--- /dev/null
+#ifndef _BLK_CGROUP_H
+#define _BLK_CGROUP_H
+/*
+ * Common Block IO controller cgroup interface
+ *
+ * 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/cgroup.h>
+#include <linux/u64_stats_sync.h>
+#include <linux/seq_file.h>
+#include <linux/radix-tree.h>
+#include <linux/blkdev.h>
+#include <linux/atomic.h>
+
+/* Max limits for throttle policy */
+#define THROTL_IOPS_MAX UINT_MAX
+
+/* CFQ specific, out here for blkcg->cfq_weight */
+#define CFQ_WEIGHT_MIN 10
+#define CFQ_WEIGHT_MAX 1000
+#define CFQ_WEIGHT_DEFAULT 500
+
+#ifdef CONFIG_BLK_CGROUP
+
+enum blkg_rwstat_type {
+ BLKG_RWSTAT_READ,
+ BLKG_RWSTAT_WRITE,
+ BLKG_RWSTAT_SYNC,
+ BLKG_RWSTAT_ASYNC,
+
+ BLKG_RWSTAT_NR,
+ BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR,
+};
+
+struct blkcg_gq;
+
+struct blkcg {
+ struct cgroup_subsys_state css;
+ spinlock_t lock;
+
+ struct radix_tree_root blkg_tree;
+ struct blkcg_gq *blkg_hint;
+ struct hlist_head blkg_list;
+
+ /* TODO: per-policy storage in blkcg */
+ unsigned int cfq_weight; /* belongs to cfq */
+ unsigned int cfq_leaf_weight;
+};
+
+struct blkg_stat {
+ struct u64_stats_sync syncp;
+ uint64_t cnt;
+};
+
+struct blkg_rwstat {
+ struct u64_stats_sync syncp;
+ uint64_t cnt[BLKG_RWSTAT_NR];
+};
+
+/*
+ * 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 has its private
+ * data on each blkg, the size of which is determined by
+ * blkcg_policy->pd_size. blkcg core allocates and frees such areas
+ * together with blkg and invokes pd_init/exit_fn() methods.
+ *
+ * Such private data must embed struct blkg_policy_data (pd) at the
+ * beginning and pd_size can't be smaller than pd.
+ */
+struct blkg_policy_data {
+ /* the blkg and policy id this per-policy data belongs to */
+ struct blkcg_gq *blkg;
+ int plid;
+
+ /* used during policy activation */
+ struct list_head alloc_node;
+};
+
+/* 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;
+
+ /* request allocation list for this blkcg-q pair */
+ struct request_list rl;
+
+ /* reference count */
+ atomic_t refcnt;
+
+ /* is this blkg online? protected by both blkcg and q locks */
+ bool online;
+
+ struct blkg_policy_data *pd[BLKCG_MAX_POLS];
+
+ struct rcu_head rcu_head;
+};
+
+typedef void (blkcg_pol_init_pd_fn)(struct blkcg_gq *blkg);
+typedef void (blkcg_pol_online_pd_fn)(struct blkcg_gq *blkg);
+typedef void (blkcg_pol_offline_pd_fn)(struct blkcg_gq *blkg);
+typedef void (blkcg_pol_exit_pd_fn)(struct blkcg_gq *blkg);
+typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkcg_gq *blkg);
+
+struct blkcg_policy {
+ int plid;
+ /* policy specific private data size */
+ size_t pd_size;
+ /* cgroup files for the policy */
+ struct cftype *cftypes;
+
+ /* operations */
+ blkcg_pol_init_pd_fn *pd_init_fn;
+ blkcg_pol_online_pd_fn *pd_online_fn;
+ blkcg_pol_offline_pd_fn *pd_offline_fn;
+ blkcg_pol_exit_pd_fn *pd_exit_fn;
+ blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn;
+};
+
+extern struct blkcg blkcg_root;
+
+struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q);
+struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
+ struct request_queue *q);
+int blkcg_init_queue(struct request_queue *q);
+void blkcg_drain_queue(struct request_queue *q);
+void blkcg_exit_queue(struct request_queue *q);
+
+/* 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 request_queue *q,
+ const struct blkcg_policy *pol);
+void blkcg_deactivate_policy(struct request_queue *q,
+ const struct blkcg_policy *pol);
+
+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);
+u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
+ const struct blkg_rwstat *rwstat);
+u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off);
+u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
+ int off);
+
+u64 blkg_stat_recursive_sum(struct blkg_policy_data *pd, int off);
+struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkg_policy_data *pd,
+ int off);
+
+struct blkg_conf_ctx {
+ struct gendisk *disk;
+ struct blkcg_gq *blkg;
+ u64 v;
+};
+
+int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
+ const char *input, struct blkg_conf_ctx *ctx);
+void blkg_conf_finish(struct blkg_conf_ctx *ctx);
+
+
+static inline struct blkcg *css_to_blkcg(struct cgroup_subsys_state *css)
+{
+ return css ? container_of(css, struct blkcg, css) : NULL;
+}
+
+static inline struct blkcg *task_blkcg(struct task_struct *tsk)
+{
+ return css_to_blkcg(task_css(tsk, blkio_cgrp_id));
+}
+
+static inline struct blkcg *bio_blkcg(struct bio *bio)
+{
+ if (bio && bio->bi_css)
+ return css_to_blkcg(bio->bi_css);
+ return task_blkcg(current);
+}
+
+/**
+ * blkcg_parent - get the parent of a blkcg
+ * @blkcg: blkcg of interest
+ *
+ * Return the parent blkcg of @blkcg. Can be called anytime.
+ */
+static inline struct blkcg *blkcg_parent(struct blkcg *blkcg)
+{
+ return css_to_blkcg(blkcg->css.parent);
+}
+
+/**
+ * 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;
+}
+
+/**
+ * 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;
+}
+
+/**
+ * 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)
+{
+ char *p;
+
+ p = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
+ if (!p) {
+ strncpy(buf, "<unavailable>", buflen);
+ return -ENAMETOOLONG;
+ }
+
+ memmove(buf, p, buf + buflen - p);
+ return 0;
+}
+
+/**
+ * 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)
+{
+ WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
+ atomic_inc(&blkg->refcnt);
+}
+
+void __blkg_release_rcu(struct rcu_head *rcu);
+
+/**
+ * blkg_put - put a blkg reference
+ * @blkg: blkg to put
+ */
+static inline void blkg_put(struct blkcg_gq *blkg)
+{
+ WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
+ if (atomic_dec_and_test(&blkg->refcnt))
+ call_rcu(&blkg->rcu_head, __blkg_release_rcu);
+}
+
+struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg, struct request_queue *q,
+ bool update_hint);
+
+/**
+ * blkg_for_each_descendant_pre - pre-order walk of a blkg's descendants
+ * @d_blkg: loop cursor pointing to the current descendant
+ * @pos_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, false)))
+
+/**
+ * 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, false)))
+
+/**
+ * blk_get_rl - get request_list to use
+ * @q: request_queue of interest
+ * @bio: bio which will be attached to the allocated request (may be %NULL)
+ *
+ * The caller wants to allocate a request from @q to use for @bio. Find
+ * the request_list to use and obtain a reference on it. Should be called
+ * under queue_lock. This function is guaranteed to return non-%NULL
+ * request_list.
+ */
+static inline struct request_list *blk_get_rl(struct request_queue *q,
+ struct bio *bio)
+{
+ struct blkcg *blkcg;
+ struct blkcg_gq *blkg;
+
+ rcu_read_lock();
+
+ blkcg = bio_blkcg(bio);
+
+ /* bypass blkg lookup and use @q->root_rl directly for root */
+ if (blkcg == &blkcg_root)
+ goto root_rl;
+
+ /*
+ * Try to use blkg->rl. blkg lookup may fail under memory pressure
+ * or if either the blkcg or queue is going away. Fall back to
+ * root_rl in such cases.
+ */
+ blkg = blkg_lookup_create(blkcg, q);
+ if (unlikely(IS_ERR(blkg)))
+ goto root_rl;
+
+ blkg_get(blkg);
+ rcu_read_unlock();
+ return &blkg->rl;
+root_rl:
+ rcu_read_unlock();
+ return &q->root_rl;
+}
+
+/**
+ * blk_put_rl - put request_list
+ * @rl: request_list to put
+ *
+ * Put the reference acquired by blk_get_rl(). Should be called under
+ * queue_lock.
+ */
+static inline void blk_put_rl(struct request_list *rl)
+{
+ /* root_rl may not have blkg set */
+ if (rl->blkg && rl->blkg->blkcg != &blkcg_root)
+ blkg_put(rl->blkg);
+}
+
+/**
+ * blk_rq_set_rl - associate a request with a request_list
+ * @rq: request of interest
+ * @rl: target request_list
+ *
+ * Associate @rq with @rl so that accounting and freeing can know the
+ * request_list @rq came from.
+ */
+static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl)
+{
+ rq->rl = rl;
+}
+
+/**
+ * blk_rq_rl - return the request_list a request came from
+ * @rq: request of interest
+ *
+ * Return the request_list @rq is allocated from.
+ */
+static inline struct request_list *blk_rq_rl(struct request *rq)
+{
+ return rq->rl;
+}
+
+struct request_list *__blk_queue_next_rl(struct request_list *rl,
+ struct request_queue *q);
+/**
+ * blk_queue_for_each_rl - iterate through all request_lists of a request_queue
+ *
+ * Should be used under queue_lock.
+ */
+#define blk_queue_for_each_rl(rl, q) \
+ for ((rl) = &(q)->root_rl; (rl); (rl) = __blk_queue_next_rl((rl), (q)))
+
+static inline void blkg_stat_init(struct blkg_stat *stat)
+{
+ u64_stats_init(&stat->syncp);
+}
+
+/**
+ * blkg_stat_add - add a value to a blkg_stat
+ * @stat: target blkg_stat
+ * @val: value to add
+ *
+ * Add @val to @stat. The caller is responsible for synchronizing calls to
+ * this function.
+ */
+static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
+{
+ u64_stats_update_begin(&stat->syncp);
+ stat->cnt += val;
+ u64_stats_update_end(&stat->syncp);
+}
+
+/**
+ * blkg_stat_read - read the current value of a blkg_stat
+ * @stat: blkg_stat to read
+ *
+ * Read the current value of @stat. This function can be called without
+ * synchroniztion and takes care of u64 atomicity.
+ */
+static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
+{
+ unsigned int start;
+ uint64_t v;
+
+ do {
+ start = u64_stats_fetch_begin_irq(&stat->syncp);
+ v = stat->cnt;
+ } while (u64_stats_fetch_retry_irq(&stat->syncp, start));
+
+ return v;
+}
+
+/**
+ * blkg_stat_reset - reset a blkg_stat
+ * @stat: blkg_stat to reset
+ */
+static inline void blkg_stat_reset(struct blkg_stat *stat)
+{
+ stat->cnt = 0;
+}
+
+/**
+ * blkg_stat_merge - merge a blkg_stat into another
+ * @to: the destination blkg_stat
+ * @from: the source
+ *
+ * Add @from's count to @to.
+ */
+static inline void blkg_stat_merge(struct blkg_stat *to, struct blkg_stat *from)
+{
+ blkg_stat_add(to, blkg_stat_read(from));
+}
+
+static inline void blkg_rwstat_init(struct blkg_rwstat *rwstat)
+{
+ u64_stats_init(&rwstat->syncp);
+}
+
+/**
+ * blkg_rwstat_add - add a value to a blkg_rwstat
+ * @rwstat: target blkg_rwstat
+ * @rw: mask of REQ_{WRITE|SYNC}
+ * @val: value to add
+ *
+ * Add @val to @rwstat. The counters are chosen according to @rw. The
+ * caller is responsible for synchronizing calls to this function.
+ */
+static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
+ int rw, uint64_t val)
+{
+ u64_stats_update_begin(&rwstat->syncp);
+
+ if (rw & REQ_WRITE)
+ rwstat->cnt[BLKG_RWSTAT_WRITE] += val;
+ else
+ rwstat->cnt[BLKG_RWSTAT_READ] += val;
+ if (rw & REQ_SYNC)
+ rwstat->cnt[BLKG_RWSTAT_SYNC] += val;
+ else
+ rwstat->cnt[BLKG_RWSTAT_ASYNC] += val;
+
+ u64_stats_update_end(&rwstat->syncp);
+}
+
+/**
+ * blkg_rwstat_read - read the current values of a blkg_rwstat
+ * @rwstat: blkg_rwstat to read
+ *
+ * Read the current snapshot of @rwstat and return it as the return value.
+ * This function can be called without synchronization and takes care of
+ * u64 atomicity.
+ */
+static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
+{
+ unsigned int start;
+ struct blkg_rwstat tmp;
+
+ do {
+ start = u64_stats_fetch_begin_irq(&rwstat->syncp);
+ tmp = *rwstat;
+ } while (u64_stats_fetch_retry_irq(&rwstat->syncp, start));
+
+ return tmp;
+}
+
+/**
+ * blkg_rwstat_total - read the total count of a blkg_rwstat
+ * @rwstat: blkg_rwstat to read
+ *
+ * Return the total count of @rwstat regardless of the IO direction. This
+ * function can be called without synchronization and takes care of u64
+ * atomicity.
+ */
+static inline uint64_t blkg_rwstat_total(struct blkg_rwstat *rwstat)
+{
+ struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
+
+ return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE];
+}
+
+/**
+ * blkg_rwstat_reset - reset a blkg_rwstat
+ * @rwstat: blkg_rwstat to reset
+ */
+static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
+{
+ memset(rwstat->cnt, 0, sizeof(rwstat->cnt));
+}
+
+/**
+ * blkg_rwstat_merge - merge a blkg_rwstat into another
+ * @to: the destination blkg_rwstat
+ * @from: the source
+ *
+ * Add @from's counts to @to.
+ */
+static inline void blkg_rwstat_merge(struct blkg_rwstat *to,
+ struct blkg_rwstat *from)
+{
+ struct blkg_rwstat v = blkg_rwstat_read(from);
+ int i;
+
+ u64_stats_update_begin(&to->syncp);
+ for (i = 0; i < BLKG_RWSTAT_NR; i++)
+ to->cnt[i] += v.cnt[i];
+ u64_stats_update_end(&to->syncp);
+}
+
+#else /* CONFIG_BLK_CGROUP */
+
+struct cgroup;
+struct blkcg;
+
+struct blkg_policy_data {
+};
+
+struct blkcg_gq {
+};
+
+struct blkcg_policy {
+};
+
+static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }
+static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
+static inline void blkcg_drain_queue(struct request_queue *q) { }
+static inline void blkcg_exit_queue(struct request_queue *q) { }
+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 blkcg *bio_blkcg(struct bio *bio) { return NULL; }
+
+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 struct request_list *blk_get_rl(struct request_queue *q,
+ struct bio *bio) { return &q->root_rl; }
+static inline void blk_put_rl(struct request_list *rl) { }
+static inline void blk_rq_set_rl(struct request *rq, struct request_list *rl) { }
+static inline struct request_list *blk_rq_rl(struct request *rq) { return &rq->q->root_rl; }
+
+#define blk_queue_for_each_rl(rl, q) \
+ for ((rl) = &(q)->root_rl; (rl); (rl) = NULL)
+
+#endif /* CONFIG_BLK_CGROUP */
+#endif /* _BLK_CGROUP_H */
Code Review / kvmfornfv.git / blobdiff