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Message-ID: <86802c440803211704u4fb07074w934f32d2f95bf6a7@mail.gmail.com>
Date: Fri, 21 Mar 2008 17:04:03 -0700
From: "Yinghai Lu" <yhlu.kernel@gmail.com>
To: "Ingo Molnar" <mingo@elte.hu>
Subject: Re: [PATCH] x86_64: early memtest to find bad ram
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
       "H. Peter Anvin" <hpa@zytor.com>,
       "kernel list" <linux-kernel@vger.kernel.org>
In-Reply-To: <20080321120313.GD25225@elte.hu>
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References: <200803202358.33722.yhlu.kernel@gmail.com>
	 <20080321120313.GD25225@elte.hu>
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On Fri, Mar 21, 2008 at 5:03 AM, Ingo Molnar <mingo@elte.hu> wrote:
>
>  * Yinghai Lu <yhlu.kernel.send@gmail.com> wrote:
>
>  > do simple memtest after init_memory_mapping
>  >
>  > use find_e820_area_size to find all ram range that is not reserved.
>  >
>  > and do some simple bits test to find some bad ram.
>  >
>  > if find some bad ram, use reserve_early to exclude that range.
>
>  very nice patch! I always thought that this was the proper way to do
>  memtest - and we could in fact also do something like this after SMP
>  bringup, and hit the memory bus via multiple CPUs. [that will need a
>  different enumeration though than e820 maps]
or
1. core0/node0 check all memory at first
2. every core0 will check all memory later one by one.

>
>  one structural observation: please make this unified functionality, so
>  that 32-bit kernels can make use of it too.

that will need to use PAE to switch 2G windows ....

>
>  a small style nit from scripts/checkpatch.pl:
>
>
>  > +//           printk(KERN_DEBUG "find_e820_area_size : e820 %d [%llx, %lx]\n", i, ei->addr, ei_last);
>
>  remove such lines or make them pr_debug(). (checkpatch also found more
>  such cases)
>
>  also, please add a CONFIG_BOOTPARAM_MEMTEST=y option so that
>  distributions can enable this by default in their debug kernels.
>
>  i've applied your current version to get some testing, please send delta
>  patches against x86/latest.

thanks. will submit delta patch.

YH
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