Re: [Patch 5/8] ia64: implement crashkernel=auto

Bernhard Walle
2009-08-24T08:21:39Z

* Ingo Molnar <mingo@elte.hu> [2009-08-24 09:43]:
> * Amerigo Wang <amwang@redhat.com> wrote:
> >
> > The reason that I kept 2ULL<<30 instead of 1ULL<<31 is that '1<<30' is
> > exactly 1G, so 2ULL<<30 can be easily read as 2G. ;)
>
> i have no trouble reading 1ULL<<31 as 2G ;-) OTOH, the logic and
> pattern of the comparisons (especially without the comment) looked
> odd at first sight, until i noticed this.

Why not just something like

#define KBYTE(x) ((x)*1024ULL)
#define MBYTE(x) ((x)*1024ULL*1024)
#define GBYTE(x) ((x)*1024ULL*1024*1024)
#define TBYTE(x) ((x)*1024ULL*1024*1024*1024)

I find GBYTE(2) much easier to read than 1ULL<<31. Honestly, I would
add a comment '/* 2G */' if I would write 1ULL<<31 in own code.

But I'm of course not one of that super kernel hackers. ;-)

Regards,
Bernhard