[ovs-dev] [PATCH] ovs-ofctl: Fix memory exhaustion failures in corner cases.

[Ben Pfaff]

On Thu, Nov 06, 2014 at 10:50:09AM -0800, Jarno Rajahalme wrote:
> With notes below:
> 
> Acked-by: Jarno Rajahalme <jrajahalme at nicira.com>
> 
> On Nov 6, 2014, at 10:03 AM, Ben Pfaff <blp at nicira.com> wrote:
> 
> > Inserting or removing a sequence of flows with different wildcard patterns
> > causes temporary use of O(n**2) memory due to pvector modifications inside
> > the classifier.  This commit fixes the problem in two easy cases.  There
> > is at least one more difficult case inside ovs-vswitchd that this does not
> > fix.
> 
> I’m curious about the case inside ovs-vswitchd...

It occurs when you do an "ovs-ofctl del-flows" that deletes all of the
subtables.  Each subtable deletion creates a new copy of the pvector but
we can't free the old one yet.  Bang!