On Sat, Jan 15, 2022 at 6:16 AM Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > > On Sat, Jan 15, 2022 at 12:06 AM Andrew Morton > <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > > > > Speed up fork() by up to 40% by refcounting the anon vma name field. > > What? > > No. > > This doesn't speed up anything at all. > > The refcounting of the anon-vma name field avoids a 40% regression > that comes from adding the field in the first place, but this commit > message makes it sound like this series is speeding up fork() by 40%. > > I don't mind the series, but I absolutely mind these kinds of horribly > misleading commit messages. > > This is literally the first commit in the series - and the series in > no way improves performance by 40% in the end, it just first makes it > worse, and then fixes the regression. > > I can speed up any function by a thousand percent - if I'm just > allowed to make it horribly slow first, and only count the final > speedup win when I remove the overhead of the garbage I added. Thanks for fixing it! I see in your tree it is changed to: "Avoid performance regression of the new anon vma name field refcounting it." Please let me know if anything else is left to be done here. > > Linus
