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From:   chengming.zhou@linux.dev
To:     axboe@kernel.dk, tj@kernel.org
Cc:     josef@toxicpanda.com, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
        Chengming Zhou <zhouchengming@bytedance.com>
Subject: [PATCH 2/2] blk-throttle: only enable blk-stat when BLK_DEV_THROTTLING_LOW
Date:   Thu, 13 Apr 2023 00:07:54 +0800
Message-Id: <20230412160754.1981705-2-chengming.zhou@linux.dev>
In-Reply-To: <20230412160754.1981705-1-chengming.zhou@linux.dev>
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From: Chengming Zhou <zhouchengming@bytedance.com>

blk_throtl_register() will unconditionally enable blk-stat for gendisk
when register, even when we have no BLK_DEV_THROTTLING_LOW config.

Since the kernel always has only BLK_DEV_THROTTLING config and the
BLK_DEV_THROTTLING_LOW config is still in EXPERIMENTAL state, we can
just skip blk-stat when !BLK_DEV_THROTTLING_LOW.

Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
---
 block/blk-throttle.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index 47e9d8be68f3..3c07c9cfa70a 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -2439,11 +2439,12 @@ void blk_throtl_register(struct gendisk *disk)
 #ifndef CONFIG_BLK_DEV_THROTTLING_LOW
 	/* if no low limit, use previous default */
 	td->throtl_slice = DFL_THROTL_SLICE_HD;
-#endif
 
+#else
 	td->track_bio_latency = !queue_is_mq(q);
 	if (!td->track_bio_latency)
 		blk_stat_enable_accounting(q);
+#endif
 }
 
 #ifdef CONFIG_BLK_DEV_THROTTLING_LOW
-- 
2.39.2