812d402648
This includes both the number of bios merged into requests belonging to this cgroup as well as the number of requests merged together. In the past, we've observed different merging behavior across upstream kernels, some by design some actual bugs. This stat helps a lot in debugging such problems when applications report decreased throughput with a new kernel version. This needed adding an extra elevator function to capture bios being merged as I did not want to pollute elevator code with blkiocg knowledge and hence needed the accounting invocation to come from CFQ. Signed-off-by: Divyesh Shah<dpshah@google.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
180 lines
5.5 KiB
C
180 lines
5.5 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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/* 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_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_MERGED + 1][BLKIO_STAT_TOTAL];
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#ifdef CONFIG_DEBUG_BLK_CGROUP
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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_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_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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#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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#endif
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#endif /* _BLK_CGROUP_H */
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