Messages in this thread | | | Date | Tue, 12 Jun 2012 20:29:39 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH 1/2 v2] x86: add max_addr boot option |
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On 06/12/2012 07:21 PM, Kamezawa Hiroyuki wrote: > > But now, we know mem= boot option is buggy....it acts as max_addr= > option, we have concerns that 'someone may fix mem= option as sane as ia64. because > it's buggy". > > We'd like to fix mem= boot option by ourselves and preserve old behavior > with max_addr= boot option, which ia64 has. >
Now I'm *really* confused.
Realistically, there is no point in the old mem= behavior of assuming a contiguous chunk of memory up to that point; it simply doesn't match how modern hardware is constructed. Your notion that ia64 is "sane" is probably more of "outdated" in my opinion.
As such, the current behavior for mem= seems like the right thing and the change was intentional (not to mention has been in place since kernel 2.5.65, back in 2003); it also solves your requirements. If you are concerned about it, it would make more sense to make sure it is documented as intentional.
In fact, it looks like IA64 introduced a divergence when the max_addr= patch was introduced in 2004. You're basically proposing the same divergence for x86 now; talk about having the tail wag the dog.
Sorry. NAK.
-hpa
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