linux/block/blk-cgroup.h
Vivek Goyal 3e25206689 blkio: Implement dynamic io controlling policy registration
o One of the goals of block IO controller is that it should be able to
  support mulitple io control policies, some of which be operational at
  higher level in storage hierarchy.

o To begin with, we had one io controlling policy implemented by CFQ, and
  I hard coded the CFQ functions called by blkio. This created issues when
  CFQ is compiled as module.

o This patch implements a basic dynamic io controlling policy registration
  functionality in blkio. This is similar to elevator functionality where
  ioschedulers register the functions dynamically.

o Now in future, when more IO controlling policies are implemented, these
  can dynakically register with block IO controller.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2009-12-04 16:38:14 +01:00

127 lines
3.6 KiB
C

#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>
#ifdef CONFIG_BLK_CGROUP
struct blkio_cgroup {
struct cgroup_subsys_state css;
unsigned int weight;
spinlock_t lock;
struct hlist_head blkg_list;
};
struct blkio_group {
/* An rcu protected unique identifier for the group */
void *key;
struct hlist_node blkcg_node;
unsigned short blkcg_id;
#ifdef CONFIG_DEBUG_BLK_CGROUP
/* Store cgroup path */
char path[128];
/* How many times this group has been removed from service tree */
unsigned long dequeue;
#endif
/* The device MKDEV(major, minor), this group has been created for */
dev_t dev;
/* total disk time and nr sectors dispatched by this group */
unsigned long time;
unsigned long sectors;
};
extern bool blkiocg_css_tryget(struct blkio_cgroup *blkcg);
extern void blkiocg_css_put(struct blkio_cgroup *blkcg);
typedef void (blkio_unlink_group_fn) (void *key, struct blkio_group *blkg);
typedef void (blkio_update_group_weight_fn) (struct blkio_group *blkg,
unsigned int weight);
struct blkio_policy_ops {
blkio_unlink_group_fn *blkio_unlink_group_fn;
blkio_update_group_weight_fn *blkio_update_group_weight_fn;
};
struct blkio_policy_type {
struct list_head list;
struct blkio_policy_ops ops;
};
/* Blkio controller policy registration */
extern void blkio_policy_register(struct blkio_policy_type *);
extern void blkio_policy_unregister(struct blkio_policy_type *);
#else
struct blkio_group {
};
struct blkio_policy_type {
};
static inline void blkio_policy_register(struct blkio_policy_type *blkiop) { }
static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
#endif
#define BLKIO_WEIGHT_MIN 100
#define BLKIO_WEIGHT_MAX 1000
#define BLKIO_WEIGHT_DEFAULT 500
#ifdef CONFIG_DEBUG_BLK_CGROUP
static inline char *blkg_path(struct blkio_group *blkg)
{
return blkg->path;
}
void blkiocg_update_blkio_group_dequeue_stats(struct blkio_group *blkg,
unsigned long dequeue);
#else
static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
static inline void blkiocg_update_blkio_group_dequeue_stats(
struct blkio_group *blkg, unsigned long dequeue) {}
#endif
#ifdef CONFIG_BLK_CGROUP
extern struct blkio_cgroup blkio_root_cgroup;
extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
extern void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
struct blkio_group *blkg, void *key, dev_t dev);
extern int blkiocg_del_blkio_group(struct blkio_group *blkg);
extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,
void *key);
void blkiocg_update_blkio_group_stats(struct blkio_group *blkg,
unsigned long time, unsigned long sectors);
#else
struct cgroup;
static inline struct blkio_cgroup *
cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
static inline void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
struct blkio_group *blkg, void *key, dev_t dev)
{
}
static inline int
blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; }
static inline struct blkio_group *
blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) { return NULL; }
static inline void blkiocg_update_blkio_group_stats(struct blkio_group *blkg,
unsigned long time, unsigned long sectors)
{
}
#endif
#endif /* _BLK_CGROUP_H */