Messages in this thread | | | Date | Thu, 14 Jan 2010 21:24:51 +0800 | From | Wu Fengguang <> | Subject | Re: [ RESEND PATCH v3] Memory-Hotplug: Fix the bug on interface /dev/mem for 64-bit kernel |
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Kame,
On Tue, Jan 12, 2010 at 05:04:33PM +0900, KAMEZAWA Hiroyuki wrote:
> 3 points... > 1. I think this patch cannot be compiled in archs other than x86. Right ? > IOW, please add static inline dummy...
Good catch!
> 2. pgdat->[start,end], totalram_pages etc...are updated at memory hotplug. > Please place the hook nearby them.
arch/x86/mm/init_64.c:arch_add_memory() updates max_pfn_mapped, in this sense it's equally OK to update max_pfn/max_low_pfn etc before the call to arch_add_memory() ;)
> 3. I recommend you yo use memory hotplug notifier. > If it's allowed, it will be cleaner.
Hmm, notifier is for _outsider_ subsystems. It smells a bit overkill to do notifier _inside_ the hotplug code.
> It seems there are no strict ordering to update parameters this patch touches.
I tend to agree. That said, it does help keep our mind straight if we do it in some logical order: max_pfn => max_pfn_mapped => totalram_pages etc.
Thanks, Fengguang
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