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Date: Mon, 28 Apr 2014 17:55:40 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Jianyu Zhan <nasa4836@gmail.com>
Cc: Michal Hocko <mhocko@suse.cz>, Andrew Morton <akpm@linux-foundation.org>,
        kirill.shutemov@linux.intel.com, Rik van Riel <riel@redhat.com>,
        Jiang Liu <liuj97@gmail.com>, Johannes Weiner <hannes@cmpxchg.org>,
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        khalid.aziz@oracle.com, "linux-mm@kvack.org" <linux-mm@kvack.org>,
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Subject: Re: [PATCH RFC 2/2] mm: introdule compound_head_by_tail()
Message-ID: <20140428155540.GJ27561@twins.programming.kicks-ass.net>
References: <c232030f96bdc60aef967b0d350208e74dc7f57d.1398605516.git.nasa4836@gmail.com>
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On Mon, Apr 28, 2014 at 11:53:28PM +0800, Jianyu Zhan wrote:
> Actually, I checked the assembled code, the compiler is _not_
> so smart to recognize this case. It just does optimization as
> the hint unlikely() told it.

What version, and why didn't your changelog include this useful
information?