> On Dec 3, 2018, at 8:13 AM, Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > > On Mon, Dec 03, 2018 at 02:59:36PM +0100, Vlastimil Babka wrote: >> On 11/28/18 3:01 PM, Matthew Wilcox wrote: >>> Some of the functions in vmalloc.c have as many as nine arguments. >>> So I thought I'd have a quick go at bundling the ones that make sense >>> into a struct and pass around a pointer to that struct. Well, it made >>> the generated code worse, >> >> Worse in which metric? > > More instructions to accomplish the same thing. > >>> so I thought I'd share my attempt so nobody >>> else bothers (or soebody points out that I did something stupid). >> >> I guess in some of the functions the args parameter could be const? >> Might make some difference. >> >> Anyway this shouldn't be a fast path, so even if the generated code is >> e.g. somewhat larger, then it still might make sense to reduce the >> insane parameter lists. > > It might ... I'm not sure it's even easier to program than the original > though. My intuition is that if all the fields of vm_args were initialized together (in the same function), and a 'const struct vm_args *' was provided as an argument to other functions, code would be better (at least better than what you got right now). I’m not saying it is easily applicable in this use-case (since I didn’t check).
