#include <linux/ioprio.h>
#include <linux/kdev_t.h>
#include <linux/module.h>
#include <linux/sched/signal.h>
#include <linux/err.h>
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/slab.h>
#include <linux/genhd.h>
#include <linux/delay.h>
#include <linux/atomic.h>
#include <linux/ctype.h>
#include <linux/blk-cgroup.h>
#include <linux/tracehook.h>
#include <linux/psi.h>
#include "blk.h"
#define MAX_KEY_LEN 100
static DEFINE_MUTEX(blkcg_pol_register_mutex);
static DEFINE_MUTEX(blkcg_pol_mutex);
struct blkcg blkcg_root;
EXPORT_SYMBOL_GPL(blkcg_root);
struct cgroup_subsys_state * const blkcg_root_css = &blkcg_root.css;
EXPORT_SYMBOL_GPL(blkcg_root_css);
static struct blkcg_policy *blkcg_policy[BLKCG_MAX_POLS];
static LIST_HEAD(all_blkcgs);
bool blkcg_debug_stats = false;
static struct workqueue_struct *blkcg_punt_bio_wq;
static bool blkcg_policy_enabled(struct request_queue *q,
const struct blkcg_policy *pol)
{
return pol && test_bit(pol->plid, q->blkcg_pols);
}
static void blkg_free(struct blkcg_gq *blkg)
{
int i;
if (!blkg)
return;
for (i = 0; i < BLKCG_MAX_POLS; i++)
if (blkg->pd[i])
blkcg_policy[i]->pd_free_fn(blkg->pd[i]);
free_percpu(blkg->iostat_cpu);
percpu_ref_exit(&blkg->refcnt);
kfree(blkg);
}
static void __blkg_release(struct rcu_head *rcu)
{
struct blkcg_gq *blkg = container_of(rcu, struct blkcg_gq, rcu_head);
WARN_ON(!bio_list_empty(&blkg->async_bios));
css_put(&blkg->blkcg->css);
if (blkg->parent)
blkg_put(blkg->parent);
blkg_free(blkg);
}
static void blkg_release(struct percpu_ref *ref)
{
struct blkcg_gq *blkg = container_of(ref, struct blkcg_gq, refcnt);
call_rcu(&blkg->rcu_head, __blkg_release);
}
static void blkg_async_bio_workfn(struct work_struct *work)
{
struct blkcg_gq *blkg = container_of(work, struct blkcg_gq,
async_bio_work);
struct bio_list bios = BIO_EMPTY_LIST;
struct bio *bio;
struct blk_plug plug;
bool need_plug = false;
spin_lock_bh(&blkg->async_bio_lock);
bio_list_merge(&bios, &blkg->async_bios);
bio_list_init(&blkg->async_bios);
spin_unlock_bh(&blkg->async_bio_lock);
if (bios.head && bios.head->bi_next) {
need_plug = true;
blk_start_plug(&plug);
}
while ((bio = bio_list_pop(&bios)))
submit_bio(bio);
if (need_plug)
blk_finish_plug(&plug);
}
static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct request_queue *q,
gfp_t gfp_mask)
{
struct blkcg_gq *blkg;
int i, cpu;
blkg = kzalloc_node(sizeof(*blkg), gfp_mask, q->node);
if (!blkg)
return NULL;
if (percpu_ref_init(&blkg->refcnt, blkg_release, 0, gfp_mask))
goto err_free;
blkg->iostat_cpu = alloc_percpu_gfp(struct blkg_iostat_set, gfp_mask);
if (!blkg->iostat_cpu)
goto err_free;
blkg->q = q;
INIT_LIST_HEAD(&blkg->q_node);
spin_lock_init(&blkg->async_bio_lock);
bio_list_init(&blkg->async_bios);
INIT_WORK(&blkg->async_bio_work, blkg_async_bio_workfn);
blkg->blkcg = blkcg;
u64_stats_init(&blkg->iostat.sync);
for_each_possible_cpu(cpu)
u64_stats_init(&per_cpu_ptr(blkg->iostat_cpu, cpu)->sync);
for (i = 0; i < BLKCG_MAX_POLS; i++) {
struct blkcg_policy *pol = blkcg_policy[i];
struct blkg_policy_data *pd;
if (!blkcg_policy_enabled(q, pol))
continue;
pd = pol->pd_alloc_fn(gfp_mask, q, blkcg);
if (!pd)
goto err_free;
blkg->pd[i] = pd;
pd->blkg = blkg;
pd->plid = i;
}
return blkg;
err_free:
blkg_free(blkg);
return NULL;
}
struct blkcg_gq *blkg_lookup_slowpath(struct blkcg *blkcg,
struct request_queue *q, bool update_hint)
{
struct blkcg_gq *blkg;
blkg = radix_tree_lookup(&blkcg->blkg_tree, q->id);
if (blkg && blkg->q == q) {
if (update_hint) {
lockdep_assert_held(&q->queue_lock);
rcu_assign_pointer(blkcg->blkg_hint, blkg);
}
return blkg;
}
return NULL;
}
EXPORT_SYMBOL_GPL(blkg_lookup_slowpath);
static struct blkcg_gq *blkg_create(struct blkcg *blkcg,
struct request_queue *q,
struct blkcg_gq *new_blkg)
{
struct blkcg_gq *blkg;
int i, ret;
WARN_ON_ONCE(!rcu_read_lock_held());
lockdep_assert_held(&q->queue_lock);
if (blk_queue_dying(q)) {
ret = -ENODEV;
goto err_free_blkg;
}
if (!css_tryget_online(&blkcg->css)) {
ret = -ENODEV;
goto err_free_blkg;
}
if (!new_blkg) {
new_blkg = blkg_alloc(blkcg, q, GFP_NOWAIT | __GFP_NOWARN);
if (unlikely(!new_blkg)) {
ret = -ENOMEM;
goto err_put_css;
}
}
blkg = new_blkg;
if (blkcg_parent(blkcg)) {
blkg->parent = __blkg_lookup(blkcg_parent(blkcg), q, false);
if (WARN_ON_ONCE(!blkg->parent)) {
ret = -ENODEV;
goto err_put_css;
}
blkg_get(blkg->parent);
}
for (i = 0; i < BLKCG_MAX_POLS; i++) {
struct blkcg_policy *pol = blkcg_policy[i];
if (blkg->pd[i] && pol->pd_init_fn)
pol->pd_init_fn(blkg->pd[i]);
}
spin_lock(&blkcg->lock);
ret = radix_tree_insert(&blkcg->blkg_tree, q->id, blkg);
if (likely(!ret)) {
hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);
list_add(&blkg->q_node, &q->blkg_list);
for (i = 0; i < BLKCG_MAX_POLS; i++) {
struct blkcg_policy *pol = blkcg_policy[i];
if (blkg->pd[i] && pol->pd_online_fn)
pol->pd_online_fn(blkg->pd[i]);
}
}
blkg->online = true;
spin_unlock(&blkcg->lock);
if (!ret)
return blkg;
blkg_put(blkg);
return ERR_PTR(ret);
err_put_css:
css_put(&blkcg->css);
err_free_blkg:
blkg_free(new_blkg);
return ERR_PTR(ret);
}
static struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
struct request_queue *q)
{
struct blkcg_gq *blkg;
unsigned long flags;
WARN_ON_ONCE(!rcu_read_lock_held());
blkg = blkg_lookup(blkcg, q);
if (blkg)
return blkg;
spin_lock_irqsave(&q->queue_lock, flags);
blkg = __blkg_lookup(blkcg, q, true);
if (blkg)
goto found;
while (true) {
struct blkcg *pos = blkcg;
struct blkcg *parent = blkcg_parent(blkcg);
struct blkcg_gq *ret_blkg = q->root_blkg;
while (parent) {
blkg = __blkg_lookup(parent, q, false);
if (blkg) {
ret_blkg = blkg;
break;
}
pos = parent;
parent = blkcg_parent(parent);
}
blkg = blkg_create(pos, q, NULL);
if (IS_ERR(blkg)) {
blkg = ret_blkg;
break;
}
if (pos == blkcg)
break;
}
found:
spin_unlock_irqrestore(&q->queue_lock, flags);
return blkg;
}
static void blkg_destroy(struct blkcg_gq *blkg)
{
struct blkcg *blkcg = blkg->blkcg;
int i;
lockdep_assert_held(&blkg->q->queue_lock);
lockdep_assert_held(&blkcg->lock);
WARN_ON_ONCE(list_empty(&blkg->q_node));
WARN_ON_ONCE(hlist_unhashed(&blkg->blkcg_node));
for (i = 0; i < BLKCG_MAX_POLS; i++) {
struct blkcg_policy *pol = blkcg_policy[i];
if (blkg->pd[i] && pol->pd_offline_fn)
pol->pd_offline_fn(blkg->pd[i]);
}
blkg->online = false;
radix_tree_delete(&blkcg->blkg_tree, blkg->q->id);
list_del_init(&blkg->q_node);
hlist_del_init_rcu(&blkg->blkcg_node);
if (rcu_access_pointer(blkcg->blkg_hint) == blkg)
rcu_assign_pointer(blkcg->blkg_hint, NULL);
percpu_ref_kill(&blkg->refcnt);
}
static void blkg_destroy_all(struct request_queue *q)
{
struct blkcg_gq *blkg, *n;
spin_lock_irq(&q->queue_lock);
list_for_each_entry_safe(blkg, n, &q->blkg_list, q_node) {
struct blkcg *blkcg = blkg->blkcg;
spin_lock(&blkcg->lock);
blkg_destroy(blkg);
spin_unlock(&blkcg->lock);
}
q->root_blkg = NULL;
spin_unlock_irq(&q->queue_lock);
}
static int blkcg_reset_stats(struct cgroup_subsys_state *css,
struct cftype *cftype, u64 val)
{
struct blkcg *blkcg = css_to_blkcg(css);
struct blkcg_gq *blkg;
int i, cpu;
mutex_lock(&blkcg_pol_mutex);
spin_lock_irq(&blkcg->lock);
hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) {
for_each_possible_cpu(cpu) {
struct blkg_iostat_set *bis =
per_cpu_ptr(blkg->iostat_cpu, cpu);
memset(bis, 0, sizeof(*bis));
}
memset(&blkg->iostat, 0, sizeof(blkg->iostat));
for (i = 0; i < BLKCG_MAX_POLS; i++) {
struct blkcg_policy *pol = blkcg_policy[i];
if (blkg->pd[i] && pol->pd_reset_stats_fn)
pol->pd_reset_stats_fn(blkg->pd[i]);
}
}
spin_unlock_irq(&blkcg->lock);
mutex_unlock(&blkcg_pol_mutex);
return 0;
}
const char *blkg_dev_name(struct blkcg_gq *blkg)
{
if (blkg->q->backing_dev_info->dev)
return bdi_dev_name(blkg->q->backing_dev_info);
return NULL;
}
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)
{
struct blkcg_gq *blkg;
u64 total = 0;
rcu_read_lock();
hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) {
spin_lock_irq(&blkg->q->queue_lock);
if (blkcg_policy_enabled(blkg->q, pol))
total += prfill(sf, blkg->pd[pol->plid], data);
spin_unlock_irq(&blkg->q->queue_lock);
}
rcu_read_unlock();
if (show_total)
seq_printf(sf, "Total %llu\n", (unsigned long long)total);
}
EXPORT_SYMBOL_GPL(blkcg_print_blkgs);
u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v)
{
const char *dname = blkg_dev_name(pd->blkg);
if (!dname)
return 0;
seq_printf(sf, "%s %llu\n", dname, (unsigned long long)v);
return v;
}
EXPORT_SYMBOL_GPL(__blkg_prfill_u64);
static struct blkcg_gq *blkg_lookup_check(struct blkcg *blkcg,
const struct blkcg_policy *pol,
struct request_queue *q)
{
WARN_ON_ONCE(!rcu_read_lock_held());
lockdep_assert_held(&q->queue_lock);
if (!blkcg_policy_enabled(q, pol))
return ERR_PTR(-EOPNOTSUPP);
return __blkg_lookup(blkcg, q, true );
}
struct block_device *blkcg_conf_open_bdev(char **inputp)
{
char *input = *inputp;
unsigned int major, minor;
struct block_device *bdev;
int key_len;
if (sscanf(input, "%u:%u%n", &major, &minor, &key_len) != 2)
return ERR_PTR(-EINVAL);
input += key_len;
if (!isspace(*input))
return ERR_PTR(-EINVAL);
input = skip_spaces(input);
bdev = blkdev_get_no_open(MKDEV(major, minor));
if (!bdev)
return ERR_PTR(-ENODEV);
if (bdev_is_partition(bdev)) {
blkdev_put_no_open(bdev);
return ERR_PTR(-ENODEV);
}
*inputp = input;
return bdev;
}
int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
char *input, struct blkg_conf_ctx *ctx)
__acquires(rcu) __acquires(&bdev->bd_disk->queue->queue_lock)
{
struct block_device *bdev;
struct request_queue *q;
struct blkcg_gq *blkg;
int ret;
bdev = blkcg_conf_open_bdev(&input);
if (IS_ERR(bdev))
return PTR_ERR(bdev);
q = bdev->bd_disk->queue;
rcu_read_lock();
spin_lock_irq(&q->queue_lock);
blkg = blkg_lookup_check(blkcg, pol, q);
if (IS_ERR(blkg)) {
ret = PTR_ERR(blkg);
goto fail_unlock;
}
if (blkg)
goto success;
while (true) {
struct blkcg *pos = blkcg;
struct blkcg *parent;
struct blkcg_gq *new_blkg;
parent = blkcg_parent(blkcg);
while (parent && !__blkg_lookup(parent, q, false)) {
pos = parent;
parent = blkcg_parent(parent);
}
spin_unlock_irq(&q->queue_lock);
rcu_read_unlock();
new_blkg = blkg_alloc(pos, q, GFP_KERNEL);
if (unlikely(!new_blkg)) {
ret = -ENOMEM;
goto fail;
}
if (radix_tree_preload(GFP_KERNEL)) {
blkg_free(new_blkg);
ret = -ENOMEM;
goto fail;
}
rcu_read_lock();
spin_lock_irq(&q->queue_lock);
blkg = blkg_lookup_check(pos, pol, q);
if (IS_ERR(blkg)) {
ret = PTR_ERR(blkg);
blkg_free(new_blkg);
goto fail_preloaded;
}
if (blkg) {
blkg_free(new_blkg);
} else {
blkg = blkg_create(pos, q, new_blkg);
if (IS_ERR(blkg)) {
ret = PTR_ERR(blkg);
goto fail_preloaded;
}
}
radix_tree_preload_end();
if (pos == blkcg)
goto success;
}
success:
ctx->bdev = bdev;
ctx->blkg = blkg;
ctx->body = input;
return 0;
fail_preloaded:
radix_tree_preload_end();
fail_unlock:
spin_unlock_irq(&q->queue_lock);
rcu_read_unlock();
fail:
blkdev_put_no_open(bdev);
if (ret == -EBUSY) {
msleep(10);
ret = restart_syscall();
}
return ret;
}
EXPORT_SYMBOL_GPL(blkg_conf_prep);
void blkg_conf_finish(struct blkg_conf_ctx *ctx)
__releases(&ctx->bdev->bd_disk->queue->queue_lock) __releases(rcu)
{
spin_unlock_irq(&ctx->bdev->bd_disk->queue->queue_lock);
rcu_read_unlock();
blkdev_put_no_open(ctx->bdev);
}
EXPORT_SYMBOL_GPL(blkg_conf_finish);
static void blkg_iostat_set(struct blkg_iostat *dst, struct blkg_iostat *src)
{
int i;
for (i = 0; i < BLKG_IOSTAT_NR; i++) {
dst->bytes[i] = src->bytes[i];
dst->ios[i] = src->ios[i];
}
}
static void blkg_iostat_add(struct blkg_iostat *dst, struct blkg_iostat *src)
{
int i;
for (i = 0; i < BLKG_IOSTAT_NR; i++) {
dst->bytes[i] += src->bytes[i];
dst->ios[i] += src->ios[i];
}
}
static void blkg_iostat_sub(struct blkg_iostat *dst, struct blkg_iostat *src)
{
int i;
for (i = 0; i < BLKG_IOSTAT_NR; i++) {
dst->bytes[i] -= src->bytes[i];
dst->ios[i] -= src->ios[i];
}
}
static void blkcg_rstat_flush(struct cgroup_subsys_state *css, int cpu)
{
struct blkcg *blkcg = css_to_blkcg(css);
struct blkcg_gq *blkg;
rcu_read_lock();
hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) {
struct blkcg_gq *parent = blkg->parent;
struct blkg_iostat_set *bisc = per_cpu_ptr(blkg->iostat_cpu, cpu);
struct blkg_iostat cur, delta;
unsigned int seq;
do {
seq = u64_stats_fetch_begin(&bisc->sync);
blkg_iostat_set(&cur, &bisc->cur);
} while (u64_stats_fetch_retry(&bisc->sync, seq));
u64_stats_update_begin(&blkg->iostat.sync);
blkg_iostat_set(&delta, &cur);
blkg_iostat_sub(&delta, &bisc->last);
blkg_iostat_add(&blkg->iostat.cur, &delta);
blkg_iostat_add(&bisc->last, &delta);
u64_stats_update_end(&blkg->iostat.sync);
if (parent) {
u64_stats_update_begin(&parent->iostat.sync);
blkg_iostat_set(&delta, &blkg->iostat.cur);
blkg_iostat_sub(&delta, &blkg->iostat.last);
blkg_iostat_add(&parent->iostat.cur, &delta);
blkg_iostat_add(&blkg->iostat.last, &delta);
u64_stats_update_end(&parent->iostat.sync);
}
}
rcu_read_unlock();
}
static void blkcg_fill_root_iostats(void)
{
struct class_dev_iter iter;
struct device *dev;
class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
while ((dev = class_dev_iter_next(&iter))) {
struct block_device *bdev = dev_to_bdev(dev);
struct blkcg_gq *blkg =
blk_queue_root_blkg(bdev->bd_disk->queue);
struct blkg_iostat tmp;
int cpu;
memset(&tmp, 0, sizeof(tmp));
for_each_possible_cpu(cpu) {
struct disk_stats *cpu_dkstats;
cpu_dkstats = per_cpu_ptr(bdev->bd_stats, cpu);
tmp.ios[BLKG_IOSTAT_READ] +=
cpu_dkstats->ios[STAT_READ];
tmp.ios[BLKG_IOSTAT_WRITE] +=
cpu_dkstats->ios[STAT_WRITE];
tmp.ios[BLKG_IOSTAT_DISCARD] +=
cpu_dkstats->ios[STAT_DISCARD];
tmp.bytes[BLKG_IOSTAT_READ] +=
cpu_dkstats->sectors[STAT_READ] << 9;
tmp.bytes[BLKG_IOSTAT_WRITE] +=
cpu_dkstats->sectors[STAT_WRITE] << 9;
tmp.bytes[BLKG_IOSTAT_DISCARD] +=
cpu_dkstats->sectors[STAT_DISCARD] << 9;
u64_stats_update_begin(&blkg->iostat.sync);
blkg_iostat_set(&blkg->iostat.cur, &tmp);
u64_stats_update_end(&blkg->iostat.sync);
}
}
}
static int blkcg_print_stat(struct seq_file *sf, void *v)
{
struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
struct blkcg_gq *blkg;
if (!seq_css(sf)->parent)
blkcg_fill_root_iostats();
else
cgroup_rstat_flush(blkcg->css.cgroup);
rcu_read_lock();
hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) {
struct blkg_iostat_set *bis = &blkg->iostat;
const char *dname;
char *buf;
u64 rbytes, wbytes, rios, wios, dbytes, dios;
size_t size = seq_get_buf(sf, &buf), off = 0;
int i;
bool has_stats = false;
unsigned seq;
spin_lock_irq(&blkg->q->queue_lock);
if (!blkg->online)
goto skip;
dname = blkg_dev_name(blkg);
if (!dname)
goto skip;
off += scnprintf(buf+off, size-off, "%s ", dname);
do {
seq = u64_stats_fetch_begin(&bis->sync);
rbytes = bis->cur.bytes[BLKG_IOSTAT_READ];
wbytes = bis->cur.bytes[BLKG_IOSTAT_WRITE];
dbytes = bis->cur.bytes[BLKG_IOSTAT_DISCARD];
rios = bis->cur.ios[BLKG_IOSTAT_READ];
wios = bis->cur.ios[BLKG_IOSTAT_WRITE];
dios = bis->cur.ios[BLKG_IOSTAT_DISCARD];
} while (u64_stats_fetch_retry(&bis->sync, seq));
if (rbytes || wbytes || rios || wios) {
has_stats = true;
off += scnprintf(buf+off, size-off,
"rbytes=%llu wbytes=%llu rios=%llu wios=%llu dbytes=%llu dios=%llu",
rbytes, wbytes, rios, wios,
dbytes, dios);
}
if (blkcg_debug_stats && atomic_read(&blkg->use_delay)) {
has_stats = true;
off += scnprintf(buf+off, size-off,
" use_delay=%d delay_nsec=%llu",
atomic_read(&blkg->use_delay),
(unsigned long long)atomic64_read(&blkg->delay_nsec));
}
for (i = 0; i < BLKCG_MAX_POLS; i++) {
struct blkcg_policy *pol = blkcg_policy[i];
size_t written;
if (!blkg->pd[i] || !pol->pd_stat_fn)
continue;
written = pol->pd_stat_fn(blkg->pd[i], buf+off, size-off);
if (written)
has_stats = true;
off += written;
}
if (has_stats) {
if (off < size - 1) {
off += scnprintf(buf+off, size-off, "\n");
seq_commit(sf, off);
} else {
seq_commit(sf, -1);
}
}
skip:
spin_unlock_irq(&blkg->q->queue_lock);
}
rcu_read_unlock();
return 0;
}
static struct cftype blkcg_files[] = {
{
.name = "stat",
.seq_show = blkcg_print_stat,
},
{ }
};
static struct cftype blkcg_legacy_files[] = {
{
.name = "reset_stats",
.write_u64 = blkcg_reset_stats,
},
{ }
};
static void blkcg_css_offline(struct cgroup_subsys_state *css)
{
struct blkcg *blkcg = css_to_blkcg(css);
wb_blkcg_offline(blkcg);
blkcg_unpin_online(blkcg);
}
void blkcg_destroy_blkgs(struct blkcg *blkcg)
{
spin_lock_irq(&blkcg->lock);
while (!hlist_empty(&blkcg->blkg_list)) {
struct blkcg_gq *blkg = hlist_entry(blkcg->blkg_list.first,
struct blkcg_gq, blkcg_node);
struct request_queue *q = blkg->q;
if (spin_trylock(&q->queue_lock)) {
blkg_destroy(blkg);
spin_unlock(&q->queue_lock);
} else {
spin_unlock_irq(&blkcg->lock);
cpu_relax();
spin_lock_irq(&blkcg->lock);
}
}
spin_unlock_irq(&blkcg->lock);
}
static void blkcg_css_free(struct cgroup_subsys_state *css)
{
struct blkcg *blkcg = css_to_blkcg(css);
int i;
mutex_lock(&blkcg_pol_mutex);
list_del(&blkcg->all_blkcgs_node);
for (i = 0; i < BLKCG_MAX_POLS; i++)
if (blkcg->cpd[i])
blkcg_policy[i]->cpd_free_fn(blkcg->cpd[i]);
mutex_unlock(&blkcg_pol_mutex);
kfree(blkcg);
}
static struct cgroup_subsys_state *
blkcg_css_alloc(struct cgroup_subsys_state *parent_css)
{
struct blkcg *blkcg;
struct cgroup_subsys_state *ret;
int i;
mutex_lock(&blkcg_pol_mutex);
if (!parent_css) {
blkcg = &blkcg_root;
} else {
blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL);
if (!blkcg) {
ret = ERR_PTR(-ENOMEM);
goto unlock;
}
}
for (i = 0; i < BLKCG_MAX_POLS ; i++) {
struct blkcg_policy *pol = blkcg_policy[i];
struct blkcg_policy_data *cpd;
if (!pol || !pol->cpd_alloc_fn)
continue;
cpd = pol->cpd_alloc_fn(GFP_KERNEL);
if (!cpd) {
ret = ERR_PTR(-ENOMEM);
goto free_pd_blkcg;
}
blkcg->cpd[i] = cpd;
cpd->blkcg = blkcg;
cpd->plid = i;
if (pol->cpd_init_fn)
pol->cpd_init_fn(cpd);
}
spin_lock_init(&blkcg->lock);
refcount_set(&blkcg->online_pin, 1);
INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_NOWAIT | __GFP_NOWARN);
INIT_HLIST_HEAD(&blkcg->blkg_list);
#ifdef CONFIG_CGROUP_WRITEBACK
INIT_LIST_HEAD(&blkcg->cgwb_list);
#endif
list_add_tail(&blkcg->all_blkcgs_node, &all_blkcgs);
mutex_unlock(&blkcg_pol_mutex);
return &blkcg->css;
free_pd_blkcg:
for (i--; i >= 0; i--)
if (blkcg->cpd[i])
blkcg_policy[i]->cpd_free_fn(blkcg->cpd[i]);
if (blkcg != &blkcg_root)
kfree(blkcg);
unlock:
mutex_unlock(&blkcg_pol_mutex);
return ret;
}
static int blkcg_css_online(struct cgroup_subsys_state *css)
{
struct blkcg *blkcg = css_to_blkcg(css);
struct blkcg *parent = blkcg_parent(blkcg);
if (parent)
blkcg_pin_online(parent);
return 0;
}
int blkcg_init_queue(struct request_queue *q)
{
struct blkcg_gq *new_blkg, *blkg;
bool preloaded;
int ret;
new_blkg = blkg_alloc(&blkcg_root, q, GFP_KERNEL);
if (!new_blkg)
return -ENOMEM;
preloaded = !radix_tree_preload(GFP_KERNEL);
rcu_read_lock();
spin_lock_irq(&q->queue_lock);
blkg = blkg_create(&blkcg_root, q, new_blkg);
if (IS_ERR(blkg))
goto err_unlock;
q->root_blkg = blkg;
spin_unlock_irq(&q->queue_lock);
rcu_read_unlock();
if (preloaded)
radix_tree_preload_end();
ret = blk_throtl_init(q);
if (ret)
goto err_destroy_all;
ret = blk_iolatency_init(q);
if (ret) {
blk_throtl_exit(q);
goto err_destroy_all;
}
return 0;
err_destroy_all:
blkg_destroy_all(q);
return ret;
err_unlock:
spin_unlock_irq(&q->queue_lock);
rcu_read_unlock();
if (preloaded)
radix_tree_preload_end();
return PTR_ERR(blkg);
}
void blkcg_exit_queue(struct request_queue *q)
{
blkg_destroy_all(q);
blk_throtl_exit(q);
}
static int blkcg_can_attach(struct cgroup_taskset *tset)
{
struct task_struct *task;
struct cgroup_subsys_state *dst_css;
struct io_context *ioc;
int ret = 0;
cgroup_taskset_for_each(task, dst_css, tset) {
task_lock(task);
ioc = task->io_context;
if (ioc && atomic_read(&ioc->nr_tasks) > 1)
ret = -EINVAL;
task_unlock(task);
if (ret)
break;
}
return ret;
}
static void blkcg_bind(struct cgroup_subsys_state *root_css)
{
int i;
mutex_lock(&blkcg_pol_mutex);
for (i = 0; i < BLKCG_MAX_POLS; i++) {
struct blkcg_policy *pol = blkcg_policy[i];
struct blkcg *blkcg;
if (!pol || !pol->cpd_bind_fn)
continue;
list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node)
if (blkcg->cpd[pol->plid])
pol->cpd_bind_fn(blkcg->cpd[pol->plid]);
}
mutex_unlock(&blkcg_pol_mutex);
}
static void blkcg_exit(struct task_struct *tsk)
{
if (tsk->throttle_queue)
blk_put_queue(tsk->throttle_queue);
tsk->throttle_queue = NULL;
}
struct cgroup_subsys io_cgrp_subsys = {
.css_alloc = blkcg_css_alloc,
.css_online = blkcg_css_online,
.css_offline = blkcg_css_offline,
.css_free = blkcg_css_free,
.can_attach = blkcg_can_attach,
.css_rstat_flush = blkcg_rstat_flush,
.bind = blkcg_bind,
.dfl_cftypes = blkcg_files,
.legacy_cftypes = blkcg_legacy_files,
.legacy_name = "blkio",
.exit = blkcg_exit,
#ifdef CONFIG_MEMCG
.depends_on = 1 << memory_cgrp_id,
#endif
};
EXPORT_SYMBOL_GPL(io_cgrp_subsys);
int blkcg_activate_policy(struct request_queue *q,
const struct blkcg_policy *pol)
{
struct blkg_policy_data *pd_prealloc = NULL;
struct blkcg_gq *blkg, *pinned_blkg = NULL;
int ret;
if (blkcg_policy_enabled(q, pol))
return 0;
if (queue_is_mq(q))
blk_mq_freeze_queue(q);
retry:
spin_lock_irq(&q->queue_lock);
list_for_each_entry_reverse(blkg, &q->blkg_list, q_node) {
struct blkg_policy_data *pd;
if (blkg->pd[pol->plid])
continue;
if (blkg == pinned_blkg) {
pd = pd_prealloc;
pd_prealloc = NULL;
} else {
pd = pol->pd_alloc_fn(GFP_NOWAIT | __GFP_NOWARN, q,
blkg->blkcg);
}
if (!pd) {
if (pinned_blkg)
blkg_put(pinned_blkg);
blkg_get(blkg);
pinned_blkg = blkg;
spin_unlock_irq(&q->queue_lock);
if (pd_prealloc)
pol->pd_free_fn(pd_prealloc);
pd_prealloc = pol->pd_alloc_fn(GFP_KERNEL, q,
blkg->blkcg);
if (pd_prealloc)
goto retry;
else
goto enomem;
}
blkg->pd[pol->plid] = pd;
pd->blkg = blkg;
pd->plid = pol->plid;
}
if (pol->pd_init_fn)
list_for_each_entry_reverse(blkg, &q->blkg_list, q_node)
pol->pd_init_fn(blkg->pd[pol->plid]);
__set_bit(pol->plid, q->blkcg_pols);
ret = 0;
spin_unlock_irq(&q->queue_lock);
out:
if (queue_is_mq(q))
blk_mq_unfreeze_queue(q);
if (pinned_blkg)
blkg_put(pinned_blkg);
if (pd_prealloc)
pol->pd_free_fn(pd_prealloc);
return ret;
enomem:
spin_lock_irq(&q->queue_lock);
list_for_each_entry(blkg, &q->blkg_list, q_node) {
if (blkg->pd[pol->plid]) {
pol->pd_free_fn(blkg->pd[pol->plid]);
blkg->pd[pol->plid] = NULL;
}
}
spin_unlock_irq(&q->queue_lock);
ret = -ENOMEM;
goto out;
}
EXPORT_SYMBOL_GPL(blkcg_activate_policy);
void blkcg_deactivate_policy(struct request_queue *q,
const struct blkcg_policy *pol)
{
struct blkcg_gq *blkg;
if (!blkcg_policy_enabled(q, pol))
return;
if (queue_is_mq(q))
blk_mq_freeze_queue(q);
spin_lock_irq(&q->queue_lock);
__clear_bit(pol->plid, q->blkcg_pols);
list_for_each_entry(blkg, &q->blkg_list, q_node) {
if (blkg->pd[pol->plid]) {
if (pol->pd_offline_fn)
pol->pd_offline_fn(blkg->pd[pol->plid]);
pol->pd_free_fn(blkg->pd[pol->plid]);
blkg->pd[pol->plid] = NULL;
}
}
spin_unlock_irq(&q->queue_lock);
if (queue_is_mq(q))
blk_mq_unfreeze_queue(q);
}
EXPORT_SYMBOL_GPL(blkcg_deactivate_policy);
int blkcg_policy_register(struct blkcg_policy *pol)
{
struct blkcg *blkcg;
int i, ret;
mutex_lock(&blkcg_pol_register_mutex);
mutex_lock(&blkcg_pol_mutex);
ret = -ENOSPC;
for (i = 0; i < BLKCG_MAX_POLS; i++)
if (!blkcg_policy[i])
break;
if (i >= BLKCG_MAX_POLS) {
pr_warn("blkcg_policy_register: BLKCG_MAX_POLS too small\n");
goto err_unlock;
}
if ((!pol->cpd_alloc_fn ^ !pol->cpd_free_fn) ||
(!pol->pd_alloc_fn ^ !pol->pd_free_fn))
goto err_unlock;
pol->plid = i;
blkcg_policy[pol->plid] = pol;
if (pol->cpd_alloc_fn) {
list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) {
struct blkcg_policy_data *cpd;
cpd = pol->cpd_alloc_fn(GFP_KERNEL);
if (!cpd)
goto err_free_cpds;
blkcg->cpd[pol->plid] = cpd;
cpd->blkcg = blkcg;
cpd->plid = pol->plid;
if (pol->cpd_init_fn)
pol->cpd_init_fn(cpd);
}
}
mutex_unlock(&blkcg_pol_mutex);
if (pol->dfl_cftypes)
WARN_ON(cgroup_add_dfl_cftypes(&io_cgrp_subsys,
pol->dfl_cftypes));
if (pol->legacy_cftypes)
WARN_ON(cgroup_add_legacy_cftypes(&io_cgrp_subsys,
pol->legacy_cftypes));
mutex_unlock(&blkcg_pol_register_mutex);
return 0;
err_free_cpds:
if (pol->cpd_free_fn) {
list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) {
if (blkcg->cpd[pol->plid]) {
pol->cpd_free_fn(blkcg->cpd[pol->plid]);
blkcg->cpd[pol->plid] = NULL;
}
}
}
blkcg_policy[pol->plid] = NULL;
err_unlock:
mutex_unlock(&blkcg_pol_mutex);
mutex_unlock(&blkcg_pol_register_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(blkcg_policy_register);
void blkcg_policy_unregister(struct blkcg_policy *pol)
{
struct blkcg *blkcg;
mutex_lock(&blkcg_pol_register_mutex);
if (WARN_ON(blkcg_policy[pol->plid] != pol))
goto out_unlock;
if (pol->dfl_cftypes)
cgroup_rm_cftypes(pol->dfl_cftypes);
if (pol->legacy_cftypes)
cgroup_rm_cftypes(pol->legacy_cftypes);
mutex_lock(&blkcg_pol_mutex);
if (pol->cpd_free_fn) {
list_for_each_entry(blkcg, &all_blkcgs, all_blkcgs_node) {
if (blkcg->cpd[pol->plid]) {
pol->cpd_free_fn(blkcg->cpd[pol->plid]);
blkcg->cpd[pol->plid] = NULL;
}
}
}
blkcg_policy[pol->plid] = NULL;
mutex_unlock(&blkcg_pol_mutex);
out_unlock:
mutex_unlock(&blkcg_pol_register_mutex);
}
EXPORT_SYMBOL_GPL(blkcg_policy_unregister);
bool __blkcg_punt_bio_submit(struct bio *bio)
{
struct blkcg_gq *blkg = bio->bi_blkg;
bio->bi_opf &= ~REQ_CGROUP_PUNT;
if (!blkg->parent)
return false;
spin_lock_bh(&blkg->async_bio_lock);
bio_list_add(&blkg->async_bios, bio);
spin_unlock_bh(&blkg->async_bio_lock);
queue_work(blkcg_punt_bio_wq, &blkg->async_bio_work);
return true;
}
static void blkcg_scale_delay(struct blkcg_gq *blkg, u64 now)
{
u64 old = atomic64_read(&blkg->delay_start);
if (atomic_read(&blkg->use_delay) < 0)
return;
if (time_before64(old + NSEC_PER_SEC, now) &&
atomic64_cmpxchg(&blkg->delay_start, old, now) == old) {
u64 cur = atomic64_read(&blkg->delay_nsec);
u64 sub = min_t(u64, blkg->last_delay, now - old);
int cur_use = atomic_read(&blkg->use_delay);
if (cur_use < blkg->last_use)
sub = max_t(u64, sub, blkg->last_delay >> 1);
if (unlikely(cur < sub)) {
atomic64_set(&blkg->delay_nsec, 0);
blkg->last_delay = 0;
} else {
atomic64_sub(sub, &blkg->delay_nsec);
blkg->last_delay = cur - sub;
}
blkg->last_use = cur_use;
}
}
static void blkcg_maybe_throttle_blkg(struct blkcg_gq *blkg, bool use_memdelay)
{
unsigned long pflags;
bool clamp;
u64 now = ktime_to_ns(ktime_get());
u64 exp;
u64 delay_nsec = 0;
int tok;
while (blkg->parent) {
int use_delay = atomic_read(&blkg->use_delay);
if (use_delay) {
u64 this_delay;
blkcg_scale_delay(blkg, now);
this_delay = atomic64_read(&blkg->delay_nsec);
if (this_delay > delay_nsec) {
delay_nsec = this_delay;
clamp = use_delay > 0;
}
}
blkg = blkg->parent;
}
if (!delay_nsec)
return;
if (clamp)
delay_nsec = min_t(u64, delay_nsec, 250 * NSEC_PER_MSEC);
if (use_memdelay)
psi_memstall_enter(&pflags);
exp = ktime_add_ns(now, delay_nsec);
tok = io_schedule_prepare();
do {
__set_current_state(TASK_KILLABLE);
if (!schedule_hrtimeout(&exp, HRTIMER_MODE_ABS))
break;
} while (!fatal_signal_pending(current));
io_schedule_finish(tok);
if (use_memdelay)
psi_memstall_leave(&pflags);
}
void blkcg_maybe_throttle_current(void)
{
struct request_queue *q = current->throttle_queue;
struct cgroup_subsys_state *css;
struct blkcg *blkcg;
struct blkcg_gq *blkg;
bool use_memdelay = current->use_memdelay;
if (!q)
return;
current->throttle_queue = NULL;
current->use_memdelay = false;
rcu_read_lock();
css = kthread_blkcg();
if (css)
blkcg = css_to_blkcg(css);
else
blkcg = css_to_blkcg(task_css(current, io_cgrp_id));
if (!blkcg)
goto out;
blkg = blkg_lookup(blkcg, q);
if (!blkg)
goto out;
if (!blkg_tryget(blkg))
goto out;
rcu_read_unlock();
blkcg_maybe_throttle_blkg(blkg, use_memdelay);
blkg_put(blkg);
blk_put_queue(q);
return;
out:
rcu_read_unlock();
blk_put_queue(q);
}
void blkcg_schedule_throttle(struct request_queue *q, bool use_memdelay)
{
if (unlikely(current->flags & PF_KTHREAD))
return;
if (!blk_get_queue(q))
return;
if (current->throttle_queue)
blk_put_queue(current->throttle_queue);
current->throttle_queue = q;
if (use_memdelay)
current->use_memdelay = use_memdelay;
set_notify_resume(current);
}
void blkcg_add_delay(struct blkcg_gq *blkg, u64 now, u64 delta)
{
if (WARN_ON_ONCE(atomic_read(&blkg->use_delay) < 0))
return;
blkcg_scale_delay(blkg, now);
atomic64_add(delta, &blkg->delay_nsec);
}
static inline struct blkcg_gq *blkg_tryget_closest(struct bio *bio,
struct cgroup_subsys_state *css)
{
struct blkcg_gq *blkg, *ret_blkg = NULL;
rcu_read_lock();
blkg = blkg_lookup_create(css_to_blkcg(css), bio->bi_disk->queue);
while (blkg) {
if (blkg_tryget(blkg)) {
ret_blkg = blkg;
break;
}
blkg = blkg->parent;
}
rcu_read_unlock();
return ret_blkg;
}
void bio_associate_blkg_from_css(struct bio *bio,
struct cgroup_subsys_state *css)
{
if (bio->bi_blkg)
blkg_put(bio->bi_blkg);
if (css && css->parent) {
bio->bi_blkg = blkg_tryget_closest(bio, css);
} else {
blkg_get(bio->bi_disk->queue->root_blkg);
bio->bi_blkg = bio->bi_disk->queue->root_blkg;
}
}
EXPORT_SYMBOL_GPL(bio_associate_blkg_from_css);
void bio_associate_blkg(struct bio *bio)
{
struct cgroup_subsys_state *css;
rcu_read_lock();
if (bio->bi_blkg)
css = &bio_blkcg(bio)->css;
else
css = blkcg_css();
bio_associate_blkg_from_css(bio, css);
rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(bio_associate_blkg);
void bio_clone_blkg_association(struct bio *dst, struct bio *src)
{
if (src->bi_blkg) {
if (dst->bi_blkg)
blkg_put(dst->bi_blkg);
blkg_get(src->bi_blkg);
dst->bi_blkg = src->bi_blkg;
}
}
EXPORT_SYMBOL_GPL(bio_clone_blkg_association);
static int blk_cgroup_io_type(struct bio *bio)
{
if (op_is_discard(bio->bi_opf))
return BLKG_IOSTAT_DISCARD;
if (op_is_write(bio->bi_opf))
return BLKG_IOSTAT_WRITE;
return BLKG_IOSTAT_READ;
}
void blk_cgroup_bio_start(struct bio *bio)
{
int rwd = blk_cgroup_io_type(bio), cpu;
struct blkg_iostat_set *bis;
cpu = get_cpu();
bis = per_cpu_ptr(bio->bi_blkg->iostat_cpu, cpu);
u64_stats_update_begin(&bis->sync);
if (!bio_flagged(bio, BIO_CGROUP_ACCT)) {
bio_set_flag(bio, BIO_CGROUP_ACCT);
bis->cur.bytes[rwd] += bio->bi_iter.bi_size;
}
bis->cur.ios[rwd]++;
u64_stats_update_end(&bis->sync);
if (cgroup_subsys_on_dfl(io_cgrp_subsys))
cgroup_rstat_updated(bio->bi_blkg->blkcg->css.cgroup, cpu);
put_cpu();
}
static int __init blkcg_init(void)
{
blkcg_punt_bio_wq = alloc_workqueue("blkcg_punt_bio",
WQ_MEM_RECLAIM | WQ_FREEZABLE |
WQ_UNBOUND | WQ_SYSFS, 0);
if (!blkcg_punt_bio_wq)
return -ENOMEM;
return 0;
}
subsys_initcall(blkcg_init);
module_param(blkcg_debug_stats, bool, 0644);
MODULE_PARM_DESC(blkcg_debug_stats, "True if you want debug stats, false if not"