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block: remove some blk_mq_hw_ctx debugfs entries

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Just like the blk_mq_ctx counterparts, we've got a bunch of counters
in here that are only for debugfs and are of questionnable value. They
are:

- dispatched, index of how many requests were dispatched in one go

- poll_{considered,invoked,success}, which track poll sucess rates. We're
  confident in the iopoll implementation at this point, don't bother
  tracking these.

As a bonus, this shrinks each hardware queue from 576 bytes to 512 bytes,
dropping a whole cacheline.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Jens Axboe 2021-10-18 08:53:19 -06:00
parent 9a14d6ce41
commit afd7de03c5
3 changed files with 0 additions and 93 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

67
block/blk-mq-debugfs.c
View File

@ -529,70 +529,6 @@ static int hctx_sched_tags_bitmap_show(void *data, struct seq_file *m)
return res;
}
static int hctx_io_poll_show(void *data, struct seq_file *m)
{
struct blk_mq_hw_ctx *hctx = data;
seq_printf(m, "considered=%lu\n", hctx->poll_considered);
seq_printf(m, "invoked=%lu\n", hctx->poll_invoked);
seq_printf(m, "success=%lu\n", hctx->poll_success);
return 0;
}
static ssize_t hctx_io_poll_write(void *data, const char __user *buf,
size_t count, loff_t *ppos)
{
struct blk_mq_hw_ctx *hctx = data;
hctx->poll_considered = hctx->poll_invoked = hctx->poll_success = 0;
return count;
}
static int hctx_dispatched_show(void *data, struct seq_file *m)
{
struct blk_mq_hw_ctx *hctx = data;
int i;
seq_printf(m, "%8u\t%lu\n", 0U, hctx->dispatched[0]);
for (i = 1; i < BLK_MQ_MAX_DISPATCH_ORDER - 1; i++) {
unsigned int d = 1U << (i - 1);
seq_printf(m, "%8u\t%lu\n", d, hctx->dispatched[i]);
}
seq_printf(m, "%8u+\t%lu\n", 1U << (i - 1), hctx->dispatched[i]);
return 0;
}
static ssize_t hctx_dispatched_write(void *data, const char __user *buf,
size_t count, loff_t *ppos)
{
struct blk_mq_hw_ctx *hctx = data;
int i;
for (i = 0; i < BLK_MQ_MAX_DISPATCH_ORDER; i++)
hctx->dispatched[i] = 0;
return count;
}
static int hctx_queued_show(void *data, struct seq_file *m)
{
struct blk_mq_hw_ctx *hctx = data;
seq_printf(m, "%lu\n", hctx->queued);
return 0;
}
static ssize_t hctx_queued_write(void *data, const char __user *buf,
size_t count, loff_t *ppos)
{
struct blk_mq_hw_ctx *hctx = data;
hctx->queued = 0;
return count;
}
static int hctx_run_show(void *data, struct seq_file *m)
{
struct blk_mq_hw_ctx *hctx = data;
@ -738,9 +674,6 @@ static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = {
{"tags_bitmap", 0400, hctx_tags_bitmap_show},
{"sched_tags", 0400, hctx_sched_tags_show},
{"sched_tags_bitmap", 0400, hctx_sched_tags_bitmap_show},
{"io_poll", 0600, hctx_io_poll_show, hctx_io_poll_write},
{"dispatched", 0600, hctx_dispatched_show, hctx_dispatched_write},
{"queued", 0600, hctx_queued_show, hctx_queued_write},
{"run", 0600, hctx_run_show, hctx_run_write},
{"active", 0400, hctx_active_show},
{"dispatch_busy", 0400, hctx_dispatch_busy_show},

16
block/blk-mq.c
View File

@ -382,7 +382,6 @@ static struct request *blk_mq_rq_ctx_init(struct blk_mq_alloc_data *data,
}
}
data->hctx->queued++;
return rq;
}
@ -1301,14 +1300,6 @@ struct request *blk_mq_dequeue_from_ctx(struct blk_mq_hw_ctx *hctx,
return data.rq;
}
static inline unsigned int queued_to_index(unsigned int queued)
{
if (!queued)
return 0;
return min(BLK_MQ_MAX_DISPATCH_ORDER - 1, ilog2(queued) + 1);
}
static bool __blk_mq_get_driver_tag(struct request *rq)
{
struct sbitmap_queue *bt = &rq->mq_hctx->tags->bitmap_tags;
@ -1632,8 +1623,6 @@ bool blk_mq_dispatch_rq_list(struct blk_mq_hw_ctx *hctx, struct list_head *list,
if (!list_empty(&zone_list))
list_splice_tail_init(&zone_list, list);
hctx->dispatched[queued_to_index(queued)]++;
/* If we didn't flush the entire list, we could have told the driver
* there was more coming, but that turned out to be a lie.
*/
@ -4200,14 +4189,9 @@ static int blk_mq_poll_classic(struct request_queue *q, blk_qc_t cookie,
long state = get_current_state();
int ret;
hctx->poll_considered++;
do {
hctx->poll_invoked++;
ret = q->mq_ops->poll(hctx);
if (ret > 0) {
hctx->poll_success++;
__set_current_state(TASK_RUNNING);
return ret;
}

10
include/linux/blk-mq.h
View File

@ -341,9 +341,6 @@ struct blk_mq_hw_ctx {
unsigned long queued;
/** @run: Number of dispatched requests. */
unsigned long run;
#define BLK_MQ_MAX_DISPATCH_ORDER 7
/** @dispatched: Number of dispatch requests by queue. */
unsigned long dispatched[BLK_MQ_MAX_DISPATCH_ORDER];
/** @numa_node: NUMA node the storage adapter has been connected to. */
unsigned int numa_node;
@ -363,13 +360,6 @@ struct blk_mq_hw_ctx {
/** @kobj: Kernel object for sysfs. */
struct kobject kobj;
/** @poll_considered: Count times blk_mq_poll() was called. */
unsigned long poll_considered;
/** @poll_invoked: Count how many requests blk_mq_poll() polled. */
unsigned long poll_invoked;
/** @poll_success: Count how many polled requests were completed. */
unsigned long poll_success;
#ifdef CONFIG_BLK_DEBUG_FS
/**
* @debugfs_dir: debugfs directory for this hardware queue. Named