linux-ext4 - Re: Discussion: is it time to remove dioread

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Message-ID: <20200107172236.GJ25547@quack2.suse.cz>
Date:   Tue, 7 Jan 2020 18:22:36 +0100
From:   Jan Kara <jack@...e.cz>
To:     "Theodore Y. Ts'o" <tytso@....edu>
Cc:     Jan Kara <jack@...e.cz>, Ritesh Harjani <riteshh@...ux.ibm.com>,
        Xiaoguang Wang <xiaoguang.wang@...ux.alibaba.com>,
        Ext4 Developers List <linux-ext4@...r.kernel.org>,
        joseph.qi@...ux.alibaba.com, Liu Bo <bo.liu@...ux.alibaba.com>
Subject: Re: Discussion: is it time to remove dioread_nolock?

On Tue 07-01-20 12:11:09, Theodore Y. Ts'o wrote:
> Hmm..... There's actually an even more radical option we could use,
> given that Ritesh has made dioread_nolock work on block sizes < page
> size.  We could make dioread_nolock the default, until we can revamp
> ext4_writepages() to write the data blocks first....

Yes, that's a good point. And I'm not opposed to that if it makes the life
simpler. But I'd like to see some performance numbers showing how much is
writeback using unwritten extents slower so that we don't introduce too big
regression with this...

								Honza

-- 
Jan Kara <jack@...e.com>
SUSE Labs, CR