linux-kernel - Re: [PATCH] x86: cleanup reloated

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Message-ID: <86802c440806141508i542cc69fy964250b9f226865b@mail.gmail.com>
Date:	Sat, 14 Jun 2008 15:08:37 -0700
From:	"Yinghai Lu" <yhlu.kernel@...il.com>
To:	"H. Peter Anvin" <hpa@...or.com>
Cc:	"Ingo Molnar" <mingo@...e.hu>,
	"Thomas Gleixner" <tglx@...utronix.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] x86: cleanup reloated_initrd

On Sat, Jun 14, 2008 at 12:39 PM, H. Peter Anvin <hpa@...or.com> wrote:
> Yinghai Lu wrote:
>  Signed-off-by: Yinghai Lu <yhlu.kernel@...il.com>
>>>>
>>>> Index: linux-2.6/arch/x86/kernel/setup_32.c
>>>> ===================================================================
>>>> --- linux-2.6.orig/arch/x86/kernel/setup_32.c
>>>> +++ linux-2.6/arch/x86/kernel/setup_32.c
>>>> @@ -585,6 +585,9 @@ static void __init relocate_initrd(void)
>>>>       printk(KERN_INFO "Copied RAMDISK from %016llx - %016llx to %08llx
>>>> -
>>>> %08llx\n",
>>>>               ramdisk_image, ramdisk_image + ramdisk_size - 1,
>>>>               ramdisk_here, ramdisk_here + ramdisk_size - 1);
>>>> +
>>>> +       /* need to free that, otherwise init highmem will reserve it
>>>> again
>>>> */
>>>> +       free_early(ramdisk_image, ramdisk_image+ramdisk_size);
>>>>  }
>>>>
>>> I'm somewhat confused by this... you realize that the old location and
>>> the
>>> new location of the initrd will overlap, right?
>>
>> Ying Huang add page_is_reserved_early check in
>> add_one_highpage_init(), so reserve_early high address will be
>> reserved when in init high. that is not wanted old initrd in high
>> region we will lose some ram
>>
>
> Yes, but I think the above will free part of the active area if the areas
> overlap.

overlap parts below max_low_pfn is freed with free_bootmem

and free_early only remove that entry in early_res array. and at that
time, we already called
early_res_to_bootmem.

so it is safe.

YH
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