From: Zygo Blaxell <ce3g8jdj@umail.furryterror.org>
To: Qu Wenruo <wqu@suse.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 0/4] btrfs: Make balance cancelling response faster
Date: Wed, 4 Dec 2019 21:58:32 -0500 [thread overview]
Message-ID: <20191205025832.GY22121@hungrycats.org> (raw)
In-Reply-To: <20191203064254.22683-1-wqu@suse.com>
[-- Attachment #1: Type: text/plain, Size: 2098 bytes --]
On Tue, Dec 03, 2019 at 02:42:50PM +0800, Qu Wenruo wrote:
> [PROBLEM]
> There are quite some users reporting that 'btrfs balance cancel' slow to
> cancel current running balance, or even doesn't work for certain dead
> balance loop.
>
> With the following script showing how long it takes to fully stop a
> balance:
> #!/bin/bash
> dev=/dev/test/test
> mnt=/mnt/btrfs
>
> umount $mnt &> /dev/null
> umount $dev &> /dev/null
>
> mkfs.btrfs -f $dev
> mount $dev -o nospace_cache $mnt
>
> dd if=/dev/zero bs=1M of=$mnt/large &
> dd_pid=$!
>
> sleep 3
> kill -KILL $dd_pid
> sync
>
> btrfs balance start --bg --full $mnt &
> sleep 1
>
> echo "cancel request" >> /dev/kmsg
> time btrfs balance cancel $mnt
> umount $mnt
>
> It takes around 7~10s to cancel the running balance in my test
> environment.
>
> [CAUSE]
> Btrfs uses btrfs_fs_info::balance_cancel_req to record how many cancel
> request are queued.
> However that cancelling request is only checked after relocating a block
> group.
>
> That behavior is far from optimal to provide a faster cancelling.
>
> [FIX]
> This patchset will add more cancelling check points, to make cancelling
> faster.
Nice! I look forward to using this in the future!
Does this cover device delete/resize as well? I think there needs to be
a check added for fatal signals for those to work, as they don't respond
to balance cancel.
> And also, introduce a new error injection points to cover these newly
> introduced and future check points.
>
> Qu Wenruo (4):
> btrfs: relocation: Introduce error injection points for cancelling
> balance
> btrfs: relocation: Check cancel request after each data page read
> btrfs: relocation: Check cancel request after each extent found
> btrfs: relocation: Work around dead relocation stage loop
>
> fs/btrfs/ctree.h | 1 +
> fs/btrfs/relocation.c | 23 +++++++++++++++++++++++
> fs/btrfs/volumes.c | 2 +-
> 3 files changed, 25 insertions(+), 1 deletion(-)
>
> --
> 2.24.0
>
[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 195 bytes --]
next prev parent reply other threads:[~2019-12-05 2:58 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-03 6:42 [PATCH 0/4] btrfs: Make balance cancelling response faster Qu Wenruo
2019-12-03 6:42 ` [PATCH 1/4] btrfs: relocation: Introduce error injection points for cancelling balance Qu Wenruo
2019-12-03 13:29 ` Johannes Thumshirn
2019-12-03 6:42 ` [PATCH 2/4] btrfs: relocation: Check cancel request after each data page read Qu Wenruo
2019-12-03 6:42 ` [PATCH 3/4] btrfs: relocation: Check cancel request after each extent found Qu Wenruo
2019-12-03 6:42 ` [PATCH 4/4] btrfs: relocation: Work around dead relocation stage loop Qu Wenruo
2019-12-04 16:39 ` [PATCH 0/4] btrfs: Make balance cancelling response faster David Sterba
2020-02-11 5:21 ` Qu Wenruo
2020-02-11 5:35 ` Qu Wenruo
2019-12-05 2:58 ` Zygo Blaxell [this message]
2019-12-05 3:26 ` Qu Wenruo
-- strict thread matches above, loose matches on Subject: below --
2019-12-03 6:24 Qu Wenruo
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=20191205025832.GY22121@hungrycats.org \
--to=ce3g8jdj@umail.furryterror.org \
--cc=linux-btrfs@vger.kernel.org \
--cc=wqu@suse.com \
/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).