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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>
#include <linux/radix-tree.h>
#include <linux/blkdev.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 blkcg_gq;
struct blkcg {
struct cgroup_subsys_state css;
spinlock_t lock;
struct radix_tree_root blkg_tree;
struct blkcg_gq *blkg_hint;
struct hlist_head blkg_list;
/* for policies to test whether associated blkcg has changed */
uint64_t id;
/* TODO: per-policy storage in blkcg */
unsigned int cfq_weight; /* belongs to cfq */
unsigned int cfq_leaf_weight;
};
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];
};
/*
* A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a
* request_queue (q). This is used by blkcg policies which need to track
* information per blkcg - q pair.
*
* There can be multiple active blkcg policies and each has its private
* data on each blkg, the size of which is determined by
* blkcg_policy->pd_size. blkcg core allocates and frees such areas
* together with blkg and invokes pd_init/exit_fn() methods.
*
* Such private data must embed struct blkg_policy_data (pd) at the
* beginning and pd_size can't be smaller than pd.
*/
struct blkg_policy_data {
/* the blkg and policy id this per-policy data belongs to */
struct blkcg_gq *blkg;
int plid;
/* used during policy activation */
struct list_head alloc_node;
};
/* association between a blk cgroup and a request queue */
struct blkcg_gq {
/* Pointer to the associated request_queue */
struct request_queue *q;
struct list_head q_node;
struct hlist_node blkcg_node;
struct blkcg *blkcg;
/* all non-root blkcg_gq's are guaranteed to have access to parent */
struct blkcg_gq *parent;
/* request allocation list for this blkcg-q pair */
struct request_list rl;
/* reference count */
int refcnt;
/* is this blkg online? protected by both blkcg and q locks */
bool online;
struct blkg_policy_data *pd[BLKCG_MAX_POLS];
struct rcu_head rcu_head;
};
typedef void (blkcg_pol_init_pd_fn)(struct blkcg_gq *blkg);
typedef void (blkcg_pol_online_pd_fn)(struct blkcg_gq *blkg);
typedef void (blkcg_pol_offline_pd_fn)(struct blkcg_gq *blkg);
typedef void (blkcg_pol_exit_pd_fn)(struct blkcg_gq *blkg);
typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkcg_gq *blkg);
struct blkcg_policy {
int plid;
/* policy specific private data size */
size_t pd_size;
/* cgroup files for the policy */
struct cftype *cftypes;
/* operations */
blkcg_pol_init_pd_fn *pd_init_fn;
blkcg_pol_online_pd_fn *pd_online_fn;
blkcg_pol_offline_pd_fn *pd_offline_fn;
blkcg_pol_exit_pd_fn *pd_exit_fn;
blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn;
};
extern struct blkcg blkcg_root;
struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q);
struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
struct request_queue *q);
int blkcg_init_queue(struct request_queue *q);
void blkcg_drain_queue(struct request_queue *q);
void blkcg_exit_queue(struct request_queue *q);
/* Blkio controller policy registration */
int blkcg_policy_register(struct blkcg_policy *pol);
void blkcg_policy_unregister(struct blkcg_policy *pol);
int blkcg_activate_policy(struct request_queue *q,
const struct blkcg_policy *pol);
void blkcg_deactivate_policy(struct request_queue *q,
const struct blkcg_policy *pol);
void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
u64 (*prfill)(struct seq_file *,
struct blkg_policy_data *, int),
const struct blkcg_policy *pol, int data,
bool show_total);
u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v);
u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
const struct blkg_rwstat *rwstat);
u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off);
u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
int off);
u64 blkg_stat_recursive_sum(struct blkg_policy_data *pd, int off);
struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkg_policy_data *pd,
int off);
struct blkg_conf_ctx {
struct gendisk *disk;
struct blkcg_gq *blkg;
u64 v;
};
int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
const char *input, struct blkg_conf_ctx *ctx);
void blkg_conf_finish(struct blkg_conf_ctx *ctx);
static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css)
{
return css ? container_of(css, struct blkcg, css) : NULL;
}
static inline struct blkcg *task_blkcg(struct task_struct *tsk)
{
return css_to_blkcg(task_css(tsk, blkio_subsys_id));
}
static inline struct blkcg *bio_blkcg(struct bio *bio)
{
if (bio && bio->bi_css)
return css_to_blkcg(bio->bi_css);
return task_blkcg(current);
}
/**
* blkcg_parent - get the parent of a blkcg
* @blkcg: blkcg of interest
*
* Return the parent blkcg of @blkcg. Can be called anytime.
*/
static inline struct blkcg *blkcg_parent(struct blkcg *blkcg)
{
return css_to_blkcg(css_parent(&blkcg->css));
}
/**
* 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 struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
struct blkcg_policy *pol)
{
return blkg ? blkg->pd[pol->plid] : NULL;
}
/**
* pdata_to_blkg - get blkg associated with policy private data
* @pd: policy private data of interest
*
* @pd is policy private data. Determine the blkg it's associated with.
*/
static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd)
{
return pd ? pd->blkg : NULL;
}
/**
* blkg_path - format cgroup path of blkg
* @blkg: blkg of interest
* @buf: target buffer
* @buflen: target buffer length
*
* Format the path of the cgroup of @blkg into @buf.
*/
static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen)
{
int ret;
ret = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
if (ret)
strncpy(buf, "<unavailable>", buflen);
return ret;
}
/**
* 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 blkcg_gq *blkg)
{
lockdep_assert_held(blkg->q->queue_lock);
WARN_ON_ONCE(!blkg->refcnt);
blkg->refcnt++;
}
void __blkg_release_rcu(struct rcu_head *rcu);
/**
* blkg_put - put a blkg reference
* @blkg: blkg to put
*
* The caller should be holding queue_lock.
*/
static inline void
|