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-rw-r--r--Documentation/vm/page_migration29
-rw-r--r--arch/ia64/kernel/entry.S2
-rw-r--r--include/asm-ia64/unistd.h2
-rw-r--r--include/linux/migrate.h2
-rw-r--r--include/linux/syscalls.h5
-rw-r--r--kernel/sys_ni.c1
-rw-r--r--mm/mempolicy.c4
-rw-r--r--mm/migrate.c268
8 files changed, 288 insertions, 25 deletions
diff --git a/Documentation/vm/page_migration b/Documentation/vm/page_migration
index 0a5d5fb1..99f89aa 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 bcb80ca..32c999f 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 632f2ee..bb0eb72 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 5b95d65..5dba23a 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 bd67a44..7e3f234 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 5433195..5972297 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 f432642..05b84ac 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 251a8d1..033a12f 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
+
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