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

From: Mark Lord
Date: Wed Jun 21 2006 - 00:10:56 EST


Andrew Morton wrote:
On Tue, 20 Jun 2006 23:38:57 -0400
Mark Lord <lkml@xxxxxx> 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/

Cheers
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