Date: Mon, 31 Jul 2017 14:55:56 +0200
From: Michal Hocko <mhocko@kernel.org>
To: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Cc: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
        Mel Gorman <mgorman@suse.de>, Vlastimil Babka <vbabka@suse.cz>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Jerome Glisse <jglisse@redhat.com>,
        Reza Arbab <arbab@linux.vnet.ibm.com>,
        Yasuaki Ishimatsu <yasu.isimatu@gmail.com>, qiuxishi@huawei.com,
        Kani Toshimitsu <toshi.kani@hpe.com>, slaoub@gmail.com,
        Joonsoo Kim <js1304@gmail.com>, Andi Kleen <ak@linux.intel.com>,
        Daniel Kiper <daniel.kiper@oracle.com>,
        Igor Mammedov <imammedo@redhat.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Fenghua Yu <fenghua.yu@intel.com>,
        Heiko Carstens <heiko.carstens@de.ibm.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
        Martin Schwidefsky <schwidefsky@de.ibm.com>,
        Michael Ellerman <mpe@ellerman.id.au>,
        Paul Mackerras <paulus@samba.org>,
        Thomas Gleixner <tglx@linutronix.de>, Tony Luck <tony.luck@intel.com>,
        Will Deacon <will.deacon@arm.com>
Subject: Re: [RFC PATCH 2/5] mm, arch: unify vmemmap_populate altmap handling
Message-ID: <20170731125555.GB4829@dhcp22.suse.cz>
References: <20170726083333.17754-1-mhocko@kernel.org>
 <20170726083333.17754-3-mhocko@kernel.org>
 <20170731144053.38c8b012@thinkpad>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20170731144053.38c8b012@thinkpad>
User-Agent: Mutt/1.5.23 (2014-03-12)
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1156
Lines: 28

On Mon 31-07-17 14:40:53, Gerald Schaefer wrote:
[...]
> > @@ -247,12 +248,12 @@ int __meminit vmemmap_populate(unsigned long start, unsigned long end, int node)
> >  			 * use large frames even if they are only partially
> >  			 * used.
> >  			 * Otherwise we would have also page tables since
> > -			 * vmemmap_populate gets called for each section
> > +			 * __vmemmap_populate gets called for each section
> >  			 * separately. */
> >  			if (MACHINE_HAS_EDAT1) {
> >  				void *new_page;
> > 
> > -				new_page = vmemmap_alloc_block(PMD_SIZE, node);
> > +				new_page = __vmemmap_alloc_block_buf(PMD_SIZE, node, altmap);
> >  				if (!new_page)
> >  					goto out;
> >  				pmd_val(*pm_dir) = __pa(new_page) | sgt_prot;
> 
> There is another call to vmemmap_alloc_block() in this function, a couple
> of lines below, this should also be replaced by __vmemmap_alloc_block_buf().

I've noticed that one but in general I have only transformed PMD
mappings because we shouldn't even get to pte level if the forme works
AFAICS. Memory sections should be always 2MB aligned unless I am missing
something. Or is this not true?
-- 
Michal Hocko
SUSE Labs