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-rw-r--r--mm/mempolicy.c94
1 files changed, 93 insertions, 1 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 9cc6d962831d..20d5ad39fa41 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -615,11 +615,41 @@ long do_get_mempolicy(int *policy, nodemask_t *nmask,
}
/*
+ * For now migrate_pages simply swaps out the pages from nodes that are in
+ * the source set but not in the target set. In the future, we would
+ * want a function that moves pages between the two nodesets in such
+ * a way as to preserve the physical layout as much as possible.
+ *
+ * Returns the number of page that could not be moved.
+ */
+int do_migrate_pages(struct mm_struct *mm,
+ const nodemask_t *from_nodes, const nodemask_t *to_nodes, int flags)
+{
+ LIST_HEAD(pagelist);
+ int count = 0;
+ nodemask_t nodes;
+
+ nodes_andnot(nodes, *from_nodes, *to_nodes);
+ nodes_complement(nodes, nodes);
+
+ down_read(&mm->mmap_sem);
+ check_range(mm, mm->mmap->vm_start, TASK_SIZE, &nodes,
+ flags | MPOL_MF_DISCONTIG_OK, &pagelist);
+ if (!list_empty(&pagelist)) {
+ migrate_pages(&pagelist, NULL);
+ if (!list_empty(&pagelist))
+ count = putback_lru_pages(&pagelist);
+ }
+ up_read(&mm->mmap_sem);
+ return count;
+}
+
+/*
* User space interface with variable sized bitmaps for nodelists.
*/
/* Copy a node mask from user space. */
-static int get_nodes(nodemask_t *nodes, unsigned long __user *nmask,
+static int get_nodes(nodemask_t *nodes, const unsigned long __user *nmask,
unsigned long maxnode)
{
unsigned long k;
@@ -708,6 +738,68 @@ asmlinkage long sys_set_mempolicy(int mode, unsigned long __user *nmask,
return do_set_mempolicy(mode, &nodes);
}
+/* Macro needed until Paul implements this function in kernel/cpusets.c */
+#define cpuset_mems_allowed(task) node_online_map
+
+asmlinkage long sys_migrate_pages(pid_t pid, unsigned long maxnode,
+ const unsigned long __user *old_nodes,
+ const unsigned long __user *new_nodes)
+{
+ struct mm_struct *mm;
+ struct task_struct *task;
+ nodemask_t old;
+ nodemask_t new;
+ nodemask_t task_nodes;
+ int err;
+
+ err = get_nodes(&old, old_nodes, maxnode);
+ if (err)
+ return err;
+
+ err = get_nodes(&new, new_nodes, maxnode);
+ if (err)
+ return err;
+
+ /* Find the mm_struct */
+ read_lock(&tasklist_lock);
+ task = pid ? find_task_by_pid(pid) : current;
+ if (!task) {
+ read_unlock(&tasklist_lock);
+ return -ESRCH;
+ }
+ mm = get_task_mm(task);
+ read_unlock(&tasklist_lock);
+
+ if (!mm)
+ return -EINVAL;
+
+ /*
+ * Check if this process has the right to modify the specified
+ * process. The right exists if the process has administrative
+ * capabilities, superuser priviledges or the same
+ * userid as the target process.
+ */
+ if ((current->euid != task->suid) && (current->euid != task->uid) &&
+ (current->uid != task->suid) && (current->uid != task->uid) &&
+ !capable(CAP_SYS_ADMIN)) {
+ err = -EPERM;
+ goto out;
+ }
+
+ task_nodes = cpuset_mems_allowed(task);
+ /* Is the user allowed to access the target nodes? */
+ if (!nodes_subset(new, task_nodes) && !capable(CAP_SYS_ADMIN)) {
+ err = -EPERM;
+ goto out;
+ }
+
+ err = do_migrate_pages(mm, &old, &new, MPOL_MF_MOVE);
+out:
+ mmput(mm);
+ return err;
+}
+
+
/* Retrieve NUMA policy */
asmlinkage long sys_get_mempolicy(int __user *policy,
unsigned long __user *nmask,