linux-kernel - Re: [PATCH 2/2] arm64: mm: make pfn always valid with flat memory

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Message-ID: <20160412150036.GG8066@e104818-lin.cambridge.arm.com>
Date:	Tue, 12 Apr 2016 16:00:36 +0100
From:	Catalin Marinas <catalin.marinas@....com>
To:	Xishi Qiu <qiuxishi@...wei.com>
Cc:	Chen Feng <puck.chen@...ilicon.com>, mark.rutland@....com,
	dan.zhao@...ilicon.com, mhocko@...e.com, puck.chen@...mail.com,
	ard.biesheuvel@...aro.org, suzhuangluan@...ilicon.com,
	will.deacon@....com, linux-kernel@...r.kernel.org,
	linuxarm@...wei.com, linux-mm@...ck.org,
	kirill.shutemov@...ux.intel.com, rientjes@...gle.com,
	oliver.fu@...ilicon.com, akpm@...ux-foundation.org,
	robin.murphy@....com, yudongbin@...licon.com,
	linux-arm-kernel@...ts.infradead.org, saberlily.xia@...ilicon.com
Subject: Re: [PATCH 2/2] arm64: mm: make pfn always valid with flat memory

On Mon, Apr 11, 2016 at 07:08:38PM +0800, Xishi Qiu wrote:
> On 2016/4/5 16:22, Chen Feng wrote:
> 
> > Make the pfn always valid when using flat memory.
> > If the reserved memory is not align to memblock-size,
> > there will be holes in zone.
> > 
> > This patch makes the memory in buddy always in the
> > array of mem-map.
> > 
> > Signed-off-by: Chen Feng <puck.chen@...ilicon.com>
> > Signed-off-by: Fu Jun <oliver.fu@...ilicon.com>
> > ---
> >  arch/arm64/mm/init.c | 7 ++++---
> >  1 file changed, 4 insertions(+), 3 deletions(-)
> > 
> > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> > index ea989d8..0e1d5b7 100644
> > --- a/arch/arm64/mm/init.c
> > +++ b/arch/arm64/mm/init.c
> > @@ -306,7 +306,8 @@ static void __init free_unused_memmap(void)
> 
> How about let free_unused_memmap() support for CONFIG_SPARSEMEM_VMEMMAP?

We would need extra care to check that the memmap was actually allocated
in the first place.

-- 
Catalin