On Mon, 25 Nov 2024 14:40:22 +0100 Heiko Carstens <hca@xxxxxxxxxxxxx> wrote: > On Mon, Nov 25, 2024 at 01:20:42PM +0100, Claudio Imbrenda wrote: > > On Mon, 25 Nov 2024 12:50:39 +0100 > > Heiko Carstens <hca@xxxxxxxxxxxxx> wrote: > > > > > kvm_s390_update_topology_change_report() modifies a single bit within > > > sca_utility using cmpxchg(). Given that the size of the sca_utility union > > > is two bytes this generates very inefficient code. Change the size to four > > > bytes, so better code can be generated. > > > > > > Even though the size of sca_utility doesn't reflect architecture anymore > > > this seems to be the easiest and most pragmatic approach to avoid > > > inefficient code. > > > > wouldn't an atomic bit_op be better in that case? > > I had that, but decided against it, since the generated code isn't shorter. > And it would require and unsigned long type within the union, or a cast, > which I also both disliked. fair enough Acked-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
