Re: 2.4.>=13 VM/kswapd/shmem/Oracle issue (was Re: Google's mm problems)

[Ken Brownfield <brownfld@irridia.com>]

Thanks for looking into this -- I really mean it.  I'm looking forward
to the patch and how it compares to the others I've received. ;-)

Again, good work, and thanks to all,
-- 
Ken.
brownfld@irridia.com

On Thu, Nov 15, 2001 at 06:40:36PM +0100, Andrea Arcangeli wrote:
| On Fri, Nov 09, 2001 at 03:38:51AM -0600, Ken Brownfield wrote:
| > We're seeing an easily reproducible problem that I believe to be along
| > the same lines as what Google is seeing.  I'm not sure if Oracle's SGA
| 
| FYI: yes, that's the same problem. After some debugging I found the
| exact reason of the bug, and as Daniel claimed a few weeks ago it is
| really a VM problem, not an mlock problem. And it's one thing that I
| didn't noticed while rewriting the VM, so it is reproducible on all 2.4
| kernels out there, no matter what VM is in them. The kswapd infinite
| loop that can trigger with the -ac VM when all the ZONE_DMA is
| unfreeable (now fixed in mainline with classzone) have nothing to do
| with this google problem, kswapd is right here to spend cpu time, the
| bug is not kswapd activation.
| 
| I just sent Ben (at Google) a patch that fixes the problem completly for
| me and for him and I'll try to release the real fix in the next days.
| (so far it's a dirty workaround, that is just usable fine in their and
| my memory configuration but it's not general purpose yet, but it's been
| more than enough to proof my theory so far and I've in mind how to fix
| it properly, tomorrow I hope I will implement it).
| 
| Andrea
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