Re: [PATCH] Page writeback broken after resume: wb_timer lost

[Andrew Morton <akpm@osdl.org>]

On Wed, 21 Jun 2006 00:10:55 -0400
Mark Lord <lkml@rtr.ca> wrote:

> Andrew Morton wrote:
> > On Tue, 20 Jun 2006 23:38:57 -0400
> > Mark Lord <lkml@rtr.ca> wrote:
> > 
> >>> I just gave it a try here.  With or without a suspend/resume cycle after 
> >>> boot,
> >>> the "sync" time is much quicker.  But the Dirty count in /proc/meminfo
> >>> still shows very huge (eg. 600MB) values that never really get smaller
> >>> until I type "sync".  But that subsequent "sync" only takes a couple
> >>> of seconds now, rather than 10-20 seconds like before.
> >> ..
> >>
> >> Yup, behaviour is *definitely* much better now.  I'm not sure why
> >> the /proc/meminfo "Dirty" count lags behind reality, but the disk
> >> is being kept much more up-to-date than without this patch.
> > 
> > Are you able to come up with a foolproof set of steps which would allow the
> > laggy-dirtiness to be reproduced by yours truly?
> 
> Heh.. don't I wish!
> 
> The best is still as described originally:
> 
> http://lkml.org/lkml/2006/2/6/170
> 
> Basically, "cat" a ton of huge files together into a single new one,
> and then watch /proc/meminfo to see what happens.  For me, the count
> there still just hangs at some big number like 500MB until I type "sync",
> at which point it (nearly) instantly now goes to zero.
> 
> Previous to this patch, the "sync" actually resulted in a ton of disk writes,
> but now those happen on the tail end of the "cat" command, as they should.
> 
> My kernel .config is available from http://rtr.ca/dell_i9300/kernel/latest/

Is that after a suspend/resume, or does it happen after a reboot?

Are you sure all the dirty memory doesn't get autocleaned after 30-60
seconds?