From: Chengkaitao <pilgrimtao@gmail.com>
To: axboe@kernel.dk, pjw@kernel.org, palmer@dabbelt.com,
aou@eecs.berkeley.edu, alex@ghiti.fr, ojeda@kernel.org,
boqun@kernel.org, gary@garyguo.net, bjorn3_gh@protonmail.com,
lossin@kernel.org, a.hindborg@kernel.org, aliceryhl@google.com,
tmgross@umich.edu, dakr@kernel.org, nathan@kernel.org,
nick.desaulniers+lkml@gmail.com, morbo@google.com,
justinstitt@google.com
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-riscv@lists.infradead.org, rust-for-linux@vger.kernel.org,
bpf@vger.kernel.org, llvm@lists.linux.dev,
Kaitao Cheng <chengkaitao@kylinos.cn>
Subject: [RFC 0/2] block: Introduce a BPF-based I/O scheduler
Date: Fri, 27 Mar 2026 19:47:39 +0800 [thread overview]
Message-ID: <20260327114741.91500-1-pilgrimtao@gmail.com> (raw)
From: Kaitao Cheng <chengkaitao@kylinos.cn>
I have been working on adding a new BPF-based I/O scheduler. It has both
kernel and user-space parts. In kernel space, using per-ctx, I implemented
a simple elevator that exposes a set of BPF hooks. The goal is to move the
policy side of I/O scheduling out of the kernel and into user space, which
should greatly increase flexibility and applicability. To verify that the
whole stack works end to end, I wrote a simple BPF example program. I am
calling this feature the UFQ (User-programmable Flexible Queueing) I/O
scheduler.
This patch depends on new BPF functionality that I have already posted to
the BPF community but that is not yet in mainline. Details are in these
two threads:
https://lore.kernel.org/all/20260214124042.62229-1-pilgrimtao@gmail.com/
https://lore.kernel.org/all/20260316112843.78657-1-pilgrimtao@gmail.com/
To try it, you need to apply the patches from those series first.
Note: This is still somewhat experimental. I have only done basic testing,
there may be bugs or security issues, which I plan to address in follow-up
work. I am also looking for community feedback on whether this direction
and the implementation approach make sense, and what else we should
consider.
Kaitao Cheng (2):
block: Introduce the UFQ I/O scheduler
tools/ufq_iosched: add BPF example scheduler and build scaffolding
block/Kconfig.iosched | 8 +
block/Makefile | 1 +
block/blk-merge.c | 49 +-
block/blk-mq-sched.h | 4 +
block/blk-mq.c | 8 +-
block/blk-mq.h | 2 +-
block/blk.h | 2 +
block/ufq-bpfops.c | 213 +++++++
block/ufq-iosched.c | 526 ++++++++++++++++++
block/ufq-iosched.h | 38 ++
block/ufq-kfunc.c | 91 +++
tools/ufq_iosched/.gitignore | 2 +
tools/ufq_iosched/Makefile | 262 +++++++++
tools/ufq_iosched/README.md | 136 +++++
.../include/bpf-compat/gnu/stubs.h | 12 +
tools/ufq_iosched/include/ufq/common.bpf.h | 73 +++
tools/ufq_iosched/include/ufq/common.h | 91 +++
tools/ufq_iosched/include/ufq/simple_stat.h | 21 +
tools/ufq_iosched/ufq_simple.bpf.c | 445 +++++++++++++++
tools/ufq_iosched/ufq_simple.c | 118 ++++
20 files changed, 2094 insertions(+), 8 deletions(-)
create mode 100644 block/ufq-bpfops.c
create mode 100644 block/ufq-iosched.c
create mode 100644 block/ufq-iosched.h
create mode 100644 block/ufq-kfunc.c
create mode 100644 tools/ufq_iosched/.gitignore
create mode 100644 tools/ufq_iosched/Makefile
create mode 100644 tools/ufq_iosched/README.md
create mode 100644 tools/ufq_iosched/include/bpf-compat/gnu/stubs.h
create mode 100644 tools/ufq_iosched/include/ufq/common.bpf.h
create mode 100644 tools/ufq_iosched/include/ufq/common.h
create mode 100644 tools/ufq_iosched/include/ufq/simple_stat.h
create mode 100644 tools/ufq_iosched/ufq_simple.bpf.c
create mode 100644 tools/ufq_iosched/ufq_simple.c
--
2.43.0
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next reply other threads:[~2026-03-27 11:48 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-27 11:47 Chengkaitao [this message]
2026-03-27 11:47 ` [RFC 1/2] block: Introduce the UFQ I/O scheduler Chengkaitao
2026-03-27 14:21 ` Alexei Starovoitov
2026-03-27 11:47 ` [RFC 2/2] tools/ufq_iosched: add BPF example scheduler and build scaffolding Chengkaitao
2026-03-27 17:45 ` Miguel Ojeda
2026-03-27 15:48 ` [RFC 0/2] block: Introduce a BPF-based I/O scheduler Bart Van Assche
2026-03-28 13:39 ` Chengkaitao
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