Re: [PATCH] mm: split out memory-failure declarations from internal.h

[Lorenzo Stoakes (ARM)]

On Wed, Nov 04, 2026 at 08:45:34AM -0800, Breno Leitao wrote:
> mm/internal.h carries the memory failure declarations, but only seven
> of the 81 .c files that include it use them.
>
> Move memory failure declarations to a new mm/memory-failure.h and
> include that from those seven files that need them.
>
> Move the block as is, including take_page_off_buddy(),
> put_page_back_buddy() and page_mapped_in_vma(): they live in
> page_alloc.c and page_vma_mapped.c, but are built only for
> CONFIG_MEMORY_FAILURE and called only from memory-failure.c.
>
> Keep the declarations private to mm/.
>
> No functional change.
>
> Suggested-by: Mike Rapoport <rppt@xxxxxxxxxx>
> Link: https://lore.kernel.org/all/aumt-4kfGGtoXuh-@xxxxxxxxxx/
> Signed-off-by: Breno Leitao <leitao@xxxxxxxxxx>

Thanks, nice to break this up a bit!

LGTM so:

Reviewed-by: Lorenzo Stoakes (ARM) <ljs@xxxxxxxxxx>

> ---
>  MAINTAINERS          |  1 +
>  mm/hwpoison-inject.c |  1 +
>  mm/internal.h        | 29 -----------------------------
>  mm/ksm.c             |  1 +
>  mm/memory-failure.c  |  1 +
>  mm/memory-failure.h  | 36 ++++++++++++++++++++++++++++++++++++
>  mm/memory_hotplug.c  |  1 +
>  mm/page_alloc.c      |  1 +
>  mm/page_vma_mapped.c |  1 +
>  mm/vmscan.c          |  1 +
>  10 files changed, 44 insertions(+), 29 deletions(-)
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 27d5b599558ae7..cc973903fda09d 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -12441,6 +12441,7 @@ F:	include/linux/memory-failure.h
>  F:	include/trace/events/memory-failure.h
>  F:	mm/hwpoison-inject.c
>  F:	mm/memory-failure.c
> +F:	mm/memory-failure.h
>  F:	tools/testing/selftests/mm/memory-failure.c
>
>  HYCON HY46XX TOUCHSCREEN SUPPORT
> diff --git a/mm/hwpoison-inject.c b/mm/hwpoison-inject.c
> index a11222572f9789..07032ec63080e8 100644
> --- a/mm/hwpoison-inject.c
> +++ b/mm/hwpoison-inject.c
> @@ -10,6 +10,7 @@
>  #include <linux/page-flags.h>
>  #include <linux/memcontrol.h>
>  #include "internal.h"
> +#include "memory-failure.h"
>
>  static u32 hwpoison_filter_enable;
>  static u32 hwpoison_filter_dev_major = ~0U;
> diff --git a/mm/internal.h b/mm/internal.h
> index 3e15dcdd8af768..b9278329f9a239 100644
> --- a/mm/internal.h
> +++ b/mm/internal.h
> @@ -1196,35 +1196,6 @@ static inline bool node_reclaim_enabled(void)
>  	return node_reclaim_mode & (RECLAIM_ZONE|RECLAIM_WRITE|RECLAIM_UNMAP);
>  }
>
> -/*
> - * mm/memory-failure.c
> - */
> -#ifdef CONFIG_MEMORY_FAILURE
> -int unmap_poisoned_folio(struct folio *folio, unsigned long pfn, bool must_kill);
> -void shake_folio(struct folio *folio);
> -typedef int hwpoison_filter_func_t(struct page *p);
> -void hwpoison_filter_register(hwpoison_filter_func_t *filter);
> -void hwpoison_filter_unregister(void);
> -
> -#define MAGIC_HWPOISON	0x48575053U	/* HWPS */
> -void SetPageHWPoisonTakenOff(struct page *page);
> -void ClearPageHWPoisonTakenOff(struct page *page);
> -bool take_page_off_buddy(struct page *page);
> -bool put_page_back_buddy(struct page *page);
> -struct task_struct *task_early_kill(struct task_struct *tsk, int force_early);
> -void add_to_kill_ksm(struct task_struct *tsk, const struct page *p,
> -		     struct vm_area_struct *vma, struct list_head *to_kill,
> -		     unsigned long ksm_addr);
> -unsigned long page_mapped_in_vma(const struct page *page,
> -		struct vm_area_struct *vma);
> -
> -#else
> -static inline int unmap_poisoned_folio(struct folio *folio, unsigned long pfn, bool must_kill)
> -{
> -	return -EBUSY;
> -}
> -#endif
> -
>  extern unsigned long  __must_check vm_mmap_pgoff(struct file *, unsigned long,
>          unsigned long, unsigned long,
>          unsigned long, unsigned long);
> diff --git a/mm/ksm.c b/mm/ksm.c
> index d24b129932bf79..623a2cdb392428 100644
> --- a/mm/ksm.c
> +++ b/mm/ksm.c
> @@ -44,6 +44,7 @@
>
>  #include <asm/tlbflush.h>
>  #include "internal.h"
> +#include "memory-failure.h"
>  #include "mm_slot.h"
>
>  #define CREATE_TRACE_POINTS
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index b215312f261b83..78f0a13349cb3e 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -68,6 +68,7 @@
>  #include "swap.h"
>  #include "page_alloc.h"
>  #include "internal.h"
> +#include "memory-failure.h"
>
>  static int sysctl_memory_failure_early_kill __read_mostly;
>
> diff --git a/mm/memory-failure.h b/mm/memory-failure.h
> new file mode 100644
> index 00000000000000..153aea6c610c03
> --- /dev/null
> +++ b/mm/memory-failure.h
> @@ -0,0 +1,36 @@
> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> +/*
> + * mm/ internal memory failure declarations
> + */
> +#ifndef __MM_MEMORY_FAILURE_H
> +#define __MM_MEMORY_FAILURE_H
> +
> +#include <linux/mm.h>
> +
> +#ifdef CONFIG_MEMORY_FAILURE
> +int unmap_poisoned_folio(struct folio *folio, unsigned long pfn, bool must_kill);
> +void shake_folio(struct folio *folio);
> +typedef int hwpoison_filter_func_t(struct page *p);
> +void hwpoison_filter_register(hwpoison_filter_func_t *filter);
> +void hwpoison_filter_unregister(void);
> +
> +#define MAGIC_HWPOISON	0x48575053U	/* HWPS */
> +void SetPageHWPoisonTakenOff(struct page *page);
> +void ClearPageHWPoisonTakenOff(struct page *page);
> +bool take_page_off_buddy(struct page *page);
> +bool put_page_back_buddy(struct page *page);
> +struct task_struct *task_early_kill(struct task_struct *tsk, int force_early);
> +void add_to_kill_ksm(struct task_struct *tsk, const struct page *p,
> +		     struct vm_area_struct *vma, struct list_head *to_kill,
> +		     unsigned long ksm_addr);
> +unsigned long page_mapped_in_vma(const struct page *page,
> +		struct vm_area_struct *vma);
> +
> +#else
> +static inline int unmap_poisoned_folio(struct folio *folio, unsigned long pfn, bool must_kill)
> +{
> +	return -EBUSY;
> +}
> +#endif
> +
> +#endif /* __MM_MEMORY_FAILURE_H */
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 41fcdc04e54042..b0971404f0ac0a 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -40,6 +40,7 @@
>  #include <asm/tlbflush.h>
>
>  #include "internal.h"
> +#include "memory-failure.h"
>  #include "mm_init.h"
>  #include "page_alloc.h"
>  #include "shuffle.h"
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index abebfb1f202e9b..b6d9f2c9cdef53 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -57,6 +57,7 @@
>  #include <linux/pgalloc_tag.h>
>  #include <asm/div64.h>
>  #include "internal.h"
> +#include "memory-failure.h"
>  #include "mm_init.h"
>  #include "page_alloc.h"
>  #include "shuffle.h"
> diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
> index e6b6170c2f4f72..d45d52436f99a0 100644
> --- a/mm/page_vma_mapped.c
> +++ b/mm/page_vma_mapped.c
> @@ -6,6 +6,7 @@
>  #include <linux/leafops.h>
>
>  #include "internal.h"
> +#include "memory-failure.h"
>
>  static inline bool not_found(struct page_vma_mapped_walk *pvmw)
>  {
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 50c352e9ffefc4..3db2db65319c00 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -67,6 +67,7 @@
>  #include <linux/sched/sysctl.h>
>
>  #include "internal.h"
> +#include "memory-failure.h"
>  #include "page_alloc.h"
>  #include "swap.h"
>
>
> ---
> base-commit: 8b7179210b22f8e48a82c5ceacb9d56a9c4cfec4
> base-tree: git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
> change-id: 20261104-memory-failure-split-4c7abedbe0dc
>
> Best regards,
> --
> Breno Leitao <leitao@xxxxxxxxxx>
>

--
Cheers, Lorenzo