From: Christoph Hellwig <hch@lst.de>
To: Chris Mason <clm@meta.com>
Cc: Christoph Hellwig <hch@lst.de>,
Josef Bacik <josef@toxicpanda.com>, Chris Mason <clm@fb.com>,
David Sterba <dsterba@suse.com>, Tejun Heo <tj@kernel.org>,
Jens Axboe <axboe@kernel.dk>,
cgroups@vger.kernel.org, linux-block@vger.kernel.org,
linux-btrfs@vger.kernel.org
Subject: Re: move bio cgroup punting into btrfs
Date: Wed, 29 Mar 2023 01:34:48 +0200 [thread overview]
Message-ID: <20230328233448.GA5486@lst.de> (raw)
In-Reply-To: <512eaacf-3ff6-f4f9-c856-a0e03c027501@meta.com>
On Tue, Mar 28, 2023 at 05:18:43PM -0400, Chris Mason wrote:
> Is btrfs really the only place using worker threads to submit IO, or are
> we just the only ones looking for the priority inversions w/resource
> control in place?
btrfs is the only place offloading writes from the per-cgroup writeback
to it's own not cgroup aware workqueues.
Offloading from one writeback thread to another threadpool to just
offload back to another thread to not deadlock is obviously not
an actual smart thing to do, and fortunately no one else is doing
this.
For btrfs it is on it's way out by not doing the offload just for
checksumming in a little bit, and even for compression the right fix
is just to allow more than one thread per device and cgroup. I plan
to look into that, but there's plenty higher priority work right now.
next prev parent reply other threads:[~2023-03-28 23:34 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-27 0:49 move bio cgroup punting into btrfs Christoph Hellwig
2023-03-27 0:49 ` [PATCH 1/7] btrfs: move kthread_associate_blkcg out of btrfs_submit_compressed_write Christoph Hellwig
2023-03-27 0:49 ` [PATCH 2/7] btrfs: don't free the async_extent in submit_uncompressed_range Christoph Hellwig
2023-03-27 0:49 ` [PATCH 3/7] btrfs: also use kthread_associate_blkcg for uncompressible ranges Christoph Hellwig
2023-03-27 0:49 ` [PATCH 4/7] btrfs, mm: remove the punt_to_cgroup field in struct writeback_control Christoph Hellwig
2023-03-27 0:49 ` [PATCH 5/7] btrfs, block: move REQ_CGROUP_PUNT to btrfs Christoph Hellwig
2023-03-28 1:15 ` Jens Axboe
2023-03-27 0:49 ` [PATCH 6/7] block: async_bio_lock does not need to be bh-safe Christoph Hellwig
2023-03-27 23:31 ` Jens Axboe
2023-03-27 0:49 ` [PATCH 7/7] block: make blkcg_punt_bio_submit optional Christoph Hellwig
2023-03-27 23:32 ` Jens Axboe
2023-03-27 23:18 ` move bio cgroup punting into btrfs David Sterba
2023-03-31 17:25 ` David Sterba
2023-03-28 21:18 ` Chris Mason
2023-03-28 23:34 ` Christoph Hellwig [this message]
2023-03-29 19:16 ` Tejun Heo
2023-03-30 0:15 ` Christoph Hellwig
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