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

From: Amerigo Wang
Date: Mon Aug 24 2009 - 06:22:20 EST

Bernhard Walle wrote:
* Ingo Molnar <mingo@xxxxxxx> [2009-08-24 09:43]:
* Amerigo Wang <amwang@xxxxxxxxxx> 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. ;-)

Yeah, great. Here we only need MBYTES() and GBYTES(). ;)


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