| From: |
| Ming Lei <ming.lei-AT-redhat.com> |
| To: |
| Jens Axboe <axboe-AT-kernel.dk>, linux-block-AT-vger.kernel.org |
| Subject: |
| [PATCH V5 0/6] loop: improve loop aio perf by IOCB_NOWAIT |
| Date: |
| Wed, 15 Oct 2025 19:07:25 +0800 |
| Message-ID: |
| <20251015110735.1361261-1-ming.lei@redhat.com> |
| Cc: |
| Mikulas Patocka <mpatocka-AT-redhat.com>, Zhaoyang Huang <zhaoyang.huang-AT-unisoc.com>, Dave Chinner <dchinner-AT-redhat.com>, linux-fsdevel-AT-vger.kernel.org, Christoph Hellwig <hch-AT-lst.de>, Ming Lei <ming.lei-AT-redhat.com> |
| Archive-link: |
| Article |
Hello Jens,
This patchset improves loop aio perf by using IOCB_NOWAIT for avoiding to queue aio
command to workqueue context, meantime refactor lo_rw_aio() a bit.
In my test VM, loop disk perf becomes very close to perf of the backing block
device(nvme/mq virtio-scsi).
And Mikulas verified that this way can improve 12jobs sequential readwrite io by
~5X, and basically solve the reported problem together with loop MQ change.
https://lore.kernel.org/linux-block/a8e5c76a-231f-07d1-a3...
Zhaoyang Huang also mentioned it may fix their performance issue on Android
use case.
The loop MQ change will be posted as standalone patch, because it needs
UAPI change.
V5:
- only try nowait in case that backing file supports it (Yu Kuai)
- fix one lockdep assert (syzbot)
- improve comment log (Christoph)
V4:
- rebase
- re-organize and make it more readable
V3:
- add reviewed-by tag
- rename variable & improve commit log & comment on 5/5(Christoph)
V2:
- patch style fix & cleanup (Christoph)
- fix randwrite perf regression on sparse backing file
- drop MQ change
Ming Lei (6):
loop: add helper lo_cmd_nr_bvec()
loop: add helper lo_rw_aio_prep()
loop: add lo_submit_rw_aio()
loop: move command blkcg/memcg initialization into loop_queue_work
loop: try to handle loop aio command via NOWAIT IO first
loop: add hint for handling aio via IOCB_NOWAIT
drivers/block/loop.c | 233 +++++++++++++++++++++++++++++++++++--------
1 file changed, 194 insertions(+), 39 deletions(-)
--
2.47.0
