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![Christoph Hellwig](/assets/img/avatar_default.png)
Pass the gendisk to blkcg_init_disk and blkcg_exit_disk as part of moving the blk-cgroup infrastructure to be gendisk based. Also remove the rather pointless kerneldoc comments for these internal functions with a single caller each. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Andreas Herrmann <aherrmann@suse.de> Acked-by: Tejun Heo <tj@kernel.org> Link: https://lore.kernel.org/r/20220921180501.1539876-7-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
510 lines
15 KiB
C
510 lines
15 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _BLK_CGROUP_PRIVATE_H
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#define _BLK_CGROUP_PRIVATE_H
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/*
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* block cgroup private header
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*
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* Based on ideas and code from CFQ, CFS and BFQ:
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* Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
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*
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* Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
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* Paolo Valente <paolo.valente@unimore.it>
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*
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* Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
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* Nauman Rafique <nauman@google.com>
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*/
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#include <linux/blk-cgroup.h>
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#include <linux/cgroup.h>
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#include <linux/kthread.h>
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#include <linux/blk-mq.h>
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struct blkcg_gq;
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struct blkg_policy_data;
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/* percpu_counter batch for blkg_[rw]stats, per-cpu drift doesn't matter */
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#define BLKG_STAT_CPU_BATCH (INT_MAX / 2)
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#ifdef CONFIG_BLK_CGROUP
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enum blkg_iostat_type {
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BLKG_IOSTAT_READ,
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BLKG_IOSTAT_WRITE,
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BLKG_IOSTAT_DISCARD,
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BLKG_IOSTAT_NR,
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};
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struct blkg_iostat {
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u64 bytes[BLKG_IOSTAT_NR];
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u64 ios[BLKG_IOSTAT_NR];
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};
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struct blkg_iostat_set {
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struct u64_stats_sync sync;
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struct blkg_iostat cur;
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struct blkg_iostat last;
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};
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/* association between a blk cgroup and a request queue */
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struct blkcg_gq {
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/* Pointer to the associated request_queue */
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struct request_queue *q;
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struct list_head q_node;
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struct hlist_node blkcg_node;
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struct blkcg *blkcg;
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/* all non-root blkcg_gq's are guaranteed to have access to parent */
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struct blkcg_gq *parent;
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/* reference count */
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struct percpu_ref refcnt;
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/* is this blkg online? protected by both blkcg and q locks */
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bool online;
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struct blkg_iostat_set __percpu *iostat_cpu;
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struct blkg_iostat_set iostat;
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struct blkg_policy_data *pd[BLKCG_MAX_POLS];
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spinlock_t async_bio_lock;
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struct bio_list async_bios;
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union {
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struct work_struct async_bio_work;
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struct work_struct free_work;
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};
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atomic_t use_delay;
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atomic64_t delay_nsec;
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atomic64_t delay_start;
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u64 last_delay;
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int last_use;
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struct rcu_head rcu_head;
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};
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struct blkcg {
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struct cgroup_subsys_state css;
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spinlock_t lock;
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refcount_t online_pin;
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struct radix_tree_root blkg_tree;
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struct blkcg_gq __rcu *blkg_hint;
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struct hlist_head blkg_list;
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struct blkcg_policy_data *cpd[BLKCG_MAX_POLS];
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struct list_head all_blkcgs_node;
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#ifdef CONFIG_BLK_CGROUP_FC_APPID
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char fc_app_id[FC_APPID_LEN];
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#endif
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#ifdef CONFIG_CGROUP_WRITEBACK
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struct list_head cgwb_list;
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#endif
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};
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static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css)
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{
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return css ? container_of(css, struct blkcg, css) : NULL;
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}
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/*
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* A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a
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* request_queue (q). This is used by blkcg policies which need to track
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* information per blkcg - q pair.
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*
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* There can be multiple active blkcg policies and each blkg:policy pair is
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* represented by a blkg_policy_data which is allocated and freed by each
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* policy's pd_alloc/free_fn() methods. A policy can allocate private data
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* area by allocating larger data structure which embeds blkg_policy_data
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* at the beginning.
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*/
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struct blkg_policy_data {
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/* the blkg and policy id this per-policy data belongs to */
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struct blkcg_gq *blkg;
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int plid;
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};
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/*
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* Policies that need to keep per-blkcg data which is independent from any
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* request_queue associated to it should implement cpd_alloc/free_fn()
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* methods. A policy can allocate private data area by allocating larger
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* data structure which embeds blkcg_policy_data at the beginning.
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* cpd_init() is invoked to let each policy handle per-blkcg data.
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*/
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struct blkcg_policy_data {
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/* the blkcg and policy id this per-policy data belongs to */
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struct blkcg *blkcg;
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int plid;
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};
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typedef struct blkcg_policy_data *(blkcg_pol_alloc_cpd_fn)(gfp_t gfp);
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typedef void (blkcg_pol_init_cpd_fn)(struct blkcg_policy_data *cpd);
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typedef void (blkcg_pol_free_cpd_fn)(struct blkcg_policy_data *cpd);
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typedef void (blkcg_pol_bind_cpd_fn)(struct blkcg_policy_data *cpd);
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typedef struct blkg_policy_data *(blkcg_pol_alloc_pd_fn)(gfp_t gfp,
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struct request_queue *q, struct blkcg *blkcg);
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typedef void (blkcg_pol_init_pd_fn)(struct blkg_policy_data *pd);
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typedef void (blkcg_pol_online_pd_fn)(struct blkg_policy_data *pd);
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typedef void (blkcg_pol_offline_pd_fn)(struct blkg_policy_data *pd);
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typedef void (blkcg_pol_free_pd_fn)(struct blkg_policy_data *pd);
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typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkg_policy_data *pd);
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typedef void (blkcg_pol_stat_pd_fn)(struct blkg_policy_data *pd,
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struct seq_file *s);
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struct blkcg_policy {
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int plid;
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/* cgroup files for the policy */
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struct cftype *dfl_cftypes;
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struct cftype *legacy_cftypes;
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/* operations */
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blkcg_pol_alloc_cpd_fn *cpd_alloc_fn;
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blkcg_pol_init_cpd_fn *cpd_init_fn;
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blkcg_pol_free_cpd_fn *cpd_free_fn;
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blkcg_pol_bind_cpd_fn *cpd_bind_fn;
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blkcg_pol_alloc_pd_fn *pd_alloc_fn;
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blkcg_pol_init_pd_fn *pd_init_fn;
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blkcg_pol_online_pd_fn *pd_online_fn;
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blkcg_pol_offline_pd_fn *pd_offline_fn;
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blkcg_pol_free_pd_fn *pd_free_fn;
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blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn;
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blkcg_pol_stat_pd_fn *pd_stat_fn;
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};
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extern struct blkcg blkcg_root;
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extern bool blkcg_debug_stats;
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int blkcg_init_disk(struct gendisk *disk);
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void blkcg_exit_disk(struct gendisk *disk);
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/* Blkio controller policy registration */
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int blkcg_policy_register(struct blkcg_policy *pol);
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void blkcg_policy_unregister(struct blkcg_policy *pol);
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int blkcg_activate_policy(struct request_queue *q,
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const struct blkcg_policy *pol);
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void blkcg_deactivate_policy(struct request_queue *q,
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const struct blkcg_policy *pol);
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const char *blkg_dev_name(struct blkcg_gq *blkg);
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void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
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u64 (*prfill)(struct seq_file *,
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struct blkg_policy_data *, int),
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const struct blkcg_policy *pol, int data,
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bool show_total);
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u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v);
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struct blkg_conf_ctx {
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struct block_device *bdev;
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struct blkcg_gq *blkg;
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char *body;
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};
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struct block_device *blkcg_conf_open_bdev(char **inputp);
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int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
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char *input, struct blkg_conf_ctx *ctx);
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void blkg_conf_finish(struct blkg_conf_ctx *ctx);
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/**
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* bio_issue_as_root_blkg - see if this bio needs to be issued as root blkg
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* @return: true if this bio needs to be submitted with the root blkg context.
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*
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* In order to avoid priority inversions we sometimes need to issue a bio as if
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* it were attached to the root blkg, and then backcharge to the actual owning
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* blkg. The idea is we do bio_blkcg_css() to look up the actual context for
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* the bio and attach the appropriate blkg to the bio. Then we call this helper
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* and if it is true run with the root blkg for that queue and then do any
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* backcharging to the originating cgroup once the io is complete.
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*/
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static inline bool bio_issue_as_root_blkg(struct bio *bio)
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{
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return (bio->bi_opf & (REQ_META | REQ_SWAP)) != 0;
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}
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/**
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* blkg_lookup - lookup blkg for the specified blkcg - q pair
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* @blkcg: blkcg of interest
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* @q: request_queue of interest
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*
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* Lookup blkg for the @blkcg - @q pair.
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* Must be called in a RCU critical section.
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*/
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static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg,
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struct request_queue *q)
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{
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struct blkcg_gq *blkg;
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WARN_ON_ONCE(!rcu_read_lock_held());
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if (blkcg == &blkcg_root)
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return q->root_blkg;
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blkg = rcu_dereference(blkcg->blkg_hint);
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if (blkg && blkg->q == q)
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return blkg;
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blkg = radix_tree_lookup(&blkcg->blkg_tree, q->id);
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if (blkg && blkg->q != q)
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blkg = NULL;
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return blkg;
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}
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/**
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* blkg_to_pdata - get policy private data
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* @blkg: blkg of interest
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* @pol: policy of interest
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*
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* Return pointer to private data associated with the @blkg-@pol pair.
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*/
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static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
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struct blkcg_policy *pol)
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{
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return blkg ? blkg->pd[pol->plid] : NULL;
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}
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static inline struct blkcg_policy_data *blkcg_to_cpd(struct blkcg *blkcg,
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struct blkcg_policy *pol)
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{
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return blkcg ? blkcg->cpd[pol->plid] : NULL;
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}
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/**
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* pdata_to_blkg - get blkg associated with policy private data
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* @pd: policy private data of interest
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*
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* @pd is policy private data. Determine the blkg it's associated with.
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*/
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static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd)
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{
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return pd ? pd->blkg : NULL;
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}
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static inline struct blkcg *cpd_to_blkcg(struct blkcg_policy_data *cpd)
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{
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return cpd ? cpd->blkcg : NULL;
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}
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/**
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* blkg_path - format cgroup path of blkg
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* @blkg: blkg of interest
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* @buf: target buffer
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* @buflen: target buffer length
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*
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* Format the path of the cgroup of @blkg into @buf.
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*/
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static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen)
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{
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return cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
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}
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/**
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* blkg_get - get a blkg reference
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* @blkg: blkg to get
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*
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* The caller should be holding an existing reference.
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*/
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static inline void blkg_get(struct blkcg_gq *blkg)
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{
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percpu_ref_get(&blkg->refcnt);
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}
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/**
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* blkg_tryget - try and get a blkg reference
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* @blkg: blkg to get
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*
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* This is for use when doing an RCU lookup of the blkg. We may be in the midst
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* of freeing this blkg, so we can only use it if the refcnt is not zero.
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*/
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static inline bool blkg_tryget(struct blkcg_gq *blkg)
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{
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return blkg && percpu_ref_tryget(&blkg->refcnt);
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}
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/**
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* blkg_put - put a blkg reference
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* @blkg: blkg to put
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*/
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static inline void blkg_put(struct blkcg_gq *blkg)
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{
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percpu_ref_put(&blkg->refcnt);
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}
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/**
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* blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants
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* @d_blkg: loop cursor pointing to the current descendant
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* @pos_css: used for iteration
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* @p_blkg: target blkg to walk descendants of
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*
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* Walk @c_blkg through the descendants of @p_blkg. Must be used with RCU
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* read locked. If called under either blkcg or queue lock, the iteration
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* is guaranteed to include all and only online blkgs. The caller may
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* update @pos_css by calling css_rightmost_descendant() to skip subtree.
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* @p_blkg is included in the iteration and the first node to be visited.
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*/
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#define blkg_for_each_descendant_pre(d_blkg, pos_css, p_blkg) \
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css_for_each_descendant_pre((pos_css), &(p_blkg)->blkcg->css) \
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if (((d_blkg) = blkg_lookup(css_to_blkcg(pos_css), \
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(p_blkg)->q)))
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/**
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* blkg_for_each_descendant_post - post-order walk of a blkg's descendants
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* @d_blkg: loop cursor pointing to the current descendant
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* @pos_css: used for iteration
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* @p_blkg: target blkg to walk descendants of
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*
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* Similar to blkg_for_each_descendant_pre() but performs post-order
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* traversal instead. Synchronization rules are the same. @p_blkg is
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* included in the iteration and the last node to be visited.
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*/
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#define blkg_for_each_descendant_post(d_blkg, pos_css, p_blkg) \
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css_for_each_descendant_post((pos_css), &(p_blkg)->blkcg->css) \
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if (((d_blkg) = blkg_lookup(css_to_blkcg(pos_css), \
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(p_blkg)->q)))
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bool __blkcg_punt_bio_submit(struct bio *bio);
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static inline bool blkcg_punt_bio_submit(struct bio *bio)
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{
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if (bio->bi_opf & REQ_CGROUP_PUNT)
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return __blkcg_punt_bio_submit(bio);
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else
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return false;
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}
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static inline void blkcg_bio_issue_init(struct bio *bio)
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{
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bio_issue_init(&bio->bi_issue, bio_sectors(bio));
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}
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static inline void blkcg_use_delay(struct blkcg_gq *blkg)
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{
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if (WARN_ON_ONCE(atomic_read(&blkg->use_delay) < 0))
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return;
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if (atomic_add_return(1, &blkg->use_delay) == 1)
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atomic_inc(&blkg->blkcg->css.cgroup->congestion_count);
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}
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static inline int blkcg_unuse_delay(struct blkcg_gq *blkg)
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{
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int old = atomic_read(&blkg->use_delay);
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if (WARN_ON_ONCE(old < 0))
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return 0;
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if (old == 0)
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return 0;
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/*
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* We do this song and dance because we can race with somebody else
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* adding or removing delay. If we just did an atomic_dec we'd end up
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* negative and we'd already be in trouble. We need to subtract 1 and
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* then check to see if we were the last delay so we can drop the
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* congestion count on the cgroup.
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*/
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while (old && !atomic_try_cmpxchg(&blkg->use_delay, &old, old - 1))
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;
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if (old == 0)
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return 0;
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if (old == 1)
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atomic_dec(&blkg->blkcg->css.cgroup->congestion_count);
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return 1;
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}
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/**
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* blkcg_set_delay - Enable allocator delay mechanism with the specified delay amount
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* @blkg: target blkg
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* @delay: delay duration in nsecs
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*
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* When enabled with this function, the delay is not decayed and must be
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* explicitly cleared with blkcg_clear_delay(). Must not be mixed with
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* blkcg_[un]use_delay() and blkcg_add_delay() usages.
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*/
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static inline void blkcg_set_delay(struct blkcg_gq *blkg, u64 delay)
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{
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int old = atomic_read(&blkg->use_delay);
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/* We only want 1 person setting the congestion count for this blkg. */
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if (!old && atomic_try_cmpxchg(&blkg->use_delay, &old, -1))
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atomic_inc(&blkg->blkcg->css.cgroup->congestion_count);
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atomic64_set(&blkg->delay_nsec, delay);
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}
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/**
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* blkcg_clear_delay - Disable allocator delay mechanism
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* @blkg: target blkg
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*
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* Disable use_delay mechanism. See blkcg_set_delay().
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*/
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static inline void blkcg_clear_delay(struct blkcg_gq *blkg)
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{
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int old = atomic_read(&blkg->use_delay);
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/* We only want 1 person clearing the congestion count for this blkg. */
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if (old && atomic_try_cmpxchg(&blkg->use_delay, &old, 0))
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atomic_dec(&blkg->blkcg->css.cgroup->congestion_count);
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}
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/**
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* blk_cgroup_mergeable - Determine whether to allow or disallow merges
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* @rq: request to merge into
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* @bio: bio to merge
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*
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* @bio and @rq should belong to the same cgroup and their issue_as_root should
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* match. The latter is necessary as we don't want to throttle e.g. a metadata
|
|
* update because it happens to be next to a regular IO.
|
|
*/
|
|
static inline bool blk_cgroup_mergeable(struct request *rq, struct bio *bio)
|
|
{
|
|
return rq->bio->bi_blkg == bio->bi_blkg &&
|
|
bio_issue_as_root_blkg(rq->bio) == bio_issue_as_root_blkg(bio);
|
|
}
|
|
|
|
void blk_cgroup_bio_start(struct bio *bio);
|
|
void blkcg_add_delay(struct blkcg_gq *blkg, u64 now, u64 delta);
|
|
#else /* CONFIG_BLK_CGROUP */
|
|
|
|
struct blkg_policy_data {
|
|
};
|
|
|
|
struct blkcg_policy_data {
|
|
};
|
|
|
|
struct blkcg_policy {
|
|
};
|
|
|
|
struct blkcg {
|
|
};
|
|
|
|
static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }
|
|
static inline int blkcg_init_disk(struct gendisk *disk) { return 0; }
|
|
static inline void blkcg_exit_disk(struct gendisk *disk) { }
|
|
static inline int blkcg_policy_register(struct blkcg_policy *pol) { return 0; }
|
|
static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { }
|
|
static inline int blkcg_activate_policy(struct request_queue *q,
|
|
const struct blkcg_policy *pol) { return 0; }
|
|
static inline void blkcg_deactivate_policy(struct request_queue *q,
|
|
const struct blkcg_policy *pol) { }
|
|
|
|
static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
|
|
struct blkcg_policy *pol) { return NULL; }
|
|
static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) { return NULL; }
|
|
static inline char *blkg_path(struct blkcg_gq *blkg) { return NULL; }
|
|
static inline void blkg_get(struct blkcg_gq *blkg) { }
|
|
static inline void blkg_put(struct blkcg_gq *blkg) { }
|
|
|
|
static inline bool blkcg_punt_bio_submit(struct bio *bio) { return false; }
|
|
static inline void blkcg_bio_issue_init(struct bio *bio) { }
|
|
static inline void blk_cgroup_bio_start(struct bio *bio) { }
|
|
static inline bool blk_cgroup_mergeable(struct request *rq, struct bio *bio) { return true; }
|
|
|
|
#define blk_queue_for_each_rl(rl, q) \
|
|
for ((rl) = &(q)->root_rl; (rl); (rl) = NULL)
|
|
|
|
#endif /* CONFIG_BLK_CGROUP */
|
|
|
|
#endif /* _BLK_CGROUP_PRIVATE_H */
|