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Date: Tue, 8 Oct 2013 12:13:58 +0200
From: Ingo Molnar <mingo@kernel.org>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Alex Thorlton <athorlton@sgi.com>, Ingo Molnar <mingo@redhat.com>,
        Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
        "Eric W . Biederman" <ebiederm@xmission.com>,
        "Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
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        Thomas Gleixner <tglx@linutronix.de>, linux-kernel@vger.kernel.org,
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Subject: Re: [PATCHv5 00/11] split page table lock for PMD tables
Message-ID: <20131008101358.GA8852@gmail.com>
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* Kirill A. Shutemov <kirill.shutemov@linux.intel.com> wrote:

> Ingo Molnar wrote:
> > 
> > * Kirill A. Shutemov <kirill.shutemov@linux.intel.com> wrote:
> > 
> > > > What must arch maintainers do to enable it?  Have you any particular 
> > > > suggestions, warnings etc to make their lives easier?
> > > 
> > > The last patch is a good illustration what need to be done. It's very 
> > > straight forward, I don't see any pitfalls.
> > 
> > Might make sense to stick that somewhere into Documentation/mm/, to make 
> > arch maintainers feel all warm and fuzzy if they look into enabling this 
> > feature on their architecture.
> 
> I want to rework code around page->ptl a bit more:
>  - allow pgtable_page_ctor() to fail and modify callers to handle it;
>  - if sizeof(spinlock_t) > sizeof(long) allocate the spinlock_t
>    dynamically.
> 
> It will allow to use split lock with DEBUG_SPINLOCK and DEBUG_LOCK_ALLOC.
> And it will make -rt guys happier. ;)
> 
> After that I'll document it. Does it work for you?

Sounds nice to me!

Thanks,

	Ingo