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Merge branch 'for-3.5/core' of git://git.kernel.dk/linux-block

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Merge block/IO core bits from Jens Axboe:
 "This is a bit bigger on the core side than usual, but that is purely
  because we decided to hold off on parts of Tejun's submission on 3.4
  to give it a bit more time to simmer.  As a consequence, it's seen a
  long cycle in for-next.

  It contains:

   - Bug fix from Dan, wrong locking type.
   - Relax splice gifting restriction from Eric.
   - A ton of updates from Tejun, primarily for blkcg.  This improves
     the code a lot, making the API nicer and cleaner, and also includes
     fixes for how we handle and tie policies and re-activate on
     switches.  The changes also include generic bug fixes.
   - A simple fix from Vivek, along with a fix for doing proper delayed
     allocation of the blkcg stats."

Fix up annoying conflict just due to different merge resolution in
Documentation/feature-removal-schedule.txt

* 'for-3.5/core' of git://git.kernel.dk/linux-block: (92 commits)
  blkcg: tg_stats_alloc_lock is an irq lock
  vmsplice: relax alignement requirements for SPLICE_F_GIFT
  blkcg: use radix tree to index blkgs from blkcg
  blkcg: fix blkcg->css ref leak in __blkg_lookup_create()
  block: fix elvpriv allocation failure handling
  block: collapse blk_alloc_request() into get_request()
  blkcg: collapse blkcg_policy_ops into blkcg_policy
  blkcg: embed struct blkg_policy_data in policy specific data
  blkcg: mass rename of blkcg API
  blkcg: style cleanups for blk-cgroup.h
  blkcg: remove blkio_group->path[]
  blkcg: blkg_rwstat_read() was missing inline
  blkcg: shoot down blkgs if all policies are deactivated
  blkcg: drop stuff unused after per-queue policy activation update
  blkcg: implement per-queue policy activation
  blkcg: add request_queue->root_blkg
  blkcg: make request_queue bypassing on allocation
  blkcg: make sure blkg_lookup() returns %NULL if @q is bypassing
  blkcg: make blkg_conf_prep() take @pol and return with queue lock held
  blkcg: remove static policy ID enums
  ...
This commit is contained in:
Linus Torvalds 2012-05-30 08:52:42 -07:00
commit 0d167518e0
24 changed files with 2531 additions and 3037 deletions
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4
block/Kconfig.iosched
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@ -23,8 +23,6 @@ config IOSCHED_DEADLINE
config IOSCHED_CFQ
tristate "CFQ I/O scheduler"
# If BLK_CGROUP is a module, CFQ has to be built as module.
depends on (BLK_CGROUP=m && m) || !BLK_CGROUP || BLK_CGROUP=y
default y
---help---
The CFQ I/O scheduler tries to distribute bandwidth equally
@ -34,8 +32,6 @@ config IOSCHED_CFQ
This is the default I/O scheduler.
Note: If BLK_CGROUP=m, then CFQ can be built only as module.
config CFQ_GROUP_IOSCHED
bool "CFQ Group Scheduling support"
depends on IOSCHED_CFQ && BLK_CGROUP

2248
block/blk-cgroup.c
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File diff suppressed because it is too large Load Diff

631
block/blk-cgroup.h
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@ -15,350 +15,371 @@
#include <linux/cgroup.h>
#include <linux/u64_stats_sync.h>
enum blkio_policy_id {
BLKIO_POLICY_PROP = 0, /* Proportional Bandwidth division */
BLKIO_POLICY_THROTL, /* Throttling */
};
#include <linux/seq_file.h>
#include <linux/radix-tree.h>
/* Max limits for throttle policy */
#define THROTL_IOPS_MAX UINT_MAX
#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
/* CFQ specific, out here for blkcg->cfq_weight */
#define CFQ_WEIGHT_MIN 10
#define CFQ_WEIGHT_MAX 1000
#define CFQ_WEIGHT_DEFAULT 500
#ifndef CONFIG_BLK_CGROUP
/* When blk-cgroup is a module, its subsys_id isn't a compile-time constant */
extern struct cgroup_subsys blkio_subsys;
#define blkio_subsys_id blkio_subsys.subsys_id
#endif
#ifdef CONFIG_BLK_CGROUP
enum stat_type {
/* Total time spent (in ns) between request dispatch to the driver and
* request completion for IOs doen by this cgroup. This may not be
* accurate when NCQ is turned on. */
BLKIO_STAT_SERVICE_TIME = 0,
/* Total time spent waiting in scheduler queue in ns */
BLKIO_STAT_WAIT_TIME,
/* Number of IOs queued up */
BLKIO_STAT_QUEUED,
/* All the single valued stats go below this */
BLKIO_STAT_TIME,
#ifdef CONFIG_DEBUG_BLK_CGROUP
/* Time not charged to this cgroup */
BLKIO_STAT_UNACCOUNTED_TIME,
BLKIO_STAT_AVG_QUEUE_SIZE,
BLKIO_STAT_IDLE_TIME,
BLKIO_STAT_EMPTY_TIME,
BLKIO_STAT_GROUP_WAIT_TIME,
BLKIO_STAT_DEQUEUE
#endif
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,
};
/* Per cpu stats */
enum stat_type_cpu {
BLKIO_STAT_CPU_SECTORS,
/* Total bytes transferred */
BLKIO_STAT_CPU_SERVICE_BYTES,
/* Total IOs serviced, post merge */
BLKIO_STAT_CPU_SERVICED,
/* Number of IOs merged */
BLKIO_STAT_CPU_MERGED,
BLKIO_STAT_CPU_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 */
};
enum stat_sub_type {
BLKIO_STAT_READ = 0,
BLKIO_STAT_WRITE,
BLKIO_STAT_SYNC,
BLKIO_STAT_ASYNC,
BLKIO_STAT_TOTAL
struct blkg_stat {
struct u64_stats_sync syncp;
uint64_t cnt;
};
/* blkg state flags */
enum blkg_state_flags {
BLKG_waiting = 0,
BLKG_idling,
BLKG_empty,
struct blkg_rwstat {
struct u64_stats_sync syncp;
uint64_t cnt[BLKG_RWSTAT_NR];
};
/* cgroup files owned by proportional weight policy */
enum blkcg_file_name_prop {
BLKIO_PROP_weight = 1,
BLKIO_PROP_weight_device,
BLKIO_PROP_io_service_bytes,
BLKIO_PROP_io_serviced,
BLKIO_PROP_time,
BLKIO_PROP_sectors,
BLKIO_PROP_unaccounted_time,
BLKIO_PROP_io_service_time,
BLKIO_PROP_io_wait_time,
BLKIO_PROP_io_merged,
BLKIO_PROP_io_queued,
BLKIO_PROP_avg_queue_size,
BLKIO_PROP_group_wait_time,
BLKIO_PROP_idle_time,
BLKIO_PROP_empty_time,
BLKIO_PROP_dequeue,
/*
* 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 this per-policy data belongs to */
struct blkcg_gq *blkg;
/* used during policy activation */
struct list_head alloc_node;
};
/* cgroup files owned by throttle policy */
enum blkcg_file_name_throtl {
BLKIO_THROTL_read_bps_device,
BLKIO_THROTL_write_bps_device,
BLKIO_THROTL_read_iops_device,
BLKIO_THROTL_write_iops_device,
BLKIO_THROTL_io_service_bytes,
BLKIO_THROTL_io_serviced,
/* 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;
/* reference count */
int refcnt;
struct blkg_policy_data *pd[BLKCG_MAX_POLS];
struct rcu_head rcu_head;
};
struct blkio_cgroup {
struct cgroup_subsys_state css;
unsigned int weight;
spinlock_t lock;
struct hlist_head blkg_list;
struct list_head policy_list; /* list of blkio_policy_node */
typedef void (blkcg_pol_init_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_exit_pd_fn *pd_exit_fn;
blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn;
};
struct blkio_group_stats {
/* total disk time and nr sectors dispatched by this group */
uint64_t time;
uint64_t stat_arr[BLKIO_STAT_QUEUED + 1][BLKIO_STAT_TOTAL];
#ifdef CONFIG_DEBUG_BLK_CGROUP
/* Time not charged to this cgroup */
uint64_t unaccounted_time;
extern struct blkcg blkcg_root;
/* Sum of number of IOs queued across all samples */
uint64_t avg_queue_size_sum;
/* Count of samples taken for average */
uint64_t avg_queue_size_samples;
/* How many times this group has been removed from service tree */
unsigned long dequeue;
/* Total time spent waiting for it to be assigned a timeslice. */
uint64_t group_wait_time;
uint64_t start_group_wait_time;
/* Time spent idling for this blkio_group */
uint64_t idle_time;
uint64_t start_idle_time;
/*
* Total time when we have requests queued and do not contain the
* current active queue.
*/
uint64_t empty_time;
uint64_t start_empty_time;
uint16_t flags;
#endif
};
/* Per cpu blkio group stats */
struct blkio_group_stats_cpu {
uint64_t sectors;
uint64_t stat_arr_cpu[BLKIO_STAT_CPU_NR][BLKIO_STAT_TOTAL];
struct u64_stats_sync syncp;
};
struct blkio_group {
/* An rcu protected unique identifier for the group */
void *key;
struct hlist_node blkcg_node;
unsigned short blkcg_id;
/* Store cgroup path */
char path[128];
/* The device MKDEV(major, minor), this group has been created for */
dev_t dev;
/* policy which owns this blk group */
enum blkio_policy_id plid;
/* Need to serialize the stats in the case of reset/update */
spinlock_t stats_lock;
struct blkio_group_stats stats;
/* Per cpu stats pointer */
struct blkio_group_stats_cpu __percpu *stats_cpu;
};
struct blkio_policy_node {
struct list_head node;
dev_t dev;
/* This node belongs to max bw policy or porportional weight policy */
enum blkio_policy_id plid;
/* cgroup file to which this rule belongs to */
int fileid;
union {
unsigned int weight;
/*
* Rate read/write in terms of bytes per second
* Whether this rate represents read or write is determined
* by file type "fileid".
*/
u64 bps;
unsigned int iops;
} val;
};
extern unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,
dev_t dev);
extern uint64_t blkcg_get_read_bps(struct blkio_cgroup *blkcg,
dev_t dev);
extern uint64_t blkcg_get_write_bps(struct blkio_cgroup *blkcg,
dev_t dev);
extern unsigned int blkcg_get_read_iops(struct blkio_cgroup *blkcg,
dev_t dev);
extern unsigned int blkcg_get_write_iops(struct blkio_cgroup *blkcg,
dev_t dev);
typedef void (blkio_unlink_group_fn) (void *key, struct blkio_group *blkg);
typedef void (blkio_update_group_weight_fn) (void *key,
struct blkio_group *blkg, unsigned int weight);
typedef void (blkio_update_group_read_bps_fn) (void * key,
struct blkio_group *blkg, u64 read_bps);
typedef void (blkio_update_group_write_bps_fn) (void *key,
struct blkio_group *blkg, u64 write_bps);
typedef void (blkio_update_group_read_iops_fn) (void *key,
struct blkio_group *blkg, unsigned int read_iops);
typedef void (blkio_update_group_write_iops_fn) (void *key,
struct blkio_group *blkg, unsigned int write_iops);
struct blkio_policy_ops {
blkio_unlink_group_fn *blkio_unlink_group_fn;
blkio_update_group_weight_fn *blkio_update_group_weight_fn;
blkio_update_group_read_bps_fn *blkio_update_group_read_bps_fn;
blkio_update_group_write_bps_fn *blkio_update_group_write_bps_fn;
blkio_update_group_read_iops_fn *blkio_update_group_read_iops_fn;
blkio_update_group_write_iops_fn *blkio_update_group_write_iops_fn;
};
struct blkio_policy_type {
struct list_head list;
struct blkio_policy_ops ops;
enum blkio_policy_id plid;
};
struct blkcg *cgroup_to_blkcg(struct cgroup *cgroup);
struct blkcg *bio_blkcg(struct bio *bio);
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 */
extern void blkio_policy_register(struct blkio_policy_type *);
extern void blkio_policy_unregister(struct blkio_policy_type *);
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);
static inline char *blkg_path(struct blkio_group *blkg)
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);
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);
/**
* 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->path;
return blkg ? blkg->pd[pol->plid] : NULL;
}
#else
/**
* 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;
}
struct blkio_group {
};
/**
* 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;
struct blkio_policy_type {
};
rcu_read_lock();
ret = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
rcu_read_unlock();
if (ret)
strncpy(buf, "<unavailable>", buflen);
return ret;
}
static inline void blkio_policy_register(struct blkio_policy_type *blkiop) { }
static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
/**
* 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++;
}
static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
void __blkg_release(struct blkcg_gq *blkg);
#endif
/**
* blkg_put - put a blkg reference
* @blkg: blkg to put
*
* The caller should be holding queue_lock.
*/
static inline void blkg_put(struct blkcg_gq *blkg)
{
lockdep_assert_held(blkg->q->queue_lock);
WARN_ON_ONCE(blkg->refcnt <= 0);
if (!--blkg->refcnt)
__blkg_release(blkg);
}
#define BLKIO_WEIGHT_MIN 10
#define BLKIO_WEIGHT_MAX 1000
#define BLKIO_WEIGHT_DEFAULT 500
/**
* 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);
}
#ifdef CONFIG_DEBUG_BLK_CGROUP
void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg);
void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
unsigned long dequeue);
void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg);
void blkiocg_update_idle_time_stats(struct blkio_group *blkg);
void blkiocg_set_start_empty_time(struct blkio_group *blkg);
/**
* 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;
#define BLKG_FLAG_FNS(name) \
static inline void blkio_mark_blkg_##name( \
struct blkio_group_stats *stats) \
{ \
stats->flags |= (1 << BLKG_##name); \
} \
static inline void blkio_clear_blkg_##name( \
struct blkio_group_stats *stats) \
{ \
stats->flags &= ~(1 << BLKG_##name); \
} \
static inline int blkio_blkg_##name(struct blkio_group_stats *stats) \
{ \
return (stats->flags & (1 << BLKG_##name)) != 0; \
} \
do {
start = u64_stats_fetch_begin(&stat->syncp);
v = stat->cnt;
} while (u64_stats_fetch_retry(&stat->syncp, start));
BLKG_FLAG_FNS(waiting)
BLKG_FLAG_FNS(idling)
BLKG_FLAG_FNS(empty)
#undef BLKG_FLAG_FNS
#else
static inline void blkiocg_update_avg_queue_size_stats(
struct blkio_group *blkg) {}
static inline void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
unsigned long dequeue) {}
static inline void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg)
{}
static inline void blkiocg_update_idle_time_stats(struct blkio_group *blkg) {}
static inline void blkiocg_set_start_empty_time(struct blkio_group *blkg) {}
#endif
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 inline 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 /* CONFIG_BLK_CGROUP */
#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
extern struct blkio_cgroup blkio_root_cgroup;
extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
extern struct blkio_cgroup *task_blkio_cgroup(struct task_struct *tsk);
extern void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
struct blkio_group *blkg, void *key, dev_t dev,
enum blkio_policy_id plid);
extern int blkio_alloc_blkg_stats(struct blkio_group *blkg);
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_timeslice_used(struct blkio_group *blkg,
unsigned long time,
unsigned long unaccounted_time);
void blkiocg_update_dispatch_stats(struct blkio_group *blkg, uint64_t bytes,
bool direction, bool sync);
void blkiocg_update_completion_stats(struct blkio_group *blkg,
uint64_t start_time, uint64_t io_start_time, bool direction, bool sync);
void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction,
bool sync);
void blkiocg_update_io_add_stats(struct blkio_group *blkg,
struct blkio_group *curr_blkg, bool direction, bool sync);
void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
bool direction, bool sync);
#else
struct cgroup;
static inline struct blkio_cgroup *
cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
static inline struct blkio_cgroup *
task_blkio_cgroup(struct task_struct *tsk) { return NULL; }
static inline void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
struct blkio_group *blkg, void *key, dev_t dev,
enum blkio_policy_id plid) {}
struct blkg_policy_data {
};
static inline int blkio_alloc_blkg_stats(struct blkio_group *blkg) { return 0; }
struct blkcg_gq {
};
static inline int
blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; }
struct blkcg_policy {
};
static inline struct blkio_group *
blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) { return NULL; }
static inline void blkiocg_update_timeslice_used(struct blkio_group *blkg,
unsigned long time,
unsigned long unaccounted_time)
{}
static inline void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
uint64_t bytes, bool direction, bool sync) {}
static inline void blkiocg_update_completion_stats(struct blkio_group *blkg,
uint64_t start_time, uint64_t io_start_time, bool direction,
bool sync) {}
static inline void blkiocg_update_io_merged_stats(struct blkio_group *blkg,
bool direction, bool sync) {}
static inline void blkiocg_update_io_add_stats(struct blkio_group *blkg,
struct blkio_group *curr_blkg, bool direction, bool sync) {}
static inline void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
bool direction, bool sync) {}
#endif
#endif /* _BLK_CGROUP_H */
static inline struct blkcg *cgroup_to_blkcg(struct cgroup *cgroup) { return NULL; }
static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; }
static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }
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 blkcg_policy_register(struct blkcg_policy *pol) { return 0; }
static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { }
static inline int blkcg_activate_policy(struct request_queue *q,
const struct blkcg_policy *pol) { return 0; }
static inline void blkcg_deactivate_policy(struct request_queue *q,
const struct blkcg_policy *pol) { }
static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
struct blkcg_policy *pol) { return NULL; }
static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) { return NULL; }
static inline char *blkg_path(struct blkcg_gq *blkg) { return NULL; }
static inline void blkg_get(struct blkcg_gq *blkg) { }
static inline void blkg_put(struct blkcg_gq *blkg) { }
#endif /* CONFIG_BLK_CGROUP */
#endif /* _BLK_CGROUP_H */

287
block/blk-core.c
View File

@ -29,11 +29,13 @@
#include <linux/fault-inject.h>
#include <linux/list_sort.h>
#include <linux/delay.h>
#include <linux/ratelimit.h>
#define CREATE_TRACE_POINTS
#include <trace/events/block.h>
#include "blk.h"
#include "blk-cgroup.h"
EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
@ -280,7 +282,7 @@ EXPORT_SYMBOL(blk_stop_queue);
*
* This function does not cancel any asynchronous activity arising
* out of elevator or throttling code. That would require elevaotor_exit()
* and blk_throtl_exit() to be called with queue lock initialized.
* and blkcg_exit_queue() to be called with queue lock initialized.
*
*/
void blk_sync_queue(struct request_queue *q)
@ -365,17 +367,23 @@ void blk_drain_queue(struct request_queue *q, bool drain_all)
spin_lock_irq(q->queue_lock);
elv_drain_elevator(q);
if (drain_all)
blk_throtl_drain(q);
/*
* The caller might be trying to drain @q before its
* elevator is initialized.
*/
if (q->elevator)
elv_drain_elevator(q);
blkcg_drain_queue(q);
/*
* This function might be called on a queue which failed
* driver init after queue creation. Some drivers
* (e.g. fd) get unhappy in such cases. Kick queue iff
* dispatch queue has something on it.
* driver init after queue creation or is not yet fully
* active yet. Some drivers (e.g. fd and loop) get unhappy
* in such cases. Kick queue iff dispatch queue has
* something on it and @q has request_fn set.
*/
if (!list_empty(&q->queue_head))
if (!list_empty(&q->queue_head) && q->request_fn)
__blk_run_queue(q);
drain |= q->rq.elvpriv;
@ -402,6 +410,49 @@ void blk_drain_queue(struct request_queue *q, bool drain_all)
}
}
/**
* blk_queue_bypass_start - enter queue bypass mode
* @q: queue of interest
*
* In bypass mode, only the dispatch FIFO queue of @q is used. This
* function makes @q enter bypass mode and drains all requests which were
* throttled or issued before. On return, it's guaranteed that no request
* is being throttled or has ELVPRIV set and blk_queue_bypass() %true
* inside queue or RCU read lock.
*/
void blk_queue_bypass_start(struct request_queue *q)
{
bool drain;
spin_lock_irq(q->queue_lock);
drain = !q->bypass_depth++;
queue_flag_set(QUEUE_FLAG_BYPASS, q);
spin_unlock_irq(q->queue_lock);
if (drain) {
blk_drain_queue(q, false);
/* ensure blk_queue_bypass() is %true inside RCU read lock */
synchronize_rcu();
}
}
EXPORT_SYMBOL_GPL(blk_queue_bypass_start);
/**
* blk_queue_bypass_end - leave queue bypass mode
* @q: queue of interest
*
* Leave bypass mode and restore the normal queueing behavior.
*/
void blk_queue_bypass_end(struct request_queue *q)
{
spin_lock_irq(q->queue_lock);
if (!--q->bypass_depth)
queue_flag_clear(QUEUE_FLAG_BYPASS, q);
WARN_ON_ONCE(q->bypass_depth < 0);
spin_unlock_irq(q->queue_lock);
}
EXPORT_SYMBOL_GPL(blk_queue_bypass_end);
/**
* blk_cleanup_queue - shutdown a request queue
* @q: request queue to shutdown
@ -418,6 +469,19 @@ void blk_cleanup_queue(struct request_queue *q)
queue_flag_set_unlocked(QUEUE_FLAG_DEAD, q);
spin_lock_irq(lock);
/*
* Dead queue is permanently in bypass mode till released. Note
* that, unlike blk_queue_bypass_start(), we aren't performing
* synchronize_rcu() after entering bypass mode to avoid the delay
* as some drivers create and destroy a lot of queues while
* probing. This is still safe because blk_release_queue() will be
* called only after the queue refcnt drops to zero and nothing,
* RCU or not, would be traversing the queue by then.
*/
q->bypass_depth++;
queue_flag_set(QUEUE_FLAG_BYPASS, q);
queue_flag_set(QUEUE_FLAG_NOMERGES, q);
queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
queue_flag_set(QUEUE_FLAG_DEAD, q);
@ -428,13 +492,8 @@ void blk_cleanup_queue(struct request_queue *q)
spin_unlock_irq(lock);
mutex_unlock(&q->sysfs_lock);
/*
* Drain all requests queued before DEAD marking. The caller might
* be trying to tear down @q before its elevator is initialized, in
* which case we don't want to call into draining.
*/
if (q->elevator)
blk_drain_queue(q, true);
/* drain all requests queued before DEAD marking */
blk_drain_queue(q, true);
/* @q won't process any more request, flush async actions */
del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer);
@ -498,14 +557,15 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
if (err)
goto fail_id;
if (blk_throtl_init(q))
goto fail_id;
setup_timer(&q->backing_dev_info.laptop_mode_wb_timer,
laptop_mode_timer_fn, (unsigned long) q);
setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q);
INIT_LIST_HEAD(&q->queue_head);
INIT_LIST_HEAD(&q->timeout_list);
INIT_LIST_HEAD(&q->icq_list);
#ifdef CONFIG_BLK_CGROUP
INIT_LIST_HEAD(&q->blkg_list);
#endif
INIT_LIST_HEAD(&q->flush_queue[0]);
INIT_LIST_HEAD(&q->flush_queue[1]);
INIT_LIST_HEAD(&q->flush_data_in_flight);
@ -522,6 +582,18 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
*/
q->queue_lock = &q->__queue_lock;
/*
* A queue starts its life with bypass turned on to avoid
* unnecessary bypass on/off overhead and nasty surprises during
* init. The initial bypass will be finished at the end of
* blk_init_allocated_queue().
*/
q->bypass_depth = 1;
__set_bit(QUEUE_FLAG_BYPASS, &q->queue_flags);
if (blkcg_init_queue(q))
goto fail_id;
return q;
fail_id:
@ -614,15 +686,15 @@ blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
q->sg_reserved_size = INT_MAX;
/*
* all done
*/
if (!elevator_init(q, NULL)) {
blk_queue_congestion_threshold(q);
return q;
}
/* init elevator */
if (elevator_init(q, NULL))
return NULL;
return NULL;
blk_queue_congestion_threshold(q);
/* all done, end the initial bypass */
blk_queue_bypass_end(q);
return q;
}
EXPORT_SYMBOL(blk_init_allocated_queue);
@ -648,33 +720,6 @@ static inline void blk_free_request(struct request_queue *q, struct request *rq)
mempool_free(rq, q->rq.rq_pool);
}
static struct request *
blk_alloc_request(struct request_queue *q, struct io_cq *icq,
unsigned int flags, gfp_t gfp_mask)
{
struct request *rq = mempool_alloc(q->rq.rq_pool, gfp_mask);
if (!rq)
return NULL;
blk_rq_init(q, rq);
rq->cmd_flags = flags | REQ_ALLOCED;
if (flags & REQ_ELVPRIV) {
rq->elv.icq = icq;
if (unlikely(elv_set_request(q, rq, gfp_mask))) {
mempool_free(rq, q->rq.rq_pool);
return NULL;
}
/* @rq->elv.icq holds on to io_context until @rq is freed */
if (icq)
get_io_context(icq->ioc);
}
return rq;
}
/*
* ioc_batching returns true if the ioc is a valid batching request and
* should be given priority access to a request.
@ -762,6 +807,22 @@ static bool blk_rq_should_init_elevator(struct bio *bio)
return true;
}
/**
* rq_ioc - determine io_context for request allocation
* @bio: request being allocated is for this bio (can be %NULL)
*
* Determine io_context to use for request allocation for @bio. May return
* %NULL if %current->io_context doesn't exist.
*/
static struct io_context *rq_ioc(struct bio *bio)
{
#ifdef CONFIG_BLK_CGROUP
if (bio && bio->bi_ioc)
return bio->bi_ioc;
#endif
return current->io_context;
}
/**
* get_request - get a free request
* @q: request_queue to allocate request from
@ -779,7 +840,7 @@ static bool blk_rq_should_init_elevator(struct bio *bio)
static struct request *get_request(struct request_queue *q, int rw_flags,
struct bio *bio, gfp_t gfp_mask)
{
struct request *rq = NULL;
struct request *rq;
struct request_list *rl = &q->rq;
struct elevator_type *et;
struct io_context *ioc;
@ -789,7 +850,7 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
int may_queue;
retry:
et = q->elevator->type;
ioc = current->io_context;
ioc = rq_ioc(bio);
if (unlikely(blk_queue_dead(q)))
return NULL;
@ -808,7 +869,7 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
*/
if (!ioc && !retried) {
spin_unlock_irq(q->queue_lock);
create_io_context(current, gfp_mask, q->node);
create_io_context(gfp_mask, q->node);
spin_lock_irq(q->queue_lock);
retried = true;
goto retry;
@ -831,7 +892,7 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
* process is not a "batcher", and not
* exempted by the IO scheduler
*/
goto out;
return NULL;
}
}
}
@ -844,7 +905,7 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
* allocated with any setting of ->nr_requests
*/
if (rl->count[is_sync] >= (3 * q->nr_requests / 2))
goto out;
return NULL;
rl->count[is_sync]++;
rl->starved[is_sync] = 0;
@ -859,8 +920,7 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
* Also, lookup icq while holding queue_lock. If it doesn't exist,
* it will be created after releasing queue_lock.
*/
if (blk_rq_should_init_elevator(bio) &&
!test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags)) {
if (blk_rq_should_init_elevator(bio) && !blk_queue_bypass(q)) {
rw_flags |= REQ_ELVPRIV;
rl->elvpriv++;
if (et->icq_cache && ioc)
@ -871,41 +931,36 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
rw_flags |= REQ_IO_STAT;
spin_unlock_irq(q->queue_lock);
/* create icq if missing */
if ((rw_flags & REQ_ELVPRIV) && unlikely(et->icq_cache && !icq)) {
icq = ioc_create_icq(q, gfp_mask);
if (!icq)
goto fail_icq;
/* allocate and init request */
rq = mempool_alloc(q->rq.rq_pool, gfp_mask);
if (!rq)
goto fail_alloc;
blk_rq_init(q, rq);
rq->cmd_flags = rw_flags | REQ_ALLOCED;
/* init elvpriv */
if (rw_flags & REQ_ELVPRIV) {
if (unlikely(et->icq_cache && !icq)) {
create_io_context(gfp_mask, q->node);
ioc = rq_ioc(bio);
if (!ioc)
goto fail_elvpriv;
icq = ioc_create_icq(ioc, q, gfp_mask);
if (!icq)
goto fail_elvpriv;
}
rq->elv.icq = icq;
if (unlikely(elv_set_request(q, rq, bio, gfp_mask)))
goto fail_elvpriv;
/* @rq->elv.icq holds io_context until @rq is freed */
if (icq)
get_io_context(icq->ioc);
}
rq = blk_alloc_request(q, icq, rw_flags, gfp_mask);
fail_icq:
if (unlikely(!rq)) {
/*
* Allocation failed presumably due to memory. Undo anything
* we might have messed up.
*
* Allocating task should really be put onto the front of the
* wait queue, but this is pretty rare.
*/
spin_lock_irq(q->queue_lock);
freed_request(q, rw_flags);
/*
* in the very unlikely event that allocation failed and no
* requests for this direction was pending, mark us starved
* so that freeing of a request in the other direction will
* notice us. another possible fix would be to split the
* rq mempool into READ and WRITE
*/
rq_starved:
if (unlikely(rl->count[is_sync] == 0))
rl->starved[is_sync] = 1;
goto out;
}
out:
/*
* ioc may be NULL here, and ioc_batching will be false. That's
* OK, if the queue is under the request limit then requests need
@ -916,8 +971,48 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
ioc->nr_batch_requests--;
trace_block_getrq(q, bio, rw_flags & 1);
out:
return rq;
fail_elvpriv:
/*
* elvpriv init failed. ioc, icq and elvpriv aren't mempool backed
* and may fail indefinitely under memory pressure and thus
* shouldn't stall IO. Treat this request as !elvpriv. This will
* disturb iosched and blkcg but weird is bettern than dead.
*/
printk_ratelimited(KERN_WARNING "%s: request aux data allocation failed, iosched may be disturbed\n",
dev_name(q->backing_dev_info.dev));
rq->cmd_flags &= ~REQ_ELVPRIV;
rq->elv.icq = NULL;
spin_lock_irq(q->queue_lock);
rl->elvpriv--;
spin_unlock_irq(q->queue_lock);
goto out;
fail_alloc:
/*
* Allocation failed presumably due to memory. Undo anything we
* might have messed up.
*
* Allocating task should really be put onto the front of the wait
* queue, but this is pretty rare.
*/
spin_lock_irq(q->queue_lock);
freed_request(q, rw_flags);
/*
* in the very unlikely event that allocation failed and no
* requests for this direction was pending, mark us starved so that
* freeing of a request in the other direction will notice
* us. another possible fix would be to split the rq mempool into
* READ and WRITE
*/
rq_starved:
if (unlikely(rl->count[is_sync] == 0))
rl->starved[is_sync] = 1;
return NULL;
}
/**
@ -961,7 +1056,7 @@ static struct request *get_request_wait(struct request_queue *q, int rw_flags,
* up to a big batch of them for a small period time.
* See ioc_batching, ioc_set_batching
*/
create_io_context(current, GFP_NOIO, q->node);
create_io_context(GFP_NOIO, q->node);
ioc_set_batching(q, current->io_context);
spin_lock_irq(q->queue_lock);

126
block/blk-ioc.c
View File

@ -155,20 +155,20 @@ void put_io_context(struct io_context *ioc)
}
EXPORT_SYMBOL(put_io_context);
/* Called by the exiting task */
void exit_io_context(struct task_struct *task)
/**
* put_io_context_active - put active reference on ioc
* @ioc: ioc of interest
*
* Undo get_io_context_active(). If active reference reaches zero after
* put, @ioc can never issue further IOs and ioscheds are notified.
*/
void put_io_context_active(struct io_context *ioc)
{
struct io_context *ioc;
struct io_cq *icq;
struct hlist_node *n;
unsigned long flags;
struct io_cq *icq;
task_lock(task);
ioc = task->io_context;
task->io_context = NULL;
task_unlock(task);
if (!atomic_dec_and_test(&ioc->nr_tasks)) {
if (!atomic_dec_and_test(&ioc->active_ref)) {
put_io_context(ioc);
return;
}
@ -197,6 +197,20 @@ void exit_io_context(struct task_struct *task)
put_io_context(ioc);
}
/* Called by the exiting task */
void exit_io_context(struct task_struct *task)
{
struct io_context *ioc;
task_lock(task);
ioc = task->io_context;
task->io_context = NULL;
task_unlock(task);
atomic_dec(&ioc->nr_tasks);
put_io_context_active(ioc);
}
/**
* ioc_clear_queue - break any ioc association with the specified queue
* @q: request_queue being cleared
@ -218,19 +232,18 @@ void ioc_clear_queue(struct request_queue *q)
}
}
void create_io_context_slowpath(struct task_struct *task, gfp_t gfp_flags,
int node)
int create_task_io_context(struct task_struct *task, gfp_t gfp_flags, int node)
{
struct io_context *ioc;
ioc = kmem_cache_alloc_node(iocontext_cachep, gfp_flags | __GFP_ZERO,
node);
if (unlikely(!ioc))
return;
return -ENOMEM;
/* initialize */
atomic_long_set(&ioc->refcount, 1);
atomic_set(&ioc->nr_tasks, 1);
atomic_set(&ioc->active_ref, 1);
spin_lock_init(&ioc->lock);
INIT_RADIX_TREE(&ioc->icq_tree, GFP_ATOMIC | __GFP_HIGH);
INIT_HLIST_HEAD(&ioc->icq_list);
@ -250,6 +263,8 @@ void create_io_context_slowpath(struct task_struct *task, gfp_t gfp_flags,
else
kmem_cache_free(iocontext_cachep, ioc);
task_unlock(task);
return 0;
}
/**
@ -281,7 +296,7 @@ struct io_context *get_task_io_context(struct task_struct *task,
return ioc;
}
task_unlock(task);
} while (create_io_context(task, gfp_flags, node));
} while (!create_task_io_context(task, gfp_flags, node));
return NULL;
}
@ -325,26 +340,23 @@ EXPORT_SYMBOL(ioc_lookup_icq);
/**
* ioc_create_icq - create and link io_cq
* @ioc: io_context of interest
* @q: request_queue of interest
* @gfp_mask: allocation mask
*
* Make sure io_cq linking %current->io_context and @q exists. If either
* io_context and/or icq don't exist, they will be created using @gfp_mask.
* Make sure io_cq linking @ioc and @q exists. If icq doesn't exist, they
* will be created using @gfp_mask.
*
* The caller is responsible for ensuring @ioc won't go away and @q is
* alive and will stay alive until this function returns.
*/
struct io_cq *ioc_create_icq(struct request_queue *q, gfp_t gfp_mask)
struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
gfp_t gfp_mask)
{
struct elevator_type *et = q->elevator->type;
struct io_context *ioc;
struct io_cq *icq;
/* allocate stuff */
ioc = create_io_context(current, gfp_mask, q->node);
if (!ioc)
return NULL;
icq = kmem_cache_alloc_node(et->icq_cache, gfp_mask | __GFP_ZERO,
q->node);
if (!icq)
@ -382,74 +394,6 @@ struct io_cq *ioc_create_icq(struct request_queue *q, gfp_t gfp_mask)
return icq;
}
void ioc_set_icq_flags(struct io_context *ioc, unsigned int flags)
{
struct io_cq *icq;
struct hlist_node *n;
hlist_for_each_entry(icq, n, &ioc->icq_list, ioc_node)
icq->flags |= flags;
}
/**
* ioc_ioprio_changed - notify ioprio change
* @ioc: io_context of interest
* @ioprio: new ioprio
*
* @ioc's ioprio has changed to @ioprio. Set %ICQ_IOPRIO_CHANGED for all
* icq's. iosched is responsible for checking the bit and applying it on
* request issue path.
*/
void ioc_ioprio_changed(struct io_context *ioc, int ioprio)
{
unsigned long flags;
spin_lock_irqsave(&ioc->lock, flags);
ioc->ioprio = ioprio;
ioc_set_icq_flags(ioc, ICQ_IOPRIO_CHANGED);
spin_unlock_irqrestore(&ioc->lock, flags);
}
/**
* ioc_cgroup_changed - notify cgroup change
* @ioc: io_context of interest
*
* @ioc's cgroup has changed. Set %ICQ_CGROUP_CHANGED for all icq's.
* iosched is responsible for checking the bit and applying it on request
* issue path.
*/
void ioc_cgroup_changed(struct io_context *ioc)
{
unsigned long flags;
spin_lock_irqsave(&ioc->lock, flags);
ioc_set_icq_flags(ioc, ICQ_CGROUP_CHANGED);
spin_unlock_irqrestore(&ioc->lock, flags);
}
EXPORT_SYMBOL(ioc_cgroup_changed);
/**
* icq_get_changed - fetch and clear icq changed mask
* @icq: icq of interest
*
* Fetch and clear ICQ_*_CHANGED bits from @icq. Grabs and releases
* @icq->ioc->lock.
*/
unsigned icq_get_changed(struct io_cq *icq)
{
unsigned int changed = 0;
unsigned long flags;
if (unlikely(icq->flags & ICQ_CHANGED_MASK)) {
spin_lock_irqsave(&icq->ioc->lock, flags);
changed = icq->flags & ICQ_CHANGED_MASK;
icq->flags &= ~ICQ_CHANGED_MASK;
spin_unlock_irqrestore(&icq->ioc->lock, flags);
}
return changed;
}
EXPORT_SYMBOL(icq_get_changed);
static int __init blk_ioc_init(void)
{
iocontext_cachep = kmem_cache_create("blkdev_ioc",

6
block/blk-sysfs.c
View File

@ -9,6 +9,7 @@
#include <linux/blktrace_api.h>
#include "blk.h"
#include "blk-cgroup.h"
struct queue_sysfs_entry {
struct attribute attr;
@ -479,6 +480,8 @@ static void blk_release_queue(struct kobject *kobj)
blk_sync_queue(q);
blkcg_exit_queue(q);
if (q->elevator) {
spin_lock_irq(q->queue_lock);
ioc_clear_queue(q);
@ -486,15 +489,12 @@ static void blk_release_queue(struct kobject *kobj)
elevator_exit(q->elevator);
}
blk_throtl_exit(q);
if (rl->rq_pool)
mempool_destroy(rl->rq_pool);
if (q->queue_tags)
__blk_queue_free_tags(q);
blk_throtl_release(q);
blk_trace_shutdown(q);
bdi_destroy(&q->backing_dev_info);

719
block/blk-throttle.c
View File

@ -21,6 +21,8 @@ static int throtl_quantum = 32;
/* Throttling is performed over 100ms slice and after that slice is renewed */
static unsigned long throtl_slice = HZ/10; /* 100 ms */
static struct blkcg_policy blkcg_policy_throtl;
/* A workqueue to queue throttle related work */
static struct workqueue_struct *kthrotld_workqueue;
static void throtl_schedule_delayed_work(struct throtl_data *td,
@ -38,9 +40,17 @@ struct throtl_rb_root {
#define rb_entry_tg(node) rb_entry((node), struct throtl_grp, rb_node)
/* Per-cpu group stats */
struct tg_stats_cpu {
/* total bytes transferred */
struct blkg_rwstat service_bytes;
/* total IOs serviced, post merge */
struct blkg_rwstat serviced;
};
struct throtl_grp {
/* List of throtl groups on the request queue*/
struct hlist_node tg_node;
/* must be the first member */
struct blkg_policy_data pd;
/* active throtl group service_tree member */
struct rb_node rb_node;
@ -52,8 +62,6 @@ struct throtl_grp {
*/
unsigned long disptime;
struct blkio_group blkg;
atomic_t ref;
unsigned int flags;
/* Two lists for READ and WRITE */
@ -80,18 +88,18 @@ struct throtl_grp {
/* Some throttle limits got updated for the group */
int limits_changed;
struct rcu_head rcu_head;
/* Per cpu stats pointer */
struct tg_stats_cpu __percpu *stats_cpu;
/* List of tgs waiting for per cpu stats memory to be allocated */
struct list_head stats_alloc_node;
};
struct throtl_data
{
/* List of throtl groups */
struct hlist_head tg_list;
/* service tree for active throtl groups */
struct throtl_rb_root tg_service_tree;
struct throtl_grp *root_tg;
struct request_queue *queue;
/* Total Number of queued bios on READ and WRITE lists */
@ -108,6 +116,33 @@ struct throtl_data
int limits_changed;
};
/* list and work item to allocate percpu group stats */
static DEFINE_SPINLOCK(tg_stats_alloc_lock);
static LIST_HEAD(tg_stats_alloc_list);
static void tg_stats_alloc_fn(struct work_struct *);
static DECLARE_DELAYED_WORK(tg_stats_alloc_work, tg_stats_alloc_fn);
static inline struct throtl_grp *pd_to_tg(struct blkg_policy_data *pd)
{
return pd ? container_of(pd, struct throtl_grp, pd) : NULL;
}
static inline struct throtl_grp *blkg_to_tg(struct blkcg_gq *blkg)
{
return pd_to_tg(blkg_to_pd(blkg, &blkcg_policy_throtl));
}
static inline struct blkcg_gq *tg_to_blkg(struct throtl_grp *tg)
{
return pd_to_blkg(&tg->pd);
}
static inline struct throtl_grp *td_root_tg(struct throtl_data *td)
{
return blkg_to_tg(td->queue->root_blkg);
}
enum tg_state_flags {
THROTL_TG_FLAG_on_rr = 0, /* on round-robin busy list */
};
@ -128,244 +163,150 @@ static inline int throtl_tg_##name(const struct throtl_grp *tg) \
THROTL_TG_FNS(on_rr);
#define throtl_log_tg(td, tg, fmt, args...) \
blk_add_trace_msg((td)->queue, "throtl %s " fmt, \
blkg_path(&(tg)->blkg), ##args); \
#define throtl_log_tg(td, tg, fmt, args...) do { \
char __pbuf[128]; \
\
blkg_path(tg_to_blkg(tg), __pbuf, sizeof(__pbuf)); \
blk_add_trace_msg((td)->queue, "throtl %s " fmt, __pbuf, ##args); \
} while (0)
#define throtl_log(td, fmt, args...) \
blk_add_trace_msg((td)->queue, "throtl " fmt, ##args)
static inline struct throtl_grp *tg_of_blkg(struct blkio_group *blkg)
{
if (blkg)
return container_of(blkg, struct throtl_grp, blkg);
return NULL;
}
static inline unsigned int total_nr_queued(struct throtl_data *td)
{
return td->nr_queued[0] + td->nr_queued[1];
}
static inline struct throtl_grp *throtl_ref_get_tg(struct throtl_grp *tg)
/*
* Worker for allocating per cpu stat for tgs. This is scheduled on the
* system_nrt_wq once there are some groups on the alloc_list waiting for
* allocation.
*/
static void tg_stats_alloc_fn(struct work_struct *work)
{
atomic_inc(&tg->ref);
return tg;
static struct tg_stats_cpu *stats_cpu; /* this fn is non-reentrant */
struct delayed_work *dwork = to_delayed_work(work);
bool empty = false;
alloc_stats:
if (!stats_cpu) {
stats_cpu = alloc_percpu(struct tg_stats_cpu);
if (!stats_cpu) {
/* allocation failed, try again after some time */
queue_delayed_work(system_nrt_wq, dwork,
msecs_to_jiffies(10));
return;
}
}
spin_lock_irq(&tg_stats_alloc_lock);
if (!list_empty(&tg_stats_alloc_list)) {
struct throtl_grp *tg = list_first_entry(&tg_stats_alloc_list,
struct throtl_grp,
stats_alloc_node);
swap(tg->stats_cpu, stats_cpu);
list_del_init(&tg->stats_alloc_node);
}
empty = list_empty(&tg_stats_alloc_list);
spin_unlock_irq(&tg_stats_alloc_lock);
if (!empty)
goto alloc_stats;
}
static void throtl_free_tg(struct rcu_head *head)
static void throtl_pd_init(struct blkcg_gq *blkg)
{
struct throtl_grp *tg;
struct throtl_grp *tg = blkg_to_tg(blkg);
unsigned long flags;
tg = container_of(head, struct throtl_grp, rcu_head);
free_percpu(tg->blkg.stats_cpu);
kfree(tg);
}
static void throtl_put_tg(struct throtl_grp *tg)
{
BUG_ON(atomic_read(&tg->ref) <= 0);
if (!atomic_dec_and_test(&tg->ref))
return;
/*
* A group is freed in rcu manner. But having an rcu lock does not
* mean that one can access all the fields of blkg and assume these
* are valid. For example, don't try to follow throtl_data and
* request queue links.
*
* Having a reference to blkg under an rcu allows acess to only
* values local to groups like group stats and group rate limits
*/
call_rcu(&tg->rcu_head, throtl_free_tg);
}
static void throtl_init_group(struct throtl_grp *tg)
{
INIT_HLIST_NODE(&tg->tg_node);
RB_CLEAR_NODE(&tg->rb_node);
bio_list_init(&tg->bio_lists[0]);
bio_list_init(&tg->bio_lists[1]);
tg->limits_changed = false;
/* Practically unlimited BW */
tg->bps[0] = tg->bps[1] = -1;
tg->iops[0] = tg->iops[1] = -1;
tg->bps[READ] = -1;
tg->bps[WRITE] = -1;
tg->iops[READ] = -1;
tg->iops[WRITE] = -1;
/*
* Take the initial reference that will be released on destroy
* This can be thought of a joint reference by cgroup and
* request queue which will be dropped by either request queue
* exit or cgroup deletion path depending on who is exiting first.
* Ugh... We need to perform per-cpu allocation for tg->stats_cpu
* but percpu allocator can't be called from IO path. Queue tg on
* tg_stats_alloc_list and allocate from work item.
*/
atomic_set(&tg->ref, 1);
spin_lock_irqsave(&tg_stats_alloc_lock, flags);
list_add(&tg->stats_alloc_node, &tg_stats_alloc_list);
queue_delayed_work(system_nrt_wq, &tg_stats_alloc_work, 0);
spin_unlock_irqrestore(&tg_stats_alloc_lock, flags);
}
/* Should be called with rcu read lock held (needed for blkcg) */
static void
throtl_add_group_to_td_list(struct throtl_data *td, struct throtl_grp *tg)
static void throtl_pd_exit(struct blkcg_gq *blkg)
{
hlist_add_head(&tg->tg_node, &td->tg_list);
td->nr_undestroyed_grps++;
struct throtl_grp *tg = blkg_to_tg(blkg);
unsigned long flags;
spin_lock_irqsave(&tg_stats_alloc_lock, flags);
list_del_init(&tg->stats_alloc_node);
spin_unlock_irqrestore(&tg_stats_alloc_lock, flags);
free_percpu(tg->stats_cpu);
}
static void
__throtl_tg_fill_dev_details(struct throtl_data *td, struct throtl_grp *tg)
static void throtl_pd_reset_stats(struct blkcg_gq *blkg)
{
struct backing_dev_info *bdi = &td->queue->backing_dev_info;
unsigned int major, minor;
struct throtl_grp *tg = blkg_to_tg(blkg);
int cpu;
if (!tg || tg->blkg.dev)
if (tg->stats_cpu == NULL)
return;
/*
* Fill in device details for a group which might not have been
* filled at group creation time as queue was being instantiated
* and driver had not attached a device yet
*/
if (bdi->dev && dev_name(bdi->dev)) {
sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
tg->blkg.dev = MKDEV(major, minor);
for_each_possible_cpu(cpu) {
struct tg_stats_cpu *sc = per_cpu_ptr(tg->stats_cpu, cpu);
blkg_rwstat_reset(&sc->service_bytes);
blkg_rwstat_reset(&sc->serviced);
}
}
/*
* Should be called with without queue lock held. Here queue lock will be
* taken rarely. It will be taken only once during life time of a group
* if need be
*/
static void
throtl_tg_fill_dev_details(struct throtl_data *td, struct throtl_grp *tg)
static struct throtl_grp *throtl_lookup_tg(struct throtl_data *td,
struct blkcg *blkcg)
{
if (!tg || tg->blkg.dev)
return;
spin_lock_irq(td->queue->queue_lock);
__throtl_tg_fill_dev_details(td, tg);
spin_unlock_irq(td->queue->queue_lock);
}
static void throtl_init_add_tg_lists(struct throtl_data *td,
struct throtl_grp *tg, struct blkio_cgroup *blkcg)
{
__throtl_tg_fill_dev_details(td, tg);
/* Add group onto cgroup list */
blkiocg_add_blkio_group(blkcg, &tg->blkg, (void *)td,
tg->blkg.dev, BLKIO_POLICY_THROTL);
tg->bps[READ] = blkcg_get_read_bps(blkcg, tg->blkg.dev);
tg->bps[WRITE] = blkcg_get_write_bps(blkcg, tg->blkg.dev);
tg->iops[READ] = blkcg_get_read_iops(blkcg, tg->blkg.dev);
tg->iops[WRITE] = blkcg_get_write_iops(blkcg, tg->blkg.dev);
throtl_add_group_to_td_list(td, tg);
}
/* Should be called without queue lock and outside of rcu period */
static struct throtl_grp *throtl_alloc_tg(struct throtl_data *td)
{
struct throtl_grp *tg = NULL;
int ret;
tg = kzalloc_node(sizeof(*tg), GFP_ATOMIC, td->queue->node);
if (!tg)
return NULL;
ret = blkio_alloc_blkg_stats(&tg->blkg);
if (ret) {
kfree(tg);
return NULL;
}
throtl_init_group(tg);
return tg;
}
static struct
throtl_grp *throtl_find_tg(struct throtl_data *td, struct blkio_cgroup *blkcg)
{
struct throtl_grp *tg = NULL;
void *key = td;
/*
* This is the common case when there are no blkio cgroups.
* Avoid lookup in this case
*/
if (blkcg == &blkio_root_cgroup)
tg = td->root_tg;
else
tg = tg_of_blkg(blkiocg_lookup_group(blkcg, key));
* This is the common case when there are no blkcgs. Avoid lookup
* in this case
*/
if (blkcg == &blkcg_root)
return td_root_tg(td);
__throtl_tg_fill_dev_details(td, tg);
return tg;
return blkg_to_tg(blkg_lookup(blkcg, td->queue));
}
static struct throtl_grp * throtl_get_tg(struct throtl_data *td)
static struct throtl_grp *throtl_lookup_create_tg(struct throtl_data *td,
struct blkcg *blkcg)
{
struct throtl_grp *tg = NULL, *__tg = NULL;
struct blkio_cgroup *blkcg;
struct request_queue *q = td->queue;
/* no throttling for dead queue */
if (unlikely(blk_queue_dead(q)))
return NULL;
rcu_read_lock();
blkcg = task_blkio_cgroup(current);
tg = throtl_find_tg(td, blkcg);
if (tg) {
rcu_read_unlock();
return tg;
}
struct throtl_grp *tg = NULL;
/*
* Need to allocate a group. Allocation of group also needs allocation
* of per cpu stats which in-turn takes a mutex() and can block. Hence
* we need to drop rcu lock and queue_lock before we call alloc.
* This is the common case when there are no blkcgs. Avoid lookup
* in this case
*/
rcu_read_unlock();
spin_unlock_irq(q->queue_lock);
if (blkcg == &blkcg_root) {
tg = td_root_tg(td);
} else {
struct blkcg_gq *blkg;
tg = throtl_alloc_tg(td);
blkg = blkg_lookup_create(blkcg, q);
/* Group allocated and queue is still alive. take the lock */
spin_lock_irq(q->queue_lock);
/* Make sure @q is still alive */
if (unlikely(blk_queue_dead(q))) {
kfree(tg);
return NULL;
/* if %NULL and @q is alive, fall back to root_tg */
if (!IS_ERR(blkg))
tg = blkg_to_tg(blkg);
else if (!blk_queue_dead(q))
tg = td_root_tg(td);
}
/*
* Initialize the new group. After sleeping, read the blkcg again.
*/
rcu_read_lock();
blkcg = task_blkio_cgroup(current);
/*
* If some other thread already allocated the group while we were
* not holding queue lock, free up the group
*/
__tg = throtl_find_tg(td, blkcg);
if (__tg) {
kfree(tg);
rcu_read_unlock();
return __tg;
}
/* Group allocation failed. Account the IO to root group */
if (!tg) {
tg = td->root_tg;
return tg;
}
throtl_init_add_tg_lists(td, tg, blkcg);
rcu_read_unlock();
return tg;
}
@ -734,16 +675,41 @@ static bool tg_may_dispatch(struct throtl_data *td, struct throtl_grp *tg,
return 0;
}
static void throtl_update_dispatch_stats(struct blkcg_gq *blkg, u64 bytes,
int rw)
{
struct throtl_grp *tg = blkg_to_tg(blkg);
struct tg_stats_cpu *stats_cpu;
unsigned long flags;
/* If per cpu stats are not allocated yet, don't do any accounting. */
if (tg->stats_cpu == NULL)
return;
/*
* Disabling interrupts to provide mutual exclusion between two
* writes on same cpu. It probably is not needed for 64bit. Not
* optimizing that case yet.
*/
local_irq_save(flags);
stats_cpu = this_cpu_ptr(tg->stats_cpu);
blkg_rwstat_add(&stats_cpu->serviced, rw, 1);
blkg_rwstat_add(&stats_cpu->service_bytes, rw, bytes);
local_irq_restore(flags);
}
static void throtl_charge_bio(struct throtl_grp *tg, struct bio *bio)
{
bool rw = bio_data_dir(bio);
bool sync = rw_is_sync(bio->bi_rw);
/* Charge the bio to the group */
tg->bytes_disp[rw] += bio->bi_size;
tg->io_disp[rw]++;
blkiocg_update_dispatch_stats(&tg->blkg, bio->bi_size, rw, sync);
throtl_update_dispatch_stats(tg_to_blkg(tg), bio->bi_size, bio->bi_rw);
}
static void throtl_add_bio_tg(struct throtl_data *td, struct throtl_grp *tg,
@ -753,7 +719,7 @@ static void throtl_add_bio_tg(struct throtl_data *td, struct throtl_grp *tg,
bio_list_add(&tg->bio_lists[rw], bio);
/* Take a bio reference on tg */
throtl_ref_get_tg(tg);
blkg_get(tg_to_blkg(tg));
tg->nr_queued[rw]++;
td->nr_queued[rw]++;
throtl_enqueue_tg(td, tg);
@ -786,8 +752,8 @@ static void tg_dispatch_one_bio(struct throtl_data *td, struct throtl_grp *tg,
bio = bio_list_pop(&tg->bio_lists[rw]);
tg->nr_queued[rw]--;
/* Drop bio reference on tg */
throtl_put_tg(tg);
/* Drop bio reference on blkg */
blkg_put(tg_to_blkg(tg));
BUG_ON(td->nr_queued[rw] <= 0);
td->nr_queued[rw]--;
@ -865,8 +831,8 @@ static int throtl_select_dispatch(struct throtl_data *td, struct bio_list *bl)
static void throtl_process_limit_change(struct throtl_data *td)
{
struct throtl_grp *tg;
struct hlist_node *pos, *n;
struct request_queue *q = td->queue;
struct blkcg_gq *blkg, *n;
if (!td->limits_changed)
return;
@ -875,7 +841,9 @@ static void throtl_process_limit_change(struct throtl_data *td)
throtl_log(td, "limits changed");
hlist_for_each_entry_safe(tg, pos, n, &td->tg_list, tg_node) {
list_for_each_entry_safe(blkg, n, &q->blkg_list, q_node) {
struct throtl_grp *tg = blkg_to_tg(blkg);
if (!tg->limits_changed)
continue;
@ -973,119 +941,158 @@ throtl_schedule_delayed_work(struct throtl_data *td, unsigned long delay)
}
}
static void
throtl_destroy_tg(struct throtl_data *td, struct throtl_grp *tg)
static u64 tg_prfill_cpu_rwstat(struct seq_file *sf,
struct blkg_policy_data *pd, int off)
{
/* Something wrong if we are trying to remove same group twice */
BUG_ON(hlist_unhashed(&tg->tg_node));
struct throtl_grp *tg = pd_to_tg(pd);
struct blkg_rwstat rwstat = { }, tmp;
int i, cpu;
hlist_del_init(&tg->tg_node);
for_each_possible_cpu(cpu) {
struct tg_stats_cpu *sc = per_cpu_ptr(tg->stats_cpu, cpu);
/*
* Put the reference taken at the time of creation so that when all
* queues are gone, group can be destroyed.
*/
throtl_put_tg(tg);
td->nr_undestroyed_grps--;
}
static void throtl_release_tgs(struct throtl_data *td)
{
struct hlist_node *pos, *n;
struct throtl_grp *tg;
hlist_for_each_entry_safe(tg, pos, n, &td->tg_list, tg_node) {
/*
* If cgroup removal path got to blk_group first and removed
* it from cgroup list, then it will take care of destroying
* cfqg also.
*/
if (!blkiocg_del_blkio_group(&tg->blkg))
throtl_destroy_tg(td, tg);
tmp = blkg_rwstat_read((void *)sc + off);
for (i = 0; i < BLKG_RWSTAT_NR; i++)
rwstat.cnt[i] += tmp.cnt[i];
}
return __blkg_prfill_rwstat(sf, pd, &rwstat);
}
/*
* Blk cgroup controller notification saying that blkio_group object is being
* delinked as associated cgroup object is going away. That also means that
* no new IO will come in this group. So get rid of this group as soon as
* any pending IO in the group is finished.
*
* This function is called under rcu_read_lock(). key is the rcu protected
* pointer. That means "key" is a valid throtl_data pointer as long as we are
* rcu read lock.
*
* "key" was fetched from blkio_group under blkio_cgroup->lock. That means
* it should not be NULL as even if queue was going away, cgroup deltion
* path got to it first.
*/
void throtl_unlink_blkio_group(void *key, struct blkio_group *blkg)
static int tg_print_cpu_rwstat(struct cgroup *cgrp, struct cftype *cft,
struct seq_file *sf)
{
unsigned long flags;
struct throtl_data *td = key;
struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
spin_lock_irqsave(td->queue->queue_lock, flags);
throtl_destroy_tg(td, tg_of_blkg(blkg));
spin_unlock_irqrestore(td->queue->queue_lock, flags);
blkcg_print_blkgs(sf, blkcg, tg_prfill_cpu_rwstat, &blkcg_policy_throtl,
cft->private, true);
return 0;
}
static void throtl_update_blkio_group_common(struct throtl_data *td,
struct throtl_grp *tg)
static u64 tg_prfill_conf_u64(struct seq_file *sf, struct blkg_policy_data *pd,
int off)
{
struct throtl_grp *tg = pd_to_tg(pd);
u64 v = *(u64 *)((void *)tg + off);
if (v == -1)
return 0;
return __blkg_prfill_u64(sf, pd, v);
}
static u64 tg_prfill_conf_uint(struct seq_file *sf, struct blkg_policy_data *pd,
int off)
{
struct throtl_grp *tg = pd_to_tg(pd);
unsigned int v = *(unsigned int *)((void *)tg + off);
if (v == -1)
return 0;
return __blkg_prfill_u64(sf, pd, v);
}
static int tg_print_conf_u64(struct cgroup *cgrp, struct cftype *cft,
struct seq_file *sf)
{
blkcg_print_blkgs(sf, cgroup_to_blkcg(cgrp), tg_prfill_conf_u64,
&blkcg_policy_throtl, cft->private, false);
return 0;
}
static int tg_print_conf_uint(struct cgroup *cgrp, struct cftype *cft,
struct seq_file *sf)
{
blkcg_print_blkgs(sf, cgroup_to_blkcg(cgrp), tg_prfill_conf_uint,
&blkcg_policy_throtl, cft->private, false);
return 0;
}
static int tg_set_conf(struct cgroup *cgrp, struct cftype *cft, const char *buf,
bool is_u64)
{
struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
struct blkg_conf_ctx ctx;
struct throtl_grp *tg;
struct throtl_data *td;
int ret;
ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx);
if (ret)
return ret;
tg = blkg_to_tg(ctx.blkg);
td = ctx.blkg->q->td;
if (!ctx.v)
ctx.v = -1;
if (is_u64)
*(u64 *)((void *)tg + cft->private) = ctx.v;
else
*(unsigned int *)((void *)tg + cft->private) = ctx.v;
/* XXX: we don't need the following deferred processing */
xchg(&tg->limits_changed, true);
xchg(&td->limits_changed, true);
/* Schedule a work now to process the limit change */
throtl_schedule_delayed_work(td, 0);
blkg_conf_finish(&ctx);
return 0;
}
/*
* For all update functions, key should be a valid pointer because these
* update functions are called under blkcg_lock, that means, blkg is
* valid and in turn key is valid. queue exit path can not race because
* of blkcg_lock
*
* Can not take queue lock in update functions as queue lock under blkcg_lock
* is not allowed. Under other paths we take blkcg_lock under queue_lock.
*/
static void throtl_update_blkio_group_read_bps(void *key,
struct blkio_group *blkg, u64 read_bps)
static int tg_set_conf_u64(struct cgroup *cgrp, struct cftype *cft,
const char *buf)
{
struct throtl_data *td = key;
struct throtl_grp *tg = tg_of_blkg(blkg);
tg->bps[READ] = read_bps;
throtl_update_blkio_group_common(td, tg);
return tg_set_conf(cgrp, cft, buf, true);
}
static void throtl_update_blkio_group_write_bps(void *key,
struct blkio_group *blkg, u64 write_bps)
static int tg_set_conf_uint(struct cgroup *cgrp, struct cftype *cft,
const char *buf)
{
struct throtl_data *td = key;
struct throtl_grp *tg = tg_of_blkg(blkg);
tg->bps[WRITE] = write_bps;
throtl_update_blkio_group_common(td, tg);
return tg_set_conf(cgrp, cft, buf, false);
}
static void throtl_update_blkio_group_read_iops(void *key,
struct blkio_group *blkg, unsigned int read_iops)
{
struct throtl_data *td = key;
struct throtl_grp *tg = tg_of_blkg(blkg);
tg->iops[READ] = read_iops;
throtl_update_blkio_group_common(td, tg);
}
static void throtl_update_blkio_group_write_iops(void *key,
struct blkio_group *blkg, unsigned int write_iops)
{
struct throtl_data *td = key;
struct throtl_grp *tg = tg_of_blkg(blkg);
tg->iops[WRITE] = write_iops;
throtl_update_blkio_group_common(td, tg);
}
static struct cftype throtl_files[] = {
{
.name = "throttle.read_bps_device",
.private = offsetof(struct throtl_grp, bps[READ]),
.read_seq_string = tg_print_conf_u64,
.write_string = tg_set_conf_u64,
.max_write_len = 256,
},
{
.name = "throttle.write_bps_device",
.private = offsetof(struct throtl_grp, bps[WRITE]),
.read_seq_string = tg_print_conf_u64,
.write_string = tg_set_conf_u64,
.max_write_len = 256,
},
{
.name = "throttle.read_iops_device",
.private = offsetof(struct throtl_grp, iops[READ]),
.read_seq_string = tg_print_conf_uint,
.write_string = tg_set_conf_uint,
.max_write_len = 256,
},
{
.name = "throttle.write_iops_device",
.private = offsetof(struct throtl_grp, iops[WRITE]),
.read_seq_string = tg_print_conf_uint,
.write_string = tg_set_conf_uint,
.max_write_len = 256,
},
{
.name = "throttle.io_service_bytes",
.private = offsetof(struct tg_stats_cpu, service_bytes),
.read_seq_string = tg_print_cpu_rwstat,
},
{
.name = "throttle.io_serviced",
.private = offsetof(struct tg_stats_cpu, serviced),
.read_seq_string = tg_print_cpu_rwstat,
},
{ } /* terminate */
};
static void throtl_shutdown_wq(struct request_queue *q)
{
@ -1094,19 +1101,13 @@ static void throtl_shutdown_wq(struct request_queue *q)
cancel_delayed_work_sync(&td->throtl_work);
}
static struct blkio_policy_type blkio_policy_throtl = {
.ops = {
.blkio_unlink_group_fn = throtl_unlink_blkio_group,
.blkio_update_group_read_bps_fn =
throtl_update_blkio_group_read_bps,
.blkio_update_group_write_bps_fn =
throtl_update_blkio_group_write_bps,
.blkio_update_group_read_iops_fn =
throtl_update_blkio_group_read_iops,
.blkio_update_group_write_iops_fn =
throtl_update_blkio_group_write_iops,
},
.plid = BLKIO_POLICY_THROTL,
static struct blkcg_policy blkcg_policy_throtl = {
.pd_size = sizeof(struct throtl_grp),
.cftypes = throtl_files,
.pd_init_fn = throtl_pd_init,
.pd_exit_fn = throtl_pd_exit,
.pd_reset_stats_fn = throtl_pd_reset_stats,
};
bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
@ -1114,7 +1115,7 @@ bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
struct throtl_data *td = q->td;
struct throtl_grp *tg;
bool rw = bio_data_dir(bio), update_disptime = true;
struct blkio_cgroup *blkcg;
struct blkcg *blkcg;
bool throttled = false;
if (bio->bi_rw & REQ_THROTTLED) {
@ -1122,33 +1123,31 @@ bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
goto out;
}
/* bio_associate_current() needs ioc, try creating */
create_io_context(GFP_ATOMIC, q->node);
/*
* A throtl_grp pointer retrieved under rcu can be used to access
* basic fields like stats and io rates. If a group has no rules,
* just update the dispatch stats in lockless manner and return.
*/
rcu_read_lock();
blkcg = task_blkio_cgroup(current);
tg = throtl_find_tg(td, blkcg);
blkcg = bio_blkcg(bio);
tg = throtl_lookup_tg(td, blkcg);
if (tg) {
throtl_tg_fill_dev_details(td, tg);
if (tg_no_rule_group(tg, rw)) {
blkiocg_update_dispatch_stats(&tg->blkg, bio->bi_size,
rw, rw_is_sync(bio->bi_rw));
rcu_read_unlock();
goto out;
throtl_update_dispatch_stats(tg_to_blkg(tg),
bio->bi_size, bio->bi_rw);
goto out_unlock_rcu;
}
}
rcu_read_unlock();
/*
* Either group has not been allocated yet or it is not an unlimited
* IO group
*/
spin_lock_irq(q->queue_lock);
tg = throtl_get_tg(td);
tg = throtl_lookup_create_tg(td, blkcg);
if (unlikely(!tg))
goto out_unlock;
@ -1189,6 +1188,7 @@ bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
tg->io_disp[rw], tg->iops[rw],
tg->nr_queued[READ], tg->nr_queued[WRITE]);
bio_associate_current(bio);
throtl_add_bio_tg(q->td, tg, bio);
throttled = true;
@ -1199,6 +1199,8 @@ bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
out_unlock:
spin_unlock_irq(q->queue_lock);
out_unlock_rcu:
rcu_read_unlock();
out:
return throttled;
}
@ -1241,79 +1243,31 @@ void blk_throtl_drain(struct request_queue *q)
int blk_throtl_init(struct request_queue *q)
{
struct throtl_data *td;
struct throtl_grp *tg;
int ret;
td = kzalloc_node(sizeof(*td), GFP_KERNEL, q->node);
if (!td)
return -ENOMEM;
INIT_HLIST_HEAD(&td->tg_list);
td->tg_service_tree = THROTL_RB_ROOT;
td->limits_changed = false;
INIT_DELAYED_WORK(&td->throtl_work, blk_throtl_work);
/* alloc and Init root group. */
td->queue = q;
tg = throtl_alloc_tg(td);
if (!tg) {
kfree(td);
return -ENOMEM;
}
td->root_tg = tg;
rcu_read_lock();
throtl_init_add_tg_lists(td, tg, &blkio_root_cgroup);
rcu_read_unlock();
/* Attach throtl data to request queue */
q->td = td;
return 0;
td->queue = q;
/* activate policy */
ret = blkcg_activate_policy(q, &blkcg_policy_throtl);
if (ret)
kfree(td);
return ret;
}
void blk_throtl_exit(struct request_queue *q)
{
struct throtl_data *td = q->td;
bool wait = false;
BUG_ON(!td);
BUG_ON(!q->td);
throtl_shutdown_wq(q);
spin_lock_irq(q->queue_lock);
throtl_release_tgs(td);
/* If there are other groups */
if (td->nr_undestroyed_grps > 0)
wait = true;
spin_unlock_irq(q->queue_lock);
/*
* Wait for tg->blkg->key accessors to exit their grace periods.
* Do this wait only if there are other undestroyed groups out
* there (other than root group). This can happen if cgroup deletion
* path claimed the responsibility of cleaning up a group before
* queue cleanup code get to the group.
*
* Do not call synchronize_rcu() unconditionally as there are drivers
* which create/delete request queue hundreds of times during scan/boot
* and synchronize_rcu() can take significant time and slow down boot.
*/
if (wait)
synchronize_rcu();
/*
* Just being safe to make sure after previous flush if some body did
* update limits through cgroup and another work got queued, cancel
* it.
*/
throtl_shutdown_wq(q);
}
void blk_throtl_release(struct request_queue *q)
{
blkcg_deactivate_policy(q, &blkcg_policy_throtl);
kfree(q->td);
}
@ -1323,8 +1277,7 @@ static int __init throtl_init(void)
if (!kthrotld_workqueue)
panic("Failed to create kthrotld\n");
blkio_policy_register(&blkio_policy_throtl);
return 0;
return blkcg_policy_register(&blkcg_policy_throtl);
}
module_init(throtl_init);

32
block/blk.h
View File

@ -23,7 +23,8 @@ void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
struct bio *bio);
int blk_rq_append_bio(struct request_queue *q, struct request *rq,
struct bio *bio);
void blk_drain_queue(struct request_queue *q, bool drain_all);
void blk_queue_bypass_start(struct request_queue *q);
void blk_queue_bypass_end(struct request_queue *q);
void blk_dequeue_request(struct request *rq);
void __blk_queue_free_tags(struct request_queue *q);
bool __blk_end_bidi_request(struct request *rq, int error,
@ -144,9 +145,6 @@ void blk_queue_congestion_threshold(struct request_queue *q);
int blk_dev_init(void);
void elv_quiesce_start(struct request_queue *q);
void elv_quiesce_end(struct request_queue *q);
/*
* Return the threshold (number of used requests) at which the queue is
@ -186,32 +184,30 @@ static inline int blk_do_io_stat(struct request *rq)
*/
void get_io_context(struct io_context *ioc);
struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
struct io_cq *ioc_create_icq(struct request_queue *q, gfp_t gfp_mask);
struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
gfp_t gfp_mask);
void ioc_clear_queue(struct request_queue *q);
void create_io_context_slowpath(struct task_struct *task, gfp_t gfp_mask,
int node);
int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
/**
* create_io_context - try to create task->io_context
* @task: target task
* @gfp_mask: allocation mask
* @node: allocation node
*
* If @task->io_context is %NULL, allocate a new io_context and install it.
* Returns the current @task->io_context which may be %NULL if allocation
* failed.
* If %current->io_context is %NULL, allocate a new io_context and install
* it. Returns the current %current->io_context which may be %NULL if
* allocation failed.
*
* Note that this function can't be called with IRQ disabled because
* task_lock which protects @task->io_context is IRQ-unsafe.
* task_lock which protects %current->io_context is IRQ-unsafe.
*/
static inline struct io_context *create_io_context(struct task_struct *task,
gfp_t gfp_mask, int node)
static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
{
WARN_ON_ONCE(irqs_disabled());
if (unlikely(!task->io_context))
create_io_context_slowpath(task, gfp_mask, node);
return task->io_context;
if (unlikely(!current->io_context))
create_task_io_context(current, gfp_mask, node);
return current->io_context;
}
/*
@ -222,7 +218,6 @@ extern bool blk_throtl_bio(struct request_queue *q, struct bio *bio);
extern void blk_throtl_drain(struct request_queue *q);
extern int blk_throtl_init(struct request_queue *q);
extern void blk_throtl_exit(struct request_queue *q);
extern void blk_throtl_release(struct request_queue *q);
#else /* CONFIG_BLK_DEV_THROTTLING */
static inline bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
{
@ -231,7 +226,6 @@ static inline bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
static inline void blk_throtl_drain(struct request_queue *q) { }
static inline int blk_throtl_init(struct request_queue *q) { return 0; }
static inline void blk_throtl_exit(struct request_queue *q) { }
static inline void blk_throtl_release(struct request_queue *q) { }
#endif /* CONFIG_BLK_DEV_THROTTLING */
#endif /* BLK_INTERNAL_H */

1082
block/cfq-iosched.c
View File

File diff suppressed because it is too large Load Diff

115
block/cfq.h
View File

@ -1,115 +0,0 @@
#ifndef _CFQ_H
#define _CFQ_H
#include "blk-cgroup.h"
#ifdef CONFIG_CFQ_GROUP_IOSCHED
static inline void cfq_blkiocg_update_io_add_stats(struct blkio_group *blkg,
struct blkio_group *curr_blkg, bool direction, bool sync)
{
blkiocg_update_io_add_stats(blkg, curr_blkg, direction, sync);
}
static inline void cfq_blkiocg_update_dequeue_stats(struct blkio_group *blkg,
unsigned long dequeue)
{
blkiocg_update_dequeue_stats(blkg, dequeue);
}
static inline void cfq_blkiocg_update_timeslice_used(struct blkio_group *blkg,
unsigned long time, unsigned long unaccounted_time)
{
blkiocg_update_timeslice_used(blkg, time, unaccounted_time);
}
static inline void cfq_blkiocg_set_start_empty_time(struct blkio_group *blkg)
{
blkiocg_set_start_empty_time(blkg);
}
static inline void cfq_blkiocg_update_io_remove_stats(struct blkio_group *blkg,
bool direction, bool sync)
{
blkiocg_update_io_remove_stats(blkg, direction, sync);
}
static inline void cfq_blkiocg_update_io_merged_stats(struct blkio_group *blkg,
bool direction, bool sync)
{
blkiocg_update_io_merged_stats(blkg, direction, sync);
}
static inline void cfq_blkiocg_update_idle_time_stats(struct blkio_group *blkg)
{
blkiocg_update_idle_time_stats(blkg);
}
static inline void
cfq_blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg)
{
blkiocg_update_avg_queue_size_stats(blkg);
}
static inline void
cfq_blkiocg_update_set_idle_time_stats(struct blkio_group *blkg)
{
blkiocg_update_set_idle_time_stats(blkg);
}
static inline void cfq_blkiocg_update_dispatch_stats(struct blkio_group *blkg,
uint64_t bytes, bool direction, bool sync)
{
blkiocg_update_dispatch_stats(blkg, bytes, direction, sync);
}
static inline void cfq_blkiocg_update_completion_stats(struct blkio_group *blkg, uint64_t start_time, uint64_t io_start_time, bool direction, bool sync)
{
blkiocg_update_completion_stats(blkg, start_time, io_start_time,
direction, sync);
}
static inline void cfq_blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
struct blkio_group *blkg, void *key, dev_t dev) {
blkiocg_add_blkio_group(blkcg, blkg, key, dev, BLKIO_POLICY_PROP);
}
static inline int cfq_blkiocg_del_blkio_group(struct blkio_group *blkg)
{
return blkiocg_del_blkio_group(blkg);
}
#else /* CFQ_GROUP_IOSCHED */
static inline void cfq_blkiocg_update_io_add_stats(struct blkio_group *blkg,
struct blkio_group *curr_blkg, bool direction, bool sync) {}
static inline void cfq_blkiocg_update_dequeue_stats(struct blkio_group *blkg,
unsigned long dequeue) {}
static inline void cfq_blkiocg_update_timeslice_used(struct blkio_group *blkg,
unsigned long time, unsigned long unaccounted_time) {}
static inline void cfq_blkiocg_set_start_empty_time(struct blkio_group *blkg) {}
static inline void cfq_blkiocg_update_io_remove_stats(struct blkio_group *blkg,
bool direction, bool sync) {}
static inline void cfq_blkiocg_update_io_merged_stats(struct blkio_group *blkg,
bool direction, bool sync) {}
static inline void cfq_blkiocg_update_idle_time_stats(struct blkio_group *blkg)
{
}
static inline void
cfq_blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg) {}
static inline void
cfq_blkiocg_update_set_idle_time_stats(struct blkio_group *blkg) {}
static inline void cfq_blkiocg_update_dispatch_stats(struct blkio_group *blkg,
uint64_t bytes, bool direction, bool sync) {}
static inline void cfq_blkiocg_update_completion_stats(struct blkio_group *blkg, uint64_t start_time, uint64_t io_start_time, bool direction, bool sync) {}
static inline void cfq_blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
struct blkio_group *blkg, void *key, dev_t dev) {}
static inline int cfq_blkiocg_del_blkio_group(struct blkio_group *blkg)
{
return 0;
}
#endif /* CFQ_GROUP_IOSCHED */
#endif

8
block/deadline-iosched.c
View File

@ -337,13 +337,13 @@ static void deadline_exit_queue(struct elevator_queue *e)
/*
* initialize elevator private data (deadline_data).
*/
static void *deadline_init_queue(struct request_queue *q)
static int deadline_init_queue(struct request_queue *q)
{
struct deadline_data *dd;
dd = kmalloc_node(sizeof(*dd), GFP_KERNEL | __GFP_ZERO, q->node);
if (!dd)
return NULL;
return -ENOMEM;
INIT_LIST_HEAD(&dd->fifo_list[READ]);
INIT_LIST_HEAD(&dd->fifo_list[WRITE]);
@ -354,7 +354,9 @@ static void *deadline_init_queue(struct request_queue *q)
dd->writes_starved = writes_starved;
dd->front_merges = 1;
dd->fifo_batch = fifo_batch;
return dd;
q->elevator->elevator_data = dd;
return 0;
}
/*

121
block/elevator.c
View File

@ -38,6 +38,7 @@
#include <trace/events/block.h>
#include "blk.h"
#include "blk-cgroup.h"
static DEFINE_SPINLOCK(elv_list_lock);
static LIST_HEAD(elv_list);
@ -121,15 +122,6 @@ static struct elevator_type *elevator_get(const char *name)
return e;
}
static int elevator_init_queue(struct request_queue *q,
struct elevator_queue *eq)
{
eq->elevator_data = eq->type->ops.elevator_init_fn(q);
if (eq->elevator_data)
return 0;
return -ENOMEM;
}
static char chosen_elevator[ELV_NAME_MAX];
static int __init elevator_setup(char *str)
@ -188,7 +180,6 @@ static void elevator_release(struct kobject *kobj)
int elevator_init(struct request_queue *q, char *name)
{
struct elevator_type *e = NULL;
struct elevator_queue *eq;
int err;
if (unlikely(q->elevator))
@ -222,17 +213,16 @@ int elevator_init(struct request_queue *q, char *name)
}
}
eq = elevator_alloc(q, e);
if (!eq)
q->elevator = elevator_alloc(q, e);
if (!q->elevator)
return -ENOMEM;
err = elevator_init_queue(q, eq);
err = e->ops.elevator_init_fn(q);
if (err) {
kobject_put(&eq->kobj);
kobject_put(&q->elevator->kobj);
return err;
}
q->elevator = eq;
return 0;
}
EXPORT_SYMBOL(elevator_init);
@ -564,25 +554,6 @@ void elv_drain_elevator(struct request_queue *q)
}
}
void elv_quiesce_start(struct request_queue *q)
{
if (!q->elevator)
return;
spin_lock_irq(q->queue_lock);
queue_flag_set(QUEUE_FLAG_ELVSWITCH, q);
spin_unlock_irq(q->queue_lock);
blk_drain_queue(q, false);
}
void elv_quiesce_end(struct request_queue *q)
{
spin_lock_irq(q->queue_lock);
queue_flag_clear(QUEUE_FLAG_ELVSWITCH, q);
spin_unlock_irq(q->queue_lock);
}
void __elv_add_request(struct request_queue *q, struct request *rq, int where)
{
trace_block_rq_insert(q, rq);
@ -692,12 +663,13 @@ struct request *elv_former_request(struct request_queue *q, struct request *rq)
return NULL;
}
int elv_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask)
int elv_set_request(struct request_queue *q, struct request *rq,
struct bio *bio, gfp_t gfp_mask)
{
struct elevator_queue *e = q->elevator;
if (e->type->ops.elevator_set_req_fn)
return e->type->ops.elevator_set_req_fn(q, rq, gfp_mask);
return e->type->ops.elevator_set_req_fn(q, rq, bio, gfp_mask);
return 0;
}
@ -801,8 +773,9 @@ static struct kobj_type elv_ktype = {
.release = elevator_release,
};
int __elv_register_queue(struct request_queue *q, struct elevator_queue *e)
int elv_register_queue(struct request_queue *q)
{
struct elevator_queue *e = q->elevator;
int error;
error = kobject_add(&e->kobj, &q->kobj, "%s", "iosched");
@ -820,11 +793,6 @@ int __elv_register_queue(struct request_queue *q, struct elevator_queue *e)
}
return error;
}
int elv_register_queue(struct request_queue *q)
{
return __elv_register_queue(q, q->elevator);
}
EXPORT_SYMBOL(elv_register_queue);
void elv_unregister_queue(struct request_queue *q)
@ -907,53 +875,60 @@ EXPORT_SYMBOL_GPL(elv_unregister);
*/
static int elevator_switch(struct request_queue *q, struct elevator_type *new_e)
{
struct elevator_queue *old_elevator, *e;
struct elevator_queue *old = q->elevator;
bool registered = old->registered;
int err;
/* allocate new elevator */
e = elevator_alloc(q, new_e);
if (!e)
return -ENOMEM;
/*
* Turn on BYPASS and drain all requests w/ elevator private data.
* Block layer doesn't call into a quiesced elevator - all requests
* are directly put on the dispatch list without elevator data
* using INSERT_BACK. All requests have SOFTBARRIER set and no
* merge happens either.
*/
blk_queue_bypass_start(q);
err = elevator_init_queue(q, e);
/* unregister and clear all auxiliary data of the old elevator */
if (registered)
elv_unregister_queue(q);
spin_lock_irq(q->queue_lock);
ioc_clear_queue(q);
spin_unlock_irq(q->queue_lock);
/* allocate, init and register new elevator */
err = -ENOMEM;
q->elevator = elevator_alloc(q, new_e);
if (!q->elevator)
goto fail_init;
err = new_e->ops.elevator_init_fn(q);
if (err) {
kobject_put(&e->kobj);
return err;
kobject_put(&q->elevator->kobj);
goto fail_init;
}
/* turn on BYPASS and drain all requests w/ elevator private data */
elv_quiesce_start(q);
/* unregister old queue, register new one and kill old elevator */
if (q->elevator->registered) {
elv_unregister_queue(q);
err = __elv_register_queue(q, e);
if (registered) {
err = elv_register_queue(q);
if (err)
goto fail_register;
}
/* done, clear io_cq's, switch elevators and turn off BYPASS */
spin_lock_irq(q->queue_lock);
ioc_clear_queue(q);
old_elevator = q->elevator;
q->elevator = e;
spin_unlock_irq(q->queue_lock);
/* done, kill the old one and finish */
elevator_exit(old);
blk_queue_bypass_end(q);
elevator_exit(old_elevator);
elv_quiesce_end(q);
blk_add_trace_msg(q, "elv switch: %s", e->type->elevator_name);
blk_add_trace_msg(q, "elv switch: %s", new_e->elevator_name);
return 0;
fail_register:
/*
* switch failed, exit the new io scheduler and reattach the old
* one again (along with re-adding the sysfs dir)
*/
elevator_exit(e);
elevator_exit(q->elevator);
fail_init:
/* switch failed, restore and re-register old elevator */
q->elevator = old;
elv_register_queue(q);
elv_quiesce_end(q);
blk_queue_bypass_end(q);
return err;
}

8
block/noop-iosched.c
View File

@ -59,15 +59,17 @@ noop_latter_request(struct request_queue *q, struct request *rq)
return list_entry(rq->queuelist.next, struct request, queuelist);
}
static void *noop_init_queue(struct request_queue *q)
static int noop_init_queue(struct request_queue *q)
{
struct noop_data *nd;
nd = kmalloc_node(sizeof(*nd), GFP_KERNEL, q->node);
if (!nd)
return NULL;
return -ENOMEM;
INIT_LIST_HEAD(&nd->queue);
return nd;
q->elevator->elevator_data = nd;
return 0;
}
static void noop_exit_queue(struct elevator_queue *e)

61
fs/bio.c
View File

@ -19,12 +19,14 @@
#include <linux/swap.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/iocontext.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/mempool.h>
#include <linux/workqueue.h>
#include <linux/cgroup.h>
#include <scsi/sg.h> /* for struct sg_iovec */
#include <trace/events/block.h>
@ -418,6 +420,7 @@ void bio_put(struct bio *bio)
* last put frees it
*/
if (atomic_dec_and_test(&bio->bi_cnt)) {
bio_disassociate_task(bio);
bio->bi_next = NULL;
bio->bi_destructor(bio);
}
@ -1646,6 +1649,64 @@ struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
}
EXPORT_SYMBOL(bioset_create);
#ifdef CONFIG_BLK_CGROUP
/**
* bio_associate_current - associate a bio with %current
* @bio: target bio
*
* Associate @bio with %current if it hasn't been associated yet. Block
* layer will treat @bio as if it were issued by %current no matter which
* task actually issues it.
*
* This function takes an extra reference of @task's io_context and blkcg
* which will be put when @bio is released. The caller must own @bio,
* ensure %current->io_context exists, and is responsible for synchronizing
* calls to this function.
*/
int bio_associate_current(struct bio *bio)
{
struct io_context *ioc;
struct cgroup_subsys_state *css;
if (bio->bi_ioc)
return -EBUSY;
ioc = current->io_context;
if (!ioc)
return -ENOENT;
/* acquire active ref on @ioc and associate */
get_io_context_active(ioc);
bio->bi_ioc = ioc;
/* associate blkcg if exists */
rcu_read_lock();
css = task_subsys_state(current, blkio_subsys_id);
if (css && css_tryget(css))
bio->bi_css = css;
rcu_read_unlock();
return 0;
}
/**
* bio_disassociate_task - undo bio_associate_current()
* @bio: target bio
*/
void bio_disassociate_task(struct bio *bio)
{
if (bio->bi_ioc) {
put_io_context(bio->bi_ioc);
bio->bi_ioc = NULL;
}
if (bio->bi_css) {
css_put(bio->bi_css);
bio->bi_css = NULL;
}
}
#endif /* CONFIG_BLK_CGROUP */
static void __init biovec_init_slabs(void)
{
int i;

2
fs/ioprio.c
View File

@ -50,7 +50,7 @@ int set_task_ioprio(struct task_struct *task, int ioprio)
ioc = get_task_io_context(task, GFP_ATOMIC, NUMA_NO_NODE);
if (ioc) {
ioc_ioprio_changed(ioc, ioprio);
ioc->ioprio = ioprio;
put_io_context(ioc);
}

4
fs/splice.c
View File

@ -1388,7 +1388,7 @@ static long do_splice(struct file *in, loff_t __user *off_in,
*/
static int get_iovec_page_array(const struct iovec __user *iov,
unsigned int nr_vecs, struct page **pages,
struct partial_page *partial, int aligned,
struct partial_page *partial, bool aligned,
unsigned int pipe_buffers)
{
int buffers = 0, error = 0;
@ -1626,7 +1626,7 @@ static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov,
return -ENOMEM;
spd.nr_pages = get_iovec_page_array(iov, nr_segs, spd.pages,
spd.partial, flags & SPLICE_F_GIFT,
spd.partial, false,
pipe->buffers);
if (spd.nr_pages <= 0)
ret = spd.nr_pages;

8
include/linux/bio.h
View File

@ -269,6 +269,14 @@ extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set
extern void bvec_free_bs(struct bio_set *, struct bio_vec *, unsigned int);
extern unsigned int bvec_nr_vecs(unsigned short idx);
#ifdef CONFIG_BLK_CGROUP
int bio_associate_current(struct bio *bio);
void bio_disassociate_task(struct bio *bio);
#else /* CONFIG_BLK_CGROUP */
static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
static inline void bio_disassociate_task(struct bio *bio) { }
#endif /* CONFIG_BLK_CGROUP */
/*
* bio_set is used to allow other portions of the IO system to
* allocate their own private memory pools for bio and iovec structures.

10
include/linux/blk_types.h
View File

@ -14,6 +14,8 @@ struct bio;
struct bio_integrity_payload;
struct page;
struct block_device;
struct io_context;
struct cgroup_subsys_state;
typedef void (bio_end_io_t) (struct bio *, int);
typedef void (bio_destructor_t) (struct bio *);
@ -66,6 +68,14 @@ struct bio {
bio_end_io_t *bi_end_io;
void *bi_private;
#ifdef CONFIG_BLK_CGROUP
/*
* Optional ioc and css associated with this bio. Put on bio
* release. Read comment on top of bio_associate_current().
*/
struct io_context *bi_ioc;
struct cgroup_subsys_state *bi_css;
#endif
#if defined(CONFIG_BLK_DEV_INTEGRITY)
struct bio_integrity_payload *bi_integrity; /* data integrity */
#endif

20
include/linux/blkdev.h
View File

@ -32,10 +32,17 @@ struct blk_trace;
struct request;
struct sg_io_hdr;
struct bsg_job;
struct blkcg_gq;
#define BLKDEV_MIN_RQ 4
#define BLKDEV_MAX_RQ 128 /* Default maximum */
/*
* Maximum number of blkcg policies allowed to be registered concurrently.
* Defined here to simplify include dependency.
*/
#define BLKCG_MAX_POLS 2
struct request;
typedef void (rq_end_io_fn)(struct request *, int);
@ -363,6 +370,11 @@ struct request_queue {
struct list_head timeout_list;
struct list_head icq_list;
#ifdef CONFIG_BLK_CGROUP
DECLARE_BITMAP (blkcg_pols, BLKCG_MAX_POLS);
struct blkcg_gq *root_blkg;
struct list_head blkg_list;
#endif
struct queue_limits limits;
@ -390,12 +402,17 @@ struct request_queue {
struct mutex sysfs_lock;
int bypass_depth;
#if defined(CONFIG_BLK_DEV_BSG)
bsg_job_fn *bsg_job_fn;
int bsg_job_size;
struct bsg_class_device bsg_dev;
#endif
#ifdef CONFIG_BLK_CGROUP
struct list_head all_q_node;
#endif
#ifdef CONFIG_BLK_DEV_THROTTLING
/* Throttle data */
struct throtl_data *td;
@ -407,7 +424,7 @@ struct request_queue {
#define QUEUE_FLAG_SYNCFULL 3 /* read queue has been filled */
#define QUEUE_FLAG_ASYNCFULL 4 /* write queue has been filled */
#define QUEUE_FLAG_DEAD 5 /* queue being torn down */
#define QUEUE_FLAG_ELVSWITCH 6 /* don't use elevator, just do FIFO */
#define QUEUE_FLAG_BYPASS 6 /* act as dumb FIFO queue */
#define QUEUE_FLAG_BIDI 7 /* queue supports bidi requests */
#define QUEUE_FLAG_NOMERGES 8 /* disable merge attempts */
#define QUEUE_FLAG_SAME_COMP 9 /* complete on same CPU-group */
@ -491,6 +508,7 @@ static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
#define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
#define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
#define blk_queue_dead(q) test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
#define blk_queue_bypass(q) test_bit(QUEUE_FLAG_BYPASS, &(q)->queue_flags)
#define blk_queue_nomerges(q) test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
#define blk_queue_noxmerges(q) \
test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)

8
include/linux/elevator.h
View File

@ -28,12 +28,13 @@ typedef int (elevator_may_queue_fn) (struct request_queue *, int);
typedef void (elevator_init_icq_fn) (struct io_cq *);
typedef void (elevator_exit_icq_fn) (struct io_cq *);
typedef int (elevator_set_req_fn) (struct request_queue *, struct request *, gfp_t);
typedef int (elevator_set_req_fn) (struct request_queue *, struct request *,
struct bio *, gfp_t);
typedef void (elevator_put_req_fn) (struct request *);
typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *);
typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *);
typedef void *(elevator_init_fn) (struct request_queue *);
typedef int (elevator_init_fn) (struct request_queue *);
typedef void (elevator_exit_fn) (struct elevator_queue *);
struct elevator_ops
@ -129,7 +130,8 @@ extern void elv_unregister_queue(struct request_queue *q);
extern int elv_may_queue(struct request_queue *, int);
extern void elv_abort_queue(struct request_queue *);
extern void elv_completed_request(struct request_queue *, struct request *);
extern int elv_set_request(struct request_queue *, struct request *, gfp_t);
extern int elv_set_request(struct request_queue *q, struct request *rq,
struct bio *bio, gfp_t gfp_mask);
extern void elv_put_request(struct request_queue *, struct request *);
extern void elv_drain_elevator(struct request_queue *);

39
include/linux/iocontext.h
View File

@ -6,11 +6,7 @@
#include <linux/workqueue.h>
enum {
ICQ_IOPRIO_CHANGED = 1 << 0,
ICQ_CGROUP_CHANGED = 1 << 1,
ICQ_EXITED = 1 << 2,
ICQ_CHANGED_MASK = ICQ_IOPRIO_CHANGED | ICQ_CGROUP_CHANGED,
};
/*
@ -100,6 +96,7 @@ struct io_cq {
*/
struct io_context {
atomic_long_t refcount;
atomic_t active_ref;
atomic_t nr_tasks;
/* all the fields below are protected by this lock */
@ -120,29 +117,37 @@ struct io_context {
struct work_struct release_work;
};
static inline struct io_context *ioc_task_link(struct io_context *ioc)
/**
* get_io_context_active - get active reference on ioc
* @ioc: ioc of interest
*
* Only iocs with active reference can issue new IOs. This function
* acquires an active reference on @ioc. The caller must already have an
* active reference on @ioc.
*/
static inline void get_io_context_active(struct io_context *ioc)
{
/*
* if ref count is zero, don't allow sharing (ioc is going away, it's
* a race).
*/
if (ioc && atomic_long_inc_not_zero(&ioc->refcount)) {
atomic_inc(&ioc->nr_tasks);
return ioc;
}
WARN_ON_ONCE(atomic_long_read(&ioc->refcount) <= 0);
WARN_ON_ONCE(atomic_read(&ioc->active_ref) <= 0);
atomic_long_inc(&ioc->refcount);
atomic_inc(&ioc->active_ref);
}
return NULL;
static inline void ioc_task_link(struct io_context *ioc)
{
get_io_context_active(ioc);
WARN_ON_ONCE(atomic_read(&ioc->nr_tasks) <= 0);
atomic_inc(&ioc->nr_tasks);
}
struct task_struct;
#ifdef CONFIG_BLOCK
void put_io_context(struct io_context *ioc);
void put_io_context_active(struct io_context *ioc);
void exit_io_context(struct task_struct *task);
struct io_context *get_task_io_context(struct task_struct *task,
gfp_t gfp_flags, int node);
void ioc_ioprio_changed(struct io_context *ioc, int ioprio);
void ioc_cgroup_changed(struct io_context *ioc);
unsigned int icq_get_changed(struct io_cq *icq);
#else
struct io_context;
static inline void put_io_context(struct io_context *ioc) { }

22
include/linux/ioprio.h
View File

@ -41,27 +41,15 @@ enum {
IOPRIO_WHO_USER,
};
/*
* Fallback BE priority
*/
#define IOPRIO_NORM (4)
/*
* if process has set io priority explicitly, use that. if not, convert
* the cpu scheduler nice value to an io priority
*/
#define IOPRIO_NORM (4)
static inline int task_ioprio(struct io_context *ioc)
{
if (ioprio_valid(ioc->ioprio))
return IOPRIO_PRIO_DATA(ioc->ioprio);
return IOPRIO_NORM;
}
static inline int task_ioprio_class(struct io_context *ioc)
{
if (ioprio_valid(ioc->ioprio))
return IOPRIO_PRIO_CLASS(ioc->ioprio);
return IOPRIO_CLASS_BE;
}
static inline int task_nice_ioprio(struct task_struct *task)
{
return (task_nice(task) + 20) / 5;

2
init/Kconfig
View File

@ -803,7 +803,7 @@ config RT_GROUP_SCHED
endif #CGROUP_SCHED
config BLK_CGROUP
tristate "Block IO controller"
bool "Block IO controller"
depends on BLOCK
default n
---help---

5
kernel/fork.c
View File

@ -976,9 +976,8 @@ static int copy_io(unsigned long clone_flags, struct task_struct *tsk)
* Share io context with parent, if CLONE_IO is set
*/
if (clone_flags & CLONE_IO) {
tsk->io_context = ioc_task_link(ioc);
if (unlikely(!tsk->io_context))
return -ENOMEM;
ioc_task_link(ioc);
tsk->io_context = ioc;
} else if (ioprio_valid(ioc->ioprio)) {
new_ioc = get_task_io_context(tsk, GFP_KERNEL, NUMA_NO_NODE);
if (unlikely(!new_ioc))