aboutsummaryrefslogtreecommitdiffstats
path: root/block/blk-cgroup.h
diff options
context:
space:
mode:
Diffstat (limited to 'block/blk-cgroup.h')
-rw-r--r--block/blk-cgroup.h508
1 files changed, 508 insertions, 0 deletions
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h
new file mode 100644
index 000000000000..b927a4a0ad03
--- /dev/null
+++ b/block/blk-cgroup.h
@@ -0,0 +1,508 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BLK_CGROUP_PRIVATE_H
+#define _BLK_CGROUP_PRIVATE_H
+/*
+ * block cgroup private header
+ *
+ * Based on ideas and code from CFQ, CFS and BFQ:
+ * Copyright (C) 2003 Jens Axboe <axboe@kernel.dk>
+ *
+ * Copyright (C) 2008 Fabio Checconi <fabio@gandalf.sssup.it>
+ * Paolo Valente <paolo.valente@unimore.it>
+ *
+ * Copyright (C) 2009 Vivek Goyal <vgoyal@redhat.com>
+ * Nauman Rafique <nauman@google.com>
+ */
+
+#include <linux/blk-cgroup.h>
+#include <linux/cgroup.h>
+#include <linux/kthread.h>
+#include <linux/blk-mq.h>
+#include <linux/llist.h>
+
+struct blkcg_gq;
+struct blkg_policy_data;
+
+
+/* percpu_counter batch for blkg_[rw]stats, per-cpu drift doesn't matter */
+#define BLKG_STAT_CPU_BATCH (INT_MAX / 2)
+
+#ifdef CONFIG_BLK_CGROUP
+
+enum blkg_iostat_type {
+ BLKG_IOSTAT_READ,
+ BLKG_IOSTAT_WRITE,
+ BLKG_IOSTAT_DISCARD,
+
+ BLKG_IOSTAT_NR,
+};
+
+struct blkg_iostat {
+ u64 bytes[BLKG_IOSTAT_NR];
+ u64 ios[BLKG_IOSTAT_NR];
+};
+
+struct blkg_iostat_set {
+ struct u64_stats_sync sync;
+ struct blkcg_gq *blkg;
+ struct llist_node lnode;
+ int lqueued; /* queued in llist */
+ struct blkg_iostat cur;
+ struct blkg_iostat last;
+};
+
+/* association between a blk cgroup and a request queue */
+struct blkcg_gq {
+ /* Pointer to the associated request_queue */
+ struct request_queue *q;
+ struct list_head q_node;
+ struct hlist_node blkcg_node;
+ struct blkcg *blkcg;
+
+ /* all non-root blkcg_gq's are guaranteed to have access to parent */
+ struct blkcg_gq *parent;
+
+ /* reference count */
+ struct percpu_ref refcnt;
+
+ /* is this blkg online? protected by both blkcg and q locks */
+ bool online;
+
+ struct blkg_iostat_set __percpu *iostat_cpu;
+ struct blkg_iostat_set iostat;
+
+ struct blkg_policy_data *pd[BLKCG_MAX_POLS];
+#ifdef CONFIG_BLK_CGROUP_PUNT_BIO
+ spinlock_t async_bio_lock;
+ struct bio_list async_bios;
+#endif
+ union {
+ struct work_struct async_bio_work;
+ struct work_struct free_work;
+ };
+
+ atomic_t use_delay;
+ atomic64_t delay_nsec;
+ atomic64_t delay_start;
+ u64 last_delay;
+ int last_use;
+
+ struct rcu_head rcu_head;
+};
+
+struct blkcg {
+ struct cgroup_subsys_state css;
+ spinlock_t lock;
+ refcount_t online_pin;
+
+ struct radix_tree_root blkg_tree;
+ struct blkcg_gq __rcu *blkg_hint;
+ struct hlist_head blkg_list;
+
+ struct blkcg_policy_data *cpd[BLKCG_MAX_POLS];
+
+ struct list_head all_blkcgs_node;
+
+ /*
+ * List of updated percpu blkg_iostat_set's since the last flush.
+ */
+ struct llist_head __percpu *lhead;
+
+#ifdef CONFIG_BLK_CGROUP_FC_APPID
+ char fc_app_id[FC_APPID_LEN];
+#endif
+#ifdef CONFIG_CGROUP_WRITEBACK
+ struct list_head cgwb_list;
+#endif
+};
+
+static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css)
+{
+ return css ? container_of(css, struct blkcg, css) : NULL;
+}
+
+/*
+ * A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a
+ * request_queue (q). This is used by blkcg policies which need to track
+ * information per blkcg - q pair.
+ *
+ * There can be multiple active blkcg policies and each blkg:policy pair is
+ * represented by a blkg_policy_data which is allocated and freed by each
+ * policy's pd_alloc/free_fn() methods. A policy can allocate private data
+ * area by allocating larger data structure which embeds blkg_policy_data
+ * at the beginning.
+ */
+struct blkg_policy_data {
+ /* the blkg and policy id this per-policy data belongs to */
+ struct blkcg_gq *blkg;
+ int plid;
+ bool online;
+};
+
+/*
+ * Policies that need to keep per-blkcg data which is independent from any
+ * request_queue associated to it should implement cpd_alloc/free_fn()
+ * methods. A policy can allocate private data area by allocating larger
+ * data structure which embeds blkcg_policy_data at the beginning.
+ * cpd_init() is invoked to let each policy handle per-blkcg data.
+ */
+struct blkcg_policy_data {
+ /* the blkcg and policy id this per-policy data belongs to */
+ struct blkcg *blkcg;
+ int plid;
+};
+
+typedef struct blkcg_policy_data *(blkcg_pol_alloc_cpd_fn)(gfp_t gfp);
+typedef void (blkcg_pol_init_cpd_fn)(struct blkcg_policy_data *cpd);
+typedef void (blkcg_pol_free_cpd_fn)(struct blkcg_policy_data *cpd);
+typedef void (blkcg_pol_bind_cpd_fn)(struct blkcg_policy_data *cpd);
+typedef struct blkg_policy_data *(blkcg_pol_alloc_pd_fn)(struct gendisk *disk,
+ struct blkcg *blkcg, gfp_t gfp);
+typedef void (blkcg_pol_init_pd_fn)(struct blkg_policy_data *pd);
+typedef void (blkcg_pol_online_pd_fn)(struct blkg_policy_data *pd);
+typedef void (blkcg_pol_offline_pd_fn)(struct blkg_policy_data *pd);
+typedef void (blkcg_pol_free_pd_fn)(struct blkg_policy_data *pd);
+typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkg_policy_data *pd);
+typedef void (blkcg_pol_stat_pd_fn)(struct blkg_policy_data *pd,
+ struct seq_file *s);
+
+struct blkcg_policy {
+ int plid;
+ /* cgroup files for the policy */
+ struct cftype *dfl_cftypes;
+ struct cftype *legacy_cftypes;
+
+ /* operations */
+ blkcg_pol_alloc_cpd_fn *cpd_alloc_fn;
+ blkcg_pol_free_cpd_fn *cpd_free_fn;
+
+ blkcg_pol_alloc_pd_fn *pd_alloc_fn;
+ 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_free_pd_fn *pd_free_fn;
+ blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn;
+ blkcg_pol_stat_pd_fn *pd_stat_fn;
+};
+
+extern struct blkcg blkcg_root;
+extern bool blkcg_debug_stats;
+
+int blkcg_init_disk(struct gendisk *disk);
+void blkcg_exit_disk(struct gendisk *disk);
+
+/* Blkio controller policy registration */
+int blkcg_policy_register(struct blkcg_policy *pol);
+void blkcg_policy_unregister(struct blkcg_policy *pol);
+int blkcg_activate_policy(struct gendisk *disk, const struct blkcg_policy *pol);
+void blkcg_deactivate_policy(struct gendisk *disk,
+ const struct blkcg_policy *pol);
+
+const char *blkg_dev_name(struct blkcg_gq *blkg);
+void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
+ u64 (*prfill)(struct seq_file *,
+ struct blkg_policy_data *, int),
+ const struct blkcg_policy *pol, int data,
+ bool show_total);
+u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v);
+
+struct blkg_conf_ctx {
+ char *input;
+ char *body;
+ struct block_device *bdev;
+ struct blkcg_gq *blkg;
+};
+
+void blkg_conf_init(struct blkg_conf_ctx *ctx, char *input);
+int blkg_conf_open_bdev(struct blkg_conf_ctx *ctx);
+int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
+ struct blkg_conf_ctx *ctx);
+void blkg_conf_exit(struct blkg_conf_ctx *ctx);
+
+/**
+ * bio_issue_as_root_blkg - see if this bio needs to be issued as root blkg
+ * @return: true if this bio needs to be submitted with the root blkg context.
+ *
+ * In order to avoid priority inversions we sometimes need to issue a bio as if
+ * it were attached to the root blkg, and then backcharge to the actual owning
+ * blkg. The idea is we do bio_blkcg_css() to look up the actual context for
+ * the bio and attach the appropriate blkg to the bio. Then we call this helper
+ * and if it is true run with the root blkg for that queue and then do any
+ * backcharging to the originating cgroup once the io is complete.
+ */
+static inline bool bio_issue_as_root_blkg(struct bio *bio)
+{
+ return (bio->bi_opf & (REQ_META | REQ_SWAP)) != 0;
+}
+
+/**
+ * blkg_lookup - lookup blkg for the specified blkcg - q pair
+ * @blkcg: blkcg of interest
+ * @q: request_queue of interest
+ *
+ * Lookup blkg for the @blkcg - @q pair.
+
+ * Must be called in a RCU critical section.
+ */
+static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg,
+ struct request_queue *q)
+{
+ struct blkcg_gq *blkg;
+
+ if (blkcg == &blkcg_root)
+ return q->root_blkg;
+
+ blkg = rcu_dereference_check(blkcg->blkg_hint,
+ lockdep_is_held(&q->queue_lock));
+ if (blkg && blkg->q == q)
+ return blkg;
+
+ blkg = radix_tree_lookup(&blkcg->blkg_tree, q->id);
+ if (blkg && blkg->q != q)
+ blkg = NULL;
+ return blkg;
+}
+
+/**
+ * blkg_to_pdata - get policy private data
+ * @blkg: blkg of interest
+ * @pol: policy of interest
+ *
+ * Return pointer to private data associated with the @blkg-@pol pair.
+ */
+static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
+ struct blkcg_policy *pol)
+{
+ return blkg ? blkg->pd[pol->plid] : NULL;
+}
+
+static inline struct blkcg_policy_data *blkcg_to_cpd(struct blkcg *blkcg,
+ struct blkcg_policy *pol)
+{
+ return blkcg ? blkcg->cpd[pol->plid] : NULL;
+}
+
+/**
+ * pdata_to_blkg - get blkg associated with policy private data
+ * @pd: policy private data of interest
+ *
+ * @pd is policy private data. Determine the blkg it's associated with.
+ */
+static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd)
+{
+ return pd ? pd->blkg : NULL;
+}
+
+static inline struct blkcg *cpd_to_blkcg(struct blkcg_policy_data *cpd)
+{
+ return cpd ? cpd->blkcg : NULL;
+}
+
+/**
+ * blkg_path - format cgroup path of blkg
+ * @blkg: blkg of interest
+ * @buf: target buffer
+ * @buflen: target buffer length
+ *
+ * Format the path of the cgroup of @blkg into @buf.
+ */
+static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen)
+{
+ return cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
+}
+
+/**
+ * blkg_get - get a blkg reference
+ * @blkg: blkg to get
+ *
+ * The caller should be holding an existing reference.
+ */
+static inline void blkg_get(struct blkcg_gq *blkg)
+{
+ percpu_ref_get(&blkg->refcnt);
+}
+
+/**
+ * blkg_tryget - try and get a blkg reference
+ * @blkg: blkg to get
+ *
+ * This is for use when doing an RCU lookup of the blkg. We may be in the midst
+ * of freeing this blkg, so we can only use it if the refcnt is not zero.
+ */
+static inline bool blkg_tryget(struct blkcg_gq *blkg)
+{
+ return blkg && percpu_ref_tryget(&blkg->refcnt);
+}
+
+/**
+ * blkg_put - put a blkg reference
+ * @blkg: blkg to put
+ */
+static inline void blkg_put(struct blkcg_gq *blkg)
+{
+ percpu_ref_put(&blkg->refcnt);
+}
+
+/**
+ * blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants
+ * @d_blkg: loop cursor pointing to the current descendant
+ * @pos_css: 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_css by calling css_rightmost_descendant() to skip subtree.
+ * @p_blkg is included in the iteration and the first node to be visited.
+ */
+#define blkg_for_each_descendant_pre(d_blkg, pos_css, p_blkg) \
+ css_for_each_descendant_pre((pos_css), &(p_blkg)->blkcg->css) \
+ if (((d_blkg) = blkg_lookup(css_to_blkcg(pos_css), \
+ (p_blkg)->q)))
+
+/**
+ * blkg_for_each_descendant_post - post-order walk of a blkg's descendants
+ * @d_blkg: loop cursor pointing to the current descendant
+ * @pos_css: used for iteration
+ * @p_blkg: target blkg to walk descendants of
+ *
+ * Similar to blkg_for_each_descendant_pre() but performs post-order
+ * traversal instead. Synchronization rules are the same. @p_blkg is
+ * included in the iteration and the last node to be visited.
+ */
+#define blkg_for_each_descendant_post(d_blkg, pos_css, p_blkg) \
+ css_for_each_descendant_post((pos_css), &(p_blkg)->blkcg->css) \
+ if (((d_blkg) = blkg_lookup(css_to_blkcg(pos_css), \
+ (p_blkg)->q)))
+
+static inline void blkcg_bio_issue_init(struct bio *bio)
+{
+ bio_issue_init(&bio->bi_issue, bio_sectors(bio));
+}
+
+static inline void blkcg_use_delay(struct blkcg_gq *blkg)
+{
+ if (WARN_ON_ONCE(atomic_read(&blkg->use_delay) < 0))
+ return;
+ if (atomic_add_return(1, &blkg->use_delay) == 1)
+ atomic_inc(&blkg->blkcg->css.cgroup->congestion_count);
+}
+
+static inline int blkcg_unuse_delay(struct blkcg_gq *blkg)
+{
+ int old = atomic_read(&blkg->use_delay);
+
+ if (WARN_ON_ONCE(old < 0))
+ return 0;
+ if (old == 0)
+ return 0;
+
+ /*
+ * We do this song and dance because we can race with somebody else
+ * adding or removing delay. If we just did an atomic_dec we'd end up
+ * negative and we'd already be in trouble. We need to subtract 1 and
+ * then check to see if we were the last delay so we can drop the
+ * congestion count on the cgroup.
+ */
+ while (old && !atomic_try_cmpxchg(&blkg->use_delay, &old, old - 1))
+ ;
+
+ if (old == 0)
+ return 0;
+ if (old == 1)
+ atomic_dec(&blkg->blkcg->css.cgroup->congestion_count);
+ return 1;
+}
+
+/**
+ * blkcg_set_delay - Enable allocator delay mechanism with the specified delay amount
+ * @blkg: target blkg
+ * @delay: delay duration in nsecs
+ *
+ * When enabled with this function, the delay is not decayed and must be
+ * explicitly cleared with blkcg_clear_delay(). Must not be mixed with
+ * blkcg_[un]use_delay() and blkcg_add_delay() usages.
+ */
+static inline void blkcg_set_delay(struct blkcg_gq *blkg, u64 delay)
+{
+ int old = atomic_read(&blkg->use_delay);
+
+ /* We only want 1 person setting the congestion count for this blkg. */
+ if (!old && atomic_try_cmpxchg(&blkg->use_delay, &old, -1))
+ atomic_inc(&blkg->blkcg->css.cgroup->congestion_count);
+
+ atomic64_set(&blkg->delay_nsec, delay);
+}
+
+/**
+ * blkcg_clear_delay - Disable allocator delay mechanism
+ * @blkg: target blkg
+ *
+ * Disable use_delay mechanism. See blkcg_set_delay().
+ */
+static inline void blkcg_clear_delay(struct blkcg_gq *blkg)
+{
+ int old = atomic_read(&blkg->use_delay);
+
+ /* We only want 1 person clearing the congestion count for this blkg. */
+ if (old && atomic_try_cmpxchg(&blkg->use_delay, &old, 0))
+ atomic_dec(&blkg->blkcg->css.cgroup->congestion_count);
+}
+
+/**
+ * blk_cgroup_mergeable - Determine whether to allow or disallow merges
+ * @rq: request to merge into
+ * @bio: bio to merge
+ *
+ * @bio and @rq should belong to the same cgroup and their issue_as_root should
+ * 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 gendisk *disk,
+ const struct blkcg_policy *pol) { return 0; }
+static inline void blkcg_deactivate_policy(struct gendisk *disk,
+ 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 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 */
generated by cgit 1.2.3-korg (git 2.39.0) at 2024-04-27 17:16:50 +0000