On Tue, 2024-02-27 at 07:02 +0000, Christophe Leroy wrote: > > It could be possible to initialize the new field for each arch to > > 0, but > > instead simply inialize the field with a C99 struct inializing > > syntax. > > Why doing a full init of the struct when all fields are re-written a > few > lines after ? > > If I take the exemple of powerpc function slice_find_area_bottomup(): > > struct vm_unmapped_area_info info; > > info.flags = 0; > info.length = len; > info.align_mask = PAGE_MASK & ((1ul << pshift) - 1); > info.align_offset = 0; > > For me it looks better to just add: > > info.new_field = 0; /* or whatever value it needs to have */
Hi, Thanks for taking a look. Yes, I guess that should have some justification. I was thinking of two reasons: 1. No future additions of optional parameters would need to make tree wide changes like this. 2. The change is easier to review and get correct because the necessary context is within a single line. For example, in that function some of members are set within a while loop. The place you pointed seems to be the correct one, but a diff that had the new field set after: info.high_limit = addr; ...would look correct too, but not be. What is the concern with C99 initialization? FWIW, the full series also removes an indirect branch, and probably is a net win for performance in this path.
