On 04/19/2017 03:13 AM, Michael Ellerman wrote: > Oliver O'Halloran <oohall@xxxxxxxxx> writes: > >> On Wed, Apr 19, 2017 at 2:46 AM, Rob Herring <robh+dt@xxxxxxxxxx> wrote: >>> On Mon, Apr 17, 2017 at 7:32 PM, Tyrel Datwyler >>> <tyreld@xxxxxxxxxxxxxxxxxx> wrote: >>>> This patch introduces event tracepoints for tracking a device_nodes >>>> reference cycle as well as reconfig notifications generated in response >>>> to node/property manipulations. >>>> >>>> With the recent upstreaming of the refcount API several device_node >>>> underflows and leaks have come to my attention in the pseries (DLPAR) dynamic >>>> logical partitioning code (ie. POWER speak for hotplugging virtual and physcial >>>> resources at runtime such as cpus or IOAs). These tracepoints provide a >>>> easy and quick mechanism for validating the reference counting of >>>> device_nodes during their lifetime. >>> >>> Not really relevant for this patch, but since you are looking at >>> pseries and refcounting, the refcounting largely exists for pseries. >>> It's also hard to get right as this type of fix is fairly common. It's >>> now used for overlays, but we really probably only need to refcount >>> the overlays or changesets as a whole, not at a node level. If you >>> have any thoughts on how a different model of refcounting could work >>> for pseries, I'd like to discuss it. >> >> One idea I've been kicking around is differentiating short and long >> term references to a node. > > I actually did this a long time ago, but balked at the size of the patch > to do the conversion. Let me see if I can find it lying around ... It would be interesting to revisit this, and toss around any other ideas anyone may have. -Tyrel > > cheers > -- > To unsubscribe from this list: send the line "unsubscribe devicetree" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
