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0d2602ca30
This adds support for active queue tracking, meaning that the blk-mq tagging maintains a count of active users of a tag set. This allows us to maintain a notion of fairness between users, so that we can distribute the tag depth evenly without starving some users while allowing others to try unfair deep queues. If sharing of a tag set is detected, each hardware queue will track the depth of its own queue. And if this exceeds the total depth divided by the number of active queues, the user is actively throttled down. The active queue count is done lazily to avoid bouncing that data between submitter and completer. Each hardware queue gets marked active when it allocates its first tag, and gets marked inactive when 1) the last tag is cleared, and 2) the queue timeout grace period has passed. Signed-off-by: Jens Axboe <axboe@fb.com>
393 lines
9.4 KiB
C
393 lines
9.4 KiB
C
#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/backing-dev.h>
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#include <linux/bio.h>
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#include <linux/blkdev.h>
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#include <linux/mm.h>
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#include <linux/init.h>
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#include <linux/slab.h>
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#include <linux/workqueue.h>
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#include <linux/smp.h>
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#include <linux/blk-mq.h>
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#include "blk-mq.h"
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#include "blk-mq-tag.h"
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static void blk_mq_sysfs_release(struct kobject *kobj)
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{
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}
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struct blk_mq_ctx_sysfs_entry {
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struct attribute attr;
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ssize_t (*show)(struct blk_mq_ctx *, char *);
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ssize_t (*store)(struct blk_mq_ctx *, const char *, size_t);
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};
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struct blk_mq_hw_ctx_sysfs_entry {
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struct attribute attr;
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ssize_t (*show)(struct blk_mq_hw_ctx *, char *);
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ssize_t (*store)(struct blk_mq_hw_ctx *, const char *, size_t);
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};
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static ssize_t blk_mq_sysfs_show(struct kobject *kobj, struct attribute *attr,
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char *page)
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{
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struct blk_mq_ctx_sysfs_entry *entry;
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struct blk_mq_ctx *ctx;
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struct request_queue *q;
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ssize_t res;
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entry = container_of(attr, struct blk_mq_ctx_sysfs_entry, attr);
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ctx = container_of(kobj, struct blk_mq_ctx, kobj);
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q = ctx->queue;
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if (!entry->show)
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return -EIO;
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res = -ENOENT;
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mutex_lock(&q->sysfs_lock);
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if (!blk_queue_dying(q))
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res = entry->show(ctx, page);
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mutex_unlock(&q->sysfs_lock);
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return res;
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}
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static ssize_t blk_mq_sysfs_store(struct kobject *kobj, struct attribute *attr,
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const char *page, size_t length)
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{
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struct blk_mq_ctx_sysfs_entry *entry;
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struct blk_mq_ctx *ctx;
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struct request_queue *q;
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ssize_t res;
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entry = container_of(attr, struct blk_mq_ctx_sysfs_entry, attr);
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ctx = container_of(kobj, struct blk_mq_ctx, kobj);
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q = ctx->queue;
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if (!entry->store)
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return -EIO;
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res = -ENOENT;
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mutex_lock(&q->sysfs_lock);
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if (!blk_queue_dying(q))
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res = entry->store(ctx, page, length);
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mutex_unlock(&q->sysfs_lock);
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return res;
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}
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static ssize_t blk_mq_hw_sysfs_show(struct kobject *kobj,
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struct attribute *attr, char *page)
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{
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struct blk_mq_hw_ctx_sysfs_entry *entry;
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struct blk_mq_hw_ctx *hctx;
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struct request_queue *q;
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ssize_t res;
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entry = container_of(attr, struct blk_mq_hw_ctx_sysfs_entry, attr);
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hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
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q = hctx->queue;
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if (!entry->show)
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return -EIO;
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res = -ENOENT;
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mutex_lock(&q->sysfs_lock);
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if (!blk_queue_dying(q))
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res = entry->show(hctx, page);
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mutex_unlock(&q->sysfs_lock);
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return res;
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}
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static ssize_t blk_mq_hw_sysfs_store(struct kobject *kobj,
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struct attribute *attr, const char *page,
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size_t length)
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{
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struct blk_mq_hw_ctx_sysfs_entry *entry;
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struct blk_mq_hw_ctx *hctx;
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struct request_queue *q;
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ssize_t res;
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entry = container_of(attr, struct blk_mq_hw_ctx_sysfs_entry, attr);
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hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
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q = hctx->queue;
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if (!entry->store)
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return -EIO;
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res = -ENOENT;
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mutex_lock(&q->sysfs_lock);
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if (!blk_queue_dying(q))
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res = entry->store(hctx, page, length);
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mutex_unlock(&q->sysfs_lock);
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return res;
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}
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static ssize_t blk_mq_sysfs_dispatched_show(struct blk_mq_ctx *ctx, char *page)
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{
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return sprintf(page, "%lu %lu\n", ctx->rq_dispatched[1],
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ctx->rq_dispatched[0]);
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}
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static ssize_t blk_mq_sysfs_merged_show(struct blk_mq_ctx *ctx, char *page)
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{
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return sprintf(page, "%lu\n", ctx->rq_merged);
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}
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static ssize_t blk_mq_sysfs_completed_show(struct blk_mq_ctx *ctx, char *page)
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{
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return sprintf(page, "%lu %lu\n", ctx->rq_completed[1],
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ctx->rq_completed[0]);
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}
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static ssize_t sysfs_list_show(char *page, struct list_head *list, char *msg)
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{
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char *start_page = page;
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struct request *rq;
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page += sprintf(page, "%s:\n", msg);
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list_for_each_entry(rq, list, queuelist)
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page += sprintf(page, "\t%p\n", rq);
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return page - start_page;
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}
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static ssize_t blk_mq_sysfs_rq_list_show(struct blk_mq_ctx *ctx, char *page)
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{
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ssize_t ret;
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spin_lock(&ctx->lock);
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ret = sysfs_list_show(page, &ctx->rq_list, "CTX pending");
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spin_unlock(&ctx->lock);
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return ret;
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}
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static ssize_t blk_mq_hw_sysfs_queued_show(struct blk_mq_hw_ctx *hctx,
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char *page)
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{
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return sprintf(page, "%lu\n", hctx->queued);
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}
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static ssize_t blk_mq_hw_sysfs_run_show(struct blk_mq_hw_ctx *hctx, char *page)
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{
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return sprintf(page, "%lu\n", hctx->run);
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}
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static ssize_t blk_mq_hw_sysfs_dispatched_show(struct blk_mq_hw_ctx *hctx,
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char *page)
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{
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char *start_page = page;
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int i;
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page += sprintf(page, "%8u\t%lu\n", 0U, hctx->dispatched[0]);
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for (i = 1; i < BLK_MQ_MAX_DISPATCH_ORDER; i++) {
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unsigned long d = 1U << (i - 1);
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page += sprintf(page, "%8lu\t%lu\n", d, hctx->dispatched[i]);
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}
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return page - start_page;
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}
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static ssize_t blk_mq_hw_sysfs_rq_list_show(struct blk_mq_hw_ctx *hctx,
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char *page)
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{
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ssize_t ret;
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spin_lock(&hctx->lock);
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ret = sysfs_list_show(page, &hctx->dispatch, "HCTX pending");
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spin_unlock(&hctx->lock);
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return ret;
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}
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static ssize_t blk_mq_hw_sysfs_tags_show(struct blk_mq_hw_ctx *hctx, char *page)
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{
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return blk_mq_tag_sysfs_show(hctx->tags, page);
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}
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static ssize_t blk_mq_hw_sysfs_active_show(struct blk_mq_hw_ctx *hctx, char *page)
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{
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return sprintf(page, "%u\n", atomic_read(&hctx->nr_active));
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}
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static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page)
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{
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unsigned int i, first = 1;
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ssize_t ret = 0;
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blk_mq_disable_hotplug();
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for_each_cpu(i, hctx->cpumask) {
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if (first)
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ret += sprintf(ret + page, "%u", i);
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else
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ret += sprintf(ret + page, ", %u", i);
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first = 0;
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}
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blk_mq_enable_hotplug();
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ret += sprintf(ret + page, "\n");
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return ret;
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}
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static struct blk_mq_ctx_sysfs_entry blk_mq_sysfs_dispatched = {
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.attr = {.name = "dispatched", .mode = S_IRUGO },
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.show = blk_mq_sysfs_dispatched_show,
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};
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static struct blk_mq_ctx_sysfs_entry blk_mq_sysfs_merged = {
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.attr = {.name = "merged", .mode = S_IRUGO },
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.show = blk_mq_sysfs_merged_show,
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};
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static struct blk_mq_ctx_sysfs_entry blk_mq_sysfs_completed = {
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.attr = {.name = "completed", .mode = S_IRUGO },
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.show = blk_mq_sysfs_completed_show,
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};
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static struct blk_mq_ctx_sysfs_entry blk_mq_sysfs_rq_list = {
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.attr = {.name = "rq_list", .mode = S_IRUGO },
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.show = blk_mq_sysfs_rq_list_show,
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};
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static struct attribute *default_ctx_attrs[] = {
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&blk_mq_sysfs_dispatched.attr,
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&blk_mq_sysfs_merged.attr,
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&blk_mq_sysfs_completed.attr,
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&blk_mq_sysfs_rq_list.attr,
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NULL,
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};
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static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_queued = {
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.attr = {.name = "queued", .mode = S_IRUGO },
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.show = blk_mq_hw_sysfs_queued_show,
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};
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static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_run = {
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.attr = {.name = "run", .mode = S_IRUGO },
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.show = blk_mq_hw_sysfs_run_show,
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};
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static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_dispatched = {
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.attr = {.name = "dispatched", .mode = S_IRUGO },
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.show = blk_mq_hw_sysfs_dispatched_show,
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};
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static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_active = {
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.attr = {.name = "active", .mode = S_IRUGO },
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.show = blk_mq_hw_sysfs_active_show,
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};
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static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_pending = {
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.attr = {.name = "pending", .mode = S_IRUGO },
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.show = blk_mq_hw_sysfs_rq_list_show,
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};
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static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_tags = {
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.attr = {.name = "tags", .mode = S_IRUGO },
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.show = blk_mq_hw_sysfs_tags_show,
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};
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static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_cpus = {
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.attr = {.name = "cpu_list", .mode = S_IRUGO },
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.show = blk_mq_hw_sysfs_cpus_show,
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};
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static struct attribute *default_hw_ctx_attrs[] = {
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&blk_mq_hw_sysfs_queued.attr,
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&blk_mq_hw_sysfs_run.attr,
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&blk_mq_hw_sysfs_dispatched.attr,
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&blk_mq_hw_sysfs_pending.attr,
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&blk_mq_hw_sysfs_tags.attr,
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&blk_mq_hw_sysfs_cpus.attr,
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&blk_mq_hw_sysfs_active.attr,
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NULL,
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};
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static const struct sysfs_ops blk_mq_sysfs_ops = {
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.show = blk_mq_sysfs_show,
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.store = blk_mq_sysfs_store,
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};
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static const struct sysfs_ops blk_mq_hw_sysfs_ops = {
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.show = blk_mq_hw_sysfs_show,
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.store = blk_mq_hw_sysfs_store,
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};
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static struct kobj_type blk_mq_ktype = {
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.sysfs_ops = &blk_mq_sysfs_ops,
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.release = blk_mq_sysfs_release,
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};
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static struct kobj_type blk_mq_ctx_ktype = {
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.sysfs_ops = &blk_mq_sysfs_ops,
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.default_attrs = default_ctx_attrs,
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.release = blk_mq_sysfs_release,
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};
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static struct kobj_type blk_mq_hw_ktype = {
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.sysfs_ops = &blk_mq_hw_sysfs_ops,
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.default_attrs = default_hw_ctx_attrs,
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.release = blk_mq_sysfs_release,
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};
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void blk_mq_unregister_disk(struct gendisk *disk)
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{
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struct request_queue *q = disk->queue;
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struct blk_mq_hw_ctx *hctx;
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struct blk_mq_ctx *ctx;
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int i, j;
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queue_for_each_hw_ctx(q, hctx, i) {
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hctx_for_each_ctx(hctx, ctx, j) {
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kobject_del(&ctx->kobj);
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kobject_put(&ctx->kobj);
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}
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kobject_del(&hctx->kobj);
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kobject_put(&hctx->kobj);
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}
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kobject_uevent(&q->mq_kobj, KOBJ_REMOVE);
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kobject_del(&q->mq_kobj);
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kobject_put(&q->mq_kobj);
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kobject_put(&disk_to_dev(disk)->kobj);
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}
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int blk_mq_register_disk(struct gendisk *disk)
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{
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struct device *dev = disk_to_dev(disk);
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struct request_queue *q = disk->queue;
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struct blk_mq_hw_ctx *hctx;
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struct blk_mq_ctx *ctx;
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int ret, i, j;
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kobject_init(&q->mq_kobj, &blk_mq_ktype);
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ret = kobject_add(&q->mq_kobj, kobject_get(&dev->kobj), "%s", "mq");
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if (ret < 0)
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return ret;
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kobject_uevent(&q->mq_kobj, KOBJ_ADD);
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queue_for_each_hw_ctx(q, hctx, i) {
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kobject_init(&hctx->kobj, &blk_mq_hw_ktype);
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ret = kobject_add(&hctx->kobj, &q->mq_kobj, "%u", i);
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if (ret)
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break;
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if (!hctx->nr_ctx)
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continue;
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hctx_for_each_ctx(hctx, ctx, j) {
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kobject_init(&ctx->kobj, &blk_mq_ctx_ktype);
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ret = kobject_add(&ctx->kobj, &hctx->kobj, "cpu%u", ctx->cpu);
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if (ret)
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break;
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}
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}
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if (ret) {
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blk_mq_unregister_disk(disk);
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return ret;
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}
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return 0;
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}
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