linux/block/bfq-cgroup.c
Yu Kuai f02be9002c block, bfq: fix null pointer dereference in bfq_bio_bfqg()
Out test found a following problem in kernel 5.10, and the same problem
should exist in mainline:

BUG: kernel NULL pointer dereference, address: 0000000000000094
PGD 0 P4D 0
Oops: 0000 [#1] SMP
CPU: 7 PID: 155 Comm: kworker/7:1 Not tainted 5.10.0-01932-g19e0ace2ca1d-dirty 4
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20190727_073836-b4
Workqueue: kthrotld blk_throtl_dispatch_work_fn
RIP: 0010:bfq_bio_bfqg+0x52/0xc0
Code: 94 00 00 00 00 75 2e 48 8b 40 30 48 83 05 35 06 c8 0b 01 48 85 c0 74 3d 4b
RSP: 0018:ffffc90001a1fba0 EFLAGS: 00010002
RAX: ffff888100d60400 RBX: ffff8881132e7000 RCX: 0000000000000000
RDX: 0000000000000017 RSI: ffff888103580a18 RDI: ffff888103580a18
RBP: ffff8881132e7000 R08: 0000000000000000 R09: ffffc90001a1fe10
R10: 0000000000000a20 R11: 0000000000034320 R12: 0000000000000000
R13: ffff888103580a18 R14: ffff888114447000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88881fdc0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000094 CR3: 0000000100cdb000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 bfq_bic_update_cgroup+0x3c/0x350
 ? ioc_create_icq+0x42/0x270
 bfq_init_rq+0xfd/0x1060
 bfq_insert_requests+0x20f/0x1cc0
 ? ioc_create_icq+0x122/0x270
 blk_mq_sched_insert_requests+0x86/0x1d0
 blk_mq_flush_plug_list+0x193/0x2a0
 blk_flush_plug_list+0x127/0x170
 blk_finish_plug+0x31/0x50
 blk_throtl_dispatch_work_fn+0x151/0x190
 process_one_work+0x27c/0x5f0
 worker_thread+0x28b/0x6b0
 ? rescuer_thread+0x590/0x590
 kthread+0x153/0x1b0
 ? kthread_flush_work+0x170/0x170
 ret_from_fork+0x1f/0x30
Modules linked in:
CR2: 0000000000000094
---[ end trace e2e59ac014314547 ]---
RIP: 0010:bfq_bio_bfqg+0x52/0xc0
Code: 94 00 00 00 00 75 2e 48 8b 40 30 48 83 05 35 06 c8 0b 01 48 85 c0 74 3d 4b
RSP: 0018:ffffc90001a1fba0 EFLAGS: 00010002
RAX: ffff888100d60400 RBX: ffff8881132e7000 RCX: 0000000000000000
RDX: 0000000000000017 RSI: ffff888103580a18 RDI: ffff888103580a18
RBP: ffff8881132e7000 R08: 0000000000000000 R09: ffffc90001a1fe10
R10: 0000000000000a20 R11: 0000000000034320 R12: 0000000000000000
R13: ffff888103580a18 R14: ffff888114447000 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88881fdc0000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000094 CR3: 0000000100cdb000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Root cause is quite complex:

1) use bfq elevator for the test device.
2) create a cgroup CG
3) config blk throtl in CG

   blkg_conf_prep
    blkg_create

4) create a thread T1 and issue async io in CG:

   bio_init
    bio_associate_blkg
   ...
   submit_bio
    submit_bio_noacct
     blk_throtl_bio -> io is throttled
     // io submit is done

5) switch elevator:

   bfq_exit_queue
    blkcg_deactivate_policy
     list_for_each_entry(blkg, &q->blkg_list, q_node)
      blkg->pd[] = NULL
      // bfq policy is removed

5) thread t1 exist, then remove the cgroup CG:

   blkcg_unpin_online
    blkcg_destroy_blkgs
     blkg_destroy
      list_del_init(&blkg->q_node)
      // blkg is removed from queue list

6) switch elevator back to bfq

 bfq_init_queue
  bfq_create_group_hierarchy
   blkcg_activate_policy
    list_for_each_entry_reverse(blkg, &q->blkg_list)
     // blkg is removed from list, hence bfq policy is still NULL

7) throttled io is dispatched to bfq:

 bfq_insert_requests
  bfq_init_rq
   bfq_bic_update_cgroup
    bfq_bio_bfqg
     bfqg = blkg_to_bfqg(blkg)
     // bfqg is NULL because bfq policy is NULL

The problem is only possible in bfq because only bfq can be deactivated and
activated while queue is online, while others can only be deactivated while
the device is removed.

Fix the problem in bfq by checking if blkg is online before calling
blkg_to_bfqg().

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20221108103434.2853269-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
2022-11-08 07:13:25 -07:00

1492 lines
40 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* cgroups support for the BFQ I/O scheduler.
*/
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/blkdev.h>
#include <linux/cgroup.h>
#include <linux/ktime.h>
#include <linux/rbtree.h>
#include <linux/ioprio.h>
#include <linux/sbitmap.h>
#include <linux/delay.h>
#include "elevator.h"
#include "bfq-iosched.h"
#ifdef CONFIG_BFQ_CGROUP_DEBUG
static int bfq_stat_init(struct bfq_stat *stat, gfp_t gfp)
{
int ret;
ret = percpu_counter_init(&stat->cpu_cnt, 0, gfp);
if (ret)
return ret;
atomic64_set(&stat->aux_cnt, 0);
return 0;
}
static void bfq_stat_exit(struct bfq_stat *stat)
{
percpu_counter_destroy(&stat->cpu_cnt);
}
/**
* bfq_stat_add - add a value to a bfq_stat
* @stat: target bfq_stat
* @val: value to add
*
* Add @val to @stat. The caller must ensure that IRQ on the same CPU
* don't re-enter this function for the same counter.
*/
static inline void bfq_stat_add(struct bfq_stat *stat, uint64_t val)
{
percpu_counter_add_batch(&stat->cpu_cnt, val, BLKG_STAT_CPU_BATCH);
}
/**
* bfq_stat_read - read the current value of a bfq_stat
* @stat: bfq_stat to read
*/
static inline uint64_t bfq_stat_read(struct bfq_stat *stat)
{
return percpu_counter_sum_positive(&stat->cpu_cnt);
}
/**
* bfq_stat_reset - reset a bfq_stat
* @stat: bfq_stat to reset
*/
static inline void bfq_stat_reset(struct bfq_stat *stat)
{
percpu_counter_set(&stat->cpu_cnt, 0);
atomic64_set(&stat->aux_cnt, 0);
}
/**
* bfq_stat_add_aux - add a bfq_stat into another's aux count
* @to: the destination bfq_stat
* @from: the source
*
* Add @from's count including the aux one to @to's aux count.
*/
static inline void bfq_stat_add_aux(struct bfq_stat *to,
struct bfq_stat *from)
{
atomic64_add(bfq_stat_read(from) + atomic64_read(&from->aux_cnt),
&to->aux_cnt);
}
/**
* blkg_prfill_stat - prfill callback for bfq_stat
* @sf: seq_file to print to
* @pd: policy private data of interest
* @off: offset to the bfq_stat in @pd
*
* prfill callback for printing a bfq_stat.
*/
static u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd,
int off)
{
return __blkg_prfill_u64(sf, pd, bfq_stat_read((void *)pd + off));
}
/* bfqg stats flags */
enum bfqg_stats_flags {
BFQG_stats_waiting = 0,
BFQG_stats_idling,
BFQG_stats_empty,
};
#define BFQG_FLAG_FNS(name) \
static void bfqg_stats_mark_##name(struct bfqg_stats *stats) \
{ \
stats->flags |= (1 << BFQG_stats_##name); \
} \
static void bfqg_stats_clear_##name(struct bfqg_stats *stats) \
{ \
stats->flags &= ~(1 << BFQG_stats_##name); \
} \
static int bfqg_stats_##name(struct bfqg_stats *stats) \
{ \
return (stats->flags & (1 << BFQG_stats_##name)) != 0; \
} \
BFQG_FLAG_FNS(waiting)
BFQG_FLAG_FNS(idling)
BFQG_FLAG_FNS(empty)
#undef BFQG_FLAG_FNS
/* This should be called with the scheduler lock held. */
static void bfqg_stats_update_group_wait_time(struct bfqg_stats *stats)
{
u64 now;
if (!bfqg_stats_waiting(stats))
return;
now = ktime_get_ns();
if (now > stats->start_group_wait_time)
bfq_stat_add(&stats->group_wait_time,
now - stats->start_group_wait_time);
bfqg_stats_clear_waiting(stats);
}
/* This should be called with the scheduler lock held. */
static void bfqg_stats_set_start_group_wait_time(struct bfq_group *bfqg,
struct bfq_group *curr_bfqg)
{
struct bfqg_stats *stats = &bfqg->stats;
if (bfqg_stats_waiting(stats))
return;
if (bfqg == curr_bfqg)
return;
stats->start_group_wait_time = ktime_get_ns();
bfqg_stats_mark_waiting(stats);
}
/* This should be called with the scheduler lock held. */
static void bfqg_stats_end_empty_time(struct bfqg_stats *stats)
{
u64 now;
if (!bfqg_stats_empty(stats))
return;
now = ktime_get_ns();
if (now > stats->start_empty_time)
bfq_stat_add(&stats->empty_time,
now - stats->start_empty_time);
bfqg_stats_clear_empty(stats);
}
void bfqg_stats_update_dequeue(struct bfq_group *bfqg)
{
bfq_stat_add(&bfqg->stats.dequeue, 1);
}
void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg)
{
struct bfqg_stats *stats = &bfqg->stats;
if (blkg_rwstat_total(&stats->queued))
return;
/*
* group is already marked empty. This can happen if bfqq got new
* request in parent group and moved to this group while being added
* to service tree. Just ignore the event and move on.
*/
if (bfqg_stats_empty(stats))
return;
stats->start_empty_time = ktime_get_ns();
bfqg_stats_mark_empty(stats);
}
void bfqg_stats_update_idle_time(struct bfq_group *bfqg)
{
struct bfqg_stats *stats = &bfqg->stats;
if (bfqg_stats_idling(stats)) {
u64 now = ktime_get_ns();
if (now > stats->start_idle_time)
bfq_stat_add(&stats->idle_time,
now - stats->start_idle_time);
bfqg_stats_clear_idling(stats);
}
}
void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg)
{
struct bfqg_stats *stats = &bfqg->stats;
stats->start_idle_time = ktime_get_ns();
bfqg_stats_mark_idling(stats);
}
void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg)
{
struct bfqg_stats *stats = &bfqg->stats;
bfq_stat_add(&stats->avg_queue_size_sum,
blkg_rwstat_total(&stats->queued));
bfq_stat_add(&stats->avg_queue_size_samples, 1);
bfqg_stats_update_group_wait_time(stats);
}
void bfqg_stats_update_io_add(struct bfq_group *bfqg, struct bfq_queue *bfqq,
blk_opf_t opf)
{
blkg_rwstat_add(&bfqg->stats.queued, opf, 1);
bfqg_stats_end_empty_time(&bfqg->stats);
if (!(bfqq == ((struct bfq_data *)bfqg->bfqd)->in_service_queue))
bfqg_stats_set_start_group_wait_time(bfqg, bfqq_group(bfqq));
}
void bfqg_stats_update_io_remove(struct bfq_group *bfqg, blk_opf_t opf)
{
blkg_rwstat_add(&bfqg->stats.queued, opf, -1);
}
void bfqg_stats_update_io_merged(struct bfq_group *bfqg, blk_opf_t opf)
{
blkg_rwstat_add(&bfqg->stats.merged, opf, 1);
}
void bfqg_stats_update_completion(struct bfq_group *bfqg, u64 start_time_ns,
u64 io_start_time_ns, blk_opf_t opf)
{
struct bfqg_stats *stats = &bfqg->stats;
u64 now = ktime_get_ns();
if (now > io_start_time_ns)
blkg_rwstat_add(&stats->service_time, opf,
now - io_start_time_ns);
if (io_start_time_ns > start_time_ns)
blkg_rwstat_add(&stats->wait_time, opf,
io_start_time_ns - start_time_ns);
}
#else /* CONFIG_BFQ_CGROUP_DEBUG */
void bfqg_stats_update_io_remove(struct bfq_group *bfqg, blk_opf_t opf) { }
void bfqg_stats_update_io_merged(struct bfq_group *bfqg, blk_opf_t opf) { }
void bfqg_stats_update_completion(struct bfq_group *bfqg, u64 start_time_ns,
u64 io_start_time_ns, blk_opf_t opf) { }
void bfqg_stats_update_dequeue(struct bfq_group *bfqg) { }
void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg) { }
#endif /* CONFIG_BFQ_CGROUP_DEBUG */
#ifdef CONFIG_BFQ_GROUP_IOSCHED
/*
* blk-cgroup policy-related handlers
* The following functions help in converting between blk-cgroup
* internal structures and BFQ-specific structures.
*/
static struct bfq_group *pd_to_bfqg(struct blkg_policy_data *pd)
{
return pd ? container_of(pd, struct bfq_group, pd) : NULL;
}
struct blkcg_gq *bfqg_to_blkg(struct bfq_group *bfqg)
{
return pd_to_blkg(&bfqg->pd);
}
static struct bfq_group *blkg_to_bfqg(struct blkcg_gq *blkg)
{
return pd_to_bfqg(blkg_to_pd(blkg, &blkcg_policy_bfq));
}
/*
* bfq_group handlers
* The following functions help in navigating the bfq_group hierarchy
* by allowing to find the parent of a bfq_group or the bfq_group
* associated to a bfq_queue.
*/
static struct bfq_group *bfqg_parent(struct bfq_group *bfqg)
{
struct blkcg_gq *pblkg = bfqg_to_blkg(bfqg)->parent;
return pblkg ? blkg_to_bfqg(pblkg) : NULL;
}
struct bfq_group *bfqq_group(struct bfq_queue *bfqq)
{
struct bfq_entity *group_entity = bfqq->entity.parent;
return group_entity ? container_of(group_entity, struct bfq_group,
entity) :
bfqq->bfqd->root_group;
}
/*
* The following two functions handle get and put of a bfq_group by
* wrapping the related blk-cgroup hooks.
*/
static void bfqg_get(struct bfq_group *bfqg)
{
bfqg->ref++;
}
static void bfqg_put(struct bfq_group *bfqg)
{
bfqg->ref--;
if (bfqg->ref == 0)
kfree(bfqg);
}
static void bfqg_and_blkg_get(struct bfq_group *bfqg)
{
/* see comments in bfq_bic_update_cgroup for why refcounting bfqg */
bfqg_get(bfqg);
blkg_get(bfqg_to_blkg(bfqg));
}
void bfqg_and_blkg_put(struct bfq_group *bfqg)
{
blkg_put(bfqg_to_blkg(bfqg));
bfqg_put(bfqg);
}
void bfqg_stats_update_legacy_io(struct request_queue *q, struct request *rq)
{
struct bfq_group *bfqg = blkg_to_bfqg(rq->bio->bi_blkg);
if (!bfqg)
return;
blkg_rwstat_add(&bfqg->stats.bytes, rq->cmd_flags, blk_rq_bytes(rq));
blkg_rwstat_add(&bfqg->stats.ios, rq->cmd_flags, 1);
}
/* @stats = 0 */
static void bfqg_stats_reset(struct bfqg_stats *stats)
{
#ifdef CONFIG_BFQ_CGROUP_DEBUG
/* queued stats shouldn't be cleared */
blkg_rwstat_reset(&stats->merged);
blkg_rwstat_reset(&stats->service_time);
blkg_rwstat_reset(&stats->wait_time);
bfq_stat_reset(&stats->time);
bfq_stat_reset(&stats->avg_queue_size_sum);
bfq_stat_reset(&stats->avg_queue_size_samples);
bfq_stat_reset(&stats->dequeue);
bfq_stat_reset(&stats->group_wait_time);
bfq_stat_reset(&stats->idle_time);
bfq_stat_reset(&stats->empty_time);
#endif
}
/* @to += @from */
static void bfqg_stats_add_aux(struct bfqg_stats *to, struct bfqg_stats *from)
{
if (!to || !from)
return;
#ifdef CONFIG_BFQ_CGROUP_DEBUG
/* queued stats shouldn't be cleared */
blkg_rwstat_add_aux(&to->merged, &from->merged);
blkg_rwstat_add_aux(&to->service_time, &from->service_time);
blkg_rwstat_add_aux(&to->wait_time, &from->wait_time);
bfq_stat_add_aux(&from->time, &from->time);
bfq_stat_add_aux(&to->avg_queue_size_sum, &from->avg_queue_size_sum);
bfq_stat_add_aux(&to->avg_queue_size_samples,
&from->avg_queue_size_samples);
bfq_stat_add_aux(&to->dequeue, &from->dequeue);
bfq_stat_add_aux(&to->group_wait_time, &from->group_wait_time);
bfq_stat_add_aux(&to->idle_time, &from->idle_time);
bfq_stat_add_aux(&to->empty_time, &from->empty_time);
#endif
}
/*
* Transfer @bfqg's stats to its parent's aux counts so that the ancestors'
* recursive stats can still account for the amount used by this bfqg after
* it's gone.
*/
static void bfqg_stats_xfer_dead(struct bfq_group *bfqg)
{
struct bfq_group *parent;
if (!bfqg) /* root_group */
return;
parent = bfqg_parent(bfqg);
lockdep_assert_held(&bfqg_to_blkg(bfqg)->q->queue_lock);
if (unlikely(!parent))
return;
bfqg_stats_add_aux(&parent->stats, &bfqg->stats);
bfqg_stats_reset(&bfqg->stats);
}
void bfq_init_entity(struct bfq_entity *entity, struct bfq_group *bfqg)
{
struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
entity->weight = entity->new_weight;
entity->orig_weight = entity->new_weight;
if (bfqq) {
bfqq->ioprio = bfqq->new_ioprio;
bfqq->ioprio_class = bfqq->new_ioprio_class;
/*
* Make sure that bfqg and its associated blkg do not
* disappear before entity.
*/
bfqg_and_blkg_get(bfqg);
}
entity->parent = bfqg->my_entity; /* NULL for root group */
entity->sched_data = &bfqg->sched_data;
}
static void bfqg_stats_exit(struct bfqg_stats *stats)
{
blkg_rwstat_exit(&stats->bytes);
blkg_rwstat_exit(&stats->ios);
#ifdef CONFIG_BFQ_CGROUP_DEBUG
blkg_rwstat_exit(&stats->merged);
blkg_rwstat_exit(&stats->service_time);
blkg_rwstat_exit(&stats->wait_time);
blkg_rwstat_exit(&stats->queued);
bfq_stat_exit(&stats->time);
bfq_stat_exit(&stats->avg_queue_size_sum);
bfq_stat_exit(&stats->avg_queue_size_samples);
bfq_stat_exit(&stats->dequeue);
bfq_stat_exit(&stats->group_wait_time);
bfq_stat_exit(&stats->idle_time);
bfq_stat_exit(&stats->empty_time);
#endif
}
static int bfqg_stats_init(struct bfqg_stats *stats, gfp_t gfp)
{
if (blkg_rwstat_init(&stats->bytes, gfp) ||
blkg_rwstat_init(&stats->ios, gfp))
goto error;
#ifdef CONFIG_BFQ_CGROUP_DEBUG
if (blkg_rwstat_init(&stats->merged, gfp) ||
blkg_rwstat_init(&stats->service_time, gfp) ||
blkg_rwstat_init(&stats->wait_time, gfp) ||
blkg_rwstat_init(&stats->queued, gfp) ||
bfq_stat_init(&stats->time, gfp) ||
bfq_stat_init(&stats->avg_queue_size_sum, gfp) ||
bfq_stat_init(&stats->avg_queue_size_samples, gfp) ||
bfq_stat_init(&stats->dequeue, gfp) ||
bfq_stat_init(&stats->group_wait_time, gfp) ||
bfq_stat_init(&stats->idle_time, gfp) ||
bfq_stat_init(&stats->empty_time, gfp))
goto error;
#endif
return 0;
error:
bfqg_stats_exit(stats);
return -ENOMEM;
}
static struct bfq_group_data *cpd_to_bfqgd(struct blkcg_policy_data *cpd)
{
return cpd ? container_of(cpd, struct bfq_group_data, pd) : NULL;
}
static struct bfq_group_data *blkcg_to_bfqgd(struct blkcg *blkcg)
{
return cpd_to_bfqgd(blkcg_to_cpd(blkcg, &blkcg_policy_bfq));
}
static struct blkcg_policy_data *bfq_cpd_alloc(gfp_t gfp)
{
struct bfq_group_data *bgd;
bgd = kzalloc(sizeof(*bgd), gfp);
if (!bgd)
return NULL;
return &bgd->pd;
}
static void bfq_cpd_init(struct blkcg_policy_data *cpd)
{
struct bfq_group_data *d = cpd_to_bfqgd(cpd);
d->weight = cgroup_subsys_on_dfl(io_cgrp_subsys) ?
CGROUP_WEIGHT_DFL : BFQ_WEIGHT_LEGACY_DFL;
}
static void bfq_cpd_free(struct blkcg_policy_data *cpd)
{
kfree(cpd_to_bfqgd(cpd));
}
static struct blkg_policy_data *bfq_pd_alloc(gfp_t gfp, struct request_queue *q,
struct blkcg *blkcg)
{
struct bfq_group *bfqg;
bfqg = kzalloc_node(sizeof(*bfqg), gfp, q->node);
if (!bfqg)
return NULL;
if (bfqg_stats_init(&bfqg->stats, gfp)) {
kfree(bfqg);
return NULL;
}
/* see comments in bfq_bic_update_cgroup for why refcounting */
bfqg_get(bfqg);
return &bfqg->pd;
}
static void bfq_pd_init(struct blkg_policy_data *pd)
{
struct blkcg_gq *blkg = pd_to_blkg(pd);
struct bfq_group *bfqg = blkg_to_bfqg(blkg);
struct bfq_data *bfqd = blkg->q->elevator->elevator_data;
struct bfq_entity *entity = &bfqg->entity;
struct bfq_group_data *d = blkcg_to_bfqgd(blkg->blkcg);
entity->orig_weight = entity->weight = entity->new_weight = d->weight;
entity->my_sched_data = &bfqg->sched_data;
entity->last_bfqq_created = NULL;
bfqg->my_entity = entity; /*
* the root_group's will be set to NULL
* in bfq_init_queue()
*/
bfqg->bfqd = bfqd;
bfqg->active_entities = 0;
bfqg->online = true;
bfqg->rq_pos_tree = RB_ROOT;
}
static void bfq_pd_free(struct blkg_policy_data *pd)
{
struct bfq_group *bfqg = pd_to_bfqg(pd);
bfqg_stats_exit(&bfqg->stats);
bfqg_put(bfqg);
}
static void bfq_pd_reset_stats(struct blkg_policy_data *pd)
{
struct bfq_group *bfqg = pd_to_bfqg(pd);
bfqg_stats_reset(&bfqg->stats);
}
static void bfq_group_set_parent(struct bfq_group *bfqg,
struct bfq_group *parent)
{
struct bfq_entity *entity;
entity = &bfqg->entity;
entity->parent = parent->my_entity;
entity->sched_data = &parent->sched_data;
}
static void bfq_link_bfqg(struct bfq_data *bfqd, struct bfq_group *bfqg)
{
struct bfq_group *parent;
struct bfq_entity *entity;
/*
* Update chain of bfq_groups as we might be handling a leaf group
* which, along with some of its relatives, has not been hooked yet
* to the private hierarchy of BFQ.
*/
entity = &bfqg->entity;
for_each_entity(entity) {
struct bfq_group *curr_bfqg = container_of(entity,
struct bfq_group, entity);
if (curr_bfqg != bfqd->root_group) {
parent = bfqg_parent(curr_bfqg);
if (!parent)
parent = bfqd->root_group;
bfq_group_set_parent(curr_bfqg, parent);
}
}
}
struct bfq_group *bfq_bio_bfqg(struct bfq_data *bfqd, struct bio *bio)
{
struct blkcg_gq *blkg = bio->bi_blkg;
struct bfq_group *bfqg;
while (blkg) {
if (!blkg->online) {
blkg = blkg->parent;
continue;
}
bfqg = blkg_to_bfqg(blkg);
if (bfqg->online) {
bio_associate_blkg_from_css(bio, &blkg->blkcg->css);
return bfqg;
}
blkg = blkg->parent;
}
bio_associate_blkg_from_css(bio,
&bfqg_to_blkg(bfqd->root_group)->blkcg->css);
return bfqd->root_group;
}
/**
* bfq_bfqq_move - migrate @bfqq to @bfqg.
* @bfqd: queue descriptor.
* @bfqq: the queue to move.
* @bfqg: the group to move to.
*
* Move @bfqq to @bfqg, deactivating it from its old group and reactivating
* it on the new one. Avoid putting the entity on the old group idle tree.
*
* Must be called under the scheduler lock, to make sure that the blkg
* owning @bfqg does not disappear (see comments in
* bfq_bic_update_cgroup on guaranteeing the consistency of blkg
* objects).
*/
void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq,
struct bfq_group *bfqg)
{
struct bfq_entity *entity = &bfqq->entity;
struct bfq_group *old_parent = bfqq_group(bfqq);
/*
* No point to move bfqq to the same group, which can happen when
* root group is offlined
*/
if (old_parent == bfqg)
return;
/*
* oom_bfqq is not allowed to move, oom_bfqq will hold ref to root_group
* until elevator exit.
*/
if (bfqq == &bfqd->oom_bfqq)
return;
/*
* Get extra reference to prevent bfqq from being freed in
* next possible expire or deactivate.
*/
bfqq->ref++;
/* If bfqq is empty, then bfq_bfqq_expire also invokes
* bfq_del_bfqq_busy, thereby removing bfqq and its entity
* from data structures related to current group. Otherwise we
* need to remove bfqq explicitly with bfq_deactivate_bfqq, as
* we do below.
*/
if (bfqq == bfqd->in_service_queue)
bfq_bfqq_expire(bfqd, bfqd->in_service_queue,
false, BFQQE_PREEMPTED);
if (bfq_bfqq_busy(bfqq))
bfq_deactivate_bfqq(bfqd, bfqq, false, false);
else if (entity->on_st_or_in_serv)
bfq_put_idle_entity(bfq_entity_service_tree(entity), entity);
bfqg_and_blkg_put(old_parent);
if (entity->parent &&
entity->parent->last_bfqq_created == bfqq)
entity->parent->last_bfqq_created = NULL;
else if (bfqd->last_bfqq_created == bfqq)
bfqd->last_bfqq_created = NULL;
entity->parent = bfqg->my_entity;
entity->sched_data = &bfqg->sched_data;
/* pin down bfqg and its associated blkg */
bfqg_and_blkg_get(bfqg);
if (bfq_bfqq_busy(bfqq)) {
if (unlikely(!bfqd->nonrot_with_queueing))
bfq_pos_tree_add_move(bfqd, bfqq);
bfq_activate_bfqq(bfqd, bfqq);
}
if (!bfqd->in_service_queue && !bfqd->rq_in_driver)
bfq_schedule_dispatch(bfqd);
/* release extra ref taken above, bfqq may happen to be freed now */
bfq_put_queue(bfqq);
}
/**
* __bfq_bic_change_cgroup - move @bic to @bfqg.
* @bfqd: the queue descriptor.
* @bic: the bic to move.
* @bfqg: the group to move to.
*
* Move bic to blkcg, assuming that bfqd->lock is held; which makes
* sure that the reference to cgroup is valid across the call (see
* comments in bfq_bic_update_cgroup on this issue)
*/
static void *__bfq_bic_change_cgroup(struct bfq_data *bfqd,
struct bfq_io_cq *bic,
struct bfq_group *bfqg)
{
struct bfq_queue *async_bfqq = bic_to_bfqq(bic, 0);
struct bfq_queue *sync_bfqq = bic_to_bfqq(bic, 1);
struct bfq_entity *entity;
if (async_bfqq) {
entity = &async_bfqq->entity;
if (entity->sched_data != &bfqg->sched_data) {
bic_set_bfqq(bic, NULL, 0);
bfq_release_process_ref(bfqd, async_bfqq);
}
}
if (sync_bfqq) {
if (!sync_bfqq->new_bfqq && !bfq_bfqq_coop(sync_bfqq)) {
/* We are the only user of this bfqq, just move it */
if (sync_bfqq->entity.sched_data != &bfqg->sched_data)
bfq_bfqq_move(bfqd, sync_bfqq, bfqg);
} else {
struct bfq_queue *bfqq;
/*
* The queue was merged to a different queue. Check
* that the merge chain still belongs to the same
* cgroup.
*/
for (bfqq = sync_bfqq; bfqq; bfqq = bfqq->new_bfqq)
if (bfqq->entity.sched_data !=
&bfqg->sched_data)
break;
if (bfqq) {
/*
* Some queue changed cgroup so the merge is
* not valid anymore. We cannot easily just
* cancel the merge (by clearing new_bfqq) as
* there may be other processes using this
* queue and holding refs to all queues below
* sync_bfqq->new_bfqq. Similarly if the merge
* already happened, we need to detach from
* bfqq now so that we cannot merge bio to a
* request from the old cgroup.
*/
bfq_put_cooperator(sync_bfqq);
bfq_release_process_ref(bfqd, sync_bfqq);
bic_set_bfqq(bic, NULL, 1);
}
}
}
return bfqg;
}
void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio)
{
struct bfq_data *bfqd = bic_to_bfqd(bic);
struct bfq_group *bfqg = bfq_bio_bfqg(bfqd, bio);
uint64_t serial_nr;
serial_nr = bfqg_to_blkg(bfqg)->blkcg->css.serial_nr;
/*
* Check whether blkcg has changed. The condition may trigger
* spuriously on a newly created cic but there's no harm.
*/
if (unlikely(!bfqd) || likely(bic->blkcg_serial_nr == serial_nr))
return;
/*
* New cgroup for this process. Make sure it is linked to bfq internal
* cgroup hierarchy.
*/
bfq_link_bfqg(bfqd, bfqg);
__bfq_bic_change_cgroup(bfqd, bic, bfqg);
/*
* Update blkg_path for bfq_log_* functions. We cache this
* path, and update it here, for the following
* reasons. Operations on blkg objects in blk-cgroup are
* protected with the request_queue lock, and not with the
* lock that protects the instances of this scheduler
* (bfqd->lock). This exposes BFQ to the following sort of
* race.
*
* The blkg_lookup performed in bfq_get_queue, protected
* through rcu, may happen to return the address of a copy of
* the original blkg. If this is the case, then the
* bfqg_and_blkg_get performed in bfq_get_queue, to pin down
* the blkg, is useless: it does not prevent blk-cgroup code
* from destroying both the original blkg and all objects
* directly or indirectly referred by the copy of the
* blkg.
*
* On the bright side, destroy operations on a blkg invoke, as
* a first step, hooks of the scheduler associated with the
* blkg. And these hooks are executed with bfqd->lock held for
* BFQ. As a consequence, for any blkg associated with the
* request queue this instance of the scheduler is attached
* to, we are guaranteed that such a blkg is not destroyed, and
* that all the pointers it contains are consistent, while we
* are holding bfqd->lock. A blkg_lookup performed with
* bfqd->lock held then returns a fully consistent blkg, which
* remains consistent until this lock is held.
*
* Thanks to the last fact, and to the fact that: (1) bfqg has
* been obtained through a blkg_lookup in the above
* assignment, and (2) bfqd->lock is being held, here we can
* safely use the policy data for the involved blkg (i.e., the
* field bfqg->pd) to get to the blkg associated with bfqg,
* and then we can safely use any field of blkg. After we
* release bfqd->lock, even just getting blkg through this
* bfqg may cause dangling references to be traversed, as
* bfqg->pd may not exist any more.
*
* In view of the above facts, here we cache, in the bfqg, any
* blkg data we may need for this bic, and for its associated
* bfq_queue. As of now, we need to cache only the path of the
* blkg, which is used in the bfq_log_* functions.
*
* Finally, note that bfqg itself needs to be protected from
* destruction on the blkg_free of the original blkg (which
* invokes bfq_pd_free). We use an additional private
* refcounter for bfqg, to let it disappear only after no
* bfq_queue refers to it any longer.
*/
blkg_path(bfqg_to_blkg(bfqg), bfqg->blkg_path, sizeof(bfqg->blkg_path));
bic->blkcg_serial_nr = serial_nr;
}
/**
* bfq_flush_idle_tree - deactivate any entity on the idle tree of @st.
* @st: the service tree being flushed.
*/
static void bfq_flush_idle_tree(struct bfq_service_tree *st)
{
struct bfq_entity *entity = st->first_idle;
for (; entity ; entity = st->first_idle)
__bfq_deactivate_entity(entity, false);
}
/**
* bfq_reparent_leaf_entity - move leaf entity to the root_group.
* @bfqd: the device data structure with the root group.
* @entity: the entity to move, if entity is a leaf; or the parent entity
* of an active leaf entity to move, if entity is not a leaf.
* @ioprio_class: I/O priority class to reparent.
*/
static void bfq_reparent_leaf_entity(struct bfq_data *bfqd,
struct bfq_entity *entity,
int ioprio_class)
{
struct bfq_queue *bfqq;
struct bfq_entity *child_entity = entity;
while (child_entity->my_sched_data) { /* leaf not reached yet */
struct bfq_sched_data *child_sd = child_entity->my_sched_data;
struct bfq_service_tree *child_st = child_sd->service_tree +
ioprio_class;
struct rb_root *child_active = &child_st->active;
child_entity = bfq_entity_of(rb_first(child_active));
if (!child_entity)
child_entity = child_sd->in_service_entity;
}
bfqq = bfq_entity_to_bfqq(child_entity);
bfq_bfqq_move(bfqd, bfqq, bfqd->root_group);
}
/**
* bfq_reparent_active_queues - move to the root group all active queues.
* @bfqd: the device data structure with the root group.
* @bfqg: the group to move from.
* @st: the service tree to start the search from.
* @ioprio_class: I/O priority class to reparent.
*/
static void bfq_reparent_active_queues(struct bfq_data *bfqd,
struct bfq_group *bfqg,
struct bfq_service_tree *st,
int ioprio_class)
{
struct rb_root *active = &st->active;
struct bfq_entity *entity;
while ((entity = bfq_entity_of(rb_first(active))))
bfq_reparent_leaf_entity(bfqd, entity, ioprio_class);
if (bfqg->sched_data.in_service_entity)
bfq_reparent_leaf_entity(bfqd,
bfqg->sched_data.in_service_entity,
ioprio_class);
}
/**
* bfq_pd_offline - deactivate the entity associated with @pd,
* and reparent its children entities.
* @pd: descriptor of the policy going offline.
*
* blkio already grabs the queue_lock for us, so no need to use
* RCU-based magic
*/
static void bfq_pd_offline(struct blkg_policy_data *pd)
{
struct bfq_service_tree *st;
struct bfq_group *bfqg = pd_to_bfqg(pd);
struct bfq_data *bfqd = bfqg->bfqd;
struct bfq_entity *entity = bfqg->my_entity;
unsigned long flags;
int i;
spin_lock_irqsave(&bfqd->lock, flags);
if (!entity) /* root group */
goto put_async_queues;
/*
* Empty all service_trees belonging to this group before
* deactivating the group itself.
*/
for (i = 0; i < BFQ_IOPRIO_CLASSES; i++) {
st = bfqg->sched_data.service_tree + i;
/*
* It may happen that some queues are still active
* (busy) upon group destruction (if the corresponding
* processes have been forced to terminate). We move
* all the leaf entities corresponding to these queues
* to the root_group.
* Also, it may happen that the group has an entity
* in service, which is disconnected from the active
* tree: it must be moved, too.
* There is no need to put the sync queues, as the
* scheduler has taken no reference.
*/
bfq_reparent_active_queues(bfqd, bfqg, st, i);
/*
* The idle tree may still contain bfq_queues
* belonging to exited task because they never
* migrated to a different cgroup from the one being
* destroyed now. In addition, even
* bfq_reparent_active_queues() may happen to add some
* entities to the idle tree. It happens if, in some
* of the calls to bfq_bfqq_move() performed by
* bfq_reparent_active_queues(), the queue to move is
* empty and gets expired.
*/
bfq_flush_idle_tree(st);
}
__bfq_deactivate_entity(entity, false);
put_async_queues:
bfq_put_async_queues(bfqd, bfqg);
bfqg->online = false;
spin_unlock_irqrestore(&bfqd->lock, flags);
/*
* @blkg is going offline and will be ignored by
* blkg_[rw]stat_recursive_sum(). Transfer stats to the parent so
* that they don't get lost. If IOs complete after this point, the
* stats for them will be lost. Oh well...
*/
bfqg_stats_xfer_dead(bfqg);
}
void bfq_end_wr_async(struct bfq_data *bfqd)
{
struct blkcg_gq *blkg;
list_for_each_entry(blkg, &bfqd->queue->blkg_list, q_node) {
struct bfq_group *bfqg = blkg_to_bfqg(blkg);
bfq_end_wr_async_queues(bfqd, bfqg);
}
bfq_end_wr_async_queues(bfqd, bfqd->root_group);
}
static int bfq_io_show_weight_legacy(struct seq_file *sf, void *v)
{
struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg);
unsigned int val = 0;
if (bfqgd)
val = bfqgd->weight;
seq_printf(sf, "%u\n", val);
return 0;
}
static u64 bfqg_prfill_weight_device(struct seq_file *sf,
struct blkg_policy_data *pd, int off)
{
struct bfq_group *bfqg = pd_to_bfqg(pd);
if (!bfqg->entity.dev_weight)
return 0;
return __blkg_prfill_u64(sf, pd, bfqg->entity.dev_weight);
}
static int bfq_io_show_weight(struct seq_file *sf, void *v)
{
struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg);
seq_printf(sf, "default %u\n", bfqgd->weight);
blkcg_print_blkgs(sf, blkcg, bfqg_prfill_weight_device,
&blkcg_policy_bfq, 0, false);
return 0;
}
static void bfq_group_set_weight(struct bfq_group *bfqg, u64 weight, u64 dev_weight)
{
weight = dev_weight ?: weight;
bfqg->entity.dev_weight = dev_weight;
/*
* Setting the prio_changed flag of the entity
* to 1 with new_weight == weight would re-set
* the value of the weight to its ioprio mapping.
* Set the flag only if necessary.
*/
if ((unsigned short)weight != bfqg->entity.new_weight) {
bfqg->entity.new_weight = (unsigned short)weight;
/*
* Make sure that the above new value has been
* stored in bfqg->entity.new_weight before
* setting the prio_changed flag. In fact,
* this flag may be read asynchronously (in
* critical sections protected by a different
* lock than that held here), and finding this
* flag set may cause the execution of the code
* for updating parameters whose value may
* depend also on bfqg->entity.new_weight (in
* __bfq_entity_update_weight_prio).
* This barrier makes sure that the new value
* of bfqg->entity.new_weight is correctly
* seen in that code.
*/
smp_wmb();
bfqg->entity.prio_changed = 1;
}
}
static int bfq_io_set_weight_legacy(struct cgroup_subsys_state *css,
struct cftype *cftype,
u64 val)
{
struct blkcg *blkcg = css_to_blkcg(css);
struct bfq_group_data *bfqgd = blkcg_to_bfqgd(blkcg);
struct blkcg_gq *blkg;
int ret = -ERANGE;
if (val < BFQ_MIN_WEIGHT || val > BFQ_MAX_WEIGHT)
return ret;
ret = 0;
spin_lock_irq(&blkcg->lock);
bfqgd->weight = (unsigned short)val;
hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) {
struct bfq_group *bfqg = blkg_to_bfqg(blkg);
if (bfqg)
bfq_group_set_weight(bfqg, val, 0);
}
spin_unlock_irq(&blkcg->lock);
return ret;
}
static ssize_t bfq_io_set_device_weight(struct kernfs_open_file *of,
char *buf, size_t nbytes,
loff_t off)
{
int ret;
struct blkg_conf_ctx ctx;
struct blkcg *blkcg = css_to_blkcg(of_css(of));
struct bfq_group *bfqg;
u64 v;
ret = blkg_conf_prep(blkcg, &blkcg_policy_bfq, buf, &ctx);
if (ret)
return ret;
if (sscanf(ctx.body, "%llu", &v) == 1) {
/* require "default" on dfl */
ret = -ERANGE;
if (!v)
goto out;
} else if (!strcmp(strim(ctx.body), "default")) {
v = 0;
} else {
ret = -EINVAL;
goto out;
}
bfqg = blkg_to_bfqg(ctx.blkg);
ret = -ERANGE;
if (!v || (v >= BFQ_MIN_WEIGHT && v <= BFQ_MAX_WEIGHT)) {
bfq_group_set_weight(bfqg, bfqg->entity.weight, v);
ret = 0;
}
out:
blkg_conf_finish(&ctx);
return ret ?: nbytes;
}
static ssize_t bfq_io_set_weight(struct kernfs_open_file *of,
char *buf, size_t nbytes,
loff_t off)
{
char *endp;
int ret;
u64 v;
buf = strim(buf);
/* "WEIGHT" or "default WEIGHT" sets the default weight */
v = simple_strtoull(buf, &endp, 0);
if (*endp == '\0' || sscanf(buf, "default %llu", &v) == 1) {
ret = bfq_io_set_weight_legacy(of_css(of), NULL, v);
return ret ?: nbytes;
}
return bfq_io_set_device_weight(of, buf, nbytes, off);
}
static int bfqg_print_rwstat(struct seq_file *sf, void *v)
{
blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_rwstat,
&blkcg_policy_bfq, seq_cft(sf)->private, true);
return 0;
}
static u64 bfqg_prfill_rwstat_recursive(struct seq_file *sf,
struct blkg_policy_data *pd, int off)
{
struct blkg_rwstat_sample sum;
blkg_rwstat_recursive_sum(pd_to_blkg(pd), &blkcg_policy_bfq, off, &sum);
return __blkg_prfill_rwstat(sf, pd, &sum);
}
static int bfqg_print_rwstat_recursive(struct seq_file *sf, void *v)
{
blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
bfqg_prfill_rwstat_recursive, &blkcg_policy_bfq,
seq_cft(sf)->private, true);
return 0;
}
#ifdef CONFIG_BFQ_CGROUP_DEBUG
static int bfqg_print_stat(struct seq_file *sf, void *v)
{
blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_stat,
&blkcg_policy_bfq, seq_cft(sf)->private, false);
return 0;
}
static u64 bfqg_prfill_stat_recursive(struct seq_file *sf,
struct blkg_policy_data *pd, int off)
{
struct blkcg_gq *blkg = pd_to_blkg(pd);
struct blkcg_gq *pos_blkg;
struct cgroup_subsys_state *pos_css;
u64 sum = 0;
lockdep_assert_held(&blkg->q->queue_lock);
rcu_read_lock();
blkg_for_each_descendant_pre(pos_blkg, pos_css, blkg) {
struct bfq_stat *stat;
if (!pos_blkg->online)
continue;
stat = (void *)blkg_to_pd(pos_blkg, &blkcg_policy_bfq) + off;
sum += bfq_stat_read(stat) + atomic64_read(&stat->aux_cnt);
}
rcu_read_unlock();
return __blkg_prfill_u64(sf, pd, sum);
}
static int bfqg_print_stat_recursive(struct seq_file *sf, void *v)
{
blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
bfqg_prfill_stat_recursive, &blkcg_policy_bfq,
seq_cft(sf)->private, false);
return 0;
}
static u64 bfqg_prfill_sectors(struct seq_file *sf, struct blkg_policy_data *pd,
int off)
{
struct bfq_group *bfqg = blkg_to_bfqg(pd->blkg);
u64 sum = blkg_rwstat_total(&bfqg->stats.bytes);
return __blkg_prfill_u64(sf, pd, sum >> 9);
}
static int bfqg_print_stat_sectors(struct seq_file *sf, void *v)
{
blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
bfqg_prfill_sectors, &blkcg_policy_bfq, 0, false);
return 0;
}
static u64 bfqg_prfill_sectors_recursive(struct seq_file *sf,
struct blkg_policy_data *pd, int off)
{
struct blkg_rwstat_sample tmp;
blkg_rwstat_recursive_sum(pd->blkg, &blkcg_policy_bfq,
offsetof(struct bfq_group, stats.bytes), &tmp);
return __blkg_prfill_u64(sf, pd,
(tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE]) >> 9);
}
static int bfqg_print_stat_sectors_recursive(struct seq_file *sf, void *v)
{
blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
bfqg_prfill_sectors_recursive, &blkcg_policy_bfq, 0,
false);
return 0;
}
static u64 bfqg_prfill_avg_queue_size(struct seq_file *sf,
struct blkg_policy_data *pd, int off)
{
struct bfq_group *bfqg = pd_to_bfqg(pd);
u64 samples = bfq_stat_read(&bfqg->stats.avg_queue_size_samples);
u64 v = 0;
if (samples) {
v = bfq_stat_read(&bfqg->stats.avg_queue_size_sum);
v = div64_u64(v, samples);
}
__blkg_prfill_u64(sf, pd, v);
return 0;
}
/* print avg_queue_size */
static int bfqg_print_avg_queue_size(struct seq_file *sf, void *v)
{
blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
bfqg_prfill_avg_queue_size, &blkcg_policy_bfq,
0, false);
return 0;
}
#endif /* CONFIG_BFQ_CGROUP_DEBUG */
struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node)
{
int ret;
ret = blkcg_activate_policy(bfqd->queue, &blkcg_policy_bfq);
if (ret)
return NULL;
return blkg_to_bfqg(bfqd->queue->root_blkg);
}
struct blkcg_policy blkcg_policy_bfq = {
.dfl_cftypes = bfq_blkg_files,
.legacy_cftypes = bfq_blkcg_legacy_files,
.cpd_alloc_fn = bfq_cpd_alloc,
.cpd_init_fn = bfq_cpd_init,
.cpd_bind_fn = bfq_cpd_init,
.cpd_free_fn = bfq_cpd_free,
.pd_alloc_fn = bfq_pd_alloc,
.pd_init_fn = bfq_pd_init,
.pd_offline_fn = bfq_pd_offline,
.pd_free_fn = bfq_pd_free,
.pd_reset_stats_fn = bfq_pd_reset_stats,
};
struct cftype bfq_blkcg_legacy_files[] = {
{
.name = "bfq.weight",
.flags = CFTYPE_NOT_ON_ROOT,
.seq_show = bfq_io_show_weight_legacy,
.write_u64 = bfq_io_set_weight_legacy,
},
{
.name = "bfq.weight_device",
.flags = CFTYPE_NOT_ON_ROOT,
.seq_show = bfq_io_show_weight,
.write = bfq_io_set_weight,
},
/* statistics, covers only the tasks in the bfqg */
{
.name = "bfq.io_service_bytes",
.private = offsetof(struct bfq_group, stats.bytes),
.seq_show = bfqg_print_rwstat,
},
{
.name = "bfq.io_serviced",
.private = offsetof(struct bfq_group, stats.ios),
.seq_show = bfqg_print_rwstat,
},
#ifdef CONFIG_BFQ_CGROUP_DEBUG
{
.name = "bfq.time",
.private = offsetof(struct bfq_group, stats.time),
.seq_show = bfqg_print_stat,
},
{
.name = "bfq.sectors",
.seq_show = bfqg_print_stat_sectors,
},
{
.name = "bfq.io_service_time",
.private = offsetof(struct bfq_group, stats.service_time),
.seq_show = bfqg_print_rwstat,
},
{
.name = "bfq.io_wait_time",
.private = offsetof(struct bfq_group, stats.wait_time),
.seq_show = bfqg_print_rwstat,
},
{
.name = "bfq.io_merged",
.private = offsetof(struct bfq_group, stats.merged),
.seq_show = bfqg_print_rwstat,
},
{
.name = "bfq.io_queued",
.private = offsetof(struct bfq_group, stats.queued),
.seq_show = bfqg_print_rwstat,
},
#endif /* CONFIG_BFQ_CGROUP_DEBUG */
/* the same statistics which cover the bfqg and its descendants */
{
.name = "bfq.io_service_bytes_recursive",
.private = offsetof(struct bfq_group, stats.bytes),
.seq_show = bfqg_print_rwstat_recursive,
},
{
.name = "bfq.io_serviced_recursive",
.private = offsetof(struct bfq_group, stats.ios),
.seq_show = bfqg_print_rwstat_recursive,
},
#ifdef CONFIG_BFQ_CGROUP_DEBUG
{
.name = "bfq.time_recursive",
.private = offsetof(struct bfq_group, stats.time),
.seq_show = bfqg_print_stat_recursive,
},
{
.name = "bfq.sectors_recursive",
.seq_show = bfqg_print_stat_sectors_recursive,
},
{
.name = "bfq.io_service_time_recursive",
.private = offsetof(struct bfq_group, stats.service_time),
.seq_show = bfqg_print_rwstat_recursive,
},
{
.name = "bfq.io_wait_time_recursive",
.private = offsetof(struct bfq_group, stats.wait_time),
.seq_show = bfqg_print_rwstat_recursive,
},
{
.name = "bfq.io_merged_recursive",
.private = offsetof(struct bfq_group, stats.merged),
.seq_show = bfqg_print_rwstat_recursive,
},
{
.name = "bfq.io_queued_recursive",
.private = offsetof(struct bfq_group, stats.queued),
.seq_show = bfqg_print_rwstat_recursive,
},
{
.name = "bfq.avg_queue_size",
.seq_show = bfqg_print_avg_queue_size,
},
{
.name = "bfq.group_wait_time",
.private = offsetof(struct bfq_group, stats.group_wait_time),
.seq_show = bfqg_print_stat,
},
{
.name = "bfq.idle_time",
.private = offsetof(struct bfq_group, stats.idle_time),
.seq_show = bfqg_print_stat,
},
{
.name = "bfq.empty_time",
.private = offsetof(struct bfq_group, stats.empty_time),
.seq_show = bfqg_print_stat,
},
{
.name = "bfq.dequeue",
.private = offsetof(struct bfq_group, stats.dequeue),
.seq_show = bfqg_print_stat,
},
#endif /* CONFIG_BFQ_CGROUP_DEBUG */
{ } /* terminate */
};
struct cftype bfq_blkg_files[] = {
{
.name = "bfq.weight",
.flags = CFTYPE_NOT_ON_ROOT,
.seq_show = bfq_io_show_weight,
.write = bfq_io_set_weight,
},
{} /* terminate */
};
#else /* CONFIG_BFQ_GROUP_IOSCHED */
void bfq_bfqq_move(struct bfq_data *bfqd, struct bfq_queue *bfqq,
struct bfq_group *bfqg) {}
void bfq_init_entity(struct bfq_entity *entity, struct bfq_group *bfqg)
{
struct bfq_queue *bfqq = bfq_entity_to_bfqq(entity);
entity->weight = entity->new_weight;
entity->orig_weight = entity->new_weight;
if (bfqq) {
bfqq->ioprio = bfqq->new_ioprio;
bfqq->ioprio_class = bfqq->new_ioprio_class;
}
entity->sched_data = &bfqg->sched_data;
}
void bfq_bic_update_cgroup(struct bfq_io_cq *bic, struct bio *bio) {}
void bfq_end_wr_async(struct bfq_data *bfqd)
{
bfq_end_wr_async_queues(bfqd, bfqd->root_group);
}
struct bfq_group *bfq_bio_bfqg(struct bfq_data *bfqd, struct bio *bio)
{
return bfqd->root_group;
}
struct bfq_group *bfqq_group(struct bfq_queue *bfqq)
{
return bfqq->bfqd->root_group;
}
void bfqg_and_blkg_put(struct bfq_group *bfqg) {}
struct bfq_group *bfq_create_group_hierarchy(struct bfq_data *bfqd, int node)
{
struct bfq_group *bfqg;
int i;
bfqg = kmalloc_node(sizeof(*bfqg), GFP_KERNEL | __GFP_ZERO, node);
if (!bfqg)
return NULL;
for (i = 0; i < BFQ_IOPRIO_CLASSES; i++)
bfqg->sched_data.service_tree[i] = BFQ_SERVICE_TREE_INIT;
return bfqg;
}
#endif /* CONFIG_BFQ_GROUP_IOSCHED */