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

This moves 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):
   text	   data	    bss	    dec	    hex	filename
83721896	46511131	27582964	157815991	96814b7	../without/vmlinux
83722364	46511131	27582964	157816459	968168b	vmlinux

[jglisse@redhat.com: struct hmm is only use by HMM mirror functionality]
Link: http://lkml.kernel.org/r/20170825213133.27286-1-jglisse@redhat.com
[sfr@canb.auug.org.au: fix build (arm multi_v7_defconfig)]
Link: http://lkml.kernel.org/r/20170828181849.323ab81b@canb.auug.org.au
Link: http://lkml.kernel.org/r/20170818032858.7447-1-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/hmm.h b/include/linux/hmm.h
index 8385e75356cafeee5252eda7994ab906564c878e..28e14345bd8d030b2a4b4633765ee2bf1b46dbad 100644 (file)
--- a/include/linux/hmm.h
+++ b/include/linux/hmm.h
@@ -501,18 +501,21 @@ void hmm_device_put(struct hmm_device *hmm_device);
 
 
 /* Below are for HMM internal use only! Not to be used by device driver! */
+#if IS_ENABLED(CONFIG_HMM_MIRROR)
 void hmm_mm_destroy(struct mm_struct *mm);
 
 static inline void hmm_mm_init(struct mm_struct *mm)
 {
        mm->hmm = NULL;
 }
+#else /* IS_ENABLED(CONFIG_HMM_MIRROR) */
+static inline void hmm_mm_destroy(struct mm_struct *mm) {}
+static inline void hmm_mm_init(struct mm_struct *mm) {}
+#endif /* IS_ENABLED(CONFIG_HMM_MIRROR) */
 
-#else /* IS_ENABLED(CONFIG_HMM) */
 
-/* Below are for HMM internal use only! Not to be used by device driver! */
+#else /* IS_ENABLED(CONFIG_HMM) */
 static inline void hmm_mm_destroy(struct mm_struct *mm) {}
 static inline void hmm_mm_init(struct mm_struct *mm) {}
-
 #endif /* IS_ENABLED(CONFIG_HMM) */
 #endif /* LINUX_HMM_H */

diff --git a/include/linux/memremap.h b/include/linux/memremap.h
index f8ee1c73ad2d67e3f2968366590ce1ee3e0cc86b..79f8ba7c38940953182d05a59df970d06acc13fc 100644 (file)
--- 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 d4e6d12a0b408567d702f249b235d6cb1cb24703..643c7ae7d7b4d8dfad5fa20faf255334f133176f 100644 (file)
--- 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 de66a1127db4f8d266c87ac949076ab5cb6c2375..5195e272fc4ab2d6f7c36e4f9c169b222deab720 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -800,18 +800,27 @@ 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(&device_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 inline void get_page(struct page *page)
 {
@@ -834,9 +843,8 @@ static inline void put_page(struct page *page)
         * free and we need to inform the device driver through callback. See
         * include/linux/memremap.h and HMM for details.
         */
-       if (static_branch_unlikely(&device_private_key) &&
-           unlikely(is_device_private_page(page) ||
-                    is_device_public_page(page))) {
+       if (IS_HMM_ENABLED && unlikely(is_device_private_page(page) ||
+           unlikely(is_device_public_page(page)))) {
                put_zone_device_private_or_public_page(page);
                return;
        }

diff --git a/mm/Kconfig b/mm/Kconfig
index 7bea16697d87a3e9ba3d9be93224a250c411cb9e..9c4bdddd80c2123ac522c7d6c08453cca6c8445f 100644 (file)
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -702,8 +702,12 @@ config ARCH_HAS_HMM
        depends on MEMORY_HOTREMOVE
        depends on SPARSEMEM_VMEMMAP
 
+config MIGRATE_VMA_HELPER
+       bool
+
 config HMM
        bool
+       select MIGRATE_VMA_HELPER
 
 config HMM_MIRROR
        bool "HMM mirror CPU page table into a device page table"

diff --git a/mm/Makefile b/mm/Makefile
index 1cde2a8bed97c0d366dffa3aa304339d53348034..e3ac3aeb533badc264dac11579192acb101a693c 100644 (file)
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -39,7 +39,7 @@ obj-y                 := filemap.o mempool.o oom_kill.o \
                           mm_init.o mmu_context.o percpu.o slab_common.o \
                           compaction.o vmacache.o swap_slots.o \
                           interval_tree.o list_lru.o workingset.o \
-                          debug.o hmm.o $(mmu-y)
+                          debug.o $(mmu-y)
 
 obj-y += init-mm.o
 
@@ -104,3 +104,4 @@ obj-$(CONFIG_FRAME_VECTOR) += frame_vector.o
 obj-$(CONFIG_DEBUG_PAGE_REF) += debug_page_ref.o
 obj-$(CONFIG_HARDENED_USERCOPY) += usercopy.o
 obj-$(CONFIG_PERCPU_STATS) += percpu-stats.o
+obj-$(CONFIG_HMM) += hmm.o

diff --git a/mm/hmm.c b/mm/hmm.c
index bdb49b836bf22d6de63b5cb8dd89d96b32862e44..a88a847bccba700a1c0f51d0a819dcf365995ed1 100644 (file)
--- a/mm/hmm.c
+++ b/mm/hmm.c
@@ -35,15 +35,16 @@
 
 #define PA_SECTION_SIZE (1UL << PA_SECTION_SHIFT)
 
-
+#if defined(CONFIG_DEVICE_PRIVATE) || defined(CONFIG_DEVICE_PUBLIC)
 /*
  * Device private memory see HMM (Documentation/vm/hmm.txt) or hmm.h
  */
 DEFINE_STATIC_KEY_FALSE(device_private_key);
 EXPORT_SYMBOL(device_private_key);
+#endif /* CONFIG_DEVICE_PRIVATE || CONFIG_DEVICE_PUBLIC */
 
 
-#ifdef CONFIG_HMM
+#if IS_ENABLED(CONFIG_HMM_MIRROR)
 static const struct mmu_notifier_ops hmm_mmu_notifier_ops;
 
 /*
@@ -128,9 +129,7 @@ void hmm_mm_destroy(struct mm_struct *mm)
 {
        kfree(mm->hmm);
 }
-#endif /* CONFIG_HMM */
 
-#if IS_ENABLED(CONFIG_HMM_MIRROR)
 static void hmm_invalidate_range(struct hmm *hmm,
                                 enum hmm_update_type action,
                                 unsigned long start,

diff --git a/mm/migrate.c b/mm/migrate.c
index 618aeb5e9cde070858a45176d3b9f38c826b4aec..6954c1435833133f910a08a9cd8e0e1516084296 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2127,6 +2127,7 @@ out_unlock:
 
 #endif /* CONFIG_NUMA */
 
+#if defined(CONFIG_MIGRATE_VMA_HELPER)
 struct migrate_vma {
        struct vm_area_struct   *vma;
        unsigned long           *dst;
@@ -2980,3 +2981,4 @@ int migrate_vma(const struct migrate_vma_ops *ops,
        return 0;
 }
 EXPORT_SYMBOL(migrate_vma);
+#endif /* defined(MIGRATE_VMA_HELPER) */