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authorJens Axboe <axboe@kernel.dk>2017-06-26 08:15:27 -0600
committerJens Axboe <axboe@kernel.dk>2017-06-27 12:05:31 -0600
commitf793dfd3f39a3dc50468b06498606b3a906f42f1 (patch)
tree5bce7522f30a29ec7931e6b1cdc5d37f9e60b13e /block/blk-mq-debugfs.c
parentcb6934f8ea1a595902ca37e250e0917d4dd7b2a7 (diff)
blk-mq: expose write hints through debugfs
Useful to verify that things are working the way they should. Reading the file will return number of kb written with each write hint. Writing the file will reset the statistics. No care is taken to ensure that we don't race on updates. Drivers will write to q->write_hints[] if they handle a given write hint. Reviewed-by: Andreas Dilger <adilger@dilger.ca> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-mq-debugfs.c')
-rw-r--r--block/blk-mq-debugfs.c24
1 files changed, 24 insertions, 0 deletions
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 9edebbdce0bd..9ebc2945f991 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -135,6 +135,29 @@ static void print_stat(struct seq_file *m, struct blk_rq_stat *stat)
}
}
+static int queue_write_hint_show(void *data, struct seq_file *m)
+{
+ struct request_queue *q = data;
+ int i;
+
+ for (i = 0; i < BLK_MAX_WRITE_HINTS; i++)
+ seq_printf(m, "hint%d: %llu\n", i, q->write_hints[i]);
+
+ return 0;
+}
+
+static ssize_t queue_write_hint_store(void *data, const char __user *buf,
+ size_t count, loff_t *ppos)
+{
+ struct request_queue *q = data;
+ int i;
+
+ for (i = 0; i < BLK_MAX_WRITE_HINTS; i++)
+ q->write_hints[i] = 0;
+
+ return count;
+}
+
static int queue_poll_stat_show(void *data, struct seq_file *m)
{
struct request_queue *q = data;
@@ -730,6 +753,7 @@ static const struct blk_mq_debugfs_attr blk_mq_debugfs_queue_attrs[] = {
{"poll_stat", 0400, queue_poll_stat_show},
{"requeue_list", 0400, .seq_ops = &queue_requeue_list_seq_ops},
{"state", 0600, queue_state_show, queue_state_write},
+ {"write_hints", 0600, queue_write_hint_show, queue_write_hint_store},
{},
};