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Date: Thu, 19 Oct 2017 06:24:27 -0700
From: Matthew Wilcox <willy@infradead.org>
To: Andi Kleen <ak@linux.intel.com>
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On Wed, Oct 18, 2017 at 09:30:32PM -0700, Andi Kleen wrote:
> > Yes.  Every 64-bit repeating pattern is also a 32-bit repeating pattern.
> > Supporting a 64-bit pattern on a 32-bit kernel is painful, but it makes
> > no sense to *not* support a 64-bit pattern on a 64-bit kernel.  
> 
> But a 32bit repeating pattern is not necessarily a 64bit pattern.

Oops, I said it backwards.  What I mean is that if you have the repeating
pattern:

0x12345678 12345678 12345678 12345678 12345678 12345678

that's the same as the repeating pattern:

0x1234567812345678 1234567812345678 1234567812345678

so the 64-bit kernel is able to find all patterns that the 32-bit kernel is,
and more.