From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-42.mta1.migadu.com [95.215.58.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 018613DA7F3 for ; Thu, 20 Aug 2026 09:59:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.42 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787219955; cv=none; b=HjlSTh5Ri6hP3QuLT2VV9MY5wF+/UD1CcVDhd+2ODFfbgeHZmEdSyFSmrfK4SO24AheR8T/vENUjmGGRWkwMUUxyShiN6nPsQ4/hm3IEx8zpb6qRF09JP3P7iA1sFuSJgFgl+qR8oXiEwYiZGoOm1HdB9929k+jK+NxkO2HZ6WE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787219955; c=relaxed/simple; bh=ibyIE9gKf2iOY1+mVf6oD4UPNPJ9RqEZuDFV5F2gXBk=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=tzCIMjr36u06AM97fs1ufEi+VCC/k0W7EJuIzKg04+mJ/LvD9eAwR4ABONEBqZ5SkHD4dwVvhcp+t+YT3A+9hXPjSSVyghnUG3EqXwC/+nV0ycrblSbIP1Sk2GLYFcaBO7iHmCvj8e4MBR/MzBEQTjOaZHB6w/oYfYhn47Rnrc0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=fyDzUDzX; arc=none smtp.client-ip=95.215.58.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="fyDzUDzX" X-Envelope-To: linux-fsdevel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=ibyIE9gKf2iOY1+mVf6oD4UPNPJ9RqEZuDFV5F2gXBk=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1787219951; v=1; x=1787824751; b=fyDzUDzXcPvYUy11JLRjChoyubrTwAQsy7f3+ZeatlvDNULgvzirf4SV3nTRHNXkR6TVJ1Pb LkiCeR1vXoJVte4OHMgi3Hn6nV7Nsf4j6ThbqVxuqcoDxEjFNtO9th4AcmxaE/V/Qm2MQOPGT2v Lb/ckhDTGbPSUZV7hGr1rXFI= X-Envelope-To: linux-fsdevel@vger.kernel.org Received: from [192.168.110.173] (223.70.159.239) by smtp.migadu.com with ESMTPS id e22ed27fc468e85d; 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 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: 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 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