Date: Wed, 10 Oct 2012 09:41:45 -0400
From: Konrad Rzeszutek Wilk <konrad@kernel.org>
To: Yinghai Lu <yinghai@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
        "H. Peter Anvin" <hpa@zytor.com>, Jacob Shin <jacob.shin@amd.com>,
        Tejun Heo <tj@kernel.org>,
        Stefano Stabellini <stefano.stabellini@eu.citrix.com>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] x86, mm: Don't clear page table if next range is ram
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On Tue, Oct 09, 2012 at 06:00:12PM -0700, Yinghai Lu wrote:
> On Tue, Oct 9, 2012 at 8:46 AM, Konrad Rzeszutek Wilk <konrad@kernel.org> wrote:
> >> +                         !e820_any_mapped(addr & PAGE_MASK, next, 0))
> >
> > What is the 0 parameter for?
> 
> any type

OK, which means that it either should have a #define for it, or at least
a comment, like:

0 /* any type */

as this would make it clear at first glance what it is - without having
to dive in e820_any_mapped function to determine that.

> 
> if type != 0, the will only check entries with same type.
> 
> int
> e820_any_mapped(u64 start, u64 end, unsigned type)
> {
>         int i;
> 
>         for (i = 0; i < e820.nr_map; i++) {
>                 struct e820entry *ei = &e820.map[i];
> 
>                 if (type && ei->type != type)
>                         continue;
>                 if (ei->addr >= end || ei->addr + ei->size <= start)
>                         continue;
>                 return 1;
>         }
>         return 0;
> }
> 
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