From: Nathan Huckleberry <nhuck@google.com>
To: linux-kernel@vger.kernel.org, dm-devel@redhat.com,
Alasdair Kergon <agk@redhat.com>,
Mike Snitzer <snitzer@kernel.org>
Cc: Eric Biggers <ebiggers@kernel.org>,
Sami Tolvanen <samitolvanen@google.com>,
Nathan Huckleberry <nhuck@google.com>
Subject: [PATCH 0/3] dm-verity: optionally use tasklets in dm-verity
Date: Fri, 22 Jul 2022 09:38:20 +0000 [thread overview]
Message-ID: <20220722093823.4158756-1-nhuck@google.com> (raw)
Using tasklets for disk verification can reduce IO latency. When there are
accelerated hash instructions it is often better to compute the hash immediately
using a tasklet rather than deferring verification to a work-queue. This
reduces time spent waiting to schedule work-queue jobs, but requires spending
slightly more time in interrupt context.
A tasklet can only be used for verification if all the required hashes are
already in the dm-bufio cache. If verification cannot be done in a tasklet, we
fallback the existing work-queue implementation.
To allow tasklets to query the dm-bufio cache, the dm-bufio code must not sleep.
This patchset adds a flag to dm-bufio that disallows sleeping.
The following shows a speed comparison of random reads on a dm-verity device.
The dm-verity device uses a 1G ramdisk for data and a 1G ramdisk for hashes.
One test was run using tasklets and one test was run using the existing
work-queue solution. Both tests were run when the dm-bufio cache was hot. The
tasklet implementation performs significantly better since there is no time
waiting for work-queue jobs to be scheduled.
# /data/fio /data/tasklet.fio | grep READ
READ: bw=181MiB/s (190MB/s), 181MiB/s-181MiB/s (190MB/s-190MB/s), io=512MiB
(537MB), run=2827-2827msec
# /data/fio /data/workqueue.fio | grep READ
READ: bw=23.6MiB/s (24.8MB/s), 23.6MiB/s-23.6MiB/s (24.8MB/s-24.8MB/s),
io=512MiB (537MB), run=21688-21688msec
Nathan Huckleberry (3):
dm-bufio: Add flags for dm_bufio_client_create
dm-bufio: Add DM_BUFIO_GET_CANT_SLEEP
dm-verity: Add try_verify_in_tasklet
drivers/md/dm-bufio.c | 29 +++++--
drivers/md/dm-ebs-target.c | 3 +-
drivers/md/dm-integrity.c | 2 +-
drivers/md/dm-snap-persistent.c | 2 +-
drivers/md/dm-verity-fec.c | 4 +-
drivers/md/dm-verity-target.c | 87 ++++++++++++++++---
drivers/md/dm-verity.h | 5 ++
drivers/md/persistent-data/dm-block-manager.c | 3 +-
include/linux/dm-bufio.h | 8 +-
9 files changed, 119 insertions(+), 24 deletions(-)
--
2.37.1.359.gd136c6c3e2-goog
next reply other threads:[~2022-07-22 9:44 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-22 9:38 Nathan Huckleberry [this message]
2022-07-22 9:38 ` [PATCH 1/3] dm-bufio: Add flags for dm_bufio_client_create Nathan Huckleberry
2022-07-22 9:38 ` [PATCH 2/3] dm-bufio: Add DM_BUFIO_GET_CANT_SLEEP Nathan Huckleberry
2022-07-22 9:38 ` [PATCH 3/3] dm-verity: Add try_verify_in_tasklet Nathan Huckleberry
2022-07-26 1:58 ` Mike Snitzer
2022-07-26 3:06 ` Eric Biggers
2022-07-26 4:13 ` Mike Snitzer
2022-07-22 16:41 ` [PATCH 0/3] dm-verity: optionally use tasklets in dm-verity Christoph Hellwig
2022-07-22 17:12 ` Mike Snitzer
2022-08-15 11:35 ` Sebastian Andrzej Siewior
2022-07-22 18:12 ` [dm-devel] " Bart Van Assche
2022-07-22 18:33 ` Mike Snitzer
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=20220722093823.4158756-1-nhuck@google.com \
--to=nhuck@google.com \
--cc=agk@redhat.com \
--cc=dm-devel@redhat.com \
--cc=ebiggers@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=samitolvanen@google.com \
--cc=snitzer@kernel.org \
/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).