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From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Wed, 26 Oct 2016 15:09:41 -0700
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Subject: Re: CONFIG_VMAP_STACK, on-stack struct, and wake_up_bit
To: Mel Gorman <mgorman@techsingularity.net>
Cc: Andy Lutomirski <luto@amacapital.net>,
        Andreas Gruenbacher <agruenba@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Andy Lutomirski <luto@kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        Bob Peterson <rpeterso@redhat.com>,
        Steven Whitehouse <swhiteho@redhat.com>, linux-mm <linux-mm@kvack.org>
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On Wed, Oct 26, 2016 at 3:03 PM, Mel Gorman <mgorman@techsingularity.net> wrote:
>
> To be clear, are you referring to PeterZ's patch that avoids the lookup? If
> so, I see your point.

Yup, that's the one. I think you tested it. In fact, I'm sure you did,
because I remember seeing performance numbers from  you ;)

So yes, I'd expect my patch on its own to quite possibly regress on
NUMA systems (although I wonder how much), but I consider PeterZ's
patch the fix to that, so I wouldn't worry about it.

              Linus