Re: [PATCH] blk-rq-qos: Remove unlikely() hints from QoS checks

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In reply to: Breno Leitao: "[PATCH] blk-rq-qos: Remove unlikely() hints from QoS checks"
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From: Jens Axboe

Date: Tue Jan 06 2026 - 21:10:49 EST

On Tue, 06 Jan 2026 06:26:57 -0800, Breno Leitao wrote:
> The unlikely() annotations on QUEUE_FLAG_QOS_ENABLED checks are
> counterproductive. Writeback throttling (WBT) might be enabled by
> default, mainly because CONFIG_BLK_WBT_MQ defaults to 'y'.
>
> Branch profiling on Meta servers, which have WBT enabled, confirms 100%
> misprediction rates on these checks.
>
> [...]

Applied, thanks!

[1/1] blk-rq-qos: Remove unlikely() hints from QoS checks
commit: 7d121d701d58a92f26decb10da1d04a88b74519d

Best regards,
--
Jens Axboe