forked from Minki/linux
1cd9e039fc
Current per cpu stat allocation assumes GFP_KERNEL allocation flag. But in
IO path there are times when we want GFP_NOIO semantics. As there is no
way to pass the allocation flags to alloc_percpu(), this patch delays the
allocation of stats using a worker thread.
v2-> tejun suggested following changes. Changed the patch accordingly.
- move alloc_node location in structure
- reduce the size of names of some of the fields
- Reduce the scope of locking of alloc_list_lock
- Simplified stat_alloc_fn() by allocating stats for all
policies in one go and then assigning these to a group.
v3 -> Andrew suggested to put some comments in the code. Also raised
concerns about trying to allocate infinitely in case of allocation
failure. I have changed the logic to sleep for 10ms before retrying.
That should take care of non-preemptible UP kernels.
v4 -> Tejun had more suggestions.
- drop list_for_each_entry_all()
- instead of msleep() use queue_delayed_work()
- Some cleanups realted to more compact coding.
v5-> tejun suggested more cleanups leading to more compact code.
tj: - Relocated pcpu_stats into blkio_stat_alloc_fn().
- Minor comment update.
- This also fixes suspicious RCU usage warning caused by invoking
cgroup_path() from blkg_alloc() without holding RCU read lock.
Now that blkg_alloc() doesn't require sleepable context, RCU
read lock from blkg_lookup_create() is maintained throughout
blkg_alloc().
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
443 lines
14 KiB
C
443 lines
14 KiB
C
#ifndef _BLK_CGROUP_H
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#define _BLK_CGROUP_H
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/*
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* Common Block IO controller cgroup interface
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*
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* Based on ideas and code from CFQ, CFS and BFQ:
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* Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
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*
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* Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
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* Paolo Valente <paolo.valente@unimore.it>
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*
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* Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
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* Nauman Rafique <nauman@google.com>
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*/
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#include <linux/cgroup.h>
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#include <linux/u64_stats_sync.h>
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enum blkio_policy_id {
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BLKIO_POLICY_PROP = 0, /* Proportional Bandwidth division */
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BLKIO_POLICY_THROTL, /* Throttling */
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BLKIO_NR_POLICIES,
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};
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/* Max limits for throttle policy */
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#define THROTL_IOPS_MAX UINT_MAX
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#ifdef CONFIG_BLK_CGROUP
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enum stat_type {
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/* Total time spent (in ns) between request dispatch to the driver and
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* request completion for IOs doen by this cgroup. This may not be
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* accurate when NCQ is turned on. */
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BLKIO_STAT_SERVICE_TIME = 0,
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/* Total time spent waiting in scheduler queue in ns */
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BLKIO_STAT_WAIT_TIME,
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/* Number of IOs queued up */
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BLKIO_STAT_QUEUED,
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/* All the single valued stats go below this */
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BLKIO_STAT_TIME,
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#ifdef CONFIG_DEBUG_BLK_CGROUP
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/* Time not charged to this cgroup */
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BLKIO_STAT_UNACCOUNTED_TIME,
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BLKIO_STAT_AVG_QUEUE_SIZE,
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BLKIO_STAT_IDLE_TIME,
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BLKIO_STAT_EMPTY_TIME,
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BLKIO_STAT_GROUP_WAIT_TIME,
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BLKIO_STAT_DEQUEUE
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#endif
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};
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/* Per cpu stats */
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enum stat_type_cpu {
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BLKIO_STAT_CPU_SECTORS,
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/* Total bytes transferred */
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BLKIO_STAT_CPU_SERVICE_BYTES,
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/* Total IOs serviced, post merge */
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BLKIO_STAT_CPU_SERVICED,
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/* Number of IOs merged */
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BLKIO_STAT_CPU_MERGED,
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BLKIO_STAT_CPU_NR
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};
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enum stat_sub_type {
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BLKIO_STAT_READ = 0,
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BLKIO_STAT_WRITE,
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BLKIO_STAT_SYNC,
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BLKIO_STAT_ASYNC,
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BLKIO_STAT_TOTAL
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};
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/* blkg state flags */
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enum blkg_state_flags {
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BLKG_waiting = 0,
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BLKG_idling,
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BLKG_empty,
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};
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/* cgroup files owned by proportional weight policy */
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enum blkcg_file_name_prop {
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BLKIO_PROP_weight = 1,
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BLKIO_PROP_weight_device,
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BLKIO_PROP_io_service_bytes,
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BLKIO_PROP_io_serviced,
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BLKIO_PROP_time,
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BLKIO_PROP_sectors,
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BLKIO_PROP_unaccounted_time,
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BLKIO_PROP_io_service_time,
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BLKIO_PROP_io_wait_time,
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BLKIO_PROP_io_merged,
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BLKIO_PROP_io_queued,
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BLKIO_PROP_avg_queue_size,
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BLKIO_PROP_group_wait_time,
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BLKIO_PROP_idle_time,
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BLKIO_PROP_empty_time,
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BLKIO_PROP_dequeue,
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};
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/* cgroup files owned by throttle policy */
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enum blkcg_file_name_throtl {
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BLKIO_THROTL_read_bps_device,
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BLKIO_THROTL_write_bps_device,
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BLKIO_THROTL_read_iops_device,
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BLKIO_THROTL_write_iops_device,
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BLKIO_THROTL_io_service_bytes,
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BLKIO_THROTL_io_serviced,
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};
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struct blkio_cgroup {
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struct cgroup_subsys_state css;
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unsigned int weight;
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spinlock_t lock;
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struct hlist_head blkg_list;
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};
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struct blkio_group_stats {
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/* total disk time and nr sectors dispatched by this group */
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uint64_t time;
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uint64_t stat_arr[BLKIO_STAT_QUEUED + 1][BLKIO_STAT_TOTAL];
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#ifdef CONFIG_DEBUG_BLK_CGROUP
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/* Time not charged to this cgroup */
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uint64_t unaccounted_time;
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/* Sum of number of IOs queued across all samples */
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uint64_t avg_queue_size_sum;
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/* Count of samples taken for average */
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uint64_t avg_queue_size_samples;
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/* How many times this group has been removed from service tree */
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unsigned long dequeue;
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/* Total time spent waiting for it to be assigned a timeslice. */
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uint64_t group_wait_time;
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uint64_t start_group_wait_time;
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/* Time spent idling for this blkio_group */
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uint64_t idle_time;
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uint64_t start_idle_time;
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/*
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* Total time when we have requests queued and do not contain the
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* current active queue.
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*/
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uint64_t empty_time;
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uint64_t start_empty_time;
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uint16_t flags;
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#endif
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};
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/* Per cpu blkio group stats */
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struct blkio_group_stats_cpu {
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uint64_t sectors;
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uint64_t stat_arr_cpu[BLKIO_STAT_CPU_NR][BLKIO_STAT_TOTAL];
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struct u64_stats_sync syncp;
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};
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struct blkio_group_conf {
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unsigned int weight;
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unsigned int iops[2];
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u64 bps[2];
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};
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/* per-blkg per-policy data */
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struct blkg_policy_data {
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/* the blkg this per-policy data belongs to */
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struct blkio_group *blkg;
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/* Configuration */
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struct blkio_group_conf conf;
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struct blkio_group_stats stats;
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/* Per cpu stats pointer */
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struct blkio_group_stats_cpu __percpu *stats_cpu;
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/* pol->pdata_size bytes of private data used by policy impl */
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char pdata[] __aligned(__alignof__(unsigned long long));
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};
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struct blkio_group {
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/* Pointer to the associated request_queue */
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struct request_queue *q;
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struct list_head q_node;
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struct hlist_node blkcg_node;
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struct blkio_cgroup *blkcg;
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/* Store cgroup path */
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char path[128];
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/* reference count */
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int refcnt;
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/* Need to serialize the stats in the case of reset/update */
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spinlock_t stats_lock;
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struct blkg_policy_data *pd[BLKIO_NR_POLICIES];
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/* List of blkg waiting for per cpu stats memory to be allocated */
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struct list_head alloc_node;
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struct rcu_head rcu_head;
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};
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typedef void (blkio_init_group_fn)(struct blkio_group *blkg);
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typedef void (blkio_update_group_weight_fn)(struct request_queue *q,
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struct blkio_group *blkg, unsigned int weight);
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typedef void (blkio_update_group_read_bps_fn)(struct request_queue *q,
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struct blkio_group *blkg, u64 read_bps);
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typedef void (blkio_update_group_write_bps_fn)(struct request_queue *q,
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struct blkio_group *blkg, u64 write_bps);
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typedef void (blkio_update_group_read_iops_fn)(struct request_queue *q,
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struct blkio_group *blkg, unsigned int read_iops);
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typedef void (blkio_update_group_write_iops_fn)(struct request_queue *q,
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struct blkio_group *blkg, unsigned int write_iops);
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struct blkio_policy_ops {
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blkio_init_group_fn *blkio_init_group_fn;
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blkio_update_group_weight_fn *blkio_update_group_weight_fn;
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blkio_update_group_read_bps_fn *blkio_update_group_read_bps_fn;
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blkio_update_group_write_bps_fn *blkio_update_group_write_bps_fn;
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blkio_update_group_read_iops_fn *blkio_update_group_read_iops_fn;
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blkio_update_group_write_iops_fn *blkio_update_group_write_iops_fn;
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};
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struct blkio_policy_type {
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struct list_head list;
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struct blkio_policy_ops ops;
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enum blkio_policy_id plid;
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size_t pdata_size; /* policy specific private data size */
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};
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extern int blkcg_init_queue(struct request_queue *q);
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extern void blkcg_drain_queue(struct request_queue *q);
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extern void blkcg_exit_queue(struct request_queue *q);
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/* Blkio controller policy registration */
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extern void blkio_policy_register(struct blkio_policy_type *);
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extern void blkio_policy_unregister(struct blkio_policy_type *);
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extern void blkg_destroy_all(struct request_queue *q, bool destroy_root);
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extern void update_root_blkg_pd(struct request_queue *q,
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enum blkio_policy_id plid);
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/**
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* blkg_to_pdata - get policy private data
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* @blkg: blkg of interest
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* @pol: policy of interest
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*
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* Return pointer to private data associated with the @blkg-@pol pair.
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*/
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static inline void *blkg_to_pdata(struct blkio_group *blkg,
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struct blkio_policy_type *pol)
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{
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return blkg ? blkg->pd[pol->plid]->pdata : NULL;
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}
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/**
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* pdata_to_blkg - get blkg associated with policy private data
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* @pdata: policy private data of interest
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* @pol: policy @pdata is for
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*
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* @pdata is policy private data for @pol. Determine the blkg it's
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* associated with.
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*/
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static inline struct blkio_group *pdata_to_blkg(void *pdata,
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struct blkio_policy_type *pol)
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{
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if (pdata) {
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struct blkg_policy_data *pd =
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container_of(pdata, struct blkg_policy_data, pdata);
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return pd->blkg;
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}
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return NULL;
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}
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static inline char *blkg_path(struct blkio_group *blkg)
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{
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return blkg->path;
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}
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/**
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* blkg_get - get a blkg reference
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* @blkg: blkg to get
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*
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* The caller should be holding queue_lock and an existing reference.
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*/
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static inline void blkg_get(struct blkio_group *blkg)
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{
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lockdep_assert_held(blkg->q->queue_lock);
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WARN_ON_ONCE(!blkg->refcnt);
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blkg->refcnt++;
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}
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void __blkg_release(struct blkio_group *blkg);
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/**
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* blkg_put - put a blkg reference
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* @blkg: blkg to put
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*
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* The caller should be holding queue_lock.
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*/
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static inline void blkg_put(struct blkio_group *blkg)
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{
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lockdep_assert_held(blkg->q->queue_lock);
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WARN_ON_ONCE(blkg->refcnt <= 0);
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if (!--blkg->refcnt)
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__blkg_release(blkg);
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}
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#else
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struct blkio_group {
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};
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struct blkio_policy_type {
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};
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static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
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static inline void blkcg_drain_queue(struct request_queue *q) { }
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static inline void blkcg_exit_queue(struct request_queue *q) { }
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static inline void blkio_policy_register(struct blkio_policy_type *blkiop) { }
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static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
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static inline void blkg_destroy_all(struct request_queue *q,
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bool destory_root) { }
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static inline void update_root_blkg_pd(struct request_queue *q,
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enum blkio_policy_id plid) { }
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static inline void *blkg_to_pdata(struct blkio_group *blkg,
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struct blkio_policy_type *pol) { return NULL; }
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static inline struct blkio_group *pdata_to_blkg(void *pdata,
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struct blkio_policy_type *pol) { return NULL; }
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static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
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static inline void blkg_get(struct blkio_group *blkg) { }
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static inline void blkg_put(struct blkio_group *blkg) { }
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#endif
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#define BLKIO_WEIGHT_MIN 10
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#define BLKIO_WEIGHT_MAX 1000
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#define BLKIO_WEIGHT_DEFAULT 500
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#ifdef CONFIG_DEBUG_BLK_CGROUP
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void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol);
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void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol,
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unsigned long dequeue);
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void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol);
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void blkiocg_update_idle_time_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol);
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void blkiocg_set_start_empty_time(struct blkio_group *blkg,
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struct blkio_policy_type *pol);
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#define BLKG_FLAG_FNS(name) \
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static inline void blkio_mark_blkg_##name( \
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struct blkio_group_stats *stats) \
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{ \
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stats->flags |= (1 << BLKG_##name); \
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} \
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static inline void blkio_clear_blkg_##name( \
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struct blkio_group_stats *stats) \
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{ \
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stats->flags &= ~(1 << BLKG_##name); \
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} \
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static inline int blkio_blkg_##name(struct blkio_group_stats *stats) \
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{ \
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return (stats->flags & (1 << BLKG_##name)) != 0; \
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} \
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BLKG_FLAG_FNS(waiting)
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BLKG_FLAG_FNS(idling)
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BLKG_FLAG_FNS(empty)
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#undef BLKG_FLAG_FNS
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#else
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static inline void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol) { }
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static inline void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol, unsigned long dequeue) { }
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static inline void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol) { }
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static inline void blkiocg_update_idle_time_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol) { }
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static inline void blkiocg_set_start_empty_time(struct blkio_group *blkg,
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struct blkio_policy_type *pol) { }
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#endif
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#ifdef CONFIG_BLK_CGROUP
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extern struct blkio_cgroup blkio_root_cgroup;
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extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
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extern struct blkio_cgroup *bio_blkio_cgroup(struct bio *bio);
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extern struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
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struct request_queue *q);
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struct blkio_group *blkg_lookup_create(struct blkio_cgroup *blkcg,
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struct request_queue *q,
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enum blkio_policy_id plid,
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bool for_root);
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void blkiocg_update_timeslice_used(struct blkio_group *blkg,
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struct blkio_policy_type *pol,
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unsigned long time,
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unsigned long unaccounted_time);
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void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol,
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uint64_t bytes, bool direction, bool sync);
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void blkiocg_update_completion_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol,
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uint64_t start_time,
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uint64_t io_start_time, bool direction,
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bool sync);
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void blkiocg_update_io_merged_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol,
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bool direction, bool sync);
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void blkiocg_update_io_add_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol,
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struct blkio_group *curr_blkg, bool direction,
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bool sync);
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void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol,
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bool direction, bool sync);
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#else
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struct cgroup;
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static inline struct blkio_cgroup *
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cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
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static inline struct blkio_cgroup *
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bio_blkio_cgroup(struct bio *bio) { return NULL; }
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static inline struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
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void *key) { return NULL; }
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static inline void blkiocg_update_timeslice_used(struct blkio_group *blkg,
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struct blkio_policy_type *pol, unsigned long time,
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unsigned long unaccounted_time) { }
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static inline void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol, uint64_t bytes,
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bool direction, bool sync) { }
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static inline void blkiocg_update_completion_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol, uint64_t start_time,
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uint64_t io_start_time, bool direction, bool sync) { }
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static inline void blkiocg_update_io_merged_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol, bool direction,
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bool sync) { }
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static inline void blkiocg_update_io_add_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol,
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struct blkio_group *curr_blkg, bool direction,
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bool sync) { }
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static inline void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
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struct blkio_policy_type *pol, bool direction,
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bool sync) { }
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#endif
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#endif /* _BLK_CGROUP_H */
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