11 files changed, 111 insertions, 5 deletions

diff --git a/arch/i386/kernel/syscall_table.S b/arch/i386/kernel/syscall_table.S
index f7ba4acc20ec..6ff3e5243226 100644
--- a/arch/i386/kernel/syscall_table.S
+++ b/arch/i386/kernel/syscall_table.S
@@ -293,3 +293,4 @@ ENTRY(sys_call_table)
         .long sys_inotify_init
         .long sys_inotify_add_watch
         .long sys_inotify_rm_watch
+        .long sys_migrate_pages
diff --git a/arch/ia64/kernel/entry.S b/arch/ia64/kernel/entry.S
index 0741b066b98f..7a6ffd613789 100644
--- a/arch/ia64/kernel/entry.S
+++ b/arch/ia64/kernel/entry.S
@@ -1600,5 +1600,6 @@ sys_call_table:
         data8 sys_inotify_init
         data8 sys_inotify_add_watch
         data8 sys_inotify_rm_watch
+        data8 sys_migrate_pages                 // 1280
 
         .org sys_call_table + 8*NR_syscalls     // guard against failures to increase NR_syscalls
diff --git a/arch/x86_64/ia32/ia32entry.S b/arch/x86_64/ia32/ia32entry.S
index df0773c9bdbe..1f0ff5adc80e 100644
--- a/arch/x86_64/ia32/ia32entry.S
+++ b/arch/x86_64/ia32/ia32entry.S
@@ -643,6 +643,7 @@ ia32_sys_call_table:
         .quad sys_inotify_init
         .quad sys_inotify_add_watch
         .quad sys_inotify_rm_watch
+        .quad sys_migrate_pages
 ia32_syscall_end:               
         .rept IA32_NR_syscalls-(ia32_syscall_end-ia32_sys_call_table)/8
                 .quad ni_syscall
diff --git a/include/asm-i386/unistd.h b/include/asm-i386/unistd.h
index fe38b9a96233..481c3c0ea720 100644
--- a/include/asm-i386/unistd.h
+++ b/include/asm-i386/unistd.h
@@ -299,8 +299,9 @@
 #define __NR_inotify_init       291
 #define __NR_inotify_add_watch  292
 #define __NR_inotify_rm_watch   293
+#define __NR_migrate_pages      294
 
-#define NR_syscalls 294
+#define NR_syscalls 295
 
 /*
  * user-visible error numbers are in the range -1 - -128: see
diff --git a/include/asm-ia64/unistd.h b/include/asm-ia64/unistd.h
index 2bf543493cb8..962f9bd1bdff 100644
--- a/include/asm-ia64/unistd.h
+++ b/include/asm-ia64/unistd.h
@@ -269,12 +269,13 @@
 #define __NR_inotify_init               1277
 #define __NR_inotify_add_watch          1278
 #define __NR_inotify_rm_watch           1279
+#define __NR_migrate_pages              1280
 
 #ifdef __KERNEL__
 
 #include <linux/config.h>
 
-#define NR_syscalls                     256 /* length of syscall table */
+#define NR_syscalls                     270 /* length of syscall table */
 
 #define __ARCH_WANT_SYS_RT_SIGACTION
 
diff --git a/include/asm-x86_64/ia32_unistd.h b/include/asm-x86_64/ia32_unistd.h
index d5166ec3868d..e8843362a6cc 100644
--- a/include/asm-x86_64/ia32_unistd.h
+++ b/include/asm-x86_64/ia32_unistd.h
@@ -299,7 +299,8 @@
 #define __NR_ia32_inotify_init          291
 #define __NR_ia32_inotify_add_watch     292
 #define __NR_ia32_inotify_rm_watch      293
+#define __NR_ia32_migrate_pages         294
 
-#define IA32_NR_syscalls 294    /* must be > than biggest syscall! */
+#define IA32_NR_syscalls 295    /* must be > than biggest syscall! */
 
 #endif /* _ASM_X86_64_IA32_UNISTD_H_ */
diff --git a/include/asm-x86_64/unistd.h b/include/asm-x86_64/unistd.h
index 2c42150bce0c..e6f896161c11 100644
--- a/include/asm-x86_64/unistd.h
+++ b/include/asm-x86_64/unistd.h
@@ -571,8 +571,10 @@ __SYSCALL(__NR_inotify_init, sys_inotify_init)
 __SYSCALL(__NR_inotify_add_watch, sys_inotify_add_watch)
 #define __NR_inotify_rm_watch   255
 __SYSCALL(__NR_inotify_rm_watch, sys_inotify_rm_watch)
+#define __NR_migrate_pages      256
+__SYSCALL(__NR_migrate_pages, sys_migrate_pages)
 
-#define __NR_syscall_max __NR_inotify_rm_watch
+#define __NR_syscall_max __NR_migrate_pages
 #ifndef __NO_STUBS
 
 /* user-visible error numbers are in the range -1 - -4095 */
diff --git a/include/linux/mempolicy.h b/include/linux/mempolicy.h
index 05443a766cb8..3e61e829681d 100644
--- a/include/linux/mempolicy.h
+++ b/include/linux/mempolicy.h
@@ -162,6 +162,9 @@ static inline void check_highest_zone(int k)
                 policy_zone = k;
 }
 
+int do_migrate_pages(struct mm_struct *mm,
+        const nodemask_t *from_nodes, const nodemask_t *to_nodes, int flags);
+
 #else
 
 struct mempolicy {};
diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h
index c7007b1db91d..e910d1a481df 100644
--- a/include/linux/syscalls.h
+++ b/include/linux/syscalls.h
@@ -511,5 +511,7 @@ asmlinkage long sys_ioprio_set(int which, int who, int ioprio);
 asmlinkage long sys_ioprio_get(int which, int who);
 asmlinkage long sys_set_mempolicy(int mode, unsigned long __user *nmask,
                                         unsigned long maxnode);
+asmlinkage long sys_migrate_pages(pid_t pid, unsigned long maxnode,
+                        const unsigned long __user *from, const unsigned long __user *to);
 
 #endif
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index 1ab2370e2efa..7a8bc7f60d91 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -82,6 +82,7 @@ cond_syscall(compat_sys_socketcall);
 cond_syscall(sys_inotify_init);
 cond_syscall(sys_inotify_add_watch);
 cond_syscall(sys_inotify_rm_watch);
+cond_syscall(sys_migrate_pages);
 
 /* arch-specific weak syscall entries */
 cond_syscall(sys_pciconfig_read);
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,