Re: 2.6.28-rc8 big regression in VM

[Wu Fengguang <fengguang.wu@intel.com>]

On Tue, Dec 16, 2008 at 09:52:19PM +0200, Lukas Hejtmanek wrote:
> On Tue, Dec 16, 2008 at 12:59:38PM +0800, Wu Fengguang wrote:
> > > > modprobe filecache
> > > > free; cp /proc/filecache /tmp/a;
> > > > echo 3 > /proc/sys/vm/drop_caches
> > > > free; cp /proc/filecache /tmp/b;
> > > > 
> > > > and send me the outputs a and b?
> > > 
> > > unfortunately, it causes an oops (0000 [#1] SMP) in d_path + 0x31/0x110, code
> > > 48 85 c0 74 2f <48> 8b 40 30 48
> > > rax = 0x100000001
> > > 
> > > (it does not save the oops into any log, thus I only wrote down possibly most
> > > important clues)
> > 
> > Sorry I made a silly mistake while rebasing the patch to 2.6.28.
> > The attached patch works OK here.
> 
> so, here are the files.

Thank you.

It looks like most of cached pages were successfully freed:

        247788 => 69856 pages

To get more concrete numbers, could you send more info by running the
following commands?

cp /proc/meminfo meminfo-1
cp /proc/vmstat vmstat-1
sync
echo 3 > /proc/sys/vm/drop_caches
cp /proc/meminfo meminfo-2
cp /proc/vmstat vmstat-2

Thanks,
Fengguang