linux-ext4 - Re: [ext3] kjournald writing after each read despite noatime,commit=nnn

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Date:	Thu, 1 Jan 2009 14:35:20 -0500
From:	Dave Johnson <dave-lkml-01@...terclick.org>
To:	Bart Samwel <bart@...wel.tk>
Cc:	linux-kernel@...r.kernel.org, linux-ext4@...r.kernel.org
Subject: Re: [ext3] kjournald writing after each read despite noatime,commit=nnn

Dave Johnson writes:
> Bart Samwel writes:
> > This looks like it's a generic property of syncing an ext3 file system.
> > Try turning off laptop_mode and then running "sync". You will probably
> > see the same behaviour.
> 
> yep, every sync() causes a gratuitous write to disk N seconds later
> even when no data has been read or written since the last sync().

Woops, correction, every sync() call causes a single gratuitous write,
no delay.

$ for n in 1 2 3 4 5; do sync; done

Jan  1 14:32:54 gw kernel: kjournald(760): WRITE block 2682 on hda1 
Jan  1 14:32:54 gw kernel: kjournald(760): WRITE block 2684 on hda1 
Jan  1 14:32:54 gw kernel: kjournald(760): WRITE block 2686 on hda1 
Jan  1 14:32:54 gw kernel: kjournald(760): WRITE block 2688 on hda1 
Jan  1 14:32:54 gw kernel: kjournald(760): WRITE block 2690 on hda1 

-- 
Dave
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