From: Omar Sandoval <osandov@xxxxxx>
In preparation for putting blk-mq debugging information in debugfs,
create a directory tree mirroring the one in sysfs:
# tree -d /sys/kernel/debug/block
/sys/kernel/debug/block
|-- nvme0n1
| `-- mq
| |-- 0
| | `-- cpu0
| |-- 1
| | `-- cpu1
| |-- 2
| | `-- cpu2
| `-- 3
| `-- cpu3
`-- vda
`-- mq
`-- 0
|-- cpu0
|-- cpu1
|-- cpu2
`-- cpu3
Also add the scaffolding for the actual files that will go in here,
either under the hardware queue or software queue directories.
Signed-off-by: Omar Sandoval <osandov@xxxxxx>
---
block/Makefile | 1 +
block/blk-mq-debugfs.c | 152 +++++++++++++++++++++++++++++++++++++++++++++++++
block/blk-mq-sysfs.c | 8 +++
block/blk-mq.c | 2 +
block/blk-mq.h | 33 +++++++++++
include/linux/blkdev.h | 5 ++
6 files changed, 201 insertions(+)
create mode 100644 block/blk-mq-debugfs.c
diff --git a/block/Makefile b/block/Makefile
index 3ee0abd7205a..6cabe6bd2882 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -26,3 +26,4 @@ obj-$(CONFIG_BLK_DEV_INTEGRITY) += bio-integrity.o blk-integrity.o t10-pi.o
obj-$(CONFIG_BLK_MQ_PCI) += blk-mq-pci.o
obj-$(CONFIG_BLK_DEV_ZONED) += blk-zoned.o
obj-$(CONFIG_BLK_WBT) += blk-wbt.o
+obj-$(CONFIG_DEBUG_FS) += blk-mq-debugfs.o
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
new file mode 100644
index 000000000000..01711bbf5ade
--- /dev/null
+++ b/block/blk-mq-debugfs.c
@@ -0,0 +1,152 @@
+/*
+ * Copyright (C) 2017 Facebook
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public
+ * License v2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <linux/kernel.h>
+#include <linux/blkdev.h>
+#include <linux/debugfs.h>
+
+#include <linux/blk-mq.h>
+#include "blk-mq.h"
+
+struct blk_mq_debugfs_attr {
+ const char *name;
+ umode_t mode;
+ const struct file_operations *fops;
+};
+
+static struct dentry *block_debugfs_root;
+
+static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = {
+};
+
+static const struct blk_mq_debugfs_attr blk_mq_debugfs_ctx_attrs[] = {
+};
+
+int blk_mq_debugfs_register(struct request_queue *q, const char *name)
+{
+ if (!block_debugfs_root)
+ return -ENOENT;
+
+ q->debugfs_dir = debugfs_create_dir(name, block_debugfs_root);
+ if (!q->debugfs_dir)
+ goto err;
+
+ if (blk_mq_debugfs_register_hctxs(q))
+ goto err;
+
+ return 0;
+
+err:
+ blk_mq_debugfs_unregister(q);
+ return -ENOMEM;
+}
+
+void blk_mq_debugfs_unregister(struct request_queue *q)
+{
+ debugfs_remove_recursive(q->debugfs_dir);
+ q->mq_debugfs_dir = NULL;
+ q->debugfs_dir = NULL;
+}
+
+static int blk_mq_debugfs_register_ctx(struct request_queue *q,
+ struct blk_mq_ctx *ctx,
+ struct dentry *hctx_dir)
+{
+ struct dentry *ctx_dir;
+ char name[20];
+ int i;
+
+ snprintf(name, sizeof(name), "cpu%u", ctx->cpu);
+ ctx_dir = debugfs_create_dir(name, hctx_dir);
+ if (!ctx_dir)
+ return -ENOMEM;
+
+ for (i = 0; i < ARRAY_SIZE(blk_mq_debugfs_ctx_attrs); i++) {
+ const struct blk_mq_debugfs_attr *attr;
+
+ attr = &blk_mq_debugfs_ctx_attrs[i];
+ if (!debugfs_create_file(attr->name, attr->mode, ctx_dir, ctx,
+ attr->fops))
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+static int blk_mq_debugfs_register_hctx(struct request_queue *q,
+ struct blk_mq_hw_ctx *hctx)
+{
+ struct blk_mq_ctx *ctx;
+ struct dentry *hctx_dir;
+ char name[20];
+ int i;
+
+ snprintf(name, sizeof(name), "%u", hctx->queue_num);
+ hctx_dir = debugfs_create_dir(name, q->mq_debugfs_dir);
+ if (!hctx_dir)
+ return -ENOMEM;
+
+ for (i = 0; i < ARRAY_SIZE(blk_mq_debugfs_hctx_attrs); i++) {
+ const struct blk_mq_debugfs_attr *attr;
+
+ attr = &blk_mq_debugfs_hctx_attrs[i];
+ if (!debugfs_create_file(attr->name, attr->mode, hctx_dir, hctx,
+ attr->fops))
+ return -ENOMEM;
+ }
+
+ hctx_for_each_ctx(hctx, ctx, i) {
+ if (blk_mq_debugfs_register_ctx(q, ctx, hctx_dir))
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+int blk_mq_debugfs_register_hctxs(struct request_queue *q)
+{
+ struct blk_mq_hw_ctx *hctx;
+ int i;
+
+ if (!q->debugfs_dir)
+ return -ENOENT;
+
+ q->mq_debugfs_dir = debugfs_create_dir("mq", q->debugfs_dir);
+ if (!q->mq_debugfs_dir)
+ goto err;
+
+ queue_for_each_hw_ctx(q, hctx, i) {
+ if (blk_mq_debugfs_register_hctx(q, hctx))
+ goto err;
+ }
+
+ return 0;
+
+err:
+ blk_mq_debugfs_unregister_hctxs(q);
+ return -ENOMEM;
+}
+
+void blk_mq_debugfs_unregister_hctxs(struct request_queue *q)
+{
+ debugfs_remove_recursive(q->mq_debugfs_dir);
+ q->mq_debugfs_dir = NULL;
+}
+
+void blk_mq_debugfs_init(void)
+{
+ block_debugfs_root = debugfs_create_dir("block", NULL);
+}
diff --git a/block/blk-mq-sysfs.c b/block/blk-mq-sysfs.c
index 2caecaa98e40..91b93ca1c1e0 100644
--- a/block/blk-mq-sysfs.c
+++ b/block/blk-mq-sysfs.c
@@ -468,6 +468,8 @@ static void __blk_mq_unregister_dev(struct device *dev, struct request_queue *q)
kobject_put(&hctx->kobj);
}
+ blk_mq_debugfs_unregister(q);
+
kobject_uevent(&q->mq_kobj, KOBJ_REMOVE);
kobject_del(&q->mq_kobj);
kobject_put(&q->mq_kobj);
@@ -517,6 +519,8 @@ int blk_mq_register_dev(struct device *dev, struct request_queue *q)
kobject_uevent(&q->mq_kobj, KOBJ_ADD);
+ blk_mq_debugfs_register(q, kobject_name(&dev->kobj));
+
queue_for_each_hw_ctx(q, hctx, i) {
ret = blk_mq_register_hctx(hctx);
if (ret)
@@ -542,6 +546,8 @@ void blk_mq_sysfs_unregister(struct request_queue *q)
if (!q->mq_sysfs_init_done)
return;
+ blk_mq_debugfs_unregister_hctxs(q);
+
queue_for_each_hw_ctx(q, hctx, i)
blk_mq_unregister_hctx(hctx);
}
@@ -554,6 +560,8 @@ int blk_mq_sysfs_register(struct request_queue *q)
if (!q->mq_sysfs_init_done)
return ret;
+ blk_mq_debugfs_register_hctxs(q);
+
queue_for_each_hw_ctx(q, hctx, i) {
ret = blk_mq_register_hctx(hctx);
if (ret)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index ee69e5e89769..d9668d192722 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -2796,6 +2796,8 @@ void blk_mq_enable_hotplug(void)
static int __init blk_mq_init(void)
{
+ blk_mq_debugfs_init();
+
cpuhp_setup_state_multi(CPUHP_BLK_MQ_DEAD, "block/mq:dead", NULL,
blk_mq_hctx_notify_dead);
diff --git a/block/blk-mq.h b/block/blk-mq.h
index 0c7c034d9ddd..6c24b901acd7 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -78,6 +78,39 @@ extern int blk_mq_sysfs_register(struct request_queue *q);
extern void blk_mq_sysfs_unregister(struct request_queue *q);
extern void blk_mq_hctx_kobj_init(struct blk_mq_hw_ctx *hctx);
+/*
+ * debugfs helpers
+ */
+#ifdef CONFIG_DEBUG_FS
+void blk_mq_debugfs_init(void);
+int blk_mq_debugfs_register(struct request_queue *q, const char *name);
+void blk_mq_debugfs_unregister(struct request_queue *q);
+int blk_mq_debugfs_register_hctxs(struct request_queue *q);
+void blk_mq_debugfs_unregister_hctxs(struct request_queue *q);
+#else
+static inline void blk_mq_debugfs_init(void)
+{
+}
+
+int blk_mq_debugfs_register(struct request_queue *q, const char *name);
+{
+ return 0;
+}
+
+void blk_mq_debugfs_unregister(struct request_queue *q)
+{
+}
+
+int blk_mq_debugfs_register_hctxs(struct request_queue *q)
+{
+ return 0;
+}
+
+void blk_mq_debugfs_unregister_hctxs(struct request_queue *q)
+{
+}
+#endif
+
extern void blk_mq_rq_timed_out(struct request *req, bool reserved);
void blk_mq_release(struct request_queue *q);
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 25564857f5f8..0ee283f3cffe 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -571,6 +571,11 @@ struct request_queue {
struct list_head tag_set_list;
struct bio_set *bio_split;
+#ifdef CONFIG_DEBUG_FS
+ struct dentry *debugfs_dir;
+ struct dentry *mq_debugfs_dir;
+#endif
+
bool mq_sysfs_init_done;
};
--
2.11.0
--
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