On Fri, Feb 08, 2019 at 04:18:38PM +0000, Bruce Richardson wrote: > On Fri, Feb 08, 2019 at 10:37:40AM -0500, Neil Horman wrote: > > On Thu, Feb 07, 2019 at 03:03:28PM +0000, Bruce Richardson wrote: > > > On Thu, Feb 07, 2019 at 09:34:26AM -0500, Neil Horman wrote: > > > > On Wed, Feb 06, 2019 at 02:17:45PM +0000, Bruce Richardson wrote: > > > > > On Wed, Feb 06, 2019 at 07:22:54AM -0500, Neil Horman wrote: > > > > > > On Wed, Feb 06, 2019 at 11:01:30AM +0000, Bruce Richardson wrote: > > > > > > > Since compat library is only a single header, we can easily move > > > > > > > it into > > > > > > > the EAL common headers instead of tracking it separately. The > > > > > > > downside of > > > > > > > this is that it becomes a little more difficult to have any libs > > > > > > > that are > > > > > > > built before EAL depend on it. Thankfully, this is not a major > > > > > > > problem as > > > > > > > the only library which uses rte_compat.h and is built before EAL > > > > > > > (kvargs) > > > > > > > already has the path to the compat.h header file explicitly > > > > > > > called out as > > > > > > > an include path. > > > > > > > > > > > > > > However, to ensure that we don't hit problems later with this, we > > > > > > > can add > > > > > > > EAL common headers folder to the global include list in the meson > > > > > > > build > > > > > > > which means that all common headers can be safely used by all > > > > > > > libraries, no > > > > > > > matter what their build order. > > > > > > > > > > > > > This assumes that the compat lib will always just be a header > > > > > > though, no? Will > > > > > > this work in the event that someone wants to add some compatibility > > > > > > code that > > > > > > requires its own C compilation unit? > > > > > > > > > > > > > > > > No, it probably won't work, you'll hit an issue with any libraries > > > > > that > > > > > don't depend on EAL and need that functionality. The question is > > > > > whether > > > > > this is likely to be an issue in the future for us. I'd say the > > > > > possiblity > > > > > is fairly remote, but I'm open to input on it. > > > > > > > > > Im afraid I don't have any more visibility on that than anyone else. > > > > The fact > > > > that it hasn't been needed yet is likely a good sign, but I am > > > > concerned at the > > > > notion that this change enjoins us from having that flexibility. > > > > > > > Yes. However, in general is it not the case that compatibility code > > > belongs > > > in the actual library wanting to provide the compatibility? That is what > > > has been done up till now. If we do need compatibility code placed more > > > centrally, I think EAL is as good a place for it as any - the only library > > > which doesn't depend on EAL now is kvargs, so our risk area is pretty low, > > > I think. > > > > > > Also, if we do need a compat libraries with .c files in it, there is no > > > reason we can't undo this change. It would be no more user visible than > > > adding a .c file to the existing structure, given that in both cases an > > > extra .so file will appear in the build output. > > > > > If the consensus is that compat code can all live in the EAL library, then > > I'm > > ok with it, even if its C code. The only thing I don't want is for our > > plan to > > be, in the event we need C code, to immediately undo this change. That just > > doesn't make sense to me. > > > > So, if you're ok with compat C code in eal, then > > Acked-by: Neil Horman <nhor...@tuxdriver.com> > > > Can you clarify what you would see as the compat C code that would be > needed - perhaps an example from another project? From the little function > versioning I've done in DPDK, I would have thought what was in the headers > was enough for all cases we might encounter. > I can't, hence my ACK. I was really just concerned that we were making a change that enjoined us from being able to add C compilation units should we need them, but if we can add them directly to the EAL libraries, I'm satisfied with that.
Neil > /Bruce >
