Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH] <linux/page-isolation.h>: provide stubs for
 MEMORY_ISOLATION not set (for Microblaze)
To:     Mike Rapoport <rppt@linux.ibm.com>
Cc:     LKML <linux-kernel@vger.kernel.org>, Linux MM <linux-mm@kvack.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Michal Nazarewicz <mina86@mina86.com>,
        Wen Congyang <wency@cn.fujitsu.com>,
        Michal Simek <monstr@monstr.eu>,
        Christoph Hellwig <hch@lst.de>,
        kernel test robot <lkp@intel.com>
References: <1f6b42e6-b6b5-40e3-92b4-77bd610d3e49@infradead.org>
 <20200907070511.GN424181@linux.ibm.com>
From:   Randy Dunlap <rdunlap@infradead.org>
Message-ID: <8a1a155a-50ac-170f-13b2-01123bfc396f@infradead.org>
Date:   Mon, 7 Sep 2020 15:15:58 -0700
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
 Thunderbird/68.10.0
MIME-Version: 1.0
In-Reply-To: <20200907070511.GN424181@linux.ibm.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 9/7/20 12:05 AM, Mike Rapoport wrote:
> Hi Randy,
> 
> On Sun, Sep 06, 2020 at 12:33:08PM -0700, Randy Dunlap wrote:
>> From: Randy Dunlap <rdunlap@infradead.org>
>>
>> Fix build errors in Microblaze when CONFIG_MEMORY_ISOLATION is not
>> set/enabled by adding stubs for 3 missing functions.
> 
> I've tried to follow Kconfig dependencies to see how could we have both
> CONTIG_ALLOC=y and CONFIG_MEMORY_ISOLATION=n and I could not find how
> was this possible.
> 
> We have 
> 
> config CONTIG_ALLOC
> 	def_bool (MEMORY_ISOLATION && COMPACTION) || CMA
> 
> and
> 
> config CMA
> 	bool "Contiguous Memory Allocator"
> 	depends on MMU
> 	select MIGRATION
> 	select MEMORY_ISOLATION
> 
> and alloc_contig_range() is hidden behind '#ifdef CONFIG_CONTIG_ALLOC'
> 
> In any rate, I think the better fix would be to update Kconfig
> dependencies rather than add stubs for these functions.

OK, working on that. Should have something soon.


>> Fixes these build errors:
>>
>> gcc-9.3.0-nolibc/microblaze-linux/bin/microblaze-linux-ld: mm/page_alloc.o: in function `alloc_contig_range':
>> (.text+0xa0c0): undefined reference to `start_isolate_page_range'
>> gcc-9.3.0-nolibc/microblaze-linux/bin/microblaze-linux-ld: (.text+0xa2bc): undefined reference to `test_pages_isolated'
>> gcc-9.3.0-nolibc/microblaze-linux/bin/microblaze-linux-ld: (.text+0xa378): undefined reference to `undo_isolate_page_range'
>>
>> Fixes: 0815f3d81d76 ("mm: page_isolation: MIGRATE_CMA isolation functions added") # v3.10
>> Fixes: b023f46813cd ("memory-hotplug: skip HWPoisoned page when offlining pages") # v3.10
>> Reported-by: kernel test robot <lkp@intel.com>
>> Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
>> Cc: Michal Nazarewicz <mina86@mina86.com>
>> Cc: Wen Congyang <wency@cn.fujitsu.com>
>> Cc: Michal Simek <monstr@monstr.eu>
>> Cc: Christoph Hellwig <hch@lst.de>
>> Cc: Andrew Morton <akpm@linux-foundation.org>
>> Cc: Mike Rapoport <rppt@linux.ibm.com>
>> Cc: linux-mm@kvack.org
>> ---
>>  include/linux/page-isolation.h |   16 ++++++++++++++++
>>  1 file changed, 16 insertions(+)


-- 
~Randy