Re: [PATCH 02/10] mm: system wide ALLOC_NO_WATERMARK

Daniel Phillips
2007-08-06T19:15:34Z

On Monday 06 August 2007 11:51, Christoph Lameter wrote:
> On Mon, 6 Aug 2007, Daniel Phillips wrote:
> > On Monday 06 August 2007 11:42, Christoph Lameter wrote:
> > > On Mon, 6 Aug 2007, Daniel Phillips wrote:
> > > > Currently your system likely would have died here, so ending up
> > > > with a reserve page temporarily on the wrong node is already an
> > > > improvement.
> > >
> > > The system would have died? Why?
> >
> > Because a block device may have deadlocked here, leaving the system
> > unable to clean dirty memory, or unable to load executables over
> > the network for example.
>
> So this is a locking problem that has not been taken care of?

A deadlock problem that we used to call memory recursion deadlock, aka:
somebody in the vm writeout path needs to allocate memory, but there is
no memory, so vm writeout stops forever.

Regards,

Daniel