original development tree for Linux kernel GTP module; now long in mainline.
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#ifndef _BLK_CGROUP_H
#define _BLK_CGROUP_H
/*
* Common Block IO controller cgroup interface
*
* Based on ideas and code from CFQ, CFS and BFQ:
* Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
*
* Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
* Paolo Valente <paolo.valente@unimore.it>
*
* Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
* Nauman Rafique <nauman@google.com>
*/
#include <linux/cgroup.h>
#include <linux/u64_stats_sync.h>
#include <linux/seq_file.h>
/* Max limits for throttle policy */
#define THROTL_IOPS_MAX UINT_MAX
/* CFQ specific, out here for blkcg->cfq_weight */
#define CFQ_WEIGHT_MIN 10
#define CFQ_WEIGHT_MAX 1000
#define CFQ_WEIGHT_DEFAULT 500
#ifdef CONFIG_BLK_CGROUP
enum blkg_rwstat_type {
BLKG_RWSTAT_READ,
BLKG_RWSTAT_WRITE,
BLKG_RWSTAT_SYNC,
BLKG_RWSTAT_ASYNC,
BLKG_RWSTAT_NR,
BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR,
};
struct blkio_cgroup {
struct cgroup_subsys_state css;
spinlock_t lock;
struct hlist_head blkg_list;
/* for policies to test whether associated blkcg has changed */
uint64_t id;
/* TODO: per-policy storage in blkio_cgroup */
unsigned int cfq_weight; /* belongs to cfq */
};
struct blkg_stat {
struct u64_stats_sync syncp;
uint64_t cnt;
};
struct blkg_rwstat {
struct u64_stats_sync syncp;
uint64_t cnt[BLKG_RWSTAT_NR];
};
/* per-blkg per-policy data */
struct blkg_policy_data {
/* the blkg this per-policy data belongs to */
struct blkio_group *blkg;
/* used during policy activation */
struct list_head alloc_node;
/* pol->pdata_size bytes of private data used by policy impl */
char pdata[] __aligned(__alignof__(unsigned long long));
};
struct blkio_group {
/* Pointer to the associated request_queue */
struct request_queue *q;
struct list_head q_node;
struct hlist_node blkcg_node;
struct blkio_cgroup *blkcg;
/* Store cgroup path */
char path[128];
/* reference count */
int refcnt;
struct blkg_policy_data *pd[BLKCG_MAX_POLS];
struct rcu_head rcu_head;
};
typedef void (blkio_init_group_fn)(struct blkio_group *blkg);
typedef void (blkio_exit_group_fn)(struct blkio_group *blkg);
typedef void (blkio_reset_group_stats_fn)(struct blkio_group *blkg);
struct blkio_policy_ops {
blkio_init_group_fn *blkio_init_group_fn;
blkio_exit_group_fn *blkio_exit_group_fn;
blkio_reset_group_stats_fn *blkio_reset_group_stats_fn;
};
struct blkio_policy_type {
struct blkio_policy_ops ops;
int plid;
size_t pdata_size; /* policy specific private data size */
struct cftype *cftypes; /* cgroup files for the policy */
};
extern int blkcg_init_queue(struct request_queue *q);
extern void blkcg_drain_queue(struct request_queue *q);
extern void blkcg_exit_queue(struct request_queue *q);
/* Blkio controller policy registration */
extern int blkio_policy_register(struct blkio_policy_type *);
extern void blkio_policy_unregister(struct blkio_policy_type *);
extern int blkcg_activate_policy(struct request_queue *q,
const struct blkio_policy_type *pol);
extern void blkcg_deactivate_policy(struct request_queue *q,
const struct blkio_policy_type *pol);
void blkcg_print_blkgs(struct seq_file *sf, struct blkio_cgroup *blkcg,
u64 (*prfill)(struct seq_file *, void *, int),
const struct blkio_policy_type *pol, int data,
bool show_total);
u64 __blkg_prfill_u64(struct seq_file *sf, void *pdata, u64 v);
u64 __blkg_prfill_rwstat(struct seq_file *sf, void *pdata,
const struct blkg_rwstat *rwstat);
u64 blkg_prfill_stat(struct seq_file *sf, void *pdata, int off);
u64 blkg_prfill_rwstat(struct seq_file *sf, void *pdata, int off);
struct blkg_conf_ctx {
struct gendisk *disk;
struct blkio_group *blkg;
u64 v;
};
int blkg_conf_prep(struct blkio_cgroup *blkcg,
const struct blkio_policy_type *pol, const char *input,
struct blkg_conf_ctx *ctx);
void blkg_conf_finish(struct blkg_conf_ctx *ctx);
/**
* blkg_to_pdata - get policy private data
* @blkg: blkg of interest
* @pol: policy of interest
*
* Return pointer to private data associated with the @blkg-@pol pair.
*/
static inline void *blkg_to_pdata(struct blkio_group *blkg,
struct blkio_policy_type *pol)
{
return blkg ? blkg->pd[pol->plid]->pdata : NULL;
}
/**
* pdata_to_blkg - get blkg associated with policy private data
* @pdata: policy private data of interest
*
* @pdata is policy private data. Determine the blkg it's associated with.
*/
static inline struct blkio_group *pdata_to_blkg(void *pdata)
{
if (pdata) {
struct blkg_policy_data *pd =
container_of(pdata, struct blkg_policy_data, pdata);
return pd->blkg;
}
return NULL;
}
static inline char *blkg_path(struct blkio_group *blkg)
{
return blkg->path;
}
/**
* blkg_get - get a blkg reference
* @blkg: blkg to get
*
* The caller should be holding queue_lock and an existing reference.
*/
static inline void blkg_get(struct blkio_group *blkg)
{
lockdep_assert_held(blkg->q->queue_lock);
WARN_ON_ONCE(!blkg->refcnt);
blkg->refcnt++;
}
void __blkg_release(struct blkio_group *blkg);
/**
* blkg_put - put a blkg reference
* @blkg: blkg to put
*
* The caller should be holding queue_lock.
*/
static inline void blkg_put(struct blkio_group *blkg)
{
lockdep_assert_held(blkg->q->queue_lock);
WARN_ON_ONCE(blkg->refcnt <= 0);
if (!--blkg->refcnt)
__blkg_release(blkg);
}
/**
* blkg_stat_add - add a value to a blkg_stat
* @stat: target blkg_stat
* @val: value to add
*
* Add @val to @stat. The caller is responsible for synchronizing calls to
* this function.
*/
static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
{
u64_stats_update_begin(&stat->syncp);
stat->cnt += val;
u64_stats_update_end(&stat->syncp);
}
/**
* blkg_stat_read - read the current value of a blkg_stat
* @stat: blkg_stat to read
*
* Read the current value of @stat. This function can be called without
* synchroniztion and takes care of u64 atomicity.
*/
static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
{
unsigned int start;
uint64_t v;
do {
start = u64_stats_fetch_begin(&stat->syncp);
v = stat->cnt;
} while (u64_stats_fetch_retry(&stat->syncp, start));
return v;
}
/**
* blkg_stat_reset - reset a blkg_stat
* @stat: blkg_stat to reset
*/
static inline void blkg_stat_reset(struct blkg_stat *stat)
{
stat->cnt = 0;
}
/**
* blkg_rwstat_add - add a value to a blkg_rwstat
* @rwstat: target blkg_rwstat
* @rw: mask of REQ_{WRITE|SYNC}
* @val: value to add
*
* Add @val to @rwstat. The counters are chosen according to @rw. The
* caller is responsible for synchronizing calls to this function.
*/
static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
int rw, uint64_t val)
{
u64_stats_update_begin(&rwstat->syncp);
if (rw & REQ_WRITE)
rwstat->cnt[BLKG_RWSTAT_WRITE] += val;
else
rwstat->cnt[BLKG_RWSTAT_READ] += val;
if (rw & REQ_SYNC)
rwstat->cnt[BLKG_RWSTAT_SYNC] += val;
else
rwstat->cnt[BLKG_RWSTAT_ASYNC] += val;
u64_stats_update_end(&rwstat->syncp);
}
/**
* blkg_rwstat_read - read the current values of a blkg_rwstat
* @rwstat: blkg_rwstat to read
*
* Read the current snapshot of @rwstat and return it as the return value.
* This function can be called without synchronization and takes care of
* u64 atomicity.
*/
static struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
{
unsigned int start;
struct blkg_rwstat tmp;
do {
start = u64_stats_fetch_begin(&rwstat->syncp);
tmp = *rwstat;
} while (u64_stats_fetch_retry(&rwstat->syncp, start));
return tmp;
}
/**
* blkg_rwstat_sum - read the total count of a blkg_rwstat
* @rwstat: blkg_rwstat to read
*
* Return the total count of @rwstat regardless of the IO direction. This
* function can be called without synchronization and takes care of u64
* atomicity.
*/
static inline uint64_t blkg_rwstat_sum(struct blkg_rwstat *rwstat)
{
struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE];
}
/**
* blkg_rwstat_reset - reset a blkg_rwstat
* @rwstat: blkg_rwstat to reset
*/
static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
{
memset(rwstat->cnt, 0, sizeof(rwstat->cnt));
}
#else
struct blkio_group {
};
struct blkio_policy_type {
};
static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
static inline void blkcg_drain_queue(struct request_queue *q) { }
static inline void blkcg_exit_queue(struct request_queue *q) { }
static inline int blkio_policy_register(struct blkio_policy_type *blkiop) { return 0; }
static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
static inline int blkcg_activate_policy(struct request_queue *q,
const struct blkio_policy_type *pol) { return 0; }
static inline void blkcg_deactivate_policy(struct request_queue *q,
const struct blkio_policy_type *pol) { }
static inline void *blkg_to_pdata(struct blkio_group *blkg,
struct blkio_policy_type *pol) { return NULL; }
static inline struct blkio_group *pdata_to_blkg(void *pdata,
struct blkio_policy_type *pol) { return NULL; }
static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
static inline void blkg_get(struct blkio_group *blkg) { }
static inline void blkg_put(struct blkio_group *blkg) { }
#endif
#ifdef CONFIG_BLK_CGROUP
extern struct blkio_cgroup blkio_root_cgroup;
extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
extern struct blkio_cgroup *bio_blkio_cgroup(struct bio *bio);
extern struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
struct request_queue *q);
struct blkio_group *blkg_lookup_create(struct blkio_cgroup *blkcg,
struct request_queue *q);
#else
struct cgroup;
static inline struct blkio_cgroup *
cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
static inline struct blkio_cgroup *
bio_blkio_cgroup(struct bio *bio) { return NULL; }
static inline struct blkio_group *blkg_lookup(struct blkio_cgroup *blkcg,
void *key) { return NULL; }
#endif
#endif /* _BLK_CGROUP_H */