[PATCH] Make CONFIG_MIGRATION available w/o CONFIG_NUMA

Gerald Schaefer
2008-07-11T13:39:20Z

Subject: [PATCH] Make CONFIG_MIGRATION available w/o CONFIG_NUMA

From: Gerald Schaefer <gerald.schaefer@de.ibm.com>

We'd like to support CONFIG_MEMORY_HOTREMOVE on s390, which depends on
CONFIG_MIGRATION. So far, CONFIG_MIGRATION is only available with NUMA
support.

This patch makes CONFIG_MIGRATION selectable for architectures that define
ARCH_ENABLE_MEMORY_HOTREMOVE. When MIGRATION is enabled w/o NUMA, the kernel
won't compile because migrate_vmas() does not know about vm_ops->migrate()
and vma_migratable() does not know about policy_zone. To fix this, those
two functions can be restricted to '#ifdef CONFIG_NUMA' because they are
not being used w/o NUMA. vma_migratable() is moved over from migrate.h to
mempolicy.h.

Acked-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com>
---

include/linux/mempolicy.h | 19 +++++++++++++++++++
include/linux/migrate.h | 21 ---------------------
mm/Kconfig | 2 +-
mm/migrate.c | 2 +-
4 files changed, 21 insertions(+), 23 deletions(-)

Index: linux-2.6/mm/Kconfig
===================================================================
--- linux-2.6.orig/mm/Kconfig
+++ linux-2.6/mm/Kconfig
@@ -174,7 +174,7 @@ config SPLIT_PTLOCK_CPUS
config MIGRATION
bool "Page migration"
def_bool y
- depends on NUMA
+ depends on NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE
help
Allows the migration of the physical location of pages of processes
while the virtual addresses are not changed. This is useful for
Index: linux-2.6/include/linux/migrate.h
===================================================================
--- linux-2.6.orig/include/linux/migrate.h
+++ linux-2.6/include/linux/migrate.h
@@ -3,28 +3,10 @@

#include <linux/mm.h>
#include <linux/mempolicy.h>
-#include <linux/pagemap.h>

typedef struct page *new_page_t(struct page *, unsigned long private, int **);

#ifdef CONFIG_MIGRATION
-/* Check if a vma is migratable */
-static inline int vma_migratable(struct vm_area_struct *vma)
-{
- if (vma->vm_flags & (VM_IO|VM_HUGETLB|VM_PFNMAP|VM_RESERVED))
- return 0;
- /*
- * Migration allocates pages in the highest zone. If we cannot
- * do so then migration (at least from node to node) is not
- * possible.
- */
- if (vma->vm_file &&
- gfp_zone(mapping_gfp_mask(vma->vm_file->f_mapping))
- < policy_zone)
- return 0;
- return 1;
-}
-
extern int isolate_lru_page(struct page *p, struct list_head *pagelist);
extern int putback_lru_pages(struct list_head *l);
extern int migrate_page(struct address_space *,
@@ -39,9 +21,6 @@ extern int migrate_vmas(struct mm_struct
const nodemask_t *from, const nodemask_t *to,
unsigned long flags);
#else
-static inline int vma_migratable(struct vm_area_struct *vma)
- { return 0; }
-
static inline int isolate_lru_page(struct page *p, struct list_head *list)
{ return -ENOSYS; }
static inline int putback_lru_pages(struct list_head *l) { return 0; }
Index: linux-2.6/mm/migrate.c
===================================================================
--- linux-2.6.orig/mm/migrate.c
+++ linux-2.6/mm/migrate.c
@@ -1070,7 +1070,6 @@ out2:
mmput(mm);
return err;
}
-#endif

/*
* Call migration functions in the vma_ops that may prepare
@@ -1092,3 +1091,4 @@ int migrate_vmas(struct mm_struct *mm, c
}
return err;
}
+#endif
Index: linux-2.6/include/linux/mempolicy.h
===================================================================
--- linux-2.6.orig/include/linux/mempolicy.h
+++ linux-2.6/include/linux/mempolicy.h
@@ -2,6 +2,7 @@
#define _LINUX_MEMPOLICY_H 1

#include <linux/errno.h>
+#include <linux/pagemap.h>

/*
* NUMA memory policies for Linux.
@@ -220,6 +221,24 @@ extern int mpol_parse_str(char *str, str
extern int mpol_to_str(char *buffer, int maxlen, struct mempolicy *pol,
int no_context);
#endif
+
+/* Check if a vma is migratable */
+static inline int vma_migratable(struct vm_area_struct *vma)
+{
+ if (vma->vm_flags & (VM_IO|VM_HUGETLB|VM_PFNMAP|VM_RESERVED))
+ return 0;
+ /*
+ * Migration allocates pages in the highest zone. If we cannot
+ * do so then migration (at least from node to node) is not
+ * possible.
+ */
+ if (vma->vm_file &&
+ gfp_zone(mapping_gfp_mask(vma->vm_file->f_mapping))
+ < policy_zone)
+ return 0;
+ return 1;
+}
+
#else

struct mempolicy {};