On Thu, Nov 08, 2018 at 01:22:54PM -0800, Andy Lutomirski wrote: > > > > > > Why are these __packed? It seems like it'll generate bad code for no > > > obvious purpose. > > > > That prevents any possibility that the compiler will insert padding, although in > > 64-bit kernel this should not happen to either struct. Also all xstate > > components here are packed. > > > > They both seem like bugs, perhaps. As I understand it, __packed > removes padding, but it also forces the compiler to expect the fields > to be unaligned even if they are actually aligned. How is that? Andy, mind to point where you get that this attribute forces compiler to make such assumption?