From: Christoph Hellwig <hch@lst.de>
To: yukuai@fygo.io
Cc: "Christoph Hellwig" <hch@lst.de>, "Jens Axboe" <axboe@kernel.dk>,
"Tejun Heo" <tj@kernel.org>, "Josef Bacik" <josef@toxicpanda.com>,
"Johannes Weiner" <hannes@cmpxchg.org>,
"Michal Koutný" <mkoutny@suse.com>, "Tao Cui" <cui.tao@linux.dev>,
"Jan Kara" <jack@suse.cz>, "Ming Lei" <ming.lei@redhat.com>,
"Jonathan Corbet" <corbet@lwn.net>,
"Shuah Khan" <skhan@linuxfoundation.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>,
"Pankaj Gupta" <pankaj.gupta.linux@gmail.com>,
"Dan Williams" <djbw@kernel.org>,
"Vishal Verma" <vishal.l.verma@intel.com>,
"Dave Jiang" <dave.jiang@intel.com>,
"Alison Schofield" <alison.schofield@intel.com>,
"Ira Weiny" <iweiny@kernel.org>,
"Andreas Gruenbacher" <agruenba@redhat.com>,
"Matthew Wilcox" <willy@infradead.org>,
"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>,
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 v2 2/4] blk-cgroup: use a request_queue rhashtable for blkg lookup
Date: Fri, 14 Aug 2026 10:15:31 +0200 [thread overview]
Message-ID: <20260814081531.GA13546@lst.de> (raw)
In-Reply-To: <f7350050-062a-4ced-9396-05ac33ac3e60@fnnas.com>
On Fri, Aug 14, 2026 at 03:50:04PM +0800, Yu Kuai wrote:
> > Are these fast path operations? Otherwise we can walk all rhashtable
> > entries without an extra list, but it might be slower.
>
> All users are from sysfs/cgroupfs API, I think they can be considered slow path,
> however currently spinlock is held in these procedures, I think it's better to
> convert them to blkg_lookup based iterate after spinlock is converted to the
> blkcg_mutex.
Sounds good. Maybe put that into the commit log?
> > Please add must_hold and/or lockdep annotations for this instead of just
> > a comment.
> >
> > Also maybe mention that this does not acquire a reference and the caller
> > must already hold one?
>
> Perhaps it's more accurate that the blkg is pinned by IO or caller already
> hold one?
Sounds good.
next prev parent reply other threads:[~2026-08-14 8:15 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-11 6:47 [RFC PATCH v2 0/4] blk-cgroup: store blkcg in bio before blkcg_mutex conversion Yu Kuai
2026-08-11 6:47 ` [RFC PATCH v2 1/4] blk-cgroup: wait for old blkgs to leave queue before disk rebind Yu Kuai
2026-08-14 6:50 ` Christoph Hellwig
2026-08-11 6:47 ` [RFC PATCH v2 2/4] blk-cgroup: use a request_queue rhashtable for blkg lookup Yu Kuai
2026-08-14 7:12 ` Christoph Hellwig
2026-08-14 7:50 ` Yu Kuai
2026-08-14 8:15 ` Christoph Hellwig [this message]
2026-08-11 6:47 ` [RFC PATCH v2 3/4] blk-cgroup: store blkcg in bio instead of blkg Yu Kuai
2026-08-11 6:47 ` [RFC PATCH v2 4/4] blk-cgroup: move async bio punt state to blkcg Yu Kuai
2026-08-14 6:45 ` [RFC PATCH v2 0/4] blk-cgroup: store blkcg in bio before blkcg_mutex conversion Christoph Hellwig
2026-08-14 7:53 ` yu kuai
2026-08-14 8:16 ` Christoph Hellwig
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260814081531.GA13546@lst.de \
--to=hch@lst.de \
--cc=agk@redhat.com \
--cc=agruenba@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=alison.schofield@intel.com \
--cc=axboe@kernel.dk \
--cc=baohua@kernel.org \
--cc=baoquan.he@linux.dev \
--cc=bmarzins@redhat.com \
--cc=cgroups@vger.kernel.org \
--cc=chrisl@kernel.org \
--cc=colyli@fygo.io \
--cc=corbet@lwn.net \
--cc=cui.tao@linux.dev \
--cc=dave.jiang@intel.com \
--cc=djbw@kernel.org \
--cc=dm-devel@lists.linux.dev \
--cc=gfs2@lists.linux.dev \
--cc=hannes@cmpxchg.org \
--cc=iweiny@kernel.org \
--cc=jack@suse.cz \
--cc=josef@toxicpanda.com \
--cc=kasong@tencent.com \
--cc=kent.overstreet@linux.dev \
--cc=linux-bcache@vger.kernel.org \
--cc=linux-block@vger.kernel.org \
--cc=linux-doc@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-raid@vger.kernel.org \
--cc=magiclinan@didiglobal.com \
--cc=ming.lei@redhat.com \
--cc=mkoutny@suse.com \
--cc=mpatocka@redhat.com \
--cc=nphamcs@gmail.com \
--cc=nvdimm@lists.linux.dev \
--cc=pankaj.gupta.linux@gmail.com \
--cc=shikemeng@huaweicloud.com \
--cc=skhan@linuxfoundation.org \
--cc=snitzer@kernel.org \
--cc=song@kernel.org \
--cc=tj@kernel.org \
--cc=virtualization@lists.linux.dev \
--cc=vishal.l.verma@intel.com \
--cc=willy@infradead.org \
--cc=xiao@kernel.org \
--cc=youngjun.park@lge.com \
--cc=yukuai@fygo.io \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).