[PATCH] mm/shmem: fix build failure when CONFIG_TRANSPARENT_HUGEPAGE is not set

[PATCH] mm/shmem: fix build failure when CONFIG_TRANSPARENT_HUGEPAGE is not set

[cgel.zte]

From: Yang Yang <yang.yang29@zte.com.cn>

shmem_add_to_page_cache() use THP_FILE_FALLBACK even if
CONFIG_TRANSPARENT_HUGEPAGE is not set and triggers this
compile error.

Add ifdef CONFIG_TRANSPARENT_HUGEPAGE in shmem_add_to_page_cache().

In file included from <command-line>:
mm/shmem.c: In function ‘shmem_add_to_page_cache’:
././include/linux/compiler_types.h:352:38: error: call to ‘__compiletime_assert_327’ declared with attribute error: BUILD_BUG failed
  352 |  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
      |                                      ^
././include/linux/compiler_types.h:333:4: note: in definition of macro ‘__compiletime_assert’
  333 |    prefix ## suffix();    \
      |    ^~~~~~
././include/linux/compiler_types.h:352:2: note: in expansion of macro ‘_compiletime_assert’
  352 |  _compiletime_assert(condition, msg, __compiletime_assert_, __COUNTER__)
      |  ^~~~~~~~~~~~~~~~~~~
./include/linux/build_bug.h:39:37: note: in expansion of macro ‘compiletime_assert’
   39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
      |                                     ^~~~~~~~~~~~~~~~~~
./include/linux/build_bug.h:59:21: note: in expansion of macro ‘BUILD_BUG_ON_MSG’
   59 | #define BUILD_BUG() BUILD_BUG_ON_MSG(1, "BUILD_BUG failed")
      |                     ^~~~~~~~~~~~~~~~
./include/linux/vm_event_item.h:148:30: note: in expansion of macro ‘BUILD_BUG’
  148 | #define THP_FILE_FALLBACK ({ BUILD_BUG(); 0; })
      |                              ^~~~~~~~~
mm/shmem.c:721:20: note: in expansion of macro ‘THP_FILE_FALLBACK’
  721 |     count_vm_event(THP_FILE_FALLBACK);
      |                    ^~~~~~~~~~~~~~~~~
  CC      arch/x86/events/intel/p4.o
make[1]: *** [scripts/Makefile.build:288: mm/shmem.o] Error 1
make: *** [Makefile:1997: mm] Error 2
make: *** Waiting for unfinished jobs....

Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Reported-by: Zeal Robot <zealci@zte.com.cn>
---
 mm/shmem.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/shmem.c b/mm/shmem.c
index 107f1e4dd0aa..f01ceedf88c0 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -717,10 +717,12 @@ static int shmem_add_to_page_cache(struct folio *folio,
 	if (!folio_test_swapcache(folio)) {
 		error = mem_cgroup_charge(folio, charge_mm, gfp);
 		if (error) {
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
 			if (folio_test_large(folio)) {
 				count_vm_event(THP_FILE_FALLBACK);
 				count_vm_event(THP_FILE_FALLBACK_CHARGE);
 			}
+#endif
 			goto error;
 		}
 	}
-- 
2.25.1

Re: [PATCH] mm/shmem: fix build failure when CONFIG_TRANSPARENT_HUGEPAGE is not set

[Andrew Morton]

On Thu,  5 May 2022 11:33:55 +0000 cgel.zte@gmail.com wrote:

> From: Yang Yang <yang.yang29@zte.com.cn>
> 
> shmem_add_to_page_cache() use THP_FILE_FALLBACK even if
> CONFIG_TRANSPARENT_HUGEPAGE is not set and triggers this
> compile error.
> 
> Add ifdef CONFIG_TRANSPARENT_HUGEPAGE in shmem_add_to_page_cache().

Thanks.

> --- a/mm/shmem.c
> +++ b/mm/shmem.c
> @@ -717,10 +717,12 @@ static int shmem_add_to_page_cache(struct folio *folio,
>  	if (!folio_test_swapcache(folio)) {
>  		error = mem_cgroup_charge(folio, charge_mm, gfp);
>  		if (error) {
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
>  			if (folio_test_large(folio)) {
>  				count_vm_event(THP_FILE_FALLBACK);
>  				count_vm_event(THP_FILE_FALLBACK_CHARGE);
>  			}
> +#endif
>  			goto error;
>  		}
>  	}

I believe Matthew address this in version 2 of "Folio patches for
5.19".

I'm aiming to get that (and much more!) pushed out or Monday's linux-next.