, &sense);
g->fops = &idecd_ops;
- g->flags |= GENHD_FL_REMOVABLE;
+ g->flags |= GENHD_FL_REMOVABLE | GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE;
+ g->events = DISK_EVENT_MEDIA_CHANGE;
add_disk(g);
return 0;
disk->first_minor = minor;
sprintf(disk->disk_name, "sr%d", minor);
disk->fops = &sr_bdops;
- disk->flags = GENHD_FL_CD;
+ disk->flags = GENHD_FL_CD | GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE;
disk->events = DISK_EVENT_MEDIA_CHANGE | DISK_EVENT_EJECT_REQUEST;
blk_queue_rq_timeout(sdev->request_queue, SR_TIMEOUT);
res = __blkdev_get(bdev, mode, 0);
if (whole) {
+ struct gendisk *disk = whole->bd_disk;
+
/* finish claiming */
mutex_lock(&bdev->bd_mutex);
spin_lock(&bdev_lock);
spin_unlock(&bdev_lock);
/*
- * Block event polling for write claims. Any write
- * holder makes the write_holder state stick until all
- * are released. This is good enough and tracking
- * individual writeable reference is too fragile given
- * the way @mode is used in blkdev_get/put().
+ * Block event polling for write claims if requested. Any
+ * write holder makes the write_holder state stick until
+ * all are released. This is good enough and tracking
+ * individual writeable reference is too fragile given the
+ * way @mode is used in blkdev_get/put().
*/
- if (!res && (mode & FMODE_WRITE) && !bdev->bd_write_holder) {
+ if ((disk->flags & GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE) &&
+ !res && (mode & FMODE_WRITE) && !bdev->bd_write_holder) {
bdev->bd_write_holder = true;
- disk_block_events(bdev->bd_disk);
+ disk_block_events(disk);
}
mutex_unlock(&bdev->bd_mutex);
struct device_attribute *attr, char *buf)
{
struct hd_struct *p = dev_to_part(dev);
- return sprintf(buf, "%u\n", p->discard_alignment);
+ struct gendisk *disk = dev_to_disk(dev);
+
+ return sprintf(buf, "%u\n",
+ queue_limit_discard_alignment(&disk->queue->limits,
+ p->start_sect));
}
ssize_t part_stat_show(struct device *dev,
p->start_sect = start;
p->alignment_offset =
queue_limit_alignment_offset(&disk->queue->limits, start);
- p->discard_alignment =
- queue_limit_discard_alignment(&disk->queue->limits, start);
p->nr_sects = len;
p->partno = partno;
p->policy = get_disk_ro(disk);
__REQ_IO_STAT, /* account I/O stat */
__REQ_MIXED_MERGE, /* merge of different types, fail separately */
__REQ_SECURE, /* secure discard (used with __REQ_DISCARD) */
- __REQ_ON_PLUG, /* on plug list */
__REQ_NR_BITS, /* stops here */
};
#define REQ_IO_STAT (1 << __REQ_IO_STAT)
#define REQ_MIXED_MERGE (1 << __REQ_MIXED_MERGE)
#define REQ_SECURE (1 << __REQ_SECURE)
-#define REQ_ON_PLUG (1 << __REQ_ON_PLUG)
#endif /* __LINUX_BLK_TYPES_H */
unsigned char misaligned;
unsigned char discard_misaligned;
unsigned char cluster;
- signed char discard_zeroes_data;
+ unsigned char discard_zeroes_data;
};
struct request_queue
* for flush operations
*/
unsigned int flush_flags;
+ unsigned int flush_not_queueable:1;
+ unsigned int flush_queue_delayed:1;
unsigned int flush_pending_idx:1;
unsigned int flush_running_idx:1;
unsigned long flush_pending_since;
extern void blk_queue_rq_timed_out(struct request_queue *, rq_timed_out_fn *);
extern void blk_queue_rq_timeout(struct request_queue *, unsigned int);
extern void blk_queue_flush(struct request_queue *q, unsigned int flush);
+extern void blk_queue_flush_queueable(struct request_queue *q, bool queueable);
extern struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev);
extern int blk_rq_map_sg(struct request_queue *, struct request *, struct scatterlist *);
{
unsigned int alignment = (sector << 9) & (lim->discard_granularity - 1);
+ if (!lim->max_discard_sectors)
+ return 0;
+
return (lim->discard_granularity + lim->discard_alignment - alignment)
& (lim->discard_granularity - 1);
}
static inline unsigned int queue_discard_zeroes_data(struct request_queue *q)
{
- if (q->limits.discard_zeroes_data == 1)
+ if (q->limits.max_discard_sectors && q->limits.discard_zeroes_data == 1)
return 1;
return 0;
return bdev->bd_block_size;
}
+static inline bool queue_flush_queueable(struct request_queue *q)
+{
+ return !q->flush_not_queueable;
+}
+
typedef struct {struct page *v;} Sector;
unsigned char *read_dev_sector(struct block_device *, sector_t, Sector *);
sector_t start_sect;
sector_t nr_sects;
sector_t alignment_offset;
- unsigned int discard_alignment;
struct device __dev;
struct kobject *holder_dir;
int policy, partno;
#define GENHD_FL_SUPPRESS_PARTITION_INFO 32
#define GENHD_FL_EXT_DEVT 64 /* allow extended devt */
#define GENHD_FL_NATIVE_CAPACITY 128
+#define GENHD_FL_BLOCK_EVENTS_ON_EXCL_WRITE 256
enum {
DISK_EVENT_MEDIA_CHANGE = 1 << 0, /* media changed */
unsigned long background_thresh;
unsigned long dirty_thresh;
unsigned long bdi_thresh;
- unsigned long nr_dirty, nr_io, nr_more_io, nr_wb;
+ unsigned long nr_dirty, nr_io, nr_more_io;
struct inode *inode;
- nr_wb = nr_dirty = nr_io = nr_more_io = 0;
+ nr_dirty = nr_io = nr_more_io = 0;
spin_lock(&inode_wb_list_lock);
list_for_each_entry(inode, &wb->b_dirty, i_wb_list)
nr_dirty++;
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