On 03/04, Linus Torvalds wrote: > > On Tue, 4 Mar 2025 at 02:55, Oleg Nesterov <oleg@xxxxxxxxxx> wrote: > > > > > + * Really only alpha needs 32-bit fields, but > > > + * might as well do it for 64-bit architectures > > > + * since that's what we've historically done, > > > + * and it makes 'head_tail' always be a simple > > > + * 'unsigned long'. > > > + */ > > > +#ifdef CONFIG_64BIT > > > + typedef unsigned int pipe_index_t; > > > +#else > > > + typedef unsigned short pipe_index_t; > > > +#endif > > > > I am just curious, why we can't use "unsigned short" unconditionally > > and avoid #ifdef ? > > > > Is "unsigned int" more efficient on 64-bit? > > The main reason is that a "unsigned short" write on alpha isn't atomic Yes, I have already realized this when I tried to actually read the comment, see my next email in reply to myself. But thanks for your detailed explanation! Oleg.
