On Wed, Sep 19, 2012 at 02:58:02PM +0200, Dag-Erling Sm??rgrav wrote: > Konstantin Belousov <kostik...@gmail.com> writes: > > "Dag-Erling Sm??rgrav" <d...@des.no> writes: > > > + otable = fdp->fd_ofiles; > > > + ofileflags = fdp->fd_ofileflags; > > These two new calculations could be unused if the function return early. > > I assume you mean assignments, not calculations. I trust the compiler > to move them to where they are needed - a trivial optimization with SSA. It is a dereference before the assignment, so I perceive it as the calculation. No, I do not think that compiler can move the dereference, because there are many sequential points between the calculation and use of the result.
> > > > + ntable = malloc(nnfiles * sizeof(*ntable) + > > > + nnfiles * sizeof(*nfileflags) + > > > + sizeof(struct freetable), > > > M_FILEDESC, M_ZERO | M_WAITOK); > > Please use the horizontal space less lavishly. > > I was aiming for readability, not compatibility with equipment that went > out of use before I was born. Well, my eyes can only see so many lines in the emacs window. So if you referenced older equipment meaning me being born before you, so be it. :) > > > I think that this calculation, as well as fo calculation below, does > > not take a required alignment of struct freetable into consideration. > > Correct, thanks for pointing it out. The easiest solution is to place > the struct freetable between the file array and the flag array. As I know, for all ABIs FreeBSD run on, the structure alignment is the alignment of the most requiring member. You would introduce very tacit dependency between struct file and struct freetable.
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