8 files changed, 288 insertions, 25 deletions

diff --git a/Documentation/vm/page_migration b/Documentation/vm/page_migration
index 0a5d5fb18854..99f89aa10169 100644
--- a/Documentation/vm/page_migration
+++ b/Documentation/vm/page_migration
@@ -26,8 +26,13 @@ a process are located. See also the numa_maps manpage in the numactl package.
 Manual migration is useful if for example the scheduler has relocated
 a process to a processor on a distant node. A batch scheduler or an
 administrator may detect the situation and move the pages of the process
-nearer to the new processor. At some point in the future we may have
-some mechanism in the scheduler that will automatically move the pages.
+nearer to the new processor. The kernel itself does only provide
+manual page migration support. Automatic page migration may be implemented
+through user space processes that move pages. A special function call
+"move_pages" allows the moving of individual pages within a process.
+A NUMA profiler may f.e. obtain a log showing frequent off node
+accesses and may use the result to move pages to more advantageous
+locations.
 
 Larger installations usually partition the system using cpusets into
 sections of nodes. Paul Jackson has equipped cpusets with the ability to
@@ -62,22 +67,14 @@ A. In kernel use of migrate_pages()
    It also prevents the swapper or other scans to encounter
    the page.
 
-2. Generate a list of newly allocates pages. These pages will contain the
-   contents of the pages from the first list after page migration is
-   complete.
+2. We need to have a function of type new_page_t that can be
+   passed to migrate_pages(). This function should figure out
+   how to allocate the correct new page given the old page.
 
 3. The migrate_pages() function is called which attempts
-   to do the migration. It returns the moved pages in the
-   list specified as the third parameter and the failed
-   migrations in the fourth parameter. When the function
-   returns the first list will contain the pages that could still be retried.
-
-4. The leftover pages of various types are returned
-   to the LRU using putback_to_lru_pages() or otherwise
-   disposed of. The pages will still have the refcount as
-   increased by isolate_lru_pages() if putback_to_lru_pages() is not
-   used! The kernel may want to handle the various cases of failures in
-   different ways.
+   to do the migration. It will call the function to allocate
+   the new page for each page that is considered for
+   moving.
 
 B. How migrate_pages() works
 ----------------------------
diff --git a/arch/ia64/kernel/entry.S b/arch/ia64/kernel/entry.S
index bcb80ca5cf40..32c999f58d12 100644
--- a/arch/ia64/kernel/entry.S
+++ b/arch/ia64/kernel/entry.S
@@ -1584,7 +1584,7 @@ sys_call_table:
         data8 sys_keyctl
         data8 sys_ioprio_set
         data8 sys_ioprio_get                    // 1275
-        data8 sys_ni_syscall
+        data8 sys_move_pages
         data8 sys_inotify_init
         data8 sys_inotify_add_watch
         data8 sys_inotify_rm_watch
diff --git a/include/asm-ia64/unistd.h b/include/asm-ia64/unistd.h
index 632f2eedf72c..bb0eb727dcd0 100644
--- a/include/asm-ia64/unistd.h
+++ b/include/asm-ia64/unistd.h
@@ -265,7 +265,7 @@
 #define __NR_keyctl                     1273
 #define __NR_ioprio_set                 1274
 #define __NR_ioprio_get                 1275
-/* 1276 is available for reuse (was briefly sys_set_zone_reclaim) */
+#define __NR_move_pages                 1276
 #define __NR_inotify_init               1277
 #define __NR_inotify_add_watch          1278
 #define __NR_inotify_rm_watch           1279
diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index 5b95d6568dc4..5dba23a1c0d0 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -3,7 +3,7 @@
 
 #include <linux/mm.h>
 
-typedef struct page *new_page_t(struct page *, unsigned long private);
+typedef struct page *new_page_t(struct page *, unsigned long private, int **);
 
 #ifdef CONFIG_MIGRATION
 extern int isolate_lru_page(struct page *p, struct list_head *pagelist);
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index bd67a4413df7..7e3f23490918 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -516,6 +516,11 @@ asmlinkage long sys_set_mempolicy(int mode, unsigned long __user *nmask,
 asmlinkage long sys_migrate_pages(pid_t pid, unsigned long maxnode,
                                 const unsigned long __user *from,
                                 const unsigned long __user *to);
+asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages,
+                                const void __user * __user *pages,
+                                const int __user *nodes,
+                                int __user *status,
+                                int flags);
 asmlinkage long sys_mbind(unsigned long start, unsigned long len,
                                 unsigned long mode,
                                 unsigned long __user *nmask,
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 5433195040f1..597229749dec 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -87,6 +87,7 @@ cond_syscall(sys_inotify_init);
 cond_syscall(sys_inotify_add_watch);
 cond_syscall(sys_inotify_rm_watch);
 cond_syscall(sys_migrate_pages);
+cond_syscall(sys_move_pages);
 cond_syscall(sys_chown16);
 cond_syscall(sys_fchown16);
 cond_syscall(sys_getegid16);
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index f432642e9e66..05b84acf0bb3 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -588,7 +588,7 @@ static void migrate_page_add(struct page *page, struct list_head *pagelist,
                 isolate_lru_page(page, pagelist);
 }
 
-static struct page *new_node_page(struct page *page, unsigned long node)
+static struct page *new_node_page(struct page *page, unsigned long node, int **x)
 {
         return alloc_pages_node(node, GFP_HIGHUSER, 0);
 }
@@ -698,7 +698,7 @@ int do_migrate_pages(struct mm_struct *mm,
 
 }
 
-static struct page *new_vma_page(struct page *page, unsigned long private)
+static struct page *new_vma_page(struct page *page, unsigned long private, int **x)
 {
         struct vm_area_struct *vma = (struct vm_area_struct *)private;
 
diff --git a/mm/migrate.c b/mm/migrate.c
index 251a8d158257..033a12f4c949 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -25,6 +25,8 @@
 #include <linux/cpu.h>
 #include <linux/cpuset.h>
 #include <linux/writeback.h>
+#include <linux/mempolicy.h>
+#include <linux/vmalloc.h>
 
 #include "internal.h"
 
@@ -62,9 +64,8 @@ int isolate_lru_page(struct page *page, struct list_head *pagelist)
 }
 
 /*
- * migrate_prep() needs to be called after we have compiled the list of pages
- * to be migrated using isolate_lru_page() but before we begin a series of calls
- * to migrate_pages().
+ * migrate_prep() needs to be called before we start compiling a list of pages
+ * to be migrated using isolate_lru_page().
  */
 int migrate_prep(void)
 {
@@ -588,7 +589,8 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
                         struct page *page, int force)
 {
         int rc = 0;
-        struct page *newpage = get_new_page(page, private);
+        int *result = NULL;
+        struct page *newpage = get_new_page(page, private, &result);
 
         if (!newpage)
                 return -ENOMEM;
@@ -642,6 +644,12 @@ move_newpage:
          * then this will free the page.
          */
         move_to_lru(newpage);
+        if (result) {
+                if (rc)
+                        *result = rc;
+                else
+                        *result = page_to_nid(newpage);
+        }
         return rc;
 }
 
@@ -710,3 +718,255 @@ out:
         return nr_failed + retry;
 }
 
+#ifdef CONFIG_NUMA
+/*
+ * Move a list of individual pages
+ */
+struct page_to_node {
+        unsigned long addr;
+        struct page *page;
+        int node;
+        int status;
+};
+
+static struct page *new_page_node(struct page *p, unsigned long private,
+                int **result)
+{
+        struct page_to_node *pm = (struct page_to_node *)private;
+
+        while (pm->node != MAX_NUMNODES && pm->page != p)
+                pm++;
+
+        if (pm->node == MAX_NUMNODES)
+                return NULL;
+
+        *result = &pm->status;
+
+        return alloc_pages_node(pm->node, GFP_HIGHUSER, 0);
+}
+
+/*
+ * Move a set of pages as indicated in the pm array. The addr
+ * field must be set to the virtual address of the page to be moved
+ * and the node number must contain a valid target node.
+ */
+static int do_move_pages(struct mm_struct *mm, struct page_to_node *pm,
+                                int migrate_all)
+{
+        int err;
+        struct page_to_node *pp;
+        LIST_HEAD(pagelist);
+
+        down_read(&mm->mmap_sem);
+
+        /*
+         * Build a list of pages to migrate
+         */
+        migrate_prep();
+        for (pp = pm; pp->node != MAX_NUMNODES; pp++) {
+                struct vm_area_struct *vma;
+                struct page *page;
+
+                /*
+                 * A valid page pointer that will not match any of the
+                 * pages that will be moved.
+                 */
+                pp->page = ZERO_PAGE(0);
+
+                err = -EFAULT;
+                vma = find_vma(mm, pp->addr);
+                if (!vma)
+                        goto set_status;
+
+                page = follow_page(vma, pp->addr, FOLL_GET);
+                err = -ENOENT;
+                if (!page)
+                        goto set_status;
+
+                if (PageReserved(page))         /* Check for zero page */
+                        goto put_and_set;
+
+                pp->page = page;
+                err = page_to_nid(page);
+
+                if (err == pp->node)
+                        /*
+                         * Node already in the right place
+                         */
+                        goto put_and_set;
+
+                err = -EACCES;
+                if (page_mapcount(page) > 1 &&
+                                !migrate_all)
+                        goto put_and_set;
+
+                err = isolate_lru_page(page, &pagelist);
+put_and_set:
+                /*
+                 * Either remove the duplicate refcount from
+                 * isolate_lru_page() or drop the page ref if it was
+                 * not isolated.
+                 */
+                put_page(page);
+set_status:
+                pp->status = err;
+        }
+
+        if (!list_empty(&pagelist))
+                err = migrate_pages(&pagelist, new_page_node,
+                                (unsigned long)pm);
+        else
+                err = -ENOENT;
+
+        up_read(&mm->mmap_sem);
+        return err;
+}
+
+/*
+ * Determine the nodes of a list of pages. The addr in the pm array
+ * must have been set to the virtual address of which we want to determine
+ * the node number.
+ */
+static int do_pages_stat(struct mm_struct *mm, struct page_to_node *pm)
+{
+        down_read(&mm->mmap_sem);
+
+        for ( ; pm->node != MAX_NUMNODES; pm++) {
+                struct vm_area_struct *vma;
+                struct page *page;
+                int err;
+
+                err = -EFAULT;
+                vma = find_vma(mm, pm->addr);
+                if (!vma)
+                        goto set_status;
+
+                page = follow_page(vma, pm->addr, 0);
+                err = -ENOENT;
+                /* Use PageReserved to check for zero page */
+                if (!page || PageReserved(page))
+                        goto set_status;
+
+                err = page_to_nid(page);
+set_status:
+                pm->status = err;
+        }
+
+        up_read(&mm->mmap_sem);
+        return 0;
+}
+
+/*
+ * Move a list of pages in the address space of the currently executing
+ * process.
+ */
+asmlinkage long sys_move_pages(pid_t pid, unsigned long nr_pages,
+                        const void __user * __user *pages,
+                        const int __user *nodes,
+                        int __user *status, int flags)
+{
+        int err = 0;
+        int i;
+        struct task_struct *task;
+        nodemask_t task_nodes;
+        struct mm_struct *mm;
+        struct page_to_node *pm = NULL;
+
+        /* Check flags */
+        if (flags & ~(MPOL_MF_MOVE|MPOL_MF_MOVE_ALL))
+                return -EINVAL;
+
+        if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
+                return -EPERM;
+
+        /* 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 privileges 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_NICE)) {
+                err = -EPERM;
+                goto out2;
+        }
+
+        task_nodes = cpuset_mems_allowed(task);
+
+        /* Limit nr_pages so that the multiplication may not overflow */
+        if (nr_pages >= ULONG_MAX / sizeof(struct page_to_node) - 1) {
+                err = -E2BIG;
+                goto out2;
+        }
+
+        pm = vmalloc((nr_pages + 1) * sizeof(struct page_to_node));
+        if (!pm) {
+                err = -ENOMEM;
+                goto out2;
+        }
+
+        /*
+         * Get parameters from user space and initialize the pm
+         * array. Return various errors if the user did something wrong.
+         */
+        for (i = 0; i < nr_pages; i++) {
+                const void *p;
+
+                err = -EFAULT;
+                if (get_user(p, pages + i))
+                        goto out;
+
+                pm[i].addr = (unsigned long)p;
+                if (nodes) {
+                        int node;
+
+                        if (get_user(node, nodes + i))
+                                goto out;
+
+                        err = -ENODEV;
+                        if (!node_online(node))
+                                goto out;
+
+                        err = -EACCES;
+                        if (!node_isset(node, task_nodes))
+                                goto out;
+
+                        pm[i].node = node;
+                }
+        }
+        /* End marker */
+        pm[nr_pages].node = MAX_NUMNODES;
+
+        if (nodes)
+                err = do_move_pages(mm, pm, flags & MPOL_MF_MOVE_ALL);
+        else
+                err = do_pages_stat(mm, pm);
+
+        if (err >= 0)
+                /* Return status information */
+                for (i = 0; i < nr_pages; i++)
+                        if (put_user(pm[i].status, status + i))
+                                err = -EFAULT;
+
+out:
+        vfree(pm);
+out2:
+        mmput(mm);
+        return err;
+}
+#endif
+