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Merge branch 'blkcg-cfq-hierarchy' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup into for-3.9/core

Browse Source 
Tejun writes:

Hello, Jens.

Please consider pulling from the following branch to receive cfq blkcg
hierarchy support.  The branch is based on top of v3.8-rc2.

  git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git blkcg-cfq-hierarchy

The patchset was reviewd in the following thread.

  http://thread.gmane.org/gmane.linux.kernel.cgroups/5571
This commit is contained in:
Jens Axboe 2013-01-11 19:53:53 +01:00
commit ac9a197451
7 changed files with 902 additions and 174 deletions
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58
Documentation/block/cfq-iosched.txt
View File

@ -102,6 +102,64 @@ processing of request. Therefore, increasing the value can imporve the
performace although this can cause the latency of some I/O to increase due
to more number of requests.
CFQ Group scheduling
====================
CFQ supports blkio cgroup and has "blkio." prefixed files in each
blkio cgroup directory. It is weight-based and there are four knobs
for configuration - weight[_device] and leaf_weight[_device].
Internal cgroup nodes (the ones with children) can also have tasks in
them, so the former two configure how much proportion the cgroup as a
whole is entitled to at its parent's level while the latter two
configure how much proportion the tasks in the cgroup have compared to
its direct children.
Another way to think about it is assuming that each internal node has
an implicit leaf child node which hosts all the tasks whose weight is
configured by leaf_weight[_device]. Let's assume a blkio hierarchy
composed of five cgroups - root, A, B, AA and AB - with the following
weights where the names represent the hierarchy.
weight leaf_weight
root : 125 125
A : 500 750
B : 250 500
AA : 500 500
AB : 1000 500
root never has a parent making its weight is meaningless. For backward
compatibility, weight is always kept in sync with leaf_weight. B, AA
and AB have no child and thus its tasks have no children cgroup to
compete with. They always get 100% of what the cgroup won at the
parent level. Considering only the weights which matter, the hierarchy
looks like the following.
root
/ | \
A B leaf
500 250 125
/ | \
AA AB leaf
500 1000 750
If all cgroups have active IOs and competing with each other, disk
time will be distributed like the following.
Distribution below root. The total active weight at this level is
A:500 + B:250 + C:125 = 875.
root-leaf : 125 / 875 =~ 14%
A : 500 / 875 =~ 57%
B(-leaf) : 250 / 875 =~ 28%
A has children and further distributes its 57% among the children and
the implicit leaf node. The total active weight at this level is
AA:500 + AB:1000 + A-leaf:750 = 2250.
A-leaf : ( 750 / 2250) * A =~ 19%
AA(-leaf) : ( 500 / 2250) * A =~ 12%
AB(-leaf) : (1000 / 2250) * A =~ 25%
CFQ IOPS Mode for group scheduling
===================================
Basic CFQ design is to provide priority based time slices. Higher priority

35
Documentation/cgroups/blkio-controller.txt
View File

@ -94,13 +94,11 @@ Throttling/Upper Limit policy
Hierarchical Cgroups
====================
- Currently none of the IO control policy supports hierarchical groups. But
cgroup interface does allow creation of hierarchical cgroups and internally
IO policies treat them as flat hierarchy.
- Currently only CFQ supports hierarchical groups. For throttling,
cgroup interface does allow creation of hierarchical cgroups and
internally it treats them as flat hierarchy.
So this patch will allow creation of cgroup hierarchcy but at the backend
everything will be treated as flat. So if somebody created a hierarchy like
as follows.
If somebody created a hierarchy like as follows.
root
/ \
@ -108,16 +106,20 @@ Hierarchical Cgroups
|
test3
CFQ and throttling will practically treat all groups at same level.
CFQ will handle the hierarchy correctly but and throttling will
practically treat all groups at same level. For details on CFQ
hierarchy support, refer to Documentation/block/cfq-iosched.txt.
Throttling will treat the hierarchy as if it looks like the
following.
pivot
/ / \ \
root test1 test2 test3
Down the line we can implement hierarchical accounting/control support
and also introduce a new cgroup file "use_hierarchy" which will control
whether cgroup hierarchy is viewed as flat or hierarchical by the policy..
This is how memory controller also has implemented the things.
Nesting cgroups, while allowed, isn't officially supported and blkio
genereates warning when cgroups nest. Once throttling implements
hierarchy support, hierarchy will be supported and the warning will
be removed.
Various user visible config options
===================================
@ -172,6 +174,12 @@ Proportional weight policy files
dev weight
8:16 300
- blkio.leaf_weight[_device]
- Equivalents of blkio.weight[_device] for the purpose of
deciding how much weight tasks in the given cgroup has while
competing with the cgroup's child cgroups. For details,
please refer to Documentation/block/cfq-iosched.txt.
- blkio.time
- disk time allocated to cgroup per device in milliseconds. First
two fields specify the major and minor number of the device and
@ -279,6 +287,11 @@ Proportional weight policy files
and minor number of the device and third field specifies the number
of times a group was dequeued from a particular device.
- blkio.*_recursive
- Recursive version of various stats. These files show the
same information as their non-recursive counterparts but
include stats from all the descendant cgroups.
Throttling/Upper limit policy files
-----------------------------------
- blkio.throttle.read_bps_device

277
block/blk-cgroup.c
View File

@ -26,11 +26,32 @@
static DEFINE_MUTEX(blkcg_pol_mutex);
struct blkcg blkcg_root = { .cfq_weight = 2 * CFQ_WEIGHT_DEFAULT };
struct blkcg blkcg_root = { .cfq_weight = 2 * CFQ_WEIGHT_DEFAULT,
.cfq_leaf_weight = 2 * CFQ_WEIGHT_DEFAULT, };
EXPORT_SYMBOL_GPL(blkcg_root);
static struct blkcg_policy *blkcg_policy[BLKCG_MAX_POLS];
static struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg,
struct request_queue *q, bool update_hint);
/**
* blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants
* @d_blkg: loop cursor pointing to the current descendant
* @pos_cgrp: used for iteration
* @p_blkg: target blkg to walk descendants of
*
* Walk @c_blkg through the descendants of @p_blkg. Must be used with RCU
* read locked. If called under either blkcg or queue lock, the iteration
* is guaranteed to include all and only online blkgs. The caller may
* update @pos_cgrp by calling cgroup_rightmost_descendant() to skip
* subtree.
*/
#define blkg_for_each_descendant_pre(d_blkg, pos_cgrp, p_blkg) \
cgroup_for_each_descendant_pre((pos_cgrp), (p_blkg)->blkcg->css.cgroup) \
if (((d_blkg) = __blkg_lookup(cgroup_to_blkcg(pos_cgrp), \
(p_blkg)->q, false)))
static bool blkcg_policy_enabled(struct request_queue *q,
const struct blkcg_policy *pol)
{
@ -112,9 +133,10 @@ static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct request_queue *q,
blkg->pd[i] = pd;
pd->blkg = blkg;
pd->plid = i;
/* invoke per-policy init */
if (blkcg_policy_enabled(blkg->q, pol))
if (pol->pd_init_fn)
pol->pd_init_fn(blkg);
}
@ -125,8 +147,19 @@ err_free:
return NULL;
}
/**
* __blkg_lookup - internal version of blkg_lookup()
* @blkcg: blkcg of interest
* @q: request_queue of interest
* @update_hint: whether to update lookup hint with the result or not
*
* This is internal version and shouldn't be used by policy
* implementations. Looks up blkgs for the @blkcg - @q pair regardless of
* @q's bypass state. If @update_hint is %true, the caller should be
* holding @q->queue_lock and lookup hint is updated on success.
*/
static struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg,
struct request_queue *q)
struct request_queue *q, bool update_hint)
{
struct blkcg_gq *blkg;
@ -135,14 +168,19 @@ static struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg,
return blkg;
/*
* Hint didn't match. Look up from the radix tree. Note that we
* may not be holding queue_lock and thus are not sure whether
* @blkg from blkg_tree has already been removed or not, so we
* can't update hint to the lookup result. Leave it to the caller.
* Hint didn't match. Look up from the radix tree. Note that the
* hint can only be updated under queue_lock as otherwise @blkg
* could have already been removed from blkg_tree. The caller is
* responsible for grabbing queue_lock if @update_hint.
*/
blkg = radix_tree_lookup(&blkcg->blkg_tree, q->id);
if (blkg && blkg->q == q)
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;
}
@ -162,7 +200,7 @@ struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q)
if (unlikely(blk_queue_bypass(q)))
return NULL;
return __blkg_lookup(blkcg, q);
return __blkg_lookup(blkcg, q, false);
}
EXPORT_SYMBOL_GPL(blkg_lookup);
@ -170,75 +208,129 @@ EXPORT_SYMBOL_GPL(blkg_lookup);
* If @new_blkg is %NULL, this function tries to allocate a new one as
* necessary using %GFP_ATOMIC. @new_blkg is always consumed on return.
*/
static struct blkcg_gq *__blkg_lookup_create(struct blkcg *blkcg,
struct request_queue *q,
struct blkcg_gq *new_blkg)
static struct blkcg_gq *blkg_create(struct blkcg *blkcg,
struct request_queue *q,
struct blkcg_gq *new_blkg)
{
struct blkcg_gq *blkg;
int ret;
int i, ret;
WARN_ON_ONCE(!rcu_read_lock_held());
lockdep_assert_held(q->queue_lock);
/* lookup and update hint on success, see __blkg_lookup() for details */
blkg = __blkg_lookup(blkcg, q);
if (blkg) {
rcu_assign_pointer(blkcg->blkg_hint, blkg);
goto out_free;
}
/* blkg holds a reference to blkcg */
if (!css_tryget(&blkcg->css)) {
blkg = ERR_PTR(-EINVAL);
goto out_free;
ret = -EINVAL;
goto err_free_blkg;
}
/* allocate */
if (!new_blkg) {
new_blkg = blkg_alloc(blkcg, q, GFP_ATOMIC);
if (unlikely(!new_blkg)) {
blkg = ERR_PTR(-ENOMEM);
goto out_put;
ret = -ENOMEM;
goto err_put_css;
}
}
blkg = new_blkg;
/* insert */
/* link parent and insert */
if (blkcg_parent(blkcg)) {
blkg->parent = __blkg_lookup(blkcg_parent(blkcg), q, false);
if (WARN_ON_ONCE(!blkg->parent)) {
blkg = ERR_PTR(-EINVAL);
goto err_put_css;
}
blkg_get(blkg->parent);
}
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);
}
}
blkg->online = true;
spin_unlock(&blkcg->lock);
if (!ret)
return blkg;
blkg = ERR_PTR(ret);
out_put:
/* @blkg failed fully initialized, use the usual release path */
blkg_put(blkg);
return ERR_PTR(ret);
err_put_css:
css_put(&blkcg->css);
out_free:
err_free_blkg:
blkg_free(new_blkg);
return blkg;
return ERR_PTR(ret);
}
/**
* blkg_lookup_create - lookup blkg, try to create one if not there
* @blkcg: blkcg of interest
* @q: request_queue of interest
*
* Lookup blkg for the @blkcg - @q pair. If it doesn't exist, try to
* create one. blkg creation is performed recursively from blkcg_root such
* that all non-root blkg's have access to the parent blkg. This function
* should be called under RCU read lock and @q->queue_lock.
*
* Returns pointer to the looked up or created blkg on success, ERR_PTR()
* value on error. If @q is dead, returns ERR_PTR(-EINVAL). If @q is not
* dead and bypassing, returns ERR_PTR(-EBUSY).
*/
struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
struct request_queue *q)
{
struct blkcg_gq *blkg;
WARN_ON_ONCE(!rcu_read_lock_held());
lockdep_assert_held(q->queue_lock);
/*
* This could be the first entry point of blkcg implementation and
* we shouldn't allow anything to go through for a bypassing queue.
*/
if (unlikely(blk_queue_bypass(q)))
return ERR_PTR(blk_queue_dying(q) ? -EINVAL : -EBUSY);
return __blkg_lookup_create(blkcg, q, NULL);
blkg = __blkg_lookup(blkcg, q, true);
if (blkg)
return blkg;
/*
* Create blkgs walking down from blkcg_root to @blkcg, so that all
* non-root blkgs have access to their parents.
*/
while (true) {
struct blkcg *pos = blkcg;
struct blkcg *parent = blkcg_parent(blkcg);
while (parent && !__blkg_lookup(parent, q, false)) {
pos = parent;
parent = blkcg_parent(parent);
}
blkg = blkg_create(pos, q, NULL);
if (pos == blkcg || IS_ERR(blkg))
return blkg;
}
}
EXPORT_SYMBOL_GPL(blkg_lookup_create);
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);
@ -247,6 +339,14 @@ static void blkg_destroy(struct blkcg_gq *blkg)
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);
}
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);
@ -301,8 +401,10 @@ static void blkg_rcu_free(struct rcu_head *rcu_head)
void __blkg_release(struct blkcg_gq *blkg)
{
/* release the extra blkcg reference this blkg has been holding */
/* release the blkcg and parent blkg refs this blkg has been holding */
css_put(&blkg->blkcg->css);
if (blkg->parent)
blkg_put(blkg->parent);
/*
* A group is freed in rcu manner. But having an rcu lock does not
@ -402,8 +504,9 @@ static const char *blkg_dev_name(struct blkcg_gq *blkg)
*
* This function invokes @prfill on each blkg of @blkcg if pd for the
* policy specified by @pol exists. @prfill is invoked with @sf, the
* policy data and @data. If @show_total is %true, the sum of the return
* values from @prfill is printed with "Total" label at the end.
* policy data and @data and the matching queue lock held. If @show_total
* is %true, the sum of the return values from @prfill is printed with
* "Total" label at the end.
*
* This is to be used to construct print functions for
* cftype->read_seq_string method.
@ -418,11 +521,14 @@ void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
struct hlist_node *n;
u64 total = 0;
spin_lock_irq(&blkcg->lock);
hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node)
rcu_read_lock();
hlist_for_each_entry_rcu(blkg, n, &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(&blkcg->lock);
spin_unlock_irq(blkg->q->queue_lock);
}
rcu_read_unlock();
if (show_total)
seq_printf(sf, "Total %llu\n", (unsigned long long)total);
@ -481,6 +587,7 @@ u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
seq_printf(sf, "%s Total %llu\n", dname, (unsigned long long)v);
return v;
}
EXPORT_SYMBOL_GPL(__blkg_prfill_rwstat);
/**
* blkg_prfill_stat - prfill callback for blkg_stat
@ -513,6 +620,82 @@ u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
}
EXPORT_SYMBOL_GPL(blkg_prfill_rwstat);
/**
* blkg_stat_recursive_sum - collect hierarchical blkg_stat
* @pd: policy private data of interest
* @off: offset to the blkg_stat in @pd
*
* Collect the blkg_stat specified by @off from @pd and all its online
* descendants and return the sum. The caller must be holding the queue
* lock for online tests.
*/
u64 blkg_stat_recursive_sum(struct blkg_policy_data *pd, int off)
{
struct blkcg_policy *pol = blkcg_policy[pd->plid];
struct blkcg_gq *pos_blkg;
struct cgroup *pos_cgrp;
u64 sum;
lockdep_assert_held(pd->blkg->q->queue_lock);
sum = blkg_stat_read((void *)pd + off);
rcu_read_lock();
blkg_for_each_descendant_pre(pos_blkg, pos_cgrp, pd_to_blkg(pd)) {
struct blkg_policy_data *pos_pd = blkg_to_pd(pos_blkg, pol);
struct blkg_stat *stat = (void *)pos_pd + off;
if (pos_blkg->online)
sum += blkg_stat_read(stat);
}
rcu_read_unlock();
return sum;
}
EXPORT_SYMBOL_GPL(blkg_stat_recursive_sum);
/**
* blkg_rwstat_recursive_sum - collect hierarchical blkg_rwstat
* @pd: policy private data of interest
* @off: offset to the blkg_stat in @pd
*
* Collect the blkg_rwstat specified by @off from @pd and all its online
* descendants and return the sum. The caller must be holding the queue
* lock for online tests.
*/
struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkg_policy_data *pd,
int off)
{
struct blkcg_policy *pol = blkcg_policy[pd->plid];
struct blkcg_gq *pos_blkg;
struct cgroup *pos_cgrp;
struct blkg_rwstat sum;
int i;
lockdep_assert_held(pd->blkg->q->queue_lock);
sum = blkg_rwstat_read((void *)pd + off);
rcu_read_lock();
blkg_for_each_descendant_pre(pos_blkg, pos_cgrp, pd_to_blkg(pd)) {
struct blkg_policy_data *pos_pd = blkg_to_pd(pos_blkg, pol);
struct blkg_rwstat *rwstat = (void *)pos_pd + off;
struct blkg_rwstat tmp;
if (!pos_blkg->online)
continue;
tmp = blkg_rwstat_read(rwstat);
for (i = 0; i < BLKG_RWSTAT_NR; i++)
sum.cnt[i] += tmp.cnt[i];
}
rcu_read_unlock();
return sum;
}
EXPORT_SYMBOL_GPL(blkg_rwstat_recursive_sum);
/**
* blkg_conf_prep - parse and prepare for per-blkg config update
* @blkcg: target block cgroup
@ -658,6 +841,7 @@ static struct cgroup_subsys_state *blkcg_css_alloc(struct cgroup *cgroup)
return ERR_PTR(-ENOMEM);
blkcg->cfq_weight = CFQ_WEIGHT_DEFAULT;
blkcg->cfq_leaf_weight = CFQ_WEIGHT_DEFAULT;
blkcg->id = atomic64_inc_return(&id_seq); /* root is 0, start from 1 */
done:
spin_lock_init(&blkcg->lock);
@ -777,7 +961,7 @@ int blkcg_activate_policy(struct request_queue *q,
const struct blkcg_policy *pol)
{
LIST_HEAD(pds);
struct blkcg_gq *blkg;
struct blkcg_gq *blkg, *new_blkg;
struct blkg_policy_data *pd, *n;
int cnt = 0, ret;
bool preloaded;
@ -786,19 +970,27 @@ int blkcg_activate_policy(struct request_queue *q,
return 0;
/* preallocations for root blkg */
blkg = blkg_alloc(&blkcg_root, q, GFP_KERNEL);
if (!blkg)
new_blkg = blkg_alloc(&blkcg_root, q, GFP_KERNEL);
if (!new_blkg)
return -ENOMEM;
preloaded = !radix_tree_preload(GFP_KERNEL);
blk_queue_bypass_start(q);
/* make sure the root blkg exists and count the existing blkgs */
/*
* Make sure the root blkg exists and count the existing blkgs. As
* @q is bypassing at this point, blkg_lookup_create() can't be
* used. Open code it.
*/
spin_lock_irq(q->queue_lock);
rcu_read_lock();
blkg = __blkg_lookup_create(&blkcg_root, q, blkg);
blkg = __blkg_lookup(&blkcg_root, q, false);
if (blkg)
blkg_free(new_blkg);
else
blkg = blkg_create(&blkcg_root, q, new_blkg);
rcu_read_unlock();
if (preloaded)
@ -846,6 +1038,7 @@ int blkcg_activate_policy(struct request_queue *q,
blkg->pd[pol->plid] = pd;
pd->blkg = blkg;
pd->plid = pol->plid;
pol->pd_init_fn(blkg);
spin_unlock(&blkg->blkcg->lock);
@ -892,6 +1085,8 @@ void blkcg_deactivate_policy(struct request_queue *q,
/* grab blkcg lock too while removing @pd from @blkg */
spin_lock(&blkg->blkcg->lock);
if (pol->pd_offline_fn)
pol->pd_offline_fn(blkg);
if (pol->pd_exit_fn)
pol->pd_exit_fn(blkg);

68
block/blk-cgroup.h
View File

@ -54,6 +54,7 @@ struct blkcg {
/* TODO: per-policy storage in blkcg */
unsigned int cfq_weight; /* belongs to cfq */
unsigned int cfq_leaf_weight;
};
struct blkg_stat {
@ -80,8 +81,9 @@ struct blkg_rwstat {
* beginning and pd_size can't be smaller than pd.
*/
struct blkg_policy_data {
/* the blkg this per-policy data belongs to */
/* the blkg and policy id this per-policy data belongs to */
struct blkcg_gq *blkg;
int plid;
/* used during policy activation */
struct list_head alloc_node;
@ -94,17 +96,27 @@ struct blkcg_gq {
struct list_head q_node;
struct hlist_node blkcg_node;
struct blkcg *blkcg;
/* all non-root blkcg_gq's are guaranteed to have access to parent */
struct blkcg_gq *parent;
/* request allocation list for this blkcg-q pair */
struct request_list rl;
/* reference count */
int refcnt;
/* is this blkg online? protected by both blkcg and q locks */
bool online;
struct blkg_policy_data *pd[BLKCG_MAX_POLS];
struct rcu_head rcu_head;
};
typedef void (blkcg_pol_init_pd_fn)(struct blkcg_gq *blkg);
typedef void (blkcg_pol_online_pd_fn)(struct blkcg_gq *blkg);
typedef void (blkcg_pol_offline_pd_fn)(struct blkcg_gq *blkg);
typedef void (blkcg_pol_exit_pd_fn)(struct blkcg_gq *blkg);
typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkcg_gq *blkg);
@ -117,6 +129,8 @@ struct blkcg_policy {
/* operations */
blkcg_pol_init_pd_fn *pd_init_fn;
blkcg_pol_online_pd_fn *pd_online_fn;
blkcg_pol_offline_pd_fn *pd_offline_fn;
blkcg_pol_exit_pd_fn *pd_exit_fn;
blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn;
};
@ -150,6 +164,10 @@ u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off);
u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
int off);
u64 blkg_stat_recursive_sum(struct blkg_policy_data *pd, int off);
struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkg_policy_data *pd,
int off);
struct blkg_conf_ctx {
struct gendisk *disk;
struct blkcg_gq *blkg;
@ -180,6 +198,19 @@ static inline struct blkcg *bio_blkcg(struct bio *bio)
return task_blkcg(current);
}
/**
* blkcg_parent - get the parent of a blkcg
* @blkcg: blkcg of interest
*
* Return the parent blkcg of @blkcg. Can be called anytime.
*/
static inline struct blkcg *blkcg_parent(struct blkcg *blkcg)
{
struct cgroup *pcg = blkcg->css.cgroup->parent;
return pcg ? cgroup_to_blkcg(pcg) : NULL;
}
/**
* blkg_to_pdata - get policy private data
* @blkg: blkg of interest
@ -386,6 +417,18 @@ static inline void blkg_stat_reset(struct blkg_stat *stat)
stat->cnt = 0;
}
/**
* blkg_stat_merge - merge a blkg_stat into another
* @to: the destination blkg_stat
* @from: the source
*
* Add @from's count to @to.
*/
static inline void blkg_stat_merge(struct blkg_stat *to, struct blkg_stat *from)
{
blkg_stat_add(to, blkg_stat_read(from));
}
/**
* blkg_rwstat_add - add a value to a blkg_rwstat
* @rwstat: target blkg_rwstat
@ -434,14 +477,14 @@ static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
}
/**
* blkg_rwstat_sum - read the total count of a blkg_rwstat
* blkg_rwstat_total - 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)
static inline uint64_t blkg_rwstat_total(struct blkg_rwstat *rwstat)
{
struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
@ -457,6 +500,25 @@ static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
memset(rwstat->cnt, 0, sizeof(rwstat->cnt));
}
/**
* blkg_rwstat_merge - merge a blkg_rwstat into another
* @to: the destination blkg_rwstat
* @from: the source
*
* Add @from's counts to @to.
*/
static inline void blkg_rwstat_merge(struct blkg_rwstat *to,
struct blkg_rwstat *from)
{
struct blkg_rwstat v = blkg_rwstat_read(from);
int i;
u64_stats_update_begin(&to->syncp);
for (i = 0; i < BLKG_RWSTAT_NR; i++)
to->cnt[i] += v.cnt[i];
u64_stats_update_end(&to->syncp);
}
#else /* CONFIG_BLK_CGROUP */
struct cgroup;

9
block/blk-sysfs.c
View File

@ -497,6 +497,13 @@ queue_attr_store(struct kobject *kobj, struct attribute *attr,
return res;
}
static void blk_free_queue_rcu(struct rcu_head *rcu_head)
{
struct request_queue *q = container_of(rcu_head, struct request_queue,
rcu_head);
kmem_cache_free(blk_requestq_cachep, q);
}
/**
* blk_release_queue: - release a &struct request_queue when it is no longer needed
* @kobj: the kobj belonging to the request queue to be released
@ -538,7 +545,7 @@ static void blk_release_queue(struct kobject *kobj)
bdi_destroy(&q->backing_dev_info);
ida_simple_remove(&blk_queue_ida, q->id);
kmem_cache_free(blk_requestq_cachep, q);
call_rcu(&q->rcu_head, blk_free_queue_rcu);
}
static const struct sysfs_ops queue_sysfs_ops = {

627
block/cfq-iosched.c
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File diff suppressed because it is too large Load Diff

2
include/linux/blkdev.h
View File

@ -19,6 +19,7 @@
#include <linux/gfp.h>
#include <linux/bsg.h>
#include <linux/smp.h>
#include <linux/rcupdate.h>
#include <asm/scatterlist.h>
@ -437,6 +438,7 @@ struct request_queue {
/* Throttle data */
struct throtl_data *td;
#endif
struct rcu_head rcu_head;
};
#define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */