From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: Jan Kara <jack@suse.cz>
Cc: linux-ext4@vger.kernel.org
Subject: Re: [PATCH] ext4: Avoid unnecessary transaction starts during writeback
Date: Thu, 28 May 2020 23:19:25 -0400 [thread overview]
Message-ID: <20200529031925.GL228632@mit.edu> (raw)
In-Reply-To: <20200525081215.29451-1-jack@suse.cz>
On Mon, May 25, 2020 at 10:12:15AM +0200, Jan Kara wrote:
> ext4_writepages() currently works in a loop like:
> start a transaction
> scan inode for pages to write
> map and submit these pages
> stop the transaction
>
> This loop results in starting transaction once more than is needed
> because in the last iteration we start a transaction only to scan the
> inode and find there are no pages to write. This can be significant
> increase in number of transaction starts for single-extent files or
> files that have all blocks already mapped. Furthermore we already know
> from previous iteration whether there are more pages to write or not. So
> propagate the information from mpage_prepare_extent_to_map() and avoid
> unnecessary looping in case there are no more pages to write.
>
> Signed-off-by: Jan Kara <jack@suse.cz>
Thanks, applied. I like how it shrinks the source file. :-)
- Ted
prev parent reply other threads:[~2020-05-29 3:19 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-25 8:12 [PATCH] ext4: Avoid unnecessary transaction starts during writeback Jan Kara
2020-05-29 3:19 ` Theodore Y. Ts'o [this message]
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