On 4 August 2013 13:39, Michal Hocko <mhocko@xxxxxxx> wrote:
On Sun 04-08-13 10:41:01, Manjunath Goudar wrote:This is a migration code but you are updating configuration for CMA
> 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);
which doesn't make much sense to me.
I guess you wanted to disable migration for CMA instead?
Yes you are right.Already Chen Gang has written similar patch.
> Signed-off-by: Manjunath Goudar <manjunath.goudar@xxxxxxxxxx>
> Acked-by: Arnd Bergmann <arnd@xxxxxxxxxx>
> Cc: Deepak Saxena <dsaxena@xxxxxxxxxx>
> Cc: IWAMOTO Toshihiro <iwamoto@xxxxxxxxxxxxx>
> Cc: Hirokazu Takahashi <taka@xxxxxxxxxxxxx>
> Cc: Dave Hansen <haveblue@xxxxxxxxxx>
> Cc: linux-mm@xxxxxxxxx
> Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
> Cc: Michal Hocko <mhocko@xxxxxxx>
> Cc: Balbir Singh <bsingharora@xxxxxxxxx>
> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
> ---
> 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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Michal Hocko
SUSE Labs
Manjunath Goudar