On Fri, Apr 19, 2019 at 09:02:11AM +0200, Peter Zijlstra wrote: > On Thu, Apr 18, 2019 at 05:42:55PM +0200, Thomas Gleixner wrote: > > On Thu, 18 Apr 2019, Josh Poimboeuf wrote: > > > > Another idea I had (but never got a chance to work on) was to extend the > > > x86 unwind interface to all arches. So instead of the callbacks, each > > > arch would implement something like this API: > > > I surely thought about that, but after staring at all incarnations of > > arch/*/stacktrace.c I just gave up. > > > > Aside of that quite some archs already have callback based unwinders > > because they use them for more than stacktracing and just have a single > > implementation of that loop. > > > > I'm fine either way. We can start with x86 and then let archs convert over > > their stuff, but I wouldn't hold my breath that this will be completed in > > the forseeable future. > > I suggested the same to Thomas early on, and I even spend the time to > convert some $random arch to the iterator interface, and while it is > indeed entirely feasible, it is _far_ more work. > > The callback thing OTOH is flexible enough to do what we want to do now, > and allows converting most archs to it without too much pain (as Thomas > said, many archs are already in this form and only need minor API > adjustments), which gets us in a far better place than we are now. > > And we can always go to iterators later on. But I think getting the > generic unwinder improved across all archs is a really important first > step here. Fair enough. -- Josh
