[PATCH] mm/hmm: avoid bloating arch that do not make use of HMM

[jglisse]

From: Jérôme Glisse 

This move all new code including new page migration helper behind
kernel Kconfig option so that there is no codee bloat for arch or
user that do not want to use HMM or any of its associated features.

arm allyesconfig (without all the patchset, then with and this patch):
   textdata bss dec hex filename
837218964651113127582964157815991   96814b7 
../without/vmlinux
837223644651113127582964157816459   968168b vmlinux

Signed-off-by: Jérôme Glisse 
Cc: Dan Williams 
Cc: Andrew Morton 
---
 include/linux/memremap.h | 22 +++---
 include/linux/migrate.h  | 13 +
 include/linux/mm.h   | 26 +-
 mm/Kconfig   |  4 
 mm/Makefile  |  3 ++-
 mm/hmm.c |  6 +++---
 mm/migrate.c |  2 ++
 7 files changed, 48 insertions(+), 28 deletions(-)

diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index f8ee1c73ad2d..79f8ba7c3894 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -138,18 +138,6 @@ void *devm_memremap_pages(struct device *dev, struct 
resource *res,
 struct dev_pagemap *find_dev_pagemap(resource_size_t phys);
 
 static inline bool is_zone_device_page(const struct page *page);
-
-static inline bool is_device_private_page(const struct page *page)
-{
-   return is_zone_device_page(page) &&
-   page->pgmap->type == MEMORY_DEVICE_PRIVATE;
-}
-
-static inline bool is_device_public_page(const struct page *page)
-{
-   return is_zone_device_page(page) &&
-   page->pgmap->type == MEMORY_DEVICE_PUBLIC;
-}
 #else
 static inline void *devm_memremap_pages(struct device *dev,
struct resource *res, struct percpu_ref *ref,
@@ -168,17 +156,21 @@ static inline struct dev_pagemap 
*find_dev_pagemap(resource_size_t phys)
 {
return NULL;
 }
+#endif
 
+#if defined(CONFIG_DEVICE_PRIVATE) || defined(CONFIG_DEVICE_PUBLIC)
 static inline bool is_device_private_page(const struct page *page)
 {
-   return false;
+   return is_zone_device_page(page) &&
+   page->pgmap->type == MEMORY_DEVICE_PRIVATE;
 }
 
 static inline bool is_device_public_page(const struct page *page)
 {
-   return false;
+   return is_zone_device_page(page) &&
+   page->pgmap->type == MEMORY_DEVICE_PUBLIC;
 }
-#endif
+#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
 
 /**
  * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn
diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index d4e6d12a0b40..643c7ae7d7b4 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -265,6 +265,7 @@ struct migrate_vma_ops {
 void *private);
 };
 
+#if defined(CONFIG_MIGRATE_VMA_HELPER)
 int migrate_vma(const struct migrate_vma_ops *ops,
struct vm_area_struct *vma,
unsigned long start,
@@ -272,6 +273,18 @@ int migrate_vma(const struct migrate_vma_ops *ops,
unsigned long *src,
unsigned long *dst,
void *private);
+#else
+static inline int migrate_vma(const struct migrate_vma_ops *ops,
+ struct vm_area_struct *vma,
+ unsigned long start,
+ unsigned long end,
+ unsigned long *src,
+ unsigned long *dst,
+ void *private)
+{
+   return -EINVAL;
+}
+#endif /* IS_ENABLED(CONFIG_MIGRATE_VMA_HELPER) */
 
 #endif /* CONFIG_MIGRATION */
 
diff --git a/include/linux/mm.h b/include/linux/mm.h
index d1d161efefa0..663a2916a3bf 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -796,18 +796,27 @@ static inline bool is_zone_device_page(const struct page 
*page)
 }
 #endif
 
-#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) ||  IS_ENABLED(CONFIG_DEVICE_PUBLIC)
+#if defined(CONFIG_DEVICE_PRIVATE) || defined(CONFIG_DEVICE_PUBLIC)
 void put_zone_device_private_or_public_page(struct page *page);
-#else
+DECLARE_STATIC_KEY_FALSE(device_private_key);
+#define IS_HMM_ENABLED static_branch_unlikely(_private_key)
+static inline bool is_device_private_page(const struct page *page);
+static inline bool is_device_public_page(const struct page *page);
+#else /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
 static inline void put_zone_device_private_or_public_page(struct page *page)
 {
 }
+#define IS_HMM_ENABLED 0
+static inline bool is_device_private_page(const struct page *page)
+{
+   return false;
+}
+static inline bool is_device_public_page(const struct page *page)
+{
+   return false;
+}
 #endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
 
-static inline bool is_device_private_page(const struct page *page);
-static inline bool 

[PATCH] mm/hmm: avoid bloating arch that do not make use of HMM

[jglisse]

From: Jérôme Glisse 

This move all new code including new page migration helper behind
kernel Kconfig option so that there is no codee bloat for arch or
user that do not want to use HMM or any of its associated features.

arm allyesconfig (without all the patchset, then with and this patch):
   textdata bss dec hex filename
837218964651113127582964157815991   96814b7 
../without/vmlinux
837223644651113127582964157816459   968168b vmlinux

Signed-off-by: Jérôme Glisse 
Cc: Dan Williams 
Cc: Andrew Morton 
---
 include/linux/memremap.h | 22 +++---
 include/linux/migrate.h  | 13 +
 include/linux/mm.h   | 26 +-
 mm/Kconfig   |  4 
 mm/Makefile  |  3 ++-
 mm/hmm.c |  6 +++---
 mm/migrate.c |  2 ++
 7 files changed, 48 insertions(+), 28 deletions(-)

diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index f8ee1c73ad2d..79f8ba7c3894 100644
--- a/include/linux/memremap.h
+++ b/include/linux/memremap.h
@@ -138,18 +138,6 @@ void *devm_memremap_pages(struct device *dev, struct 
resource *res,
 struct dev_pagemap *find_dev_pagemap(resource_size_t phys);
 
 static inline bool is_zone_device_page(const struct page *page);
-
-static inline bool is_device_private_page(const struct page *page)
-{
-   return is_zone_device_page(page) &&
-   page->pgmap->type == MEMORY_DEVICE_PRIVATE;
-}
-
-static inline bool is_device_public_page(const struct page *page)
-{
-   return is_zone_device_page(page) &&
-   page->pgmap->type == MEMORY_DEVICE_PUBLIC;
-}
 #else
 static inline void *devm_memremap_pages(struct device *dev,
struct resource *res, struct percpu_ref *ref,
@@ -168,17 +156,21 @@ static inline struct dev_pagemap 
*find_dev_pagemap(resource_size_t phys)
 {
return NULL;
 }
+#endif
 
+#if defined(CONFIG_DEVICE_PRIVATE) || defined(CONFIG_DEVICE_PUBLIC)
 static inline bool is_device_private_page(const struct page *page)
 {
-   return false;
+   return is_zone_device_page(page) &&
+   page->pgmap->type == MEMORY_DEVICE_PRIVATE;
 }
 
 static inline bool is_device_public_page(const struct page *page)
 {
-   return false;
+   return is_zone_device_page(page) &&
+   page->pgmap->type == MEMORY_DEVICE_PUBLIC;
 }
-#endif
+#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
 
 /**
  * get_dev_pagemap() - take a new live reference on the dev_pagemap for @pfn
diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index d4e6d12a0b40..643c7ae7d7b4 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -265,6 +265,7 @@ struct migrate_vma_ops {
 void *private);
 };
 
+#if defined(CONFIG_MIGRATE_VMA_HELPER)
 int migrate_vma(const struct migrate_vma_ops *ops,
struct vm_area_struct *vma,
unsigned long start,
@@ -272,6 +273,18 @@ int migrate_vma(const struct migrate_vma_ops *ops,
unsigned long *src,
unsigned long *dst,
void *private);
+#else
+static inline int migrate_vma(const struct migrate_vma_ops *ops,
+ struct vm_area_struct *vma,
+ unsigned long start,
+ unsigned long end,
+ unsigned long *src,
+ unsigned long *dst,
+ void *private)
+{
+   return -EINVAL;
+}
+#endif /* IS_ENABLED(CONFIG_MIGRATE_VMA_HELPER) */
 
 #endif /* CONFIG_MIGRATION */
 
diff --git a/include/linux/mm.h b/include/linux/mm.h
index d1d161efefa0..663a2916a3bf 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -796,18 +796,27 @@ static inline bool is_zone_device_page(const struct page 
*page)
 }
 #endif
 
-#if IS_ENABLED(CONFIG_DEVICE_PRIVATE) ||  IS_ENABLED(CONFIG_DEVICE_PUBLIC)
+#if defined(CONFIG_DEVICE_PRIVATE) || defined(CONFIG_DEVICE_PUBLIC)
 void put_zone_device_private_or_public_page(struct page *page);
-#else
+DECLARE_STATIC_KEY_FALSE(device_private_key);
+#define IS_HMM_ENABLED static_branch_unlikely(_private_key)
+static inline bool is_device_private_page(const struct page *page);
+static inline bool is_device_public_page(const struct page *page);
+#else /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
 static inline void put_zone_device_private_or_public_page(struct page *page)
 {
 }
+#define IS_HMM_ENABLED 0
+static inline bool is_device_private_page(const struct page *page)
+{
+   return false;
+}
+static inline bool is_device_public_page(const struct page *page)
+{
+   return false;
+}
 #endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
 
-static inline bool is_device_private_page(const struct page *page);
-static inline bool is_device_public_page(const struct page *page);
-
-DECLARE_STATIC_KEY_FALSE(device_private_key);
 
 static