From: Nilay Shroff <nilay@linux.ibm.com>
To: "Yu Kuai" <yukuai@kernel.org>, "Jens Axboe" <axboe@kernel.dk>,
"Josef Bacik" <josef@toxicpanda.com>, "Tejun Heo" <tj@kernel.org>,
"Johannes Weiner" <hannes@cmpxchg.org>,
"Michal Koutný" <mkoutny@suse.com>,
"Jonathan Corbet" <corbet@lwn.net>,
"Shuah Khan" <skhan@linuxfoundation.org>,
"Randy Dunlap" <rdunlap@infradead.org>,
"Coly Li" <colyli@fygo.io>,
"Kent Overstreet" <kent.overstreet@linux.dev>,
"Alasdair Kergon" <agk@redhat.com>,
"Mike Snitzer" <snitzer@kernel.org>,
"Mikulas Patocka" <mpatocka@redhat.com>,
"Benjamin Marzinski" <bmarzins@redhat.com>,
"Song Liu" <song@kernel.org>,
"Li Nan" <magiclinan@didiglobal.com>, "Xiao Ni" <xiao@kernel.org>,
"Andreas Gruenbacher" <agruenba@redhat.com>,
"Matthew Wilcox" <willy@infradead.org>, "Jan Kara" <jack@suse.cz>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Chris Li" <chrisl@kernel.org>,
"Kairui Song" <kasong@tencent.com>,
"Kemeng Shi" <shikemeng@huaweicloud.com>,
"Nhat Pham" <nphamcs@gmail.com>,
"Baoquan He" <baoquan.he@linux.dev>,
"Barry Song" <baohua@kernel.org>,
"Youngjun Park" <youngjun.park@lge.com>,
"Nathan Chancellor" <nathan@kernel.org>,
"Nick Desaulniers" <ndesaulniers@google.com>,
"Bill Wendling" <morbo@google.com>,
"Justin Stitt" <justinstitt@google.com>
Cc: Yu Kuai <yukuai@fygo.io>, Christoph Hellwig <hch@lst.de>,
Tao Cui <cuitao@kylinos.cn>,
linux-block@vger.kernel.org, cgroups@vger.kernel.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-bcache@vger.kernel.org, dm-devel@lists.linux.dev,
linux-raid@vger.kernel.org, gfs2@lists.linux.dev,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
llvm@lists.linux.dev
Subject: Re: [PATCH v3 3/3] blk-cgroup: move async bio punt state to blkcg
Date: Fri, 18 Sep 2026 11:22:39 +0530 [thread overview]
Message-ID: <1742b0d0-fbdb-433b-b2c9-b47b5cfd7666@linux.ibm.com> (raw)
In-Reply-To: <20260918041744.1526924-4-yukuai@kernel.org>
On 9/18/26 9:47 AM, Yu Kuai wrote:
> From: Yu Kuai<yukuai@fygo.io>
>
> 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.
>
> Signed-off-by: Yu Kuai<yukuai@fygo.io>
Looks good to me.
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
next prev parent reply other threads:[~2026-09-18 5:59 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-18 4:17 [PATCH v3 0/3] blk-cgroup: store blkcg in bio before blkcg_mutex conversion Yu Kuai
2026-09-18 4:17 ` [PATCH v3 1/3] blk-cgroup: use a request_queue rhashtable for blkg lookup Yu Kuai
2026-09-18 4:17 ` [PATCH v3 2/3] blk-cgroup: store blkcg in bio instead of blkg Yu Kuai
2026-09-18 7:16 ` dm review needed, was: " Christoph Hellwig
2026-09-18 9:19 ` yu kuai
2026-09-18 9:31 ` Christoph Hellwig
2026-09-18 4:17 ` [PATCH v3 3/3] blk-cgroup: move async bio punt state to blkcg Yu Kuai
2026-09-18 5:52 ` Nilay Shroff [this message]
2026-09-18 7:17 ` Christoph Hellwig
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