Re: [PATCH] x86: introduce init_memory_mapping for 32bit

From: Yinghai Lu
Date: Tue Jun 24 2008 - 18:02:56 EST


On Tue, Jun 24, 2008 at 12:22 PM, Yinghai Lu <yhlu.kernel@xxxxxxxxx> wrote:
> On Tue, Jun 24, 2008 at 4:30 AM, Ingo Molnar <mingo@xxxxxxx> wrote:
>>
>> * Yinghai Lu <yhlu.kernel@xxxxxxxxx> wrote:
>>
>>> so could use mem below max_low_pfn as early. could move several
>>> function more early instead of waiting after paging_init including
>>> moving relocate_initrd early, and kva related early done in
>>> initmem_init
>>
>> applied to tip/x86/setup-memory - thanks Yinghai.
>>
>> a sidenote:
>>
>>> 6 files changed, 128 insertions(+), 74 deletions(-)
>>
>> this patch is too large - if it causes any problems it will not be very
>> easy to figure out which exact change caused the problems.
>>
>> Lets hope it goes all fine - but in the future lets try doing
>> more+smaller patches, especially if they change some known-dangerous
>> area of the kernel.
>>
>> For example here a better splitup would have been to do 5 or more
>> patches:
>>
>> 1) first introduce init_memory_mapping() [but dont use it anywhere]
>> 2) add the init_memory_mapping() call to setup_arch()
>> 3) move remap_numa_kva()
>> 4) move relocate_initrd()
>> 5) remove the now unnecessary setup from paging_init()
>>
>> ... or something like that. The point is to manage risk: if there's
>> multiple problem areas that a change is touching, try to isolate them
>> from each other and introduce the change gradually.
>>
>> The end result is still exactly the same, but much more
>> reviewable/debuggable/bisectable.
>
> split into 3 patches, please use them to replace the old one if you like.
>
and
[PATCH] x86: fix e820_update_range size when overlapping
[PATCH] x86: get max_pfn_mapped in init_memory_mapping
[PATCH] x86: add table_top check for alloc_low_page in 64 bit
[PATCH] x86: change size if e820_update/remove_range

YH
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