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Date: Thu, 16 Aug 2012 21:42:10 +0200
From: Andrea Arcangeli <aarcange@redhat.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Subject: Re: [PATCH v3 6/7] mm: make clear_huge_page cache clear only around
 the fault address
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Cc: linux-mips@linux-mips.org, linux-sh@vger.kernel.org,
 Jan Beulich <jbeulich@novell.com>, linux-mm@kvack.org,
 "H. Peter Anvin" <hpa@zytor.com>, sparclinux@vger.kernel.org,
 Andi Kleen <ak@linux.intel.com>, Robert Richter <robert.richter@amd.com>,
 x86@kernel.org, Hugh Dickins <hughd@google.com>,
 Ingo Molnar <mingo@redhat.com>, Mel Gorman <mgorman@suse.de>,
 Alex Shi <alex.shu@intel.com>, Thomas Gleixner <tglx@linutronix.de>,
 KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
 Tim Chen <tim.c.chen@linux.intel.com>, linux-kernel@vger.kernel.org,
 Andy Lutomirski <luto@amacapital.net>, Johannes Weiner <hannes@cmpxchg.org>,
 Andrew Morton <akpm@linux-foundation.org>, linuxppc-dev@lists.ozlabs.org,
 "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
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On Thu, Aug 16, 2012 at 09:37:25PM +0300, Kirill A. Shutemov wrote:
> On Thu, Aug 16, 2012 at 08:29:44PM +0200, Andrea Arcangeli wrote:
> > On Thu, Aug 16, 2012 at 07:43:56PM +0300, Kirill A. Shutemov wrote:
> > > Hm.. I think with static_key we can avoid cache overhead here. I'll try.
> > 
> > Could you elaborate on the static_key? Is it some sort of self
> > modifying code?
> 
> Runtime code patching. See Documentation/static-keys.txt. We can patch it
> on sysctl.

I guessed it had to be patching the code, thanks for the
pointer. It looks a perfect fit for this one agreed.