Subject: Re: linux-next: build failure after merge of the mm tree

From: Andrew Morton <[email-masked]>
Date: Sun, 27 Oct 2024 18:00:15 -0700

On Mon, 28 Oct 2024 10:36:38 +1100 Stephen Rothwell <[email-masked]> wrote:

> Hi all,
> 
> After merging the mm tree, today's linux-next build (arm
> multi_v7_defconfig) failed like this:
> 
> mm/workingset.c: In function 'workingset_activation':
> mm/workingset.c:598:38: error: implicit declaration of function 'folio_memcg_charged'; did you mean 'folio_memcg_check'? [-Wimplicit-function-declaration]
>   598 |         if (mem_cgroup_disabled() || folio_memcg_charged(folio))
>       |                                      ^~~~~~~~~~~~~~~~~~~
>       |                                      folio_memcg_check
> 
> Caused by commit
> 
>   b4fa93fbd1dc ("memcg: workingset: remove folio_memcg_rcu usage")
> 
> from the mm-unstable branch of the mm tree.
> 
> this build has
> 
> # CONFIG_MEMCG is not set
> 

Thanks.  This?

--- a/include/linux/memcontrol.h~memcg-workingset-remove-folio_memcg_rcu-usage-fix
+++ a/include/linux/memcontrol.h
@@ -1055,6 +1055,11 @@ static inline struct mem_cgroup *folio_m
 	return NULL;
 }
 
+static inline bool folio_memcg_charged(struct folio *folio)
+{
+	return false;
+}
+
 static inline struct mem_cgroup *folio_memcg_check(struct folio *folio)
 {
 	return NULL;
_