From: Dave Chinner <david@fromorbit.com>
To: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: 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: Tue, 27 Aug 2019 21:51:18 +1000 [thread overview]
Message-ID: <20190827115118.GY7777@dread.disaster.area> (raw)
In-Reply-To: <1566871552-60946-1-git-send-email-joseph.qi@linux.alibaba.com>
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....
Cheers,
Dave,
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2019-08-27 11:51 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 ` Dave Chinner [this message]
2019-08-29 10:58 ` [PATCH 0/3] Revert parallel dio reads Jan Kara
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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