Re: [PATCH] pipe_read: don't wake up the writer if the pipe is still full

[Oleg Nesterov]

On 03/04, Oleg Nesterov wrote:
>
> On 03/03, Linus Torvalds 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?

Ah, I guess I misread the comment...

So, the problem is that 64-bit alpha can't write u16 "atomically" ?

Oleg.