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/migrate.h b/include/linux/migrate.h
index d4e6d12..643c7ae 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 */