mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 17:30:02 +00:00
![Ming Lei](/assets/img/avatar_default.png)
In case of BLK_MQ_F_BLOCKING, per-hctx srcu is used to protect dispatch critical area. However, this srcu instance stays at the end of hctx, and it often takes standalone cacheline, often cold. Inside srcu_read_lock() and srcu_read_unlock(), WRITE is always done on the indirect percpu variable which is allocated from heap instead of being embedded, srcu->srcu_idx is read only in srcu_read_lock(). It doesn't matter if srcu structure stays in hctx or request queue. So switch to per-request-queue srcu for protecting dispatch, and this way simplifies quiesce a lot, not mention quiesce is always done on the request queue wide. Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20211203131534.3668411-3-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
325 lines
6.9 KiB
C
325 lines
6.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#include <linux/kernel.h>
|
|
#include <linux/module.h>
|
|
#include <linux/backing-dev.h>
|
|
#include <linux/bio.h>
|
|
#include <linux/blkdev.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/init.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/workqueue.h>
|
|
#include <linux/smp.h>
|
|
|
|
#include <linux/blk-mq.h>
|
|
#include "blk.h"
|
|
#include "blk-mq.h"
|
|
#include "blk-mq-tag.h"
|
|
|
|
static void blk_mq_sysfs_release(struct kobject *kobj)
|
|
{
|
|
struct blk_mq_ctxs *ctxs = container_of(kobj, struct blk_mq_ctxs, kobj);
|
|
|
|
free_percpu(ctxs->queue_ctx);
|
|
kfree(ctxs);
|
|
}
|
|
|
|
static void blk_mq_ctx_sysfs_release(struct kobject *kobj)
|
|
{
|
|
struct blk_mq_ctx *ctx = container_of(kobj, struct blk_mq_ctx, kobj);
|
|
|
|
/* ctx->ctxs won't be released until all ctx are freed */
|
|
kobject_put(&ctx->ctxs->kobj);
|
|
}
|
|
|
|
static void blk_mq_hw_sysfs_release(struct kobject *kobj)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx = container_of(kobj, struct blk_mq_hw_ctx,
|
|
kobj);
|
|
|
|
blk_free_flush_queue(hctx->fq);
|
|
sbitmap_free(&hctx->ctx_map);
|
|
free_cpumask_var(hctx->cpumask);
|
|
kfree(hctx->ctxs);
|
|
kfree(hctx);
|
|
}
|
|
|
|
struct blk_mq_hw_ctx_sysfs_entry {
|
|
struct attribute attr;
|
|
ssize_t (*show)(struct blk_mq_hw_ctx *, char *);
|
|
ssize_t (*store)(struct blk_mq_hw_ctx *, const char *, size_t);
|
|
};
|
|
|
|
static ssize_t blk_mq_hw_sysfs_show(struct kobject *kobj,
|
|
struct attribute *attr, char *page)
|
|
{
|
|
struct blk_mq_hw_ctx_sysfs_entry *entry;
|
|
struct blk_mq_hw_ctx *hctx;
|
|
struct request_queue *q;
|
|
ssize_t res;
|
|
|
|
entry = container_of(attr, struct blk_mq_hw_ctx_sysfs_entry, attr);
|
|
hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
|
|
q = hctx->queue;
|
|
|
|
if (!entry->show)
|
|
return -EIO;
|
|
|
|
mutex_lock(&q->sysfs_lock);
|
|
res = entry->show(hctx, page);
|
|
mutex_unlock(&q->sysfs_lock);
|
|
return res;
|
|
}
|
|
|
|
static ssize_t blk_mq_hw_sysfs_store(struct kobject *kobj,
|
|
struct attribute *attr, const char *page,
|
|
size_t length)
|
|
{
|
|
struct blk_mq_hw_ctx_sysfs_entry *entry;
|
|
struct blk_mq_hw_ctx *hctx;
|
|
struct request_queue *q;
|
|
ssize_t res;
|
|
|
|
entry = container_of(attr, struct blk_mq_hw_ctx_sysfs_entry, attr);
|
|
hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
|
|
q = hctx->queue;
|
|
|
|
if (!entry->store)
|
|
return -EIO;
|
|
|
|
mutex_lock(&q->sysfs_lock);
|
|
res = entry->store(hctx, page, length);
|
|
mutex_unlock(&q->sysfs_lock);
|
|
return res;
|
|
}
|
|
|
|
static ssize_t blk_mq_hw_sysfs_nr_tags_show(struct blk_mq_hw_ctx *hctx,
|
|
char *page)
|
|
{
|
|
return sprintf(page, "%u\n", hctx->tags->nr_tags);
|
|
}
|
|
|
|
static ssize_t blk_mq_hw_sysfs_nr_reserved_tags_show(struct blk_mq_hw_ctx *hctx,
|
|
char *page)
|
|
{
|
|
return sprintf(page, "%u\n", hctx->tags->nr_reserved_tags);
|
|
}
|
|
|
|
static ssize_t blk_mq_hw_sysfs_cpus_show(struct blk_mq_hw_ctx *hctx, char *page)
|
|
{
|
|
const size_t size = PAGE_SIZE - 1;
|
|
unsigned int i, first = 1;
|
|
int ret = 0, pos = 0;
|
|
|
|
for_each_cpu(i, hctx->cpumask) {
|
|
if (first)
|
|
ret = snprintf(pos + page, size - pos, "%u", i);
|
|
else
|
|
ret = snprintf(pos + page, size - pos, ", %u", i);
|
|
|
|
if (ret >= size - pos)
|
|
break;
|
|
|
|
first = 0;
|
|
pos += ret;
|
|
}
|
|
|
|
ret = snprintf(pos + page, size + 1 - pos, "\n");
|
|
return pos + ret;
|
|
}
|
|
|
|
static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_tags = {
|
|
.attr = {.name = "nr_tags", .mode = 0444 },
|
|
.show = blk_mq_hw_sysfs_nr_tags_show,
|
|
};
|
|
static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_nr_reserved_tags = {
|
|
.attr = {.name = "nr_reserved_tags", .mode = 0444 },
|
|
.show = blk_mq_hw_sysfs_nr_reserved_tags_show,
|
|
};
|
|
static struct blk_mq_hw_ctx_sysfs_entry blk_mq_hw_sysfs_cpus = {
|
|
.attr = {.name = "cpu_list", .mode = 0444 },
|
|
.show = blk_mq_hw_sysfs_cpus_show,
|
|
};
|
|
|
|
static struct attribute *default_hw_ctx_attrs[] = {
|
|
&blk_mq_hw_sysfs_nr_tags.attr,
|
|
&blk_mq_hw_sysfs_nr_reserved_tags.attr,
|
|
&blk_mq_hw_sysfs_cpus.attr,
|
|
NULL,
|
|
};
|
|
ATTRIBUTE_GROUPS(default_hw_ctx);
|
|
|
|
static const struct sysfs_ops blk_mq_hw_sysfs_ops = {
|
|
.show = blk_mq_hw_sysfs_show,
|
|
.store = blk_mq_hw_sysfs_store,
|
|
};
|
|
|
|
static struct kobj_type blk_mq_ktype = {
|
|
.release = blk_mq_sysfs_release,
|
|
};
|
|
|
|
static struct kobj_type blk_mq_ctx_ktype = {
|
|
.release = blk_mq_ctx_sysfs_release,
|
|
};
|
|
|
|
static struct kobj_type blk_mq_hw_ktype = {
|
|
.sysfs_ops = &blk_mq_hw_sysfs_ops,
|
|
.default_groups = default_hw_ctx_groups,
|
|
.release = blk_mq_hw_sysfs_release,
|
|
};
|
|
|
|
static void blk_mq_unregister_hctx(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
struct blk_mq_ctx *ctx;
|
|
int i;
|
|
|
|
if (!hctx->nr_ctx)
|
|
return;
|
|
|
|
hctx_for_each_ctx(hctx, ctx, i)
|
|
kobject_del(&ctx->kobj);
|
|
|
|
kobject_del(&hctx->kobj);
|
|
}
|
|
|
|
static int blk_mq_register_hctx(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
struct request_queue *q = hctx->queue;
|
|
struct blk_mq_ctx *ctx;
|
|
int i, ret;
|
|
|
|
if (!hctx->nr_ctx)
|
|
return 0;
|
|
|
|
ret = kobject_add(&hctx->kobj, q->mq_kobj, "%u", hctx->queue_num);
|
|
if (ret)
|
|
return ret;
|
|
|
|
hctx_for_each_ctx(hctx, ctx, i) {
|
|
ret = kobject_add(&ctx->kobj, &hctx->kobj, "cpu%u", ctx->cpu);
|
|
if (ret)
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
void blk_mq_unregister_dev(struct device *dev, struct request_queue *q)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i;
|
|
|
|
lockdep_assert_held(&q->sysfs_dir_lock);
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i)
|
|
blk_mq_unregister_hctx(hctx);
|
|
|
|
kobject_uevent(q->mq_kobj, KOBJ_REMOVE);
|
|
kobject_del(q->mq_kobj);
|
|
kobject_put(&dev->kobj);
|
|
|
|
q->mq_sysfs_init_done = false;
|
|
}
|
|
|
|
void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx)
|
|
{
|
|
kobject_init(&hctx->kobj, &blk_mq_hw_ktype);
|
|
}
|
|
|
|
void blk_mq_sysfs_deinit(struct request_queue *q)
|
|
{
|
|
struct blk_mq_ctx *ctx;
|
|
int cpu;
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
ctx = per_cpu_ptr(q->queue_ctx, cpu);
|
|
kobject_put(&ctx->kobj);
|
|
}
|
|
kobject_put(q->mq_kobj);
|
|
}
|
|
|
|
void blk_mq_sysfs_init(struct request_queue *q)
|
|
{
|
|
struct blk_mq_ctx *ctx;
|
|
int cpu;
|
|
|
|
kobject_init(q->mq_kobj, &blk_mq_ktype);
|
|
|
|
for_each_possible_cpu(cpu) {
|
|
ctx = per_cpu_ptr(q->queue_ctx, cpu);
|
|
|
|
kobject_get(q->mq_kobj);
|
|
kobject_init(&ctx->kobj, &blk_mq_ctx_ktype);
|
|
}
|
|
}
|
|
|
|
int __blk_mq_register_dev(struct device *dev, struct request_queue *q)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int ret, i;
|
|
|
|
WARN_ON_ONCE(!q->kobj.parent);
|
|
lockdep_assert_held(&q->sysfs_dir_lock);
|
|
|
|
ret = kobject_add(q->mq_kobj, kobject_get(&dev->kobj), "%s", "mq");
|
|
if (ret < 0)
|
|
goto out;
|
|
|
|
kobject_uevent(q->mq_kobj, KOBJ_ADD);
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
ret = blk_mq_register_hctx(hctx);
|
|
if (ret)
|
|
goto unreg;
|
|
}
|
|
|
|
q->mq_sysfs_init_done = true;
|
|
|
|
out:
|
|
return ret;
|
|
|
|
unreg:
|
|
while (--i >= 0)
|
|
blk_mq_unregister_hctx(q->queue_hw_ctx[i]);
|
|
|
|
kobject_uevent(q->mq_kobj, KOBJ_REMOVE);
|
|
kobject_del(q->mq_kobj);
|
|
kobject_put(&dev->kobj);
|
|
return ret;
|
|
}
|
|
|
|
void blk_mq_sysfs_unregister(struct request_queue *q)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i;
|
|
|
|
mutex_lock(&q->sysfs_dir_lock);
|
|
if (!q->mq_sysfs_init_done)
|
|
goto unlock;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i)
|
|
blk_mq_unregister_hctx(hctx);
|
|
|
|
unlock:
|
|
mutex_unlock(&q->sysfs_dir_lock);
|
|
}
|
|
|
|
int blk_mq_sysfs_register(struct request_queue *q)
|
|
{
|
|
struct blk_mq_hw_ctx *hctx;
|
|
int i, ret = 0;
|
|
|
|
mutex_lock(&q->sysfs_dir_lock);
|
|
if (!q->mq_sysfs_init_done)
|
|
goto unlock;
|
|
|
|
queue_for_each_hw_ctx(q, hctx, i) {
|
|
ret = blk_mq_register_hctx(hctx);
|
|
if (ret)
|
|
break;
|
|
}
|
|
|
|
unlock:
|
|
mutex_unlock(&q->sysfs_dir_lock);
|
|
|
|
return ret;
|
|
}
|