On Wed, Jun 06, 2018 at 12:56:47AM +0200, Mateusz Guzik wrote: M> > M> Thank you for the kind words. It is positive feedback like this which M> > M> keeps me going! M> > M> > Btw, what was the point of checking flags || result? Most places in kernel M> > ignore flags and just test result regerdless of M_WAITOK/M_NOWAIT. M> > M> > The result is already in a register, why do you think checking for absense M> > of M_WAITOK is faster that checking for !NULL _malloc_item? M> > M> M> This part is only reachable if flags are known at compilation time. If they M> contain M> M_WAITOK, the flag check will get elided along (we know for a fact it M> passes) M> and subsequently the NULL check will be short circuited, iow for known M> M_WAITOK|M_ZERO flags this is: M> M> _malloc_item = malloc(_size, type, flags & ~ M_ZERO); M> bzero(_malloc_item, _size);
Thanks a lot for explanation! -- Gleb Smirnoff _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
