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Thu, 20 Aug 2026 09:59:10 +0000 X-Mizu-Trace-ID: e22ed27fc468e85d X-Migadu-Flow: FLOW_OUT Message-ID: <7b2733a4-71d2-43bb-b319-1ca8defba17e@linux.dev> Date: Thu, 20 Aug 2026 17:58:58 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: cui.tao@linux.dev, Yu Kuai , Christoph Hellwig , Jan Kara , Ming Lei , Jonathan Corbet , Shuah Khan , Coly Li , Kent Overstreet , Alasdair Kergon , Mike Snitzer , Mikulas Patocka , Benjamin Marzinski , Song Liu , Li Nan , Xiao Ni , Pankaj Gupta , Dan Williams , Vishal Verma , Dave Jiang , Alison Schofield , Ira Weiny , Andreas Gruenbacher , Matthew Wilcox , Andrew Morton , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Barry Song , Youngjun Park , cgroups@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-bcache@vger.kernel.org, dm-devel@lists.linux.dev, linux-raid@vger.kernel.org, nvdimm@lists.linux.dev, virtualization@lists.linux.dev, gfs2@lists.linux.dev, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC PATCH v3 3/3] blk-cgroup: move async bio punt state to blkcg To: Yu Kuai , Jens Axboe , Tejun Heo , Josef Bacik , Johannes Weiner , =?UTF-8?Q?Michal_Koutn=C3=BD?= References: <20260818070641.756747-1-yukuai@kernel.org> <20260818070641.756747-4-yukuai@kernel.org> From: Tao Cui In-Reply-To: <20260818070641.756747-4-yukuai@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-Stat-Signature: zhnn6p85dr7sbxkyjfjhowahhiqx4jn6 X-Rspamd-Queue-Id: 2CDC01C0003 X-Rspam-User: X-Rspamd-Server: rspam12 X-HE-Tag: 1787219951-420451 X-HE-Meta: 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 Tmjl1MSa A2C37O6NLk/9izPch+wfjosAW3nj+S1wHEcFN0olk49J2ZsRZ+fJyMMgtxs+LRYWu385kGsCDb7nVrmwP9w3JcyvtnokMobyRArZ32nlb/siTSNvEMF3RSOCu+xvYhehq1b5JW1MwYW3OE9AyZhSilCTQtdSTBx3h4EyOLbetqu5/sgqEU8Zx22oZ+CXj/x6Avw41XduhTeNGbMaXrOKMX9Qqi2GIndxeCzepyumoz6akYXqSFprVXHGgcGx9owe3CkTwYVF7c0gM54oW3i3yVDoA/9aVZyN87xA8sCYmREe8LE6/ku4FC6s8Eqk01lWKP0z6R2E1eWDudX7txM8+N84qUsT3WoAmKwZ4c7Dt+SPrCi8mZepz0gaQr/p6G/WUTDyC Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 在 2026/8/18 15:06, Yu Kuai 写道: > blkcg_punt_bio_submit() currently queues punted bios on blkg->async_bios, > so it has to call bio_blkg() to find or create a queue-local blkg. Bios > now carry and pin the blkcg css, so punted bio lifetime no longer needs to > be anchored by a blkg. > > Keeping the punt state in blkg can instantiate a blkg even when no blkcg > policy is enabled, just to bounce submission from a shared kthread. Move > async_bio_lock, async_bios and async_bio_work to struct blkcg, and queue > punted bios on bio_blkcg() for non-root cgroups. Root or unassociated bios > are submitted directly. > > This preserves the priority-inversion avoidance while preventing > blkcg_punt_bio_submit() from creating blkgs that are not needed by any > policy. Reviewed-by: Tao Cui