css_put(&blkg->blkcg->css);
if (blkg->parent)
blkg_put(blkg->parent);
-
- wb_congested_put(blkg->wb_congested);
-
blkg_free(blkg);
}
struct blkcg_gq *new_blkg)
{
struct blkcg_gq *blkg;
- struct bdi_writeback_congested *wb_congested;
int i, ret;
WARN_ON_ONCE(!rcu_read_lock_held());
goto err_free_blkg;
}
- wb_congested = wb_congested_get_create(q->backing_dev_info,
- blkcg->css.id,
- GFP_NOWAIT | __GFP_NOWARN);
- if (!wb_congested) {
- ret = -ENOMEM;
- goto err_put_css;
- }
-
/* allocate */
if (!new_blkg) {
new_blkg = blkg_alloc(blkcg, q, GFP_NOWAIT | __GFP_NOWARN);
if (unlikely(!new_blkg)) {
ret = -ENOMEM;
- goto err_put_congested;
+ goto err_put_css;
}
}
blkg = new_blkg;
- blkg->wb_congested = wb_congested;
/* link parent */
if (blkcg_parent(blkcg)) {
blkg->parent = __blkg_lookup(blkcg_parent(blkcg), q, false);
if (WARN_ON_ONCE(!blkg->parent)) {
ret = -ENODEV;
- goto err_put_congested;
+ goto err_put_css;
}
blkg_get(blkg->parent);
}
blkg_put(blkg);
return ERR_PTR(ret);
-err_put_congested:
- wb_congested_put(wb_congested);
err_put_css:
css_put(&blkcg->css);
err_free_blkg:
}
/**
- * __blkg_lookup_create - lookup blkg, try to create one if not there
+ * blkg_lookup_create - lookup blkg, try to create one if not there
* @blkcg: blkcg of interest
* @q: request_queue of interest
*
* Lookup blkg for the @blkcg - @q pair. If it doesn't exist, try to
* create one. blkg creation is performed recursively from blkcg_root such
* that all non-root blkg's have access to the parent blkg. This function
- * should be called under RCU read lock and @q->queue_lock.
+ * should be called under RCU read lock and takes @q->queue_lock.
*
* Returns the blkg or the closest blkg if blkg_create() fails as it walks
* down from root.
*/
-struct blkcg_gq *__blkg_lookup_create(struct blkcg *blkcg,
- struct request_queue *q)
+static struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
+ struct request_queue *q)
{
struct blkcg_gq *blkg;
+ unsigned long flags;
WARN_ON_ONCE(!rcu_read_lock_held());
- lockdep_assert_held(&q->queue_lock);
- blkg = __blkg_lookup(blkcg, q, true);
+ blkg = blkg_lookup(blkcg, q);
if (blkg)
return blkg;
+ spin_lock_irqsave(&q->queue_lock, flags);
+ blkg = __blkg_lookup(blkcg, q, true);
+ if (blkg)
+ goto found;
+
/*
* Create blkgs walking down from blkcg_root to @blkcg, so that all
* non-root blkgs have access to their parents. Returns the closest
}
blkg = blkg_create(pos, q, NULL);
- if (IS_ERR(blkg))
- return ret_blkg;
+ if (IS_ERR(blkg)) {
+ blkg = ret_blkg;
+ break;
+ }
if (pos == blkcg)
- return blkg;
- }
-}
-
-/**
- * blkg_lookup_create - find or create a blkg
- * @blkcg: target block cgroup
- * @q: target request_queue
- *
- * This looks up or creates the blkg representing the unique pair
- * of the blkcg and the request_queue.
- */
-struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
- struct request_queue *q)
-{
- struct blkcg_gq *blkg = blkg_lookup(blkcg, q);
-
- if (unlikely(!blkg)) {
- unsigned long flags;
-
- spin_lock_irqsave(&q->queue_lock, flags);
- blkg = __blkg_lookup_create(blkcg, q);
- spin_unlock_irqrestore(&q->queue_lock, flags);
+ break;
}
+found:
+ spin_unlock_irqrestore(&q->queue_lock, flags);
return blkg;
}
}
EXPORT_SYMBOL_GPL(blkg_conf_finish);
+static void blkg_iostat_set(struct blkg_iostat *dst, struct blkg_iostat *src)
+{
+ int i;
+
+ for (i = 0; i < BLKG_IOSTAT_NR; i++) {
+ dst->bytes[i] = src->bytes[i];
+ dst->ios[i] = src->ios[i];
+ }
+}
+
+static void blkg_iostat_add(struct blkg_iostat *dst, struct blkg_iostat *src)
+{
+ int i;
+
+ for (i = 0; i < BLKG_IOSTAT_NR; i++) {
+ dst->bytes[i] += src->bytes[i];
+ dst->ios[i] += src->ios[i];
+ }
+}
+
+static void blkg_iostat_sub(struct blkg_iostat *dst, struct blkg_iostat *src)
+{
+ int i;
+
+ for (i = 0; i < BLKG_IOSTAT_NR; i++) {
+ dst->bytes[i] -= src->bytes[i];
+ dst->ios[i] -= src->ios[i];
+ }
+}
+
+static void blkcg_rstat_flush(struct cgroup_subsys_state *css, int cpu)
+{
+ struct blkcg *blkcg = css_to_blkcg(css);
+ struct blkcg_gq *blkg;
+
+ rcu_read_lock();
+
+ hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) {
+ struct blkcg_gq *parent = blkg->parent;
+ struct blkg_iostat_set *bisc = per_cpu_ptr(blkg->iostat_cpu, cpu);
+ struct blkg_iostat cur, delta;
+ unsigned int seq;
+
+ /* fetch the current per-cpu values */
+ do {
+ seq = u64_stats_fetch_begin(&bisc->sync);
+ blkg_iostat_set(&cur, &bisc->cur);
+ } while (u64_stats_fetch_retry(&bisc->sync, seq));
+
+ /* propagate percpu delta to global */
+ u64_stats_update_begin(&blkg->iostat.sync);
+ blkg_iostat_set(&delta, &cur);
+ blkg_iostat_sub(&delta, &bisc->last);
+ blkg_iostat_add(&blkg->iostat.cur, &delta);
+ blkg_iostat_add(&bisc->last, &delta);
+ u64_stats_update_end(&blkg->iostat.sync);
+
+ /* propagate global delta to parent */
+ if (parent) {
+ u64_stats_update_begin(&parent->iostat.sync);
+ blkg_iostat_set(&delta, &blkg->iostat.cur);
+ blkg_iostat_sub(&delta, &blkg->iostat.last);
+ blkg_iostat_add(&parent->iostat.cur, &delta);
+ blkg_iostat_add(&blkg->iostat.last, &delta);
+ u64_stats_update_end(&parent->iostat.sync);
+ }
+ }
+
+ rcu_read_unlock();
+}
+
+/*
+ * The rstat algorithms intentionally don't handle the root cgroup to avoid
+ * incurring overhead when no cgroups are defined. For that reason,
+ * cgroup_rstat_flush in blkcg_print_stat does not actually fill out the
+ * iostat in the root cgroup's blkcg_gq.
+ *
+ * However, we would like to re-use the printing code between the root and
+ * non-root cgroups to the extent possible. For that reason, we simulate
+ * flushing the root cgroup's stats by explicitly filling in the iostat
+ * with disk level statistics.
+ */
+static void blkcg_fill_root_iostats(void)
+{
+ struct class_dev_iter iter;
+ struct device *dev;
+
+ class_dev_iter_init(&iter, &block_class, NULL, &disk_type);
+ while ((dev = class_dev_iter_next(&iter))) {
+ struct gendisk *disk = dev_to_disk(dev);
+ struct hd_struct *part = disk_get_part(disk, 0);
+ struct blkcg_gq *blkg = blk_queue_root_blkg(disk->queue);
+ struct blkg_iostat tmp;
+ int cpu;
+
+ memset(&tmp, 0, sizeof(tmp));
+ for_each_possible_cpu(cpu) {
+ struct disk_stats *cpu_dkstats;
+
+ cpu_dkstats = per_cpu_ptr(part->dkstats, cpu);
+ tmp.ios[BLKG_IOSTAT_READ] +=
+ cpu_dkstats->ios[STAT_READ];
+ tmp.ios[BLKG_IOSTAT_WRITE] +=
+ cpu_dkstats->ios[STAT_WRITE];
+ tmp.ios[BLKG_IOSTAT_DISCARD] +=
+ cpu_dkstats->ios[STAT_DISCARD];
+ // convert sectors to bytes
+ tmp.bytes[BLKG_IOSTAT_READ] +=
+ cpu_dkstats->sectors[STAT_READ] << 9;
+ tmp.bytes[BLKG_IOSTAT_WRITE] +=
+ cpu_dkstats->sectors[STAT_WRITE] << 9;
+ tmp.bytes[BLKG_IOSTAT_DISCARD] +=
+ cpu_dkstats->sectors[STAT_DISCARD] << 9;
+
+ u64_stats_update_begin(&blkg->iostat.sync);
+ blkg_iostat_set(&blkg->iostat.cur, &tmp);
+ u64_stats_update_end(&blkg->iostat.sync);
+ }
+ }
+}
+
static int blkcg_print_stat(struct seq_file *sf, void *v)
{
struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
struct blkcg_gq *blkg;
- cgroup_rstat_flush(blkcg->css.cgroup);
+ if (!seq_css(sf)->parent)
+ blkcg_fill_root_iostats();
+ else
+ cgroup_rstat_flush(blkcg->css.cgroup);
+
rcu_read_lock();
hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) {
static struct cftype blkcg_files[] = {
{
.name = "stat",
- .flags = CFTYPE_NOT_ON_ROOT,
.seq_show = blkcg_print_stat,
},
{ } /* terminate */
* blkcg_init_queue - initialize blkcg part of request queue
* @q: request_queue to initialize
*
- * Called from __blk_alloc_queue(). Responsible for initializing blkcg
+ * Called from blk_alloc_queue(). Responsible for initializing blkcg
* part of new request_queue @q.
*
* RETURNS:
return ret;
}
-static void blkg_iostat_set(struct blkg_iostat *dst, struct blkg_iostat *src)
-{
- int i;
-
- for (i = 0; i < BLKG_IOSTAT_NR; i++) {
- dst->bytes[i] = src->bytes[i];
- dst->ios[i] = src->ios[i];
- }
-}
-
-static void blkg_iostat_add(struct blkg_iostat *dst, struct blkg_iostat *src)
-{
- int i;
-
- for (i = 0; i < BLKG_IOSTAT_NR; i++) {
- dst->bytes[i] += src->bytes[i];
- dst->ios[i] += src->ios[i];
- }
-}
-
-static void blkg_iostat_sub(struct blkg_iostat *dst, struct blkg_iostat *src)
-{
- int i;
-
- for (i = 0; i < BLKG_IOSTAT_NR; i++) {
- dst->bytes[i] -= src->bytes[i];
- dst->ios[i] -= src->ios[i];
- }
-}
-
-static void blkcg_rstat_flush(struct cgroup_subsys_state *css, int cpu)
-{
- struct blkcg *blkcg = css_to_blkcg(css);
- struct blkcg_gq *blkg;
-
- rcu_read_lock();
-
- hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) {
- struct blkcg_gq *parent = blkg->parent;
- struct blkg_iostat_set *bisc = per_cpu_ptr(blkg->iostat_cpu, cpu);
- struct blkg_iostat cur, delta;
- unsigned seq;
-
- /* fetch the current per-cpu values */
- do {
- seq = u64_stats_fetch_begin(&bisc->sync);
- blkg_iostat_set(&cur, &bisc->cur);
- } while (u64_stats_fetch_retry(&bisc->sync, seq));
-
- /* propagate percpu delta to global */
- u64_stats_update_begin(&blkg->iostat.sync);
- blkg_iostat_set(&delta, &cur);
- blkg_iostat_sub(&delta, &bisc->last);
- blkg_iostat_add(&blkg->iostat.cur, &delta);
- blkg_iostat_add(&bisc->last, &delta);
- u64_stats_update_end(&blkg->iostat.sync);
-
- /* propagate global delta to parent */
- if (parent) {
- u64_stats_update_begin(&parent->iostat.sync);
- blkg_iostat_set(&delta, &blkg->iostat.cur);
- blkg_iostat_sub(&delta, &blkg->iostat.last);
- blkg_iostat_add(&parent->iostat.cur, &delta);
- blkg_iostat_add(&blkg->iostat.last, &delta);
- u64_stats_update_end(&parent->iostat.sync);
- }
- }
-
- rcu_read_unlock();
-}
-
static void blkcg_bind(struct cgroup_subsys_state *root_css)
{
int i;
{
u64 old = atomic64_read(&blkg->delay_start);
+ /* negative use_delay means no scaling, see blkcg_set_delay() */
+ if (atomic_read(&blkg->use_delay) < 0)
+ return;
+
/*
* We only want to scale down every second. The idea here is that we
* want to delay people for min(delay_nsec, NSEC_PER_SEC) in a certain
*/
void blkcg_add_delay(struct blkcg_gq *blkg, u64 now, u64 delta)
{
+ if (WARN_ON_ONCE(atomic_read(&blkg->use_delay) < 0))
+ return;
blkcg_scale_delay(blkg, now);
atomic64_add(delta, &blkg->delay_nsec);
}
+/**
+ * blkg_tryget_closest - try and get a blkg ref on the closet blkg
+ * @bio: target bio
+ * @css: target css
+ *
+ * As the failure mode here is to walk up the blkg tree, this ensure that the
+ * blkg->parent pointers are always valid. This returns the blkg that it ended
+ * up taking a reference on or %NULL if no reference was taken.
+ */
+static inline struct blkcg_gq *blkg_tryget_closest(struct bio *bio,
+ struct cgroup_subsys_state *css)
+{
+ struct blkcg_gq *blkg, *ret_blkg = NULL;
+
+ rcu_read_lock();
+ blkg = blkg_lookup_create(css_to_blkcg(css), bio->bi_disk->queue);
+ while (blkg) {
+ if (blkg_tryget(blkg)) {
+ ret_blkg = blkg;
+ break;
+ }
+ blkg = blkg->parent;
+ }
+ rcu_read_unlock();
+
+ return ret_blkg;
+}
+
+/**
+ * bio_associate_blkg_from_css - associate a bio with a specified css
+ * @bio: target bio
+ * @css: target css
+ *
+ * Associate @bio with the blkg found by combining the css's blkg and the
+ * request_queue of the @bio. An association failure is handled by walking up
+ * the blkg tree. Therefore, the blkg associated can be anything between @blkg
+ * and q->root_blkg. This situation only happens when a cgroup is dying and
+ * then the remaining bios will spill to the closest alive blkg.
+ *
+ * A reference will be taken on the blkg and will be released when @bio is
+ * freed.
+ */
+void bio_associate_blkg_from_css(struct bio *bio,
+ struct cgroup_subsys_state *css)
+{
+ if (bio->bi_blkg)
+ blkg_put(bio->bi_blkg);
+
+ if (css && css->parent) {
+ bio->bi_blkg = blkg_tryget_closest(bio, css);
+ } else {
+ blkg_get(bio->bi_disk->queue->root_blkg);
+ bio->bi_blkg = bio->bi_disk->queue->root_blkg;
+ }
+}
+EXPORT_SYMBOL_GPL(bio_associate_blkg_from_css);
+
+/**
+ * bio_associate_blkg - associate a bio with a blkg
+ * @bio: target bio
+ *
+ * Associate @bio with the blkg found from the bio's css and request_queue.
+ * If one is not found, bio_lookup_blkg() creates the blkg. If a blkg is
+ * already associated, the css is reused and association redone as the
+ * request_queue may have changed.
+ */
+void bio_associate_blkg(struct bio *bio)
+{
+ struct cgroup_subsys_state *css;
+
+ rcu_read_lock();
+
+ if (bio->bi_blkg)
+ css = &bio_blkcg(bio)->css;
+ else
+ css = blkcg_css();
+
+ bio_associate_blkg_from_css(bio, css);
+
+ rcu_read_unlock();
+}
+EXPORT_SYMBOL_GPL(bio_associate_blkg);
+
+/**
+ * bio_clone_blkg_association - clone blkg association from src to dst bio
+ * @dst: destination bio
+ * @src: source bio
+ */
+void bio_clone_blkg_association(struct bio *dst, struct bio *src)
+{
+ if (src->bi_blkg) {
+ if (dst->bi_blkg)
+ blkg_put(dst->bi_blkg);
+ blkg_get(src->bi_blkg);
+ dst->bi_blkg = src->bi_blkg;
+ }
+}
+EXPORT_SYMBOL_GPL(bio_clone_blkg_association);
+
+static int blk_cgroup_io_type(struct bio *bio)
+{
+ if (op_is_discard(bio->bi_opf))
+ return BLKG_IOSTAT_DISCARD;
+ if (op_is_write(bio->bi_opf))
+ return BLKG_IOSTAT_WRITE;
+ return BLKG_IOSTAT_READ;
+}
+
+void blk_cgroup_bio_start(struct bio *bio)
+{
+ int rwd = blk_cgroup_io_type(bio), cpu;
+ struct blkg_iostat_set *bis;
+
+ cpu = get_cpu();
+ bis = per_cpu_ptr(bio->bi_blkg->iostat_cpu, cpu);
+ u64_stats_update_begin(&bis->sync);
+
+ /*
+ * If the bio is flagged with BIO_CGROUP_ACCT it means this is a split
+ * bio and we would have already accounted for the size of the bio.
+ */
+ if (!bio_flagged(bio, BIO_CGROUP_ACCT)) {
+ bio_set_flag(bio, BIO_CGROUP_ACCT);
+ bis->cur.bytes[rwd] += bio->bi_iter.bi_size;
+ }
+ bis->cur.ios[rwd]++;
+
+ u64_stats_update_end(&bis->sync);
+ if (cgroup_subsys_on_dfl(io_cgrp_subsys))
+ cgroup_rstat_updated(bio->bi_blkg->blkcg->css.cgroup, cpu);
+ put_cpu();
+}
+
static int __init blkcg_init(void)
{
blkcg_punt_bio_wq = alloc_workqueue("blkcg_punt_bio",
projects / linux-2.6-microblaze.git / blobdiff