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Date: Fri, 18 Sep 2026 11:31:23 +0200
From: Christoph Hellwig <hch@lst.de>
To: yu kuai <yukuai@fygo.io>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
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Subject: Re: dm review needed, was: Re: [PATCH v3 2/3] blk-cgroup: store
 blkcg in bio instead of blkg
Message-ID: <20260918093123.GA13158@lst.de>
References: <20260918041744.1526924-1-yukuai@kernel.org> <20260918041744.1526924-3-yukuai@kernel.org> <20260918071634.GA10884@lst.de> <daf4ba77-4c25-4993-900d-ee1fe713d9b6@fygo.io>
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On Fri, Sep 18, 2026 at 05:19:53PM +0800, yu kuai wrote:
> So I think we don't need to restore the reference, BTW, there is another approach to
> avoid such problem in blk-throttle I don't take for now:
> 
> For bio entering blk-throttle, we can clear the new flag and blkg reference directly
> after the bio is throttled and before this bio is issuing to disk, because bio will
> not enter blk-throttle in the completion path. And since blk-throttle is the only rq_qos
> policy that can be enabled for bio-based disk, then dm_bio_record() will never see a
> bio with the new flag set.

That sounds much better, thanks!