From: "Theodore Ts'o" <tytso@mit.edu>
To: Ross Zwisler <zwisler@google.com>
Cc: Jan Kara <jack@suse.cz>, Ross Zwisler <zwisler@chromium.org>,
linux-kernel@vger.kernel.org,
Alexander Viro <viro@zeniv.linux.org.uk>,
Andreas Dilger <adilger.kernel@dilger.ca>,
Jan Kara <jack@suse.com>,
linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-mm@kvack.org, Fletcher Woodruff <fletcherw@google.com>,
Justin TerAvest <teravest@google.com>
Subject: Re: [PATCH 2/3] jbd2: introduce jbd2_inode dirty range scoping
Date: Thu, 20 Jun 2019 13:22:08 -0400 [thread overview]
Message-ID: <20190620172208.GB4650@mit.edu> (raw)
In-Reply-To: <20190620150911.GA4488@google.com>
On Thu, Jun 20, 2019 at 09:09:11AM -0600, Ross Zwisler wrote:
> We could definitely keep separate dirty ranges for each of the current and
> next transaction. I think the case where you would see a difference would be
> if you had multiple transactions in a row which grew the dirty range for a
> given jbd2_inode, and then had a random I/O workload which kept dirtying pages
> inside that enlarged dirty range.
>
> I'm not sure how often this type of workload would be a problem. For the
> workloads I've been testing which purely append to the inode, having a single
> dirty range per jbd2_inode is sufficient.
My inclination would be to keep things simple for now, unless we have
a real workload that tickles this. In the long run I'm hoping to
remove the need to do writebacks from the journal thread altogether,
by always updating the metadata blocks *after* the I/O completes,
instead of before we submit the I/O.
- Ted
next prev parent reply other threads:[~2019-06-20 17:22 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-19 17:21 [PATCH 0/3] Add dirty range scoping to jbd2 Ross Zwisler
2019-06-19 17:21 ` [PATCH 1/3] mm: add filemap_fdatawait_range_keep_errors() Ross Zwisler
2019-06-20 9:25 ` Jan Kara
2019-06-19 17:21 ` [PATCH 2/3] jbd2: introduce jbd2_inode dirty range scoping Ross Zwisler
2019-06-20 11:04 ` Jan Kara
2019-06-20 15:09 ` Ross Zwisler
2019-06-20 17:22 ` Theodore Ts'o [this message]
2019-06-19 17:21 ` [PATCH 3/3] ext4: use " Ross Zwisler
2019-06-20 11:15 ` Jan Kara
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