[PATCH 4/4] block: call blk_additional_{latency,sector} only when io_extra_stats is true

From: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
To: axboe@kernel.dk
Cc: linux-block@vger.kernel.org, danil.kipnis@cloud.ionos.com,
	jinpu.wang@cloud.ionos.com,
	Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
Subject: [PATCH 4/4] block: call blk_additional_{latency,sector} only when io_extra_stats is true
Date: Wed, 27 Jan 2021 15:59:30 +0100	[thread overview]
Message-ID: <20210127145930.8826-5-guoqing.jiang@cloud.ionos.com> (raw)
In-Reply-To: <20210127145930.8826-1-guoqing.jiang@cloud.ionos.com>

If ADDITIONAL_DISKSTAT is enabled carelessly, then it is bad to people
who don't want the additional overhead.

Now add check before call blk_additional_{latency,sector}, which guarntee
only those who really know about the attribute can account the additional
data.

Reviewed-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com>
---
 block/blk-core.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/block/blk-core.c b/block/blk-core.c
index 4271c5a8e685..f62cfc8f801e 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1313,7 +1313,8 @@ static void blk_account_io_completion(struct request *req, unsigned int bytes)
 		const int sgrp = op_stat_group(req_op(req));
 
 		part_stat_lock();
-		blk_additional_sector(req->part, sgrp, bytes >> SECTOR_SHIFT);
+		if (blk_queue_io_extra_stat(req->q))
+			blk_additional_sector(req->part, sgrp, bytes >> SECTOR_SHIFT);
 		part_stat_add(req->part, sectors[sgrp], bytes >> 9);
 		part_stat_unlock();
 	}
@@ -1332,7 +1333,8 @@ void blk_account_io_done(struct request *req, u64 now)
 
 		part_stat_lock();
 		update_io_ticks(req->part, jiffies, true);
-		blk_additional_latency(req->part, sgrp, req, 0);
+		if (blk_queue_io_extra_stat(req->q))
+			blk_additional_latency(req->part, sgrp, req, 0);
 		part_stat_inc(req->part, ios[sgrp]);
 		part_stat_add(req->part, nsecs[sgrp], now - req->start_time_ns);
 		part_stat_unlock();
@@ -1365,7 +1367,8 @@ static unsigned long __part_start_io_acct(struct block_device *part,
 	update_io_ticks(part, now, false);
 	part_stat_inc(part, ios[sgrp]);
 	part_stat_add(part, sectors[sgrp], sectors);
-	blk_additional_sector(part, sgrp, sectors);
+	if (blk_queue_io_extra_stat(part->bd_disk->queue))
+		blk_additional_sector(part, sgrp, sectors);
 	part_stat_local_inc(part, in_flight[op_is_write(op)]);
 	part_stat_unlock();
 
@@ -1400,7 +1403,8 @@ static void __part_end_io_acct(struct block_device *part, unsigned int op,
 
 	part_stat_lock();
 	update_io_ticks(part, now, true);
-	blk_additional_latency(part, sgrp, NULL, start_time);
+	if (blk_queue_io_extra_stat(part->bd_disk->queue))
+		blk_additional_latency(part, sgrp, NULL, start_time);
 	part_stat_add(part, nsecs[sgrp], jiffies_to_nsecs(duration));
 	part_stat_local_dec(part, in_flight[op_is_write(op)]);
 	part_stat_unlock();
-- 
2.17.1

