Re: [RFC][PATCH 2/9] deadlock prevention core
From: Andrew Morton
Date: Mon Aug 14 2006 - 01:26:46 EST
On Mon, 14 Aug 2006 07:03:55 +0200
Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:
> On Sun, 2006-08-13 at 21:58 -0700, Andrew Morton wrote:
> > On Mon, 14 Aug 2006 06:40:53 +0200
> > Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:
> > > Testcase:
> > >
> > > Mount an NBD device as sole swap device and mmap > physical RAM, then
> > > loop through touching pages only once.
> > Fix: don't try to swap over the network. Yes, there may be some scenarios
> > where people have no local storage, but it's reasonable to expect anyone
> > who is using Linux as an "enterprise storage platform" to stick a local
> > disk on the thing for swap.
> I wish you were right, however there seems to be a large demand to go
> diskless and swap over iSCSI because disks seem to be the nr. 1 failing
> piece of hardware in systems these days.
We could track dirty anonymous memory and throttle.
Also, there must be some value of /proc/sys/vm/min_free_kbytes at which a
machine is no longer deadlockable with any of these tricks. Do we know
what level that is?
> > That leaves MAP_SHARED, but mm-tracking-shared-dirty-pages.patch will fix
> > that, will it not?
> Will makes it less likely. One can still have memory pressure, the
> remaining bits of memory can still get stuck in socket queues for
> blocked processes.
But there's lots of reclaimable pagecache around and kswapd will free it
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/