This adds a new virtual address range based migration interface which
can migrate all the mapped pages from a virtual range of a process to
a destination node. This also exports this new function symbol.
Signed-off-by: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx>
---
include/linux/mempolicy.h | 7 +++++
include/linux/migrate.h | 3 ++
mm/mempolicy.c | 7 ++---
mm/migrate.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 83 insertions(+), 5 deletions(-)
diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
index 5e5b296..c2b4a18 100644
--- a/include/linux/mempolicy.h
+++ b/include/linux/mempolicy.h
@@ -152,6 +152,9 @@ extern struct zonelist *huge_zonelist(struct vm_area_struct *vma,
extern bool mempolicy_nodemask_intersects(struct task_struct *tsk,
const nodemask_t *mask);
extern unsigned int mempolicy_slab_node(void);
+extern int queue_pages_range(struct mm_struct *mm, unsigned long start,
+ unsigned long end, nodemask_t *nodes,
+ unsigned long flags, struct list_head *pagelist);
extern enum zone_type policy_zone;
@@ -302,4 +305,8 @@ static inline void mpol_put_task_policy(struct task_struct *task)
{
}
#endif /* CONFIG_NUMA */
+
+#define MPOL_MF_DISCONTIG_OK (MPOL_MF_INTERNAL << 0) /* Skip checks for continuous vmas */
+#define MPOL_MF_INVERT (MPOL_MF_INTERNAL << 1) /* Invert check for nodemask */
+
#endif
diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index ae8d475..e2a1af5 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -49,6 +49,9 @@ extern int migrate_page_move_mapping(struct address_space *mapping,
struct page *newpage, struct page *page,
struct buffer_head *head, enum migrate_mode mode,
int extra_count);
+
+extern int migrate_virtual_range(int pid, unsigned long vaddr,
+ unsigned long size, int nid);
#else
static inline void putback_movable_pages(struct list_head *l) {}
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 0b859af..728347a 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -100,10 +100,6 @@
#include "internal.h"
-/* Internal flags */
-#define MPOL_MF_DISCONTIG_OK (MPOL_MF_INTERNAL << 0) /* Skip checks for continuous vmas */
-#define MPOL_MF_INVERT (MPOL_MF_INTERNAL << 1) /* Invert check for nodemask */
-
static struct kmem_cache *policy_cache;
static struct kmem_cache *sn_cache;
@@ -662,7 +658,7 @@ static int queue_pages_test_walk(unsigned long start, unsigned long end,
* @nodes and @flags,) it's isolated and queued to the pagelist which is
* passed via @private.)
*/
-static int
+int
queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end,
nodemask_t *nodes, unsigned long flags,
struct list_head *pagelist)
@@ -683,6 +679,7 @@ static int queue_pages_test_walk(unsigned long start, unsigned long end,
return walk_page_range(start, end, &queue_pages_walk);
}
+EXPORT_SYMBOL(queue_pages_range);
/*
* Apply policy to a single VMA
diff --git a/mm/migrate.c b/mm/migrate.c
index 99250ae..4f20415 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1367,6 +1367,77 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
return rc;
}
+static struct page *new_node_page(struct page *page,
+ unsigned long node, int **x)
+{
+ return __alloc_pages_node(node, GFP_HIGHUSER_MOVABLE
+ | __GFP_THISNODE, 0);
+}
+
+/*
+ * migrate_virtual_range - migrate all the pages faulted within a virtual
+ * address range to a specified node.
+ *
+ * @pid: PID of the task
+ * @start: Virtual address range beginning
+ * @end: Virtual address range end
+ * @nid: Target migration node
+ *
+ * The function first scans the process VMA list to find out the VMA which
+ * contains the given virtual range. Then validates that the virtual range
+ * is within the given VMA's limits.
+ *
+ * Returns the number of pages that were not migrated or an error code.
+ */
+int migrate_virtual_range(int pid, unsigned long start,
+ unsigned long end, int nid)
+{
+ struct mm_struct *mm;
+ struct vm_area_struct *vma;
+ nodemask_t nmask;
+ int ret = -EINVAL;
+
+ LIST_HEAD(mlist);
+
+ nodes_clear(nmask);
+ nodes_setall(nmask);
+
+ if ((!start) || (!end))
+ return -EINVAL;
+
+ rcu_read_lock();
+ mm = find_task_by_vpid(pid)->mm;
+ rcu_read_unlock();
+
+ start &= PAGE_MASK;
+ end &= PAGE_MASK;
+ down_write(&mm->mmap_sem);
+ for (vma = mm->mmap; vma; vma = vma->vm_next) {
+ if ((start < vma->vm_start) || (end > vma->vm_end))
+ continue;
+
+ ret = queue_pages_range(mm, start, end, &nmask, MPOL_MF_MOVE_ALL
+ | MPOL_MF_DISCONTIG_OK, &mlist);
+ if (ret) {
+ putback_movable_pages(&mlist);
+ break;
+ }
+
+ if (list_empty(&mlist)) {
+ ret = -ENOMEM;
+ break;
+ }
+
+ ret = migrate_pages(&mlist, new_node_page, NULL, nid,
+ MIGRATE_SYNC, MR_COMPACTION);
+ if (ret)
+ putback_movable_pages(&mlist);
+ }
+ up_write(&mm->mmap_sem);
+ return ret;
+}
+EXPORT_SYMBOL(migrate_virtual_range);
+
#ifdef CONFIG_NUMA
/*
* Move a list of individual pages
--
1.8.3.1
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