On 4 August 2013 13:24, Wanpeng Li liwanp@linux.vnet.ibm.com wrote:
On Sun, Aug 04, 2013 at 10:41:01AM +0530, Manjunath Goudar wrote:
s patch adds a Kconfig dependency on an MMU being available before CMA can be enabled. Without this patch, CMA can be enabled on an MMU-less system which can lead to issues. This was discovered during randconfig testing, in which CMA was enabled w/o MMU being enabled, leading to the following error:
CC mm/migrate.o mm/migrate.c: In function ‘remove_migration_pte’: mm/migrate.c:134:3: error: implicit declaration of function
‘pmd_trans_huge’
[-Werror=implicit-function-declaration] if (pmd_trans_huge(*pmd)) ^ mm/migrate.c:137:3: error: implicit declaration of function
‘pte_offset_map’
[-Werror=implicit-function-declaration] ptep = pte_offset_map(pmd, addr);
Similar one.
In this patch MIGRATION config is not required MMU, because already CMA config depends on MMU and HAVE_MEMBLOCK if both are true then only selecting MIGRATION and MEMORY_ISOLATION.
Signed-off-by: Manjunath Goudar manjunath.goudar@linaro.org Acked-by: Arnd Bergmann arnd@linaro.org Cc: Deepak Saxena dsaxena@linaro.org Cc: IWAMOTO Toshihiro iwamoto@valinux.co.jp Cc: Hirokazu Takahashi taka@valinux.co.jp Cc: Dave Hansen haveblue@us.ibm.com Cc: linux-mm@kvack.org Cc: Johannes Weiner hannes@cmpxchg.org Cc: Michal Hocko mhocko@suse.cz Cc: Balbir Singh bsingharora@gmail.com Cc: KAMEZAWA Hiroyuki kamezawa.hiroyu@jp.fujitsu.com
mm/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/Kconfig b/mm/Kconfig index 256bfd0..ad6b98e 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -522,7 +522,7 @@ config MEM_SOFT_DIRTY
config CMA bool "Contiguous Memory Allocator"
depends on HAVE_MEMBLOCK
depends on MMU && HAVE_MEMBLOCK select MIGRATION select MEMORY_ISOLATION help-- 1.7.9.5
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Thanks
Manjunath Goudar
On Mon 05-08-13 10:10:08, Manjunath Goudar wrote:
On 4 August 2013 13:24, Wanpeng Li liwanp@linux.vnet.ibm.com wrote:
On Sun, Aug 04, 2013 at 10:41:01AM +0530, Manjunath Goudar wrote:
s patch adds a Kconfig dependency on an MMU being available before CMA can be enabled. Without this patch, CMA can be enabled on an MMU-less system which can lead to issues. This was discovered during randconfig testing, in which CMA was enabled w/o MMU being enabled, leading to the following error:
CC mm/migrate.o mm/migrate.c: In function ‘remove_migration_pte’: mm/migrate.c:134:3: error: implicit declaration of function
‘pmd_trans_huge’
[-Werror=implicit-function-declaration] if (pmd_trans_huge(*pmd)) ^ mm/migrate.c:137:3: error: implicit declaration of function
‘pte_offset_map’
[-Werror=implicit-function-declaration] ptep = pte_offset_map(pmd, addr);
Similar one.
In this patch MIGRATION config is not required MMU, because already CMA config depends on MMU and HAVE_MEMBLOCK if both are true then only selecting MIGRATION and MEMORY_ISOLATION.
No, I think it should be config MIGRATION that should depend on MMU explicitly because that is where the problem exists. It shouldn't rely on other configs to not select it automatically.
The question is. Does CMA need to depend on MMU as well? Why? But please comment on the original thread instead.
On 5 August 2013 13:02, Michal Hocko mhocko@suse.cz wrote:
On Mon 05-08-13 10:10:08, Manjunath Goudar wrote:
On 4 August 2013 13:24, Wanpeng Li liwanp@linux.vnet.ibm.com wrote:
On Sun, Aug 04, 2013 at 10:41:01AM +0530, Manjunath Goudar wrote:
s patch adds a Kconfig dependency on an MMU being available before CMA can be enabled. Without this patch, CMA can be enabled on an MMU-less system which can lead to issues. This was discovered during randconfig testing, in which CMA was enabled w/o MMU being enabled, leading to the following error:
CC mm/migrate.o mm/migrate.c: In function ‘remove_migration_pte’: mm/migrate.c:134:3: error: implicit declaration of function
‘pmd_trans_huge’
[-Werror=implicit-function-declaration] if (pmd_trans_huge(*pmd)) ^ mm/migrate.c:137:3: error: implicit declaration of function
‘pte_offset_map’
[-Werror=implicit-function-declaration] ptep = pte_offset_map(pmd, addr);
Similar one.
In this patch MIGRATION config is not required MMU, because already CMA config depends on MMU and HAVE_MEMBLOCK if both are true then only selecting MIGRATION
and
MEMORY_ISOLATION.
No, I think it should be config MIGRATION that should depend on MMU explicitly because that is where the problem exists. It shouldn't rely on other configs to not select it automatically.
Yes you are correct.
The question is. Does CMA need to depend on MMU as well? Why?
But please comment on the original thread instead.
I went through the mm/Kconfig, I think MMU dependence is not required for CMA.
--
Michal Hocko SUSE Labs
Thanks Manjunath Goudar
On Mon 05-08-13 14:07:41, Manjunath Goudar wrote:
On 5 August 2013 13:02, Michal Hocko mhocko@suse.cz wrote:
On Mon 05-08-13 10:10:08, Manjunath Goudar wrote:
On 4 August 2013 13:24, Wanpeng Li liwanp@linux.vnet.ibm.com wrote:
On Sun, Aug 04, 2013 at 10:41:01AM +0530, Manjunath Goudar wrote:
s patch adds a Kconfig dependency on an MMU being available before CMA can be enabled. Without this patch, CMA can be enabled on an MMU-less system which can lead to issues. This was discovered during randconfig testing, in which CMA was enabled w/o MMU being enabled, leading to the following error:
CC mm/migrate.o mm/migrate.c: In function ‘remove_migration_pte’: mm/migrate.c:134:3: error: implicit declaration of function
‘pmd_trans_huge’
[-Werror=implicit-function-declaration] if (pmd_trans_huge(*pmd)) ^ mm/migrate.c:137:3: error: implicit declaration of function
‘pte_offset_map’
[-Werror=implicit-function-declaration] ptep = pte_offset_map(pmd, addr);
Similar one.
In this patch MIGRATION config is not required MMU, because already CMA config depends on MMU and HAVE_MEMBLOCK if both are true then only selecting MIGRATION
and
MEMORY_ISOLATION.
No, I think it should be config MIGRATION that should depend on MMU explicitly because that is where the problem exists. It shouldn't rely on other configs to not select it automatically.
Yes you are correct.
The question is. Does CMA need to depend on MMU as well? Why? But please comment on the original thread instead.
I went through the mm/Kconfig, I think MMU dependence is not required for CMA.
OK, it turned out that it is needed in the end. Kcofing forces selects so CMA config would force MIGRATION even if that one depends on MMU.
linaro-kernel@lists.linaro.org
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Manjunath Goudar -
Michal Hocko