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From: "Theodore Ts'o" <tytso@mit.edu>
To: Thorsten Leemhuis <regressions@leemhuis.info>
Cc: hazem ahmed mohamed <hazem.ahmed.abuelfotoh@gmail.com>,
	"linux-ext4@vger.kernel.org" <linux-ext4@vger.kernel.org>,
	"adilger.kernel@dilger.ca" <adilger.kernel@dilger.ca>,
	"regressions@lists.linux.dev" <regressions@lists.linux.dev>,
	"stable@vger.kernel.org" <stable@vger.kernel.org>,
	"Mohamed Abuelfotoh, Hazem" <abuehaze@amazon.com>
Subject: Re: Ext4: Buffered random writes performance regression with dioread_nolock enabled
Date: Tue, 20 Sep 2022 22:41:56 -0400	[thread overview]
Message-ID: <Yyp59DELlYXpoCBC@mit.edu> (raw)
In-Reply-To: <48bb6266-2d5c-ffcd-6982-4fd02bfdcfc3@leemhuis.info>

Hazem started separate e-mail threads on this issue (separated by
about an hour), and I replied to the earlier one here:

    https://lore.kernel.org/all/Yypx6VQRbl3bFP2v@mit.edu/

TL;DR:

1)  The patch landed in 5.6, and improved performance for some
workloads, and also fixed a potential security problem (exposure of
stale data caused by a race).

2)  If you are using a storage device >= 128GB, and a version of
e2fsprogs v1.43.2 (released six years ago), the journal size will be
1GB, which Hazem reported resolved the problem.

3) I disagree that we should revert this commit, as it only changes a
default.  If you prefer the older behavior, you can change it with a
mount option.

						- Ted

  parent reply	other threads:[~2022-09-21  2:42 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-19 15:18 Ext4: Buffered random writes performance regression with dioread_nolock enabled hazem ahmed mohamed
2022-09-20  8:07 ` Thorsten Leemhuis
2022-09-20 13:59   ` hazem ahmed mohamed
2022-09-21  2:41   ` Theodore Ts'o [this message]
2022-09-21  9:55     ` Thorsten Leemhuis
2022-09-21  4:44 ` Ritesh Harjani (IBM)
2022-09-21 12:22   ` hazem ahmed mohamed
     [not found] <28460B7B-F66E-4BDC-9F6E-B7E77A3FEE83@amazon.com>
2022-09-21  2:07 ` Theodore Ts'o
2022-09-21 12:06   ` Mohamed Abuelfotoh, Hazem

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