From: Jan Kara <jack@suse.cz>
To: Dave Chinner <david@fromorbit.com>
Cc: Joseph Qi <joseph.qi@linux.alibaba.com>,
Theodore Ts'o <tytso@mit.edu>, Andreas Dilger <adilger@dilger.ca>,
Jan Kara <jack@suse.cz>,
linux-ext4@vger.kernel.org
Subject: Re: [PATCH 0/3] Revert parallel dio reads
Date: Thu, 29 Aug 2019 12:58:58 +0200 [thread overview]
Message-ID: <20190829105858.GA22939@quack2.suse.cz> (raw)
In-Reply-To: <20190827115118.GY7777@dread.disaster.area>
On Tue 27-08-19 21:51:18, Dave Chinner wrote:
> On Tue, Aug 27, 2019 at 10:05:49AM +0800, Joseph Qi wrote:
> > This patch set is trying to revert parallel dio reads feature at present
> > since it causes significant performance regression in mixed random
> > read/write scenario.
> >
> > Joseph Qi (3):
> > Revert "ext4: remove EXT4_STATE_DIOREAD_LOCK flag"
> > Revert "ext4: fix off-by-one error when writing back pages before dio
> > read"
> > Revert "ext4: Allow parallel DIO reads"
> >
> > fs/ext4/ext4.h | 17 +++++++++++++++++
> > fs/ext4/extents.c | 19 ++++++++++++++-----
> > fs/ext4/inode.c | 47 +++++++++++++++++++++++++++++++----------------
> > fs/ext4/ioctl.c | 4 ++++
> > fs/ext4/move_extent.c | 4 ++++
> > fs/ext4/super.c | 12 +++++++-----
> > 6 files changed, 77 insertions(+), 26 deletions(-)
>
> Before doing this, you might want to have a chat and co-ordinate
> with the folks that are currently trying to port the ext4 direct IO
> code to use the iomap infrastructure:
>
> https://lore.kernel.org/linux-ext4/20190827095221.GA1568@poseidon.bobrowski.net/T/#t
>
> That is going to need the shared locking on read and will work just
> fine with shared locking on write, too (it's the code that XFS uses
> for direct IO). So it might be best here if you work towards shared
> locking on the write side rather than just revert the shared locking
> on the read side....
Yeah, after converting ext4 DIO path to iomap infrastructure, using shared
inode lock for all aligned non-extending DIO writes will be easy so I'd
prefer if we didn't have to redo the iomap conversion patches due to these
reverts.
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2019-08-29 10:59 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-27 2:05 [PATCH 0/3] Revert parallel dio reads Joseph Qi
2019-08-27 2:05 ` [PATCH 1/3] Revert "ext4: remove EXT4_STATE_DIOREAD_LOCK flag" Joseph Qi
2019-08-27 2:05 ` [PATCH 2/3] Revert "ext4: fix off-by-one error when writing back pages before dio read" Joseph Qi
2019-08-27 2:05 ` [PATCH 3/3] Revert "ext4: Allow parallel DIO reads" Joseph Qi
2019-08-27 11:51 ` [PATCH 0/3] Revert parallel dio reads Dave Chinner
2019-08-29 10:58 ` Jan Kara [this message]
2019-08-29 19:06 ` Andreas Dilger
2019-08-30 15:35 ` Jan Kara
2019-09-10 14:10 ` Ritesh Harjani
2019-09-10 21:57 ` Jan Kara
2019-09-11 14:20 ` Ritesh Harjani
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