On 22.02.2017 11:56, Greg Kurz wrote: > From: Greg Kurz <[email protected]> [...] > This patch reverts to the historical SLOF ordering by walking PCI devices > in reverse order. This reconciles pseries with x86 machine types behavior. > It is expected to make things easier when porting existing applications to > power. [...] > This patch was posted and already discussed during 2.5 development: > > http://patchwork.ozlabs.org/patch/549925/ > > The "consensus" at the time was that guests should not rely on device > ordering (i.e. use persistent naming instead). > > I got recently contacted by OpenStack people who had several complaints > about the reverse ordering of PCI devices in pseries: different behavior > between ppc64 and x86, lots of time spent in debugging when porting > applications from x86 to ppc64 before realizing that it is caused by the > reverse ordering, necessity to carry hacky workarounds... > > One strong argument against handling this properly with persistent naming > is that it requires systemd/udev. This option is considered as painful > with CirrOS, which aims at remaining as minimal as possible and is widely > used in the OpenStack ecosystem. > > Would you re-consider your position and apply this patch ?
+1 for applying the patch. During the past months, I've also run one or two times into issues with the reversed ordering... fortunately, I was able to work around them (or fix other bugs triggered by this), but I think it would be better to return the the ascending order again to avoid further future problems. Thomas
