Re: [PATCH] <linux/page-isolation.h>: provide stubs for MEMORY_ISOLATION not set (for Microblaze)

[Randy Dunlap]

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@xxxxxxxxxxxxx>
>>
>> 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@xxxxxxxxx>
>> Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
>> Cc: Michal Nazarewicz <mina86@xxxxxxxxxx>
>> Cc: Wen Congyang <wency@xxxxxxxxxxxxxx>
>> Cc: Michal Simek <monstr@xxxxxxxxx>
>> Cc: Christoph Hellwig <hch@xxxxxx>
>> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
>> Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
>> Cc: linux-mm@xxxxxxxxx
>> ---
>>  include/linux/page-isolation.h |   16 ++++++++++++++++
>>  1 file changed, 16 insertions(+)


-- 
~Randy