forked from Minki/linux
cdc1184cf4
These stats are useful for getting a feel for the queue depth of the cgroup, i.e., how filled up its queues are at a given instant and over the existence of the cgroup. This ability is useful when debugging problems in the wild as it helps understand the application's IO pattern w/o having to read through the userspace code (coz its tedious or just not available) or w/o the ability to run blktrace (since you may not have root access and/or not want to disturb performance). Signed-off-by: Divyesh Shah<dpshah@google.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
198 lines
6.4 KiB
C
198 lines
6.4 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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#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
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#ifndef CONFIG_BLK_CGROUP
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/* When blk-cgroup is a module, its subsys_id isn't a compile-time constant */
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extern struct cgroup_subsys blkio_subsys;
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#define blkio_subsys_id blkio_subsys.subsys_id
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#endif
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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 bytes transferred */
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BLKIO_STAT_SERVICE_BYTES,
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/* Total IOs serviced, post merge */
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BLKIO_STAT_SERVICED,
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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 merged */
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BLKIO_STAT_MERGED,
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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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BLKIO_STAT_SECTORS,
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#ifdef CONFIG_DEBUG_BLK_CGROUP
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BLKIO_STAT_AVG_QUEUE_SIZE,
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BLKIO_STAT_DEQUEUE
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#endif
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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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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 sectors;
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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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/* 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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#endif
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};
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struct blkio_group {
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/* An rcu protected unique identifier for the group */
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void *key;
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struct hlist_node blkcg_node;
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unsigned short blkcg_id;
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#ifdef CONFIG_DEBUG_BLK_CGROUP
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/* Store cgroup path */
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char path[128];
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#endif
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/* The device MKDEV(major, minor), this group has been created for */
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dev_t dev;
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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 blkio_group_stats stats;
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};
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typedef void (blkio_unlink_group_fn) (void *key, struct blkio_group *blkg);
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typedef void (blkio_update_group_weight_fn) (struct blkio_group *blkg,
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unsigned int weight);
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struct blkio_policy_ops {
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blkio_unlink_group_fn *blkio_unlink_group_fn;
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blkio_update_group_weight_fn *blkio_update_group_weight_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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};
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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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#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 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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#endif
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#define BLKIO_WEIGHT_MIN 100
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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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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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void blkiocg_update_set_active_queue_stats(struct blkio_group *blkg);
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void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
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unsigned long dequeue);
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#else
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static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
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static inline void blkiocg_update_set_active_queue_stats(
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struct blkio_group *blkg) {}
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static inline void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
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unsigned long dequeue) {}
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#endif
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#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
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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 void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
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struct blkio_group *blkg, void *key, dev_t dev);
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extern int blkiocg_del_blkio_group(struct blkio_group *blkg);
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extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,
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void *key);
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void blkio_group_init(struct blkio_group *blkg);
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void blkiocg_update_timeslice_used(struct blkio_group *blkg,
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unsigned long time);
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void blkiocg_update_dispatch_stats(struct blkio_group *blkg, uint64_t bytes,
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bool direction, bool sync);
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void blkiocg_update_completion_stats(struct blkio_group *blkg,
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uint64_t start_time, uint64_t io_start_time, bool direction, bool sync);
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void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction,
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bool sync);
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void blkiocg_update_request_add_stats(struct blkio_group *blkg,
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struct blkio_group *curr_blkg, bool direction, bool sync);
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void blkiocg_update_request_remove_stats(struct blkio_group *blkg,
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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 void blkio_group_init(struct blkio_group *blkg) {}
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static inline void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
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struct blkio_group *blkg, void *key, dev_t dev) {}
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static inline int
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blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; }
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static inline struct blkio_group *
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blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) { return NULL; }
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static inline void blkiocg_update_timeslice_used(struct blkio_group *blkg,
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unsigned long time) {}
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static inline void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
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uint64_t bytes, bool direction, bool sync) {}
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static inline void blkiocg_update_completion_stats(struct blkio_group *blkg,
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uint64_t start_time, uint64_t io_start_time, bool direction,
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bool sync) {}
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static inline void blkiocg_update_io_merged_stats(struct blkio_group *blkg,
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bool direction, bool sync) {}
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static inline void blkiocg_update_request_add_stats(struct blkio_group *blkg,
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struct blkio_group *curr_blkg, bool direction, bool sync) {}
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static inline void blkiocg_update_request_remove_stats(struct blkio_group *blkg,
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bool direction, bool sync) {}
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#endif
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#endif /* _BLK_CGROUP_H */
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