On 03/26/2010 05:07 PM, Johannes Weiner wrote:
> On Fri, Mar 26, 2010 at 04:45:56PM -0700, Yinghai Lu wrote:
>> On 03/26/2010 04:06 PM, Johannes Weiner wrote:
>>> On Fri, Mar 26, 2010 at 03:21:32PM -0700, Yinghai Lu wrote:
>>>> diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c
>>>> index adedeef..fe3d953 100644
>>>> --- a/arch/x86/kernel/head32.c
>>>> +++ b/arch/x86/kernel/head32.c
>>>> @@ -47,6 +47,7 @@ void __init i386_start_kernel(void)
>>>> u64 ramdisk_image = boot_params.hdr.ramdisk_image;
>>>> u64 ramdisk_size = boot_params.hdr.ramdisk_size;
>>>> u64 ramdisk_end = ramdisk_image + ramdisk_size;
>>>> + ramdisk_end = PFN_UP(ramdisk_end) << PAGE_SHIFT;
>>>
>>> Why not PAGE_ALIGN()?
>>
>> looks like PFN_UP is more clear.
>
> Why would you convert to a pfn just to go back to a physical address,
> when all you wanted is align at the next page boundary? It looks
> rather clumsy.
reserve_early() will take phys addr
>
> PAGE_ALIGN() is pretty wide spread and I think it's clear to most
> people what it does.
we may need to clean up all those:
round_up
round_down
roundup
ALIGN
PAGE_ALIGN etc.
>
...
>>>> --- a/arch/x86/mm/init.c
>>>> +++ b/arch/x86/mm/init.c
>>>> @@ -332,6 +332,16 @@ int devmem_is_allowed(unsigned long pagenr)
>>>> void free_init_pages(char *what, unsigned long begin, unsigned long end)
>>>> {
>>>> unsigned long addr = begin;
>>>> + unsigned long addr_aligned, end_aligned;
>>>> +
>>>> + /* Make sure boundaries are page aligned */
>>>> + addr_aligned = PFN_UP(addr) << PAGE_SHIFT;
>>>> + end_aligned = PFN_DOWN(end) << PAGE_SHIFT;
>>>> +
>>>> + if (WARN(addr_aligned != addr || end_aligned != end, "free_init_pages: range [%#lx, %#lx] is not aligned\n", addr, end)) {
>>>> + addr = addr_aligned;
>>>> + end = end_aligned;
>>>> + }
>>>
>>> Maybe realign only for when it is not aligned? So to keep the fixup
>>> out of line.
>>>
>>> I suppose WARN_ON() is enough as it will print a stack trace which
>>> should be enough clue of what went wrong.
>>
>> we need to PFN_DOWN the end, and don't free the partial page.
>> otherwise could crash the system.
>
> Dito.
>
> if (WARN_ON(not_aligned)) {
> align
> }
>
> is what I meant.
>
ok i got it.
YH
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