From afd7de03c5268f74202c1dd4780a8532a11f4c6b Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Mon, 18 Oct 2021 08:53:19 -0600 Subject: [PATCH] block: remove some blk_mq_hw_ctx debugfs entries 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 Signed-off-by: Jens Axboe --- block/blk-mq-debugfs.c | 67 -------------------------------------------------- block/blk-mq.c | 16 ------------ include/linux/blk-mq.h | 10 -------- 3 files changed, 93 deletions(-) diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c index 928a16af9175..68ca5d21cda7 100644 --- a/block/blk-mq-debugfs.c +++ b/block/blk-mq-debugfs.c @@ -529,70 +529,6 @@ out: 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}, diff --git a/block/blk-mq.c b/block/blk-mq.c index 990d214a7658..bd241fd7ee49 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -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 @@ out: 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; } diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h index 95c3bd3a008e..9fb8618fb957 100644 --- a/include/linux/blk-mq.h +++ b/include/linux/blk-mq.h @@ -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 -- 2.11.0