From mboxrd@z Thu Jan  1 00:00:00 1970
From: Nigel Cunningham <ncunningham@crca.org.au>
Subject: Re: syncing the disks when entering sleep
Date: Sat, 23 Jan 2010 08:55:45 +1100
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To: "Leisner, Martin" <Martin.Leisner@xerox.com>
Cc: linux-pm@lists.linux-foundation.org
List-Id: linux-pm@vger.kernel.org

Hi.

Leisner, Martin wrote:
> 
>>   -----Original Message-----
>>   From: Rafael J. Wysocki [mailto:rjw@sisk.pl]
>>   Sent: Friday, January 22, 2010 4:38 PM
>>   To: Leisner, Martin
>>   Cc: Nigel Cunningham; linux-pm@lists.linux-foundation.org
>>   Subject: Re: [linux-pm] syncing the disks when entering sleep
>>   
>>   On Friday 22 January 2010, Leisner, Martin wrote:
>>   > To clarify what I proposed:
>>   >
>>   > if(user sets knobs)
>>   >     if(disk is spun up)
>>   >          sync
>>   >
>>   > currently the algorithm is
>>   >
>>   >     sync
>>   
>>   Yes, but Nigel said it should be
>>   
>>   if(user knob is unset)
>>             sync
>>   
>>   which I agree with.
>>   
>>   [BTW, please don't top-post in future.]
>>   
>>   Rafael
> 
> if(knob is set) {
>     if(disk is spun up)
>        sync
> } else sync
> 
> The spinup of the disk can have a very noticeable amount of time...if the user doesn't care about syncing, then the top is preferred...

That sounds much better; thanks.

As an aside, I think the writeback code needs some tweaking in general.
I don't know about you guys, but I'm seeing that sync take far longer
than I reckon it should sometimes. Just a gut feeling - not based on
having looked at /proc/meminfo first - but I'd be interested to know if
you think the same.

Nigel