From: Amerigo Wang <amwang@redhat.com>
To: Bernhard Walle <bernhard.walle@gmx.de>
Cc: Ingo Molnar <mingo@elte.hu>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, tony.luck@intel.com,
linux-ia64@vger.kernel.org, nhorman@redhat.com,
ebiederm@xmission.com, andi@firstfloor.org, fenghua.yu@intel.com,
kamezawa.hiroyu@jp.fujitsu.com, avorontsov@ru.mvista.com
Subject: Re: [Patch 5/8] ia64: implement crashkernel=auto
Date: Mon, 24 Aug 2009 18:23:06 +0800 [thread overview]
Message-ID: <4A926A0A.1000607@redhat.com> (raw)
In-Reply-To: <20090824082148.GA16457@mail1.bwalle.de>
Bernhard Walle wrote:
> * 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. ;-)
>
>
Yeah, great. Here we only need MBYTES() and GBYTES(). ;)
Thanks.
next prev parent reply other threads:[~2009-08-24 10:22 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-08-21 6:54 [Patch 0/8] V4 Implement crashkernel=auto Amerigo Wang
2009-08-21 6:54 ` [Patch 1/8] kexec: allow to shrink reserved memory Amerigo Wang
2009-08-22 0:17 ` Andrew Morton
2009-08-24 1:36 ` Amerigo Wang
2009-08-22 1:39 ` Eric W. Biederman
2009-08-24 2:02 ` Amerigo Wang
2009-08-21 6:54 ` [Patch 2/8] x86: add CONFIG_KEXEC_AUTO_RESERVE Amerigo Wang
2009-08-21 6:54 ` [Patch 3/8] x86: implement crashkernel=auto Amerigo Wang
2009-08-21 6:54 ` [Patch 4/8] ia64: add CONFIG_KEXEC_AUTO_RESERVE Amerigo Wang
2009-08-21 6:55 ` [Patch 5/8] ia64: implement crashkernel=auto Amerigo Wang
2009-08-22 0:24 ` Andrew Morton
2009-08-22 11:18 ` Ingo Molnar
2009-08-24 2:05 ` Amerigo Wang
2009-08-24 7:43 ` Ingo Molnar
2009-08-24 8:21 ` Bernhard Walle
2009-08-24 10:23 ` Amerigo Wang [this message]
2009-08-24 1:59 ` Amerigo Wang
2009-08-21 6:55 ` [Patch 6/8] powerpc: add CONFIG_KEXEC_AUTO_RESERVE Amerigo Wang
2009-08-24 13:44 ` Michael Ellerman
2009-08-24 14:45 ` M. Mohan Kumar
2009-08-25 6:37 ` Amerigo Wang
2009-08-25 10:24 ` M. Mohan Kumar
2009-08-25 6:23 ` Amerigo Wang
2009-08-25 10:28 ` M. Mohan Kumar
2009-08-26 6:59 ` Amerigo Wang
2009-08-21 6:55 ` [Patch 7/8] powerpc: implement crashkernel=auto Amerigo Wang
2009-08-21 6:55 ` [Patch 8/8] doc: update the kdump document Amerigo Wang
2009-08-22 0:06 ` [Patch 0/8] V4 Implement crashkernel=auto Andrew Morton
2009-08-24 1:34 ` Amerigo Wang
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