On Fri, 23 Feb 2024 10:30:45 -0800 Jeff Johnson <quic_jjohnson@xxxxxxxxxxx> wrote: > On 2/23/2024 9:56 AM, Steven Rostedt wrote: > > From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx> > > > > [ > > This is a treewide change. I will likely re-create this patch again in > > the second week of the merge window of v6.9 and submit it then. Hoping > > to keep the conflicts that it will cause to a minimum. > > ] > > > > With the rework of how the __string() handles dynamic strings where it > > saves off the source string in field in the helper structure[1], the > > assignment of that value to the trace event field is stored in the helper > > value and does not need to be passed in again. > > Just curious if this could be done piecemeal by first changing the > macros to be variadic macros which allows you to ignore the extra > argument. The callers could then be modified in their separate trees. > And then once all the callers have be merged, the macros could be > changed to no longer be variadic. I weighed doing that, but I think ripping off the band-aid is a better approach. One thing I found is that leaving unused parameters in the macros can cause bugs itself. I found one case doing my clean up, where an unused parameter in one of the macros was bogus, and when I made it a used parameter, it broke the build. I think for tree-wide changes, the preferred approach is to do one big patch at once. And since this only affects TRACE_EVENT() macros, it hopefully would not be too much of a burden (although out of tree users may suffer from this, but do we care?) Now one thing I could do is to not remove the parameter, but just add: WARN_ON_ONCE((src) != __data_offsets->item##_ptr_); in the __assign_str() macro to make sure that it's still the same that is assigned. But I'm not sure how useful that is, and still causes burden to have it. I never really liked the passing of the string in two places to begin with. -- Steve
