Re: [BUG] 2.4 VM sucks. Again

[Andrea Arcangeli <andrea@suse.de>]

On Fri, May 31, 2002 at 06:56:54PM +0200, Roy Sigurd Karlsbakk wrote:
> > I suspect nuke-buffers is simply always the right thing to do.  It's
> > what 2.5 is doing now (effectively).  We'll see...
> >
> > But in your case, you only have a couple of gigs of memory, iirc.
> > You shouldn't be running into catastrophic buffer_head congestion.
> > Something odd is happening.
> >
> > If you can provide a really detailed set of steps which can be
> > used by others to reproduce this, that would really help.
> 
> What I do: start lots (10-50) downloads, each with a speed of 4,5Mbps from 
> another client. The two are connected using gigEthernet. downloads are over 
> HTTP, with Tux or other servers (have tried several). If the clients are 
> reading at full speed (e.g. only a few clients, or reading directly from 
> localhost), the problem doesn't occir. However, when reading at a fixed rate, 
> it seems like the server is caching itself to death.
> 
> 
> Detailed configuration:
> 
> - 4 IBM 40gig disks in RAID-0. chunk size 1MB
> - 1 x athlon 1GHz
> - 1GB RAM - no highmem (900 meg)
> - kernel 2.4.19pre7 + patch from Andrew Morton to ditch buffers early 
>         (thread: [BUG] 2.4 VM sucks. Again)
> - gigEthernet between test client and server
> 
> Anyone got a clue?

can you try to reproduce with 2.4.19pre9aa2 just in case it's an oom
deadlock, and if it deadlocks again can you press SYSRQ+T, and many
times SYSQR+P, and send this info along the system.map (you may need the
serial console to easily gather the data if not even a SYSRQ+I is able
to let the box resurrect from the livelock). (the system.map possibly
not on l-k because it's quite big)

thanks!

Andrea